@article{mitra_minick_gavazzi_prajapati_aguilos_miao_domec_mcnulty_sun_king_et al._2024, title={Toward spectrally truthful models for gap-filling soil respiration and methane fluxes. A case study in coastal forested wetlands in North Carolina}, volume={353}, ISSN={["1873-2240"]}, url={https://doi.org/10.1016/j.agrformet.2024.110038}, DOI={10.1016/j.agrformet.2024.110038}, abstractNote={Soil respiration (Rs) and methane (FCH4) fluxes are two important metrics of ecosystem metabolism. An accurate estimate of the budget of these two greenhouse gases is critical to understanding their response to climate and land-use changes. Reconstructing continuous time series of gappy chamber Rs and eddy-covariance derived FCH4 measurements is usually done based on correlative relationships of these fluxes with environmental variables. However, current approaches do not account for the fact that different environmental drivers affect the carbon fluxes at different temporal scales. Here we propose a novel gapfilling technique that accounts for the specific spectral frequencies at which each of the environmental variables covaries with Rs and FCH4 - photosynthetically active radiation at diel scale, soil temperature at synoptic scale, and soil moisture, water table depth and atmospheric pressure at synoptic and seasonal scale. The method was applied on two operational loblolly pine plantations of different ages and a mixed hardwood forested wetland on the lower coastal plain of North Carolina. The time series of these environmental drivers were reconstructed using wavelet decomposition and a Daubechies wavelet filter. Further, to consider the joint influence of the environmental drivers, parametric (elastic net regression, support vector machine, gradient boost and artificial neural network), and nonparametric (Bayesian) statistical models were chosen, and compared the results with Q10 and Marginal Distribution Sampling (MDS) outputs. In all cases, the algorithms were trained on 70 % of the data and validated with the remaining data. Spectral-filtered models did not significantly differ from those driven by unfiltered data with respect to Rs and FCH4 predictions. While all the spectrally driven algorithms achieved high predictive accuracy against Q10, the increase in model fit compared to MDS was minimal. Spectral data filtering modestly improves model accuracy, shedding light on complex environmental and biological factors affecting greenhouse gas flux variability.}, journal={AGRICULTURAL AND FOREST METEOROLOGY}, author={Mitra, Bhaskar and Minick, Kevan and Gavazzi, Michael and Prajapati, Prajaya and Aguilos, Maricar and Miao, Guofang and Domec, Jean-Christophe and Mcnulty, Steve G. and Sun, Ge and King, John S. and et al.}, year={2024}, month={Jun} }
 @article{fischer_katul_noormets_poznikova_domec_orsag_zalud_trnka_king_2023, title={Merging flux-variance with surface renewal methods in the roughness sublayer and the atmospheric surface layer}, volume={342}, ISSN={["1873-2240"]}, DOI={10.1016/j.agrformet.2023.109692}, abstractNote={Two micrometeorological methods utilizing high-frequency sampled air temperature were tested against eddy covariance (EC) sensible heat flux (H) measurements at three sites representing agricultural, agro-forestry, and forestry systems. The two methods cover conventional and newly proposed forms of the flux-variance (FV) and surface renewal (SR) schemes of differing complexities. The sites represent measurements in surface, roughness, and roughness to surface transitional layers. Regression analyzes against EC show that the most reliable FV and SR forms estimate H with slopes within ±10% from unity and coefficient of determination R2>0.9 across all the three sites. The best performance of both FV and SR was found at the agricultural site with measurements well within the surface layer, while the worst was found for the tall forest with measurements within the roughness sublayer where its thickness needed to be additionally estimated. The main variable driving H in FV is the temperature variance, whereas in SR, it is the geometry of ramp-like structures. Since these structures are also responsible for most of the temperature variance, a novel FV-SR approach emerging from combining the methods is proposed and evaluated against EC measurements and conventional FV and SR schemes. The proposed FV-SR approach requiring only a single fast response thermocouple is potentially independent of calibration and ameliorates some of the theoretical objections that arise when combining ramp statistics with similarity arguments. The combination of methods also provides new insights into the contribution of coherent structures to the temperature variance and its dependence on atmospheric stratification. Other potential utility of the new method is to include it in multi-tool assessments of surface energy fluxes, since a convergence or divergence of the results has a high diagnostic value.}, journal={AGRICULTURAL AND FOREST METEOROLOGY}, author={Fischer, Milan and Katul, Gabriel and Noormets, Asko and Poznikova, Gabriela and Domec, Jean-Christophe and Orsag, Matej and Zalud, Zdenek and Trnka, Miroslav and King, John S.}, year={2023}, month={Nov} }
 @article{miao_noormets_gavazzi_mitra_domec_sun_mcnulty_king_2022, title={Beyond carbon flux partitioning: Carbon allocation and nonstructural carbon dynamics inferred from continuous fluxes}, ISSN={["1939-5582"]}, DOI={10.1002/eap.2655}, abstractNote={Abstract}, journal={ECOLOGICAL APPLICATIONS}, author={Miao, Guofang and Noormets, Asko and Gavazzi, Michael and Mitra, Bhaskar and Domec, Jean-Christophe and Sun, Ge and McNulty, Steve and King, John S.}, year={2022}, month={Jul} }
 @article{lin_noormets_king_marshall_akers_cucinella_fox_laviner_martin_mcnulty_et al._2022, title={Spatial variability in tree-ring carbon isotope discrimination in response to local drought across the entire loblolly pine natural range}, volume={42}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tpab097}, abstractNote={Abstract}, number={1}, journal={TREE PHYSIOLOGY}, author={Lin, Wen and Noormets, Asko and King, John S. and Marshall, John and Akers, Madison and Cucinella, Josh and Fox, Thomas R. and Laviner, Marshall A. and Martin, Timothy A. and Mcnulty, Steve and et al.}, year={2022}, month={Jan}, pages={44–58} }
 @article{lin_domec_ward_marshall_king_laviner_fox_west_sun_mcnulty_et al._2022, title={Using delta C-13 and delta O-18 to analyze loblolly pine (Pinus taeda L.) response to experimental drought and fertilization (vol 39, pg 1984, 2019)}, volume={42}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tpab162}, number={4}, journal={TREE PHYSIOLOGY}, author={Lin, Wen and Domec, Jean-Christophe and Ward, Eric J. and Marshall, John and King, John S. and Laviner, Marshall A. and Fox, Thomas R. and West, Jason B. and Sun, Ge and McNulty, Steve and et al.}, year={2022}, month={Apr}, pages={703–703} }
 @article{domec_king_carmichael_overby_wortemann_smith_miao_noormets_johnson_2021, title={Aquaporins, and not changes in root structure, provide new insights into physiological responses to drought, flooding, and salinity}, volume={72}, ISSN={["1460-2431"]}, DOI={10.1093/jxb/erab100}, abstractNote={Abstract}, number={12}, journal={JOURNAL OF EXPERIMENTAL BOTANY}, author={Domec, Jean-Christophe and King, John S. and Carmichael, Mary J. and Overby, Anna Treado and Wortemann, Remi and Smith, William K. and Miao, Guofang and Noormets, Asko and Johnson, Daniel M.}, year={2021}, month={May}, pages={4489–4501} }
 @article{aguilos_sun_noormets_domec_mcnulty_gavazzi_prajapati_minick_mitra_king_2021, title={Ecosystem Productivity and Evapotranspiration Are Tightly Coupled in Loblolly Pine (Pinus taeda L.) Plantations along the Coastal Plain of the Southeastern U.S.}, volume={12}, ISSN={1999-4907}, url={http://dx.doi.org/10.3390/f12081123}, DOI={10.3390/f12081123}, abstractNote={Forest water use efficiency (WUE), the ratio of gross primary productivity (GPP) to evapotranspiration (ET), is an important variable to understand the coupling between water and carbon cycles, and to assess resource use, ecosystem resilience, and commodity production. Here, we determined WUE for managed loblolly pine plantations over the course of a rotation on the coastal plain of North Carolina in the eastern U.S. We found that the forest annual GPP, ET, and WUE increased until age ten, which stabilized thereafter. WUE varied annually (2–44%), being higher at young plantation (YP, 3.12 ± 1.20 g C kg−1 H2O d−1) compared to a mature plantation (MP, 2.92 ± 0.45 g C kg−1 H2O d−1), with no distinct seasonal patterns. Stand age was strongly correlated with ET (R2 = 0.71) and GPP (R2 = 0.64). ET and GPP were tightly coupled (R2 = 0.86). Radiation and air temperature significantly affected GPP and ET (R2 = 0.71 − R2 = 0.82) at a monthly scale, but not WUE. Drought affected WUE (R2 = 0.35) more than ET (R2 = 0.25) or GPP (R2 = 0.07). A drought enhanced GPP in MP (19%) and YP (11%), but reduced ET 7% and 19% in MP and YP, respectively, resulting in a higher WUE (27–32%). Minor seasonal and interannual variation in forest WUE of MP (age > 10) suggested that forest functioning became stable as stands matured. We conclude that carbon and water cycles in loblolly pine plantations are tightly coupled, with different characteristics in different ages and hydrologic regimes. A stable WUE suggests that the pine ecosystem productivity can be readily predicted from ET and vice versa. The tradeoffs between water and carbon cycling should be recognized in forest management to achieve multiple ecosystem services (i.e., water supply and carbon sequestration).}, number={8}, journal={Forests}, publisher={MDPI AG}, author={Aguilos, Maricar and Sun, Ge and Noormets, Asko and Domec, Jean-Christophe and McNulty, Steven and Gavazzi, Michael and Prajapati, Prajaya and Minick, Kevan J. and Mitra, Bhaskar and King, John}, year={2021}, month={Aug}, pages={1123} }
 @article{aguilos_sun_noormets_domec_mcnulty_gavazzi_minick_mitra_prajapati_yang_et al._2021, title={Effects of land-use change and drought on decadal evapotranspiration and water balance of natural and managed forested wetlands along the southeastern US lower coastal plain}, volume={303}, ISSN={["1873-2240"]}, url={https://doi.org/10.1016/j.agrformet.2021.108381}, DOI={10.1016/j.agrformet.2021.108381}, abstractNote={Forested wetlands are important in regulating regional hydrology and climate. However, long-term studies on the hydrologic impacts of converting natural forested wetlands to pine plantations are rare for the southern US. From 2005-2018, we quantified water cycling in two post-harvest and newly-planted loblolly pine (Pinus taeda) plantations (YP2–7, 2–7 yrs old; YP2–8, 2–8 yrs old), a rotation-age loblolly pine plantation (MP, 15–28 yrs old), and a natural bottomland hardwood forest (BHF, > 100 yrs old) along the lower coastal plain of North Carolina. We quantified the differences in inter-annual and seasonal water balance and trends of evapotranspiration (ET) using eddy covariance over 37 site-years and assessed key climatic and biological drivers of ET. We found that the rotation-age plantation (MP) had higher annual ET (933 ± 63 mm) than the younger plantations (776 ± 74 mm for YP2–7 and 638 ± 190 mm for YP2–8), and the BHF (743 ± 172 mm), owing to differences in stand age, canopy cover, and micrometeorology. Chronosequence analysis of the pine sites showed that ET increased with stand age up to 10 years, then gradually stabilized for the remainder of the rotation of 28 – 30 years. YP2–8 was sensitive to water availability, decreasing ET by 30 – 43 % during the extreme 2007 – 2008 drought, but reductions in ET at MP were only 8 – 11 %. Comparing to BHF, ditching with management enhanced drainage at YP2–7 and YP2–8, while drainage was lower at the mature pine site. This study provides insight into land use-hydrology-climate interactions that have important implications for forested wetland management in a time of rapidly changing environmental conditions of the LCP of the southern US.}, journal={AGRICULTURAL AND FOREST METEOROLOGY}, author={Aguilos, Maricar and Sun, Ge and Noormets, Asko and Domec, Jean-Christophe and McNulty, Steve and Gavazzi, Michael and Minick, Kevan and Mitra, Bhaskar and Prajapati, Prajaya and Yang, Yun and et al.}, year={2021}, month={Jun} }
 @article{noormets_bracho_ward_seiler_strahm_lin_mcelligott_domec_gonzalez-benecke_jokela_et al._2021, title={Heterotrophic Respiration and the Divergence of Productivity and Carbon Sequestration}, volume={48}, ISSN={["1944-8007"]}, DOI={10.1029/2020GL092366}, abstractNote={Abstract}, number={7}, journal={GEOPHYSICAL RESEARCH LETTERS}, author={Noormets, Asko and Bracho, Rosvel and Ward, Eric and Seiler, John and Strahm, Brian and Lin, Wen and McElligott, Kristin and Domec, Jean-Christophe and Gonzalez-Benecke, Carlos and Jokela, Eric J. and et al.}, year={2021}, month={Apr} }
 @article{ile_aguilos_morkoc_minick_domec_king_2021, title={Productivity of low-input short-rotation coppice American sycamore ( Platanus occidentalis L.) grown at different planting densities as a bioenergy feedstock over two rotation cycles}, volume={146}, ISSN={["1873-2909"]}, url={https://doi.org/10.1016/j.biombioe.2021.105983}, DOI={10.1016/j.biombioe.2021.105983}, abstractNote={Short rotation coppice culture of woody crop species (SRWCs) has long been considered a sustainable method of producing biomass for bioenergy that does not compete with current food production practices. In this study, we grew American sycamore (Platanus occidentalis L.) for nine years corresponding to two rotation cycles (first rotation (FR) = 2010–2014, second rotation (SR) = 2015–2019). This was done at varying tree planting densities (1250, 2500, 5000, and 10,000 trees per hectare (tph)) on a degraded agricultural landscape under low-input (e.g. no fertilizer and low herbicide application) culture, in the Piedmont physiographic region of eastern North Carolina. Tree productivity was proportional to planting density, with the highest cumulative aboveground wood biomass in the 10,000 tph treatment, at 23.2 ± 0.9 Mg ha−1 and 39.1 ± 2.4 Mg ha−1 in the first and second rotations, respectively. These results demonstrate increasing productivity under a low-input SRWC management regime over the first two rotations. Biomass partitioning was strongly affected by planting density during FR, allocating less biomass to stems relative to other plant parts at low planting density (44–59% from 1250 to 10,000 tph, respectively). This effect disappeared during SR, however, with biomass partitioning to stems ranging from 74 to 79% across planting densities. Taken together, our results suggest that American sycamore has the potential to be effectively managed as a bioenergy feedstock with low input culture on marginal agriculture lands.}, journal={BIOMASS & BIOENERGY}, author={Ile, Omoyemeh J. and Aguilos, Maricar and Morkoc, Suna and Minick, Kevan and Domec, Jean-Christophe and King, John S.}, year={2021}, month={Mar} }
 @article{li_minick_luff_noormets_miao_mitra_domec_sun_mcnulty_king_2020, title={Effects of Microtopography on Absorptive and Transport Fine Root Biomass, Necromass, Production, Mortality and Decomposition in a Coastal Freshwater Forested Wetland, Southeastern USA}, volume={23}, ISSN={["1435-0629"]}, DOI={10.1007/s10021-019-00470-x}, abstractNote={Forested wetlands are an important carbon (C) sink. Fine roots (diameter < 2 mm) dominate belowground C cycling and can be functionally defined into absorptive roots (order 1–2) and transport roots (order ≥ 3). However, effects of microtopography on the function-based fine root dynamics in forested wetlands are poorly understood. We studied fine root biomass allocation and biomass, necromass, mass loss rate, production, mortality and decomposition of absorptive and transport roots in hummocks and hollows in a coastal plain freshwater forested wetland (FFW) in the southeastern USA using dynamic-flow method. Biomass ratios of first- to second-order roots and absorptive to transport roots and the biomass and necromass of absorptive and transport roots were significantly higher in top 0–10 cm organic peat layer than in 10–20 cm muck and mineral layer, and were significantly higher in hummocks than in hollows. The mass loss rate, production, mortality and decomposition were significantly higher in hummocks than in hollows. Absorptive roots did not have a lower mass loss rate than transport roots. Microtopography significantly affected the contributions of absorptive and transport roots to the total production, mortality and decomposition. Production, mortality and decomposition of absorptive roots were higher than those of transport roots in hummocks but lower than those of transport roots in hollows. Total (hummocks plus hollows) fine root production, mortality and decomposition were 455 ± 106 g m−2 y−1, 475 ± 79 g m−2 y−1 and 392 ± 60 g m−2 y−1, respectively. Greater mortality than decomposition resulted in net fine root C input to soil. The observed microtopographic controls on fine root dynamics have great implications for soil C cycling. As sea level rises, the relative area of hollows in coastal plain FFWs will increase, causing a decrease in fine root mass loss rate, biomass, production, mortality and decomposition and it is the balance of these processes that will determine future soil C storage and cycling.}, number={6}, journal={ECOSYSTEMS}, author={Li, Xuefeng and Minick, Kevan J. and Luff, Jordan and Noormets, Asko and Miao, Guofang and Mitra, Bhaskar and Domec, Jean-Christophe and Sun, Ge and McNulty, Steven and King, John S.}, year={2020}, month={Sep}, pages={1294–1308} }
 @article{aguilos_mitra_noormets_minick_prajapati_gavazzi_sun_mcnulty_li_domec_et al._2020, title={Long-term carbon flux and balance in managed and natural coastal forested wetlands of the Southeastern USA}, volume={288}, ISSN={["1873-2240"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85085132484&partnerID=MN8TOARS}, DOI={10.1016/j.agrformet.2020.108022}, abstractNote={Wetlands store large carbon (C) stocks and play important roles in biogeochemical C cycling. However, the effects of environmental and anthropogenic pressures on C dynamics in lower coastal plain forested wetlands in the southern U.S. are not well understood. We established four eddy flux stations in two post-harvest and newly-planted loblolly pine plantations (YP2–6, 2–6 yrs old; YP2–8, 2–8 yrs old), a rotation-aged loblolly pine plantations (MP, 15–27 yrs old), and a mixed bottomland hardwood forest (BHF, >100 yrs old) in the lower coastal plain of North Carolina, USA. We analyzed the gross primary productivity (GPP), ecosystem respiration (RE) and net ecosystem exchange (NEE) for age-related trends, interannual variability in response to climate forcing, and management-related disturbances from 2005 – 2017. For the first few years after being harvested, pine plantations were net C sources (NEE = 1133 and 897 g C m–2 yr–1 in YP2–6 and YP2–8, respectively). The MP was a strong C sink (–369 to –1131 g C m–2 yr–1) over the entire study period. In contrast, BHF was a C source (NEE = 87 g C m–2 yr–1 to 759 g C m–2 yr–1) in most years, although in the first year it did show a net C uptake (NEE = –368 g C m–2 yr–1). The source activity of BHF may have been related to increasing overstory tree mortality and diameter growth suppression. Decreases in relative extractable water in pine plantations enhanced GPP and RE. Pine plantations regained status as C sinks 5–8 years after harvest and recovered C equivalent to post-harvest losses at 8–14 years. Thus, coastal pine plantations have a net C uptake for only about half the 25-year rotation period, suggesting that they have decreased climate mitigation potential in comparison to protecting primary forests. However, primary forests in this area may be vulnerable to ecosystem transition, and subsequent C loss, due to the changing environmental conditions at the land-ocean interface.}, journal={AGRICULTURAL AND FOREST METEOROLOGY}, publisher={Elsevier BV}, author={Aguilos, Maricar and Mitra, Bhaskar and Noormets, Asko and Minick, Kevan and Prajapati, Prajaya and Gavazzi, Michael and Sun, Ge and McNulty, Steve and Li, Xuefeng and Domec, Jean-Christophe and et al.}, year={2020}, month={Jul} }
 @article{mitra_minick_miao_domec_prajapati_mcnulty_sun_king_noormets_2020, title={Spectral evidence for substrate availability rather than environmental control of methane emissions from a coastal forested wetland}, volume={291}, ISSN={["1873-2240"]}, DOI={10.1016/j.agrformet.2020.108062}, abstractNote={Knowledge of the dynamics of methane (CH4) fluxes across coastal freshwater forested wetlands, such as those found in the southeastern US remains limited. In the current study, we look at the spectral properties of ecosystem net CH4 exchange (NEECH4) time series, and its cospectral behavior with key environmental conditions (temperature (Ts5), water table (WTD) and atmospheric pressure (Pa)) and physiological fluxes (photosynthesis (GPP), transpiration (LE), sap flux (Js)) using data from a natural bottomland hardwood swamp in eastern North Carolina. NEECH4 fluxes were measured over five years (2012 – 2016) that included both wet and dry years. During the growing season, strong cospectral peaks at diurnal scale were detected between CH4 efflux and GPP, LE and Js. This suggests that the well understood diurnal cycles in the latter processes may affect CH4 production through substrate availability (GPP) and transport (sap flow and LE). The causality between different time series was established by the magnitude and consistency of phase shifts. The causal effect of Ts5 and Pa were ruled out because despite cospectral peaks with CH4, their phase relationships were inconsistent. The effect of fluctuations in WTD on CH4 efflux at synoptic scale lacked clear indications of causality, possibly due to time lags and hysteresis. The stronger cospectral peak with ecosystem scale LE rather than Js suggested that the evaporative component of LE contributed equally with plant transpiration. Hence, we conclude that while the emission of dissolved gases through plants likely takes place, it may not contribute to higher CH4 emissions as has been proposed by aerenchymatous gas transport in sedge wetlands. These findings can inform future model development by (i) highlighting the coupling between vegetation processes and CH4 emissions, and (ii) identifying specific and non-overlapping timescales for different driving factors.}, journal={AGRICULTURAL AND FOREST METEOROLOGY}, author={Mitra, Bhaskar and Minick, Kevan and Miao, Guofang and Domec, Jean-Christophe and Prajapati, Prajaya and McNulty, Steve G. and Sun, Ge and King, John S. and Noormets, Asko}, year={2020}, month={Sep} }
 @article{lin_domec_ward_marshall_kin_laviner_fox_west_sun_mcnulty_et al._2019, title={Using delta C-13 and delta O-18 to analyze loblolly pine (Pinus taeda L.) response to experimental drought and fertilization}, volume={39}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tpz096}, abstractNote={Abstract}, number={12}, journal={TREE PHYSIOLOGY}, author={Lin, Wen and Domec, Jean-Christophe and Ward, Eric J. and Marshall, John and Kin, John S. and Laviner, Marshall A. and Fox, Thomas R. and West, Jason B. and Sun, Ge and McNulty, Steve and et al.}, year={2019}, month={Dec}, pages={1984–1994} }
 @article{liu_sun_mitra_noormets_gavazzi_domec_hallema_li_fang_king_et al._2018, title={Drought and thinning have limited impacts on evapotranspiration in a managed pine plantation on the southeastern United States coastal plain}, volume={262}, ISSN={0168-1923}, url={http://dx.doi.org/10.1016/j.agrformet.2018.06.025}, DOI={10.1016/j.agrformet.2018.06.025}, abstractNote={Managed and natural coastal plain forests in the humid southeastern United States exchange large amounts of water and energy with the atmosphere through the evapotranspiration (ET) process. ET plays an important role in controlling regional hydrology, climate, and ecosystem productivity. However, long-term studies on the impacts of forest management and climatic variability on forest ET are rare, and our understanding of both external and internal drivers on seasonal and interannual ET variability is incomplete. Using techniques centered on an eddy covariance method, the present study measured year-round ET flux and associated hydrometeorological variables in a drained loblolly pine (Pinus taeda L.) plantation on the lower coastal plain of North Carolina, U.S. We found that annual ET was relatively stable (1076 ± 104 mm) in comparison to precipitation (P) (1168 ± 216 mm) during the 10-year study period when the site experienced extreme climate (2007–2008) and forest thinning (2009). At the seasonal time scale, mean ET/P varied between 0.41 and 1.51, with a mean value of 1.12 ± 0.23 and 0.72 ± 0.16 for the growing and dormant seasons, respectively. The extreme drought during 2007–2008 (mean annual P, 854 mm) only resulted in a slight decrease (∼8%) in annual ET owing to the shallow groundwater common to the study area. Although changes in leaf area index and canopy structure were large after the stand was 50% thinned in the fall of 2009, mean annual ET was similar and averaged 1055 mm and 1104 mm before (2005, 2006 and 2009) and after (2010–2015) thinning, respectively. Data suggested that annual ET recovered within two years of the thinning as a result of rapid canopy closure and growth of understory. Further analysis indicated that available energy was the key driver of ET: approximately 69% and 61% of the monthly variations in ET were explained by net radiation during the dormant and growing seasons, respectively. Overall, we concluded that drought and forest thinning had limited impacts on seasonal and annual ET in this energy limited forest ecosystem with shallow groundwater. The results from this study help to better understand regional ecohydrological processes and projecting potential effects of forest management and extreme climate on water and carbon cycles.}, journal={Agricultural and Forest Meteorology}, publisher={Elsevier BV}, author={Liu, Xiaodong and Sun, Ge and Mitra, Bhaskar and Noormets, Asko and Gavazzi, Michael J. and Domec, Jean-Christophe and Hallema, Dennis W. and Li, Jiyue and Fang, Yuan and King, John S. and et al.}, year={2018}, month={Nov}, pages={14–23} }
 @article{fischer_kelley_ward_boone_ashley_domec_williamson_king_2017, title={A critical analysis of species selection and high vs. low-input silviculture on establishment success and early productivity of model short-rotation wood-energy cropping systems}, volume={98}, ISSN={["1873-2909"]}, DOI={10.1016/j.biombioe.2017.01.027}, abstractNote={Most research on bioenergy short rotation woody crops (SRWC) has been dedicated to the genera Populus and Salix. These species generally require relatively high-input culture, including intensive weed competition control, which increases costs and environmental externalities. Widespread native early successional species, characterized by high productivity and good coppicing ability, may be better adapted to local environmental stresses and therefore could offer alternative low-input bioenergy production systems. To test this concept, we established a three-year experiment comparing a widely-used hybrid poplar (Populus nigra × P. maximowiczii, clone ‘NM6’) to two native species, American sycamore (Platanus occidentalis L.) and tuliptree (Liriodendron tulipifera L.) grown under contrasting weed and pest control at a coastal plain site in eastern North Carolina, USA. Mean cumulative aboveground wood production was significantly greater in sycamore, with yields of 46.6 Mg ha−1 under high-inputs and 32.7 Mg ha−1 under low-input culture, which rivaled the high-input NM6 yield of 32.9 Mg ha−1. NM6 under low-input management provided noncompetitive yield of 6.2 Mg ha−1. Sycamore also showed superiority in survival, biomass increment, weed resistance, treatment convergence, and within-stand uniformity. All are important characteristics for a bioenergy feedstock crop species, leading to reliable establishment and efficient biomass production. Poor performance in all traits was found for tuliptree, with a maximum yield of 1.2 Mg ha−1, suggesting this native species is a poor choice for SRWC. We conclude that careful species selection beyond the conventionally used genera may enhance reliability and decrease negative environmental impacts of the bioenergy biomass production sector.}, journal={BIOMASS & BIOENERGY}, author={Fischer, M. and Kelley, A. M. and Ward, E. J. and Boone, J. D. and Ashley, E. M. and Domec, J. -C. and Williamson, J. C. and King, J. S.}, year={2017}, month={Mar}, pages={214–227} }
 @article{lin_noormets_king_sun_mcnulty_domec_2017, title={An extractive removal step optimized for a high-throughput alpha-cellulose extraction method for delta C-13 and delta O-18 stable isotope ratio analysis in conifer tree rings}, volume={37}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tpw084}, abstractNote={Stable isotope ratios (δ13C and δ18O) of tree-ring α-cellulose are important tools in paleoclimatology, ecology, plant physiology and genetics. The Multiple Sample Isolation System for Solids (MSISS) was a major advance in the tree-ring α-cellulose extraction methods, offering greater throughput and reduced labor input compared to traditional alternatives. However, the usability of the method for resinous conifer species may be limited by the need to remove extractives from some conifer species in a separate pretreatment step. Here we test the necessity of pretreatment for α-cellulose extraction in loblolly pine (Pinus taeda L.), and the efficiency of a modified acetone-based ambient-temperature step for the removal of extractives (i) in loblolly pine from five geographic locations representing its natural range in the southeastern USA, and (ii) on five other common coniferous species (black spruce (Picea mariana Mill.), Fraser fir (Abies fraseri (Pursh) Poir.), Douglas fir (Pseudotsuga menziesii (Mirb.) Franco), Norway spruce (Picea abies (L.) Karst) and ponderosa pine (Pinus ponderosa D.)) with contrasting extractive profiles. The differences of δ13C values between the new and traditional pretreatment methods were within the precision of the isotope ratio mass spectrometry method used (±0.2‰), and the differences between δ18O values were not statistically significant. Although some unanticipated results were observed in Fraser fir, the new ambient-temperature technique was deemed as effective as the more labor-consuming and toxic traditional pretreatment protocol. The proposed technique requires a separate acetone-inert multiport system similar to MSISS, and the execution of both pretreatment and main extraction steps allows for simultaneous treatment of up to several hundred microsamples from resinous softwood, while the need of additional labor input remains minimal.}, number={1}, journal={TREE PHYSIOLOGY}, author={Lin, Wen and Noormets, Asko and King, John S. and Sun, Ge and McNulty, Steve and Domec, Jean-Christophe}, year={2017}, month={Jan}, pages={142–150} }
 @article{miao_noormets_domec_fuentes_trettin_sun_mcnulty_king_2017, title={Hydrology and microtopography control carbon dynamics in wetlands: Implications in partitioning ecosystem respiration in a coastal plain forested wetland}, volume={247}, ISSN={["1873-2240"]}, DOI={10.1016/j.agrformet.2017.08.022}, abstractNote={Wetlands store a disproportionately large fraction of organic carbon relative to their areal coverage, and thus play an important role in global climate mitigation. As destabilization of these stores through land use or environmental change represents a significant climate feedback, it is important to understand the functional regulation of respiratory processes that catabolize them. In this study, we established an eddy covariance flux tower project in a coastal plain forested wetland in North Carolina, USA, and measured total ecosystem respiration (Re) over three years (2009–2011). We evaluated the magnitude and variability of three respiration components – belowground (Rs), coarse woody debris (RCWD), and aboveground plant (Ragp) respiration at the ecosystem scale, by accounting microtopographic variation for upscaling and constraining the mass balance with Re. Strong hydrologic control was detected for Rs and RCWD, whereas Ragp and Re were relatively insensitive to water table fluctuations. In a relatively dry year (2010), this forested wetland respired a total of about 2000 g CO2-C m-2 y-1 annually, 51% as Rs, 37% as Ragp, and 12% as RCWD. During non-flooded periods Rs contributed up to 57% of Re and during flooded periods Ragp contributed up to 69%. The contribution of Rs to Re increased by 2.4% for every cm of decrease in water level at intermediate water table level, and was nearly constant when flooded or when the water level more than 15 cm below ground. The contrasting sensitivity of different respiration components highlights the need for explicit consideration of this dynamic in ecosystem and Earth System Models.}, journal={AGRICULTURAL AND FOREST METEOROLOGY}, author={Miao, Guofang and Noormets, Asko and Domec, Jean-Christophe and Fuentes, Montserrat and Trettin, Carl C. and Sun, Ge and McNulty, Steve G. and King, John S.}, year={2017}, month={Dec}, pages={343–355} }
 @article{sun_domec_amatya_2016, title={Forest evapotranspiration: Measurement and modelling at multiple scales}, DOI={10.1079/9781780646602.0032}, abstractNote={Compared with traditional engineering hydrology, forest hydrology has a relatively long history of studying the effects of vegetation in regulating streamflow through evapotranspiration (Hewlett, 1982; Swank and Crossley, 1988; Andreassian, 2004; Brown et al., 2005; Amatya et al., 2011, 2015, 2016; Sun et al., 2011b; Vose et al., 2011). It is estimated that more than half of the solar energy absorbed by land surfaces is used to evaporate water (Trenberth et al., 2009). Evapotranspiration (ET), the sum of evaporation from soil (E), canopy and litter interception (I), and plant surface and plant transpiration (T), is critical to understanding the energy, water and biogeochemical cycles in forests (Baldocchi et al., 2001; Levia et al., 2011). The linkage among energy, water and carbon balances at a forest-stand level over a long time period (Fig. 3.1), in which ET plays a key role, can be described conceptually in the following interlinked formulae (Sun et al., 2010, 2011a). Water balance:}, journal={Forest Hydrology: Processes, Management and Assessment}, author={Sun, G. and Domec, J. C. and Amatya, D. M.}, year={2016}, pages={32–50} }
 @article{judd_jackson_fonteno_domec_2016, title={Measuring root hydraulic parameters of container-grown herbaceous and woody plants using the hydraulic conductance flow meter}, volume={51}, number={2}, journal={HortScience}, author={Judd, L. A. and Jackson, B. E. and Fonteno, W. C. and Domec, J. C.}, year={2016}, pages={192–196} }
 @article{fang_sun_caldwell_mcnulty_noormets_domec_king_zhang_zhang_lin_et al._2016, title={Monthly land cover-specific evapotranspiration models derived from global eddy flux measurements and remote sensing data}, volume={9}, ISSN={["1936-0592"]}, DOI={10.1002/eco.1629}, abstractNote={Abstract}, number={2}, journal={ECOHYDROLOGY}, author={Fang, Yuan and Sun, Ge and Caldwell, Peter and McNulty, Steven G. and Noormets, Asko and Domec, Jean-Christophe and King, John and Zhang, Zhiqiang and Zhang, Xudong and Lin, Guanghui and et al.}, year={2016}, month={Mar}, pages={248–266} }
 @article{manoli_domec_novick_oishi_noormets_marani_katul_2016, title={Soil-plant-atmosphere conditions regulating convective cloud formation above southeastern US pine plantations}, volume={22}, ISSN={["1365-2486"]}, DOI={10.1111/gcb.13221}, abstractNote={Abstract}, number={6}, journal={GLOBAL CHANGE BIOLOGY}, author={Manoli, Gabriele and Domec, Jean-Christophe and Novick, Kimberly and Oishi, Andrew Christopher and Noormets, Asko and Marani, Marco and Katul, Gabriel}, year={2016}, month={Jun}, pages={2238–2254} }
 @article{will_fox_akers_domec_gonzalez-benecke_jokela_kane_laviner_lokuta_markewitz_et al._2015, title={A Range-Wide Experiment to Investigate Nutrient and Soil Moisture Interactions in Loblolly Pine Plantations}, volume={6}, ISSN={["1999-4907"]}, DOI={10.3390/f6062014}, abstractNote={The future climate of the southeastern USA is predicted to be warmer, drier and more variable in rainfall, which may increase drought frequency and intensity. Loblolly pine (Pinus taeda) is the most important commercial tree species in the world and is planted on ~11 million ha within its native range in the southeastern USA. A regional study was installed to evaluate effects of decreased rainfall and nutrient additions on loblolly pine plantation productivity and physiology. Four locations were established to capture the range-wide variability of soil and climate. Treatments were initiated in 2012 and consisted of a factorial combination of throughfall reduction (approximate 30% reduction) and fertilization (complete suite of nutrients). Tree and stand growth were measured at each site. Results after two growing seasons indicate a positive but variable response of fertilization on stand volume increment at all four sites and a negative effect of throughfall reduction at two sites. Data will be used to produce robust process model parameterizations useful for simulating loblolly pine growth and function under future, novel climate and management scenarios. The resulting improved models will provide support for developing management strategies to increase pine plantation productivity and carbon sequestration under a changing climate.}, number={6}, journal={FORESTS}, author={Will, Rodney E. and Fox, Thomas and Akers, Madison and Domec, Jean-Christophe and Gonzalez-Benecke, Carlos and Jokela, Eric J. and Kane, Michael and Laviner, Marshall A. and Lokuta, Geoffrey and Markewitz, Daniel and et al.}, year={2015}, month={Jun}, pages={2014–2028} }
 @article{boggs_sun_domec_mcnulty_treasure_2015, title={Clearcutting upland forest alters transpiration of residual trees in the riparian buffer zone}, volume={29}, ISSN={["1099-1085"]}, DOI={10.1002/hyp.10474}, abstractNote={Abstract}, number={24}, journal={HYDROLOGICAL PROCESSES}, author={Boggs, Johnny and Sun, Ge and Domec, Jean-Christophe and McNulty, Steven and Treasure, Emrys}, year={2015}, month={Nov}, pages={4979–4992} }
 @article{domec_king_ward_oishi_palmroth_radecki_bell_miao_gavazzi_johnson_et al._2015, title={Conversion of natural forests to managed forest plantations decreases tree resistance to prolonged droughts}, volume={355}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2015.04.012}, abstractNote={Throughout the southern US, past forest management practices have replaced large areas of native forests with loblolly pine plantations and have resulted in changes in forest response to extreme weather conditions. However, uncertainty remains about the response of planted versus natural species to drought across the geographical range of these forests. Taking advantage of a cluster of unmanaged stands (85–130 year-old hardwoods) and managed plantations (17–20 year-old loblolly pine) in coastal and Piedmont areas of North Carolina, tree water use, cavitation resistance, whole-tree hydraulic (Ktree) and stomatal (Gs) conductances were measured in four sites covering representative forests growing in the region. We also used a hydraulic model to predict the resilience of those sites to extreme soil drying. Our objectives were to determine: (1) if Ktree and stomatal regulation in response to atmospheric and soil droughts differ between species and sites; (2) how ecosystem type, through tree water use, resistance to cavitation and rooting profiles, affects the water uptake limit that can be reached under drought; and (3) the influence of stand species composition on critical transpiration that sets a functional water uptake limit under drought conditions. The results show that across sites, water stress affected the coordination between Ktree and Gs. As soil water content dropped below 20% relative extractable water, Ktree declined faster and thus explained the decrease in Gs and in its sensitivity to vapor pressure deficit. Compared to branches, the capability of roots to resist high xylem tension has a great impact on tree-level water use and ultimately had important implications for pine plantations resistance to future summer droughts. Model simulations revealed that the decline in Ktree due to xylem cavitation aggravated the effects of soil drying on tree transpiration. The critical transpiration rate (Ecrit), which corresponds to the maximum rate at which transpiration begins to level off to prevent irreversible hydraulic failure, was higher in managed forest plantations than in their unmanaged counterparts. However, even with this higher Ecrit, the pine plantations operated very close to their critical leaf water potentials (i.e. to their permissible water potentials without total hydraulic failure), suggesting that intensively managed plantations are more drought-sensitive and can withstand less severe drought than natural forests.}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Domec, Jean-Christophe and King, John S. and Ward, Eric and Oishi, A. Christopher and Palmroth, Sari and Radecki, Andrew and Bell, Dave M. and Miao, Guofang and Gavazzi, Michael and Johnson, Daniel M. and et al.}, year={2015}, month={Nov}, pages={58–71} }
 @misc{noormets_epron_domec_mcnulty_fox_sun_king_2015, title={Effects of forest management on productivity and carbon sequestration: A review and hypothesis}, volume={355}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2015.05.019}, abstractNote={With an increasing fraction of the world’s forests being intensively managed for meeting humanity’s need for wood, fiber and ecosystem services, quantitative understanding of the functional changes in these ecosystems in comparison with natural forests is needed. In particular, the role of managed forests as long-term carbon (C) sinks and for mitigating climate change require a detailed assessment of their carbon cycle on different temporal scales. In the current review we assess available data on the structure and function of the world’s forests, explore the main differences in the C exchange between managed and unmanaged stands, and explore potential physiological mechanisms behind both observed and expected changes. Two global databases that include classification for management indicate that managed forests are about 50 years younger, include 25% more coniferous stands, and have about 50% lower C stocks than unmanaged forests. The gross primary productivity (GPP) and total net primary productivity (NPP) are the similar, but relatively more of the assimilated carbon is allocated to aboveground pools in managed than in unmanaged forests, whereas allocation to fine roots and rhizosymbionts is lower. This shift in allocation patterns is promoted by increasing plant size, and by increased nutrient availability. Long-term carbon sequestration potential in soils is assessed through the ratio of heterotrophic respiration to total detritus production, which indicates that (i) the forest soils may be losing more carbon on an annual basis than they regain in detritus, and (ii) the deficit appears to be greater in managed forests. While climate change and management factors (esp. fertilization) both contribute to greater carbon accumulation potential in the soil, the harvest-related increase in decomposition affects the C budget over the entire harvest cycle. Although the findings do not preclude the use of forests for climate mitigation, maximizing merchantable productivity may have significant carbon costs for the soil pool. We conclude that optimal management strategies for maximizing multiple benefits from ecosystem services require better understanding of the dynamics of belowground allocation, carbohydrate availability, heterotrophic respiration, and carbon stabilization in the soil.}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Noormets, A. and Epron, D. and Domec, J. C. and McNulty, S. G. and Fox, T. and Sun, G. and King, J. S.}, year={2015}, month={Nov}, pages={124–140} }
 @article{ward_domec_laviner_fox_sun_mcnulty_king_noormets_2015, title={Fertilization intensifies drought stress: Water use and stomatal conductance of Pinus taeda in a midrotation fertilization and throughfall reduction experiment}, volume={355}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2015.04.009}, abstractNote={While mid-rotation fertilization increases productivity in many southern pine forests, it remains unclear what impact such management may have on stand water use. We examined the impact of nutrient and water availability on stem volume, leaf area, transpiration per unit ground area (EC) and canopy conductance per unit leaf area (GS) of a pine plantation during its 8th and 9th growing seasons. Treatments consisted of a factorial combination of throughfall reduction (30% reduction in throughfall versus ambient) and fertilization (a complete suite of essential nutrients) beginning in April 2012. Overall, our results indicate that despite unusually high rainfall in the study period and a lack of leaf area index (LAI) response, both EC and GS decreased in response to fertilization and throughfall reduction. Fertilization increased stem volume increment 21% in 2013. Treatment differences were greatest in the growing season of 2013, when EC was on average 19%, 13% and 29% lower in the throughfall reduction (D), fertilization (F) and combined treatment (FD) than the control (C), respectively. The responses of GS to volumetric soil water content (VWC) indicate that lower EC in F was associated with a decrease relative to C in GS at high VWC. Decreases of GS in D relative to C were associated with lower VWC, but little change in the response of GS to VWC. Decreases observed in FD resulted from a combination of these two factors. The pattern of GS responses in the different treatments suggests that structural or physiological changes underlie this fertilization response, possibly in fine root area or hydraulic conductivity. In the short term, this led to large increases in the water use efficiency of stem production, which could suggest greater resiliency to minor water stress. However, impacts on long-term sensitivity to drought remain a concern, as the EC reduction triggered by the fertilization treatment was of comparable magnitude to the 30% throughfall exclusion treatment and the greatest reductions were found in the combined treatment.}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Ward, Eric J. and Domec, Jean-Christophe and Laviner, Marshall A. and Fox, Thomas R. and Sun, Ge and McNulty, Steve and King, John and Noormets, Asko}, year={2015}, month={Nov}, pages={72–82} }
 @article{attia_domec_oren_way_moshelion_2015, title={Growth and physiological responses of isohydric and anisohydric poplars to drought}, volume={66}, ISSN={["1460-2431"]}, DOI={10.1093/jxb/erv195}, abstractNote={Highlight Isohydric poplars have high water-use efficiency, while anisohydric poplars show faster growth under a variable water supply, with implications for performance of the different genotypes for woody biomass production.}, number={14}, journal={JOURNAL OF EXPERIMENTAL BOTANY}, author={Attia, Ziv and Domec, Jean-Christophe and Oren, Ram and Way, Danielle A. and Moshelion, Menachem}, year={2015}, month={Jul}, pages={4373–4381} }
 @article{tor-ngern_oren_ward_palmroth_mccarthy_domec_2015, title={Increases in atmosphericCO(2) have little influence on transpiration of a temperate forest canopy}, volume={205}, ISSN={["1469-8137"]}, DOI={10.1111/nph.13148}, abstractNote={Summary}, number={2}, journal={NEW PHYTOLOGIST}, author={Tor-ngern, Pantana and Oren, Ram and Ward, Eric J. and Palmroth, Sari and McCarthy, Heather R. and Domec, Jean-Christophe}, year={2015}, month={Jan}, pages={518–525} }
 @article{tian_youssef_sun_chescheir_noormets_amatya_skaggs_king_mcnulty_gavazzi_et al._2015, title={Testing DRAINMOD-FOREST for predicting evapotranspiration in a mid-rotation pine plantation}, volume={355}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2015.03.028}, abstractNote={Evapotranspiration (ET) is a key component of the hydrologic cycle in terrestrial ecosystems and accurate description of ET processes is essential for developing reliable ecohydrological models. This study investigated the accuracy of ET prediction by the DRAINMOD-FOREST after its calibration/validation for predicting commonly measured hydrological variables. The model was tested by conducting an eight year simulation of drainage and shallow groundwater dynamics in a managed mid-rotation loblolly pine (Pinus taeda L.) plantation located in the coastal plain of North Carolina, USA. Modeled daily ET rates were compared to those measured in the field using the eddy covariance technique. In addition, the wavelet transform and coherence analysis were used to compare ET predictions and measurements on the time–frequency domain. Results showed that DRAINMOD-FOREST accurately predicted annual and monthly ET after a successful calibration and validation using measured drainage rates and water table depth. The model under predicted ET on an annual basis by 2%, while the Nash–Sutcliffe coefficient of model predictions on a monthly basis was 0.78. Results from wavelet transform and coherence analysis demonstrated that the model reasonably captured the high power spectra of ET at an annual scale with significantly high model-data coherency. These results suggested that the calibrated DRAINMOD-FOREST collectively captured key factors and mechanisms controlling ET dynamics in the drained pine plantation. However, the global power spectrum revealed that the model over predicted the power spectrum of ET at an annual scale, suggesting the model may have under predicted canopy conductance during non-growing seasons. In addition, this study also suggested that DRAINMOD-FOREST did not properly capture the seasonal dynamics of ET under extreme drought conditions with deeper water table depths. These results suggested further refinement to parameters, particularly vegetation related, and structures of DRAINMOD-FOREST to achieve better agreement between ET predictions and measurements in the time–frequency domain.}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Tian, Shiying and Youssef, Mohamed A. and Sun, Ge and Chescheir, George M. and Noormets, Asko and Amatya, Devendra M. and Skaggs, R. Wayne and King, John S. and McNulty, Steve and Gavazzi, Michael and et al.}, year={2015}, month={Nov}, pages={37–47} }
 @article{bonetti_manoli_domec_putti_marani_katul_2015, title={The influence of water table depth and the free atmospheric state on convective rainfall predisposition}, volume={51}, ISSN={["1944-7973"]}, DOI={10.1002/2014wr016431}, abstractNote={Abstract}, number={4}, journal={WATER RESOURCES RESEARCH}, author={Bonetti, Sara and Manoli, Gabriele and Domec, Jean-Christophe and Putti, Mario and Marani, Marco and Katul, Gabriel G.}, year={2015}, month={Apr}, pages={2283–2297} }
 @article{albaugh_domec_maier_sucre_leggett_king_2014, title={Gas exchange and stand-level estimates of water use and gross primary productivity in an experimental pine and switchgrass intercrop forestry system on the Lower Coastal Plain of North Carolina, USA}, volume={192}, ISSN={["1873-2240"]}, DOI={10.1016/j.agrformet.2014.02.013}, abstractNote={Despite growing interest in using switchgrass (Panicum virgatum L.) as a biofuel, there are limited data on the physiology of this species and its effect on stand water use and carbon (C) assimilation when grown as a forest intercrop for bioenergy. Therefore, we quantified gas exchange rates of switchgrass within intercropped plots and in pure switchgrass plots during its second growing season in an intensively managed loblolly pine (Pinus taeda L.) plantation in North Carolina. Switchgrass physiology was characterized over the growing season from June to October 2010 in terms of photosynthesis (μmol m−2 s−1), stomatal conductance (mmol m−2 s−1), and assimilation responses to photosynthetic photon flux density and intercellular carbon dioxide concentration (CO2). We then used a process-based model of the soil–plant–atmosphere continuum to scale leaf-level gas exchange data to provide estimates of pine and switchgrass stand-level water use (mm) and carbon exchange (g C m−2) over a three-year period. Peak switchgrass photosynthesis (32.7 ± 0.9 μmol m−2 s−1) and stomatal conductance (252 ± 12 mmol m−2 s−1) rates were measured in July, with minimum values (18.7 ± 1.4 μmol m−2 s−1 and 104 ± 6 mmol m−2 s−1, respectively) recorded at the end of the growing season (October). Switchgrass gas exchange and parameter estimates from the light- and CO2 response curves did not vary between treatments. However, gas exchange values differed significantly between measurement dates. Model predictions of stand-level transpiration ranged from 287 to 431 mm year−1 for pine and from 245 to 296 mm year−1 for switchgrass. Annual C exchange for loblolly pine ranged from 1165 to 1903 g m−2 compared to 1386 to 1594 g m−2 for switchgrass. At this stage of stand development, no effect of intercropping was evident and there was no effect of distance from the nearest pine row on any switchgrass gas exchange variable measured. However, we anticipate that as this intercropped system develops over time, competition for resources such as light, water or nitrogen may change, with the potential to impact switchgrass physiology and biomass production.}, journal={AGRICULTURAL AND FOREST METEOROLOGY}, author={Albaugh, Janine M. and Domec, Jean-Christophe and Maier, Chris A. and Sucre, Eric B. and Leggett, Zakiya H. and King, John S.}, year={2014}, month={Jul}, pages={27–40} }
 @article{stout_davis_domec_yang_shi_king_2014, title={Growth under field conditions affects lignin content and productivity in transgenic Populus trichocarpa with altered lignin biosynthesis}, volume={68}, ISSN={["1873-2909"]}, DOI={10.1016/j.biombioe.2014.06.008}, abstractNote={This study evaluated the potential of transgenic Populus trichocarpa with antisense 4CL for reduced total lignin and sense Cald5H for increased S/G ratio in a short rotation woody cropping (SRWC) system for bioethanol production in the Southeast USA. Trees produced from tissue-culture were planted in the Coastal Plain, Piedmont, and Mountain regions of North Carolina, USA. Trees were observed for growth differences and biomass recorded for two coppices. Insoluble lignin and S/G ratio were determined by molecular beam mass spectroscopy after the second coppice. Survival, growth form, and biomass were very consistent within construct lines. Higher total lignin content and S/G ratio were positively correlated with total aboveground biomass. The low-lignin phenotype was not completely maintained in the field, with total lignin content increasing on average more than 30.0% at all sites by the second coppice The capacity to upregulate lignin in the event of environmental stress may have helped some low-lignin lines to survive. More research focused on promising construct lines in appropriate environmental conditions is needed to clarify if a significant reduction in lignin can be achieved on a plantation scale, and whether that reduction will translate into increased efficiency of enzymatic hydrolysis.}, journal={BIOMASS & BIOENERGY}, author={Stout, Anna T. and Davis, Aletta A. and Domec, Jean-Christophe and Yang, Chenmin and Shi, Rui and King, John S.}, year={2014}, month={Sep}, pages={228–239} }
 @article{manoli_bonetti_domec_putti_katul_marani_2014, title={Tree root systems competing for soil moisture in a 3D soil-plant model}, volume={66}, ISSN={["1872-9657"]}, DOI={10.1016/j.advwatres.2014.01.006}, abstractNote={Competition for water among multiple tree rooting systems is investigated using a soil–plant model that accounts for soil moisture dynamics and root water uptake (RWU), whole plant transpiration, and leaf-level photosynthesis. The model is based on a numerical solution to the 3D Richards equation modified to account for a 3D RWU, trunk xylem, and stomatal conductances. The stomatal conductance is determined by combining a conventional biochemical demand formulation for photosynthesis with an optimization hypothesis that selects stomatal aperture so as to maximize carbon gain for a given water loss. Model results compare well with measurements of soil moisture throughout the rooting zone, of total sap flow in the trunk xylem, as well as of leaf water potential collected in a Loblolly pine forest. The model is then used to diagnose plant responses to water stress in the presence of competing rooting systems. Unsurprisingly, the overlap between rooting zones is shown to enhance soil drying. However, the 3D spatial model yielded transpiration-bulk root-zone soil moisture relations that do not deviate appreciably from their proto-typical form commonly assumed in lumped eco-hydrological models. The increased overlap among rooting systems primarily alters the timing at which the point of incipient soil moisture stress is reached by the entire soil–plant system.}, journal={ADVANCES IN WATER RESOURCES}, author={Manoli, Gabriele and Bonetti, Sara and Domec, Jean-Christophe and Putti, Mario and Katul, Gabriel and Marani, Marco}, year={2014}, month={Apr}, pages={32–42} }
 @article{domec_rivera_king_peszlen_hain_smith_frampton_2013, title={Hemlock woolly adelgid (Adelges tsugae) infestation affects water and carbon relations of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana)}, volume={199}, ISSN={0028-646X 1469-8137}, url={http://dx.doi.org/10.1111/nph.12263}, DOI={10.1111/nph.12263}, abstractNote={Summary}, number={2}, journal={New Phytologist}, publisher={Wiley}, author={Domec, Jean‐Christophe and Rivera, Laura N. and King, John S. and Peszlen, Ilona and Hain, Fred and Smith, Benjamin and Frampton, John}, year={2013}, month={Apr}, pages={452–463} }
 @article{king_ceulemans_albaugh_dillen_domec_fichot_fischer_leggett_sucre_trnka_et al._2013, title={The Challenge of Lignocellulosic Bioenergy in a Water-Limited World}, volume={63}, ISSN={["1525-3244"]}, DOI={10.1525/bio.2013.63.2.6}, abstractNote={It is hoped that lignocellulosic sources will provide energy security, offset carbon dioxide enrichment of the atmosphere, and stimulate the development of new economic sectors. However, little is known about the productivity and sustainability of plant cell-wall energy industries. In this study, we used 16 global circulation models to project the global distribution of relative water availability in the coming decades and summarized the available data on the water-use efficiency of tree- and grass-based bioenergy systems. The data on bioenergy water use were extremely limited. Productivity was strongly correlated with water-use efficiency, with C4 grasses having a distinct advantage in this regard. Our analysis of agro climatic drivers of bioenergy productivity suggests that relative water availability will be one of the most important climatic changes to consider in the design of bioenergy systems.}, number={2}, journal={BIOSCIENCE}, author={King, John S. and Ceulemans, Reinhart and Albaugh, Janine M. and Dillen, Sophie Y. and Domec, Jean-Christophe and Fichot, Regis and Fischer, Milan and Leggett, Zakiya and Sucre, Eric and Trnka, Mirek and et al.}, year={2013}, month={Feb}, pages={102–117} }
 @article{miao_noormets_domec_trettin_mcnulty_sun_king_2013, title={The effect of water table fluctuation on soil respiration in a lower coastal plain forested wetland in the southeastern US}, volume={118}, ISSN={["2169-8961"]}, DOI={10.1002/2013jg002354}, abstractNote={Abstract}, number={4}, journal={JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES}, author={Miao, Guofang and Noormets, Asko and Domec, Jean-Christophe and Trettin, Carl C. and McNulty, Steve G. and Sun, Ge and King, John S.}, year={2013}, month={Dec}, pages={1748–1762} }
 @article{ward_oren_bell_clark_mccarthy_kim_domec_2013, title={The effects of elevated CO2 and nitrogen fertilization on stomatal conductance estimated from 11 years of scaled sap flux measurements at Duke FACE}, volume={33}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tps118}, abstractNote={In this study, we employ a network of thermal dissipation probes (TDPs) monitoring sap flux density to estimate leaf-specific transpiration (E(L)) and stomatal conductance (G(S)) in Pinus taeda (L.) and Liquidambar styraciflua L. exposed to +200 ppm atmospheric CO(2) levels (eCO(2)) and nitrogen fertilization. Scaling half-hourly measurements from hundreds of sensors over 11 years, we found that P. taeda in eCO(2) intermittently (49% of monthly values) decreased stomatal conductance (G(S)) relative to the control, with a mean reduction of 13% in both total E(L) and mean daytime G(S). This intermittent response was related to changes in a hydraulic allometry index (A(H)), defined as sapwood area per unit leaf area per unit canopy height, which decreased a mean of 15% with eCO(2) over the course of the study, due mostly to a mean 19% increase in leaf area (A(L)). In contrast, L. styraciflua showed a consistent (76% of monthly values) reduction in G(S) with eCO(2) with a total reduction of 32% E(L), 31% G(S) and 23% A(H) (due to increased A(L) per sapwood area). For L. styraciflua, like P. taeda, the relationship between A(H) and G(S) at reference conditions suggested a decrease in G(S) across the range of A(H). Our findings suggest an indirect structural effect of eCO(2) on G(S) in P. taeda and a direct leaf level effect in L. styraciflua. In the initial year of fertilization, P. taeda in both CO(2) treatments, as well as L. styraciflua in eCO(2), exhibited higher G(S) with N(F) than expected from shifts in A(H), suggesting a transient direct effect on G(S). Whether treatment effects on mean leaf-specific G(S) are direct or indirect, this paper highlights that long-term treatment effects on G(S) are generally reflected in A(H) as well.}, number={2}, journal={TREE PHYSIOLOGY}, author={Ward, Eric J. and Oren, Ram and Bell, David M. and Clark, James S. and McCarthy, Heather R. and Kim, Hyun-Seok and Domec, Jean-Christophe}, year={2013}, month={Feb}, pages={135–151} }
 @article{domec_johnson_2012, title={Does homeostasis or disturbance of homeostasis in minimum leaf water potential explain the isohydric versus anisohydric behavior of Vitis vinifera L. cultivars?}, volume={32}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tps013}, abstractNote={Due to the diurnal and seasonal fluctuations in leaf-to-air vapor pressure deficit (D), one of the key regulatory roles played by stomata is to limit transpiration-induced leaf water deficit. Different types of plants are known to vary in the sensitivity of stomatal conductance (gs) to D with important consequences for their survival and growth. Plants that minimize any increase in transpiration with increasing D have a tight stomatal regulation of a constant minimum leaf water potential (Ψleaf); these plants are termed as ‘isohydric’ (Stocker 1956). Plants that have less control of Ψleaf have been termed as ‘anisohydric’ (Tardieu and Simonneau 1998). Isohydric plants maintain a constant Ψleaf by reducing gs and transpiration under drought stress. Therefore, as drought pushes soil water potential (Ψsoil) below this Ψleaf set point, the plant can no longer extract water for gas exchange. Anisohydric plants allow Ψleaf to decrease with rising D, reaching a much lower Ψleaf in droughted plants relative to well-watered plants (Tardieu and Simonneau 1998), so this strategy produces a gradient between Ψsoil and Ψleaf that allows gas exchange to continue over a greater decline in Ψsoil. Thus, anisohydric plants sustain longer periods of transpiration and photosynthesis, even under large soil water deficit, and are thought to be more drought tolerant than isohydric species (McDowell 2011). In practice, the distinctions between isohydric and anisohydric strategies are often not clear (Franks et al. 2007), even among different cultivars of the same species. For example, cultivars of poplar (Hinckley et al. 1994) and grapevine (Schultz 2003, Lovisolo et al. 2010) have been shown to exhibit both contrasting hydraulic behaviors. A third mode of behavior was also suggested by Franks et al. (2007), in which the difference between soil and midday water potential (Ψsoil − Ψleaf) is maintained seasonally constant but Ψleaf fluctuates in synchrony with soil water availability (isohydrodynamic behavior). The lack of a clear distinction between these two strategies and the complex and variable responses of stomata to D under high and low soil moisture is depicted in two papers in this issue (Rogiers et al. 2012 and Zhang et al. 2012), showing that even typically anisohydric grape (Vitis vinifera L.) cultivars (Semillon and Merlot, respectively) may constrain gs during periods of extremely low Ψsoil. The same individuals can switch from an isohydric-like behavior when transpiration is low to an anisohydric-like behavior with increasing water demand. Interestingly, both studies indicated that classifying species as either isohydric or anisohydric is a simplistic view of stomatal functioning and does not represent well the complex stomatal behavior under drying soil, and Zhang et al. (2012) also reported an isohydrodynamic behavior. Both studies suggested that when soil water is limited, gs is aimed at protecting the integrity of the hydraulic system, whereas as soil water content increases, stomata regulate transpiration less. The results of Zhang et al. (2012) indicated that under limited soil moisture the decrease in gs with increasing D was proportional to reference gs (gs at D = 1 kPa); which is in agreement with the stomata-sensitivity model developed by Oren et al. (1999) for isohydric species (see xeric line in Figure 1A). However, a significant departure from this theoretical model was observed under high soil moisture (see wet and mesic lines in Figure 1B). Similarly, in this issue Rogiers et al. (2012) showed that under Tree Physiology 32, 245–248 doi:10.1093/treephys/tps013}, number={3}, journal={TREE PHYSIOLOGY}, author={Domec, Jean-Christophe and Johnson, Daniel M.}, year={2012}, month={Mar}, pages={245–248} }
 @article{domec_lachenbruch_pruyn_spicer_2012, title={Effects of age-related increases in sapwood area, leaf area, and xylem conductivity on height-related hydraulic costs in two contrasting coniferous species}, volume={69}, ISSN={["1297-966X"]}, DOI={10.1007/s13595-011-0154-3}, abstractNote={Knowledge of vertical variation in hydraulic parameters would improve our understanding of individual trunk functioning and likely have important implications for modeling water movement to the leaves. Specifically, understanding how foliage area (A l), sapwood area (A s), and hydraulic specific conductivity (k s) vary with canopy position to affect leaf-specific conductivity (LSC) and whole-tree leaf-specific hydraulic conductance (K l) may explain some of the contrasting patterns of A l/A s reported in the literature. The general aim of the study was to characterize and compare the aboveground relationships between cumulative A l, A s, and k s for two Pacific Northwest coniferous species with contrasting sapwood areas to give insight into size-related design of trees for water transport through changes in LSC and K l. The 230-year-old ponderosa pine (Pinus ponderosa) trees had slightly smaller basal diameters than the 102-year-old Douglas-fir (Pseudostuga menziesii) trees, but contained 85% sapwood at the base compared to 30% in Douglas-fir. At the tree base, there was no evidence that A l/A s decreased with tree age or with tree size. In both species, A l/A s of branches was significantly higher than A l/A s at the tree base, but it was not different from A l/A s measured in the trunks at the top of the tree. Douglas-fir had higher A l/A s at the base than did ponderosa pine (0.42 vs. 0.24 m2 cm−2), similar patterns of change in A l/A s with height, and similar values of k s, such that LSC in Douglas-fir was 77% the value of LSC in ponderosa pine. Compensating changes to increase LSC between short and tall trees occurred through an increased in k s in tall trees but not through a reduction in A l. LSC increased logarithmically with branch path length or trunk path length whereas K l decreased significantly from top to base of old trees, but not between sections from old and young trees of similar cambial age. Even though ponderosa pine had three times more sapwood than Douglas-fir, this study revealed a common relationship of declining K l with increasing tree height and diameter between the two species, within age classes and among trees. There was no compensating decrease in A l/A s as trees got taller, which showed that a homeostasis in K l was not maintained during growth. The trend of higher allocation of biomass to sapwood over leaves in ponderosa pine is consistent with this species' tendency to inhabit drier sites than Douglas-fir.}, number={1}, journal={ANNALS OF FOREST SCIENCE}, author={Domec, Jean-Christophe and Lachenbruch, Barbara and Pruyn, Michele L. and Spicer, Rachel}, year={2012}, month={Jan}, pages={17–27} }
 @article{albaugh_sucre_leggett_domec_king_2012, title={Evaluation of intercropped switchgrass establishment under a range of experimental site preparation treatments in a forested setting on the Lower Coastal Plain of North Carolina, USA}, volume={46}, DOI={10.1016/j.biombioe.2012.06.029}, abstractNote={There is growing interest in using switchgrass (Panicum virgatum L.) as a biofuel crop and for its potential to sequester carbon. However, there are limited data on the establishment success of this species when grown as a forest intercrop in coastal plain settings of the U.S. Southeast. Therefore, we studied establishment success of switchgrass within experimental intercropped plots and in pure switchgrass plots in an intensively managed loblolly pine (Pinus taeda) plantation in eastern North Carolina. Pine trees were planted in the winter of 2008, and switchgrass was planted in the summer of 2009. Establishment success of switchgrass was measured over the growing season from May to October 2010, and quantified in terms of percent cover, height (cm), tiller density (number of tillers m−2), leaf area index and biomass (Mg ha−1). At the end of the growing season, pure switchgrass plots were taller than the intercropped treatments (114 ± 2 cm versus 98 ± 1 cm, respectively), but no significant treatment effects were evident in the other variables measured. Switchgrass biomass across all treatments increased from 2.65 ± 0.81 Mg ha−1 in 2009 to 4.14 ± 0.45 Mg ha−1 in 2010. There was no significant effect of distance from the pine row on any switchgrass growth parameters. However, we anticipate a shading effect over time that may limit switchgrass growth as the pines approach stand closure.}, journal={Biomass and Bioenergy}, author={Albaugh, J. M. and Sucre, E. B. and Leggett, Zakiya H and Domec, J. C. and King, J. S.}, year={2012}, pages={673–682} }
 @article{domec_ogee_noormets_jouangy_gavazzi_treasure_sun_mcnulty_king_2012, title={Interactive effects of nocturnal transpiration and climate change on the root hydraulic redistribution and carbon and water budgets of southern United States pine plantations}, volume={32}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tps018}, abstractNote={Deep root water uptake and hydraulic redistribution (HR) have been shown to play a major role in forest ecosystems during drought, but little is known about the impact of climate change, fertilization and soil characteristics on HR and its consequences on water and carbon fluxes. Using data from three mid-rotation loblolly pine plantations, and simulations with the process-based model MuSICA, this study indicated that HR can mitigate the effects of soil drying and had important implications for carbon uptake potential and net ecosystem exchange (NEE), especially when N fertilization is considered. At the coastal site (C), characterized by deep organic soil, HR increased dry season tree transpiration (T) by up to 40%, and such an increase affected NEE through major changes in gross primary productivity (GPP). Deep-rooted trees did not necessarily translate into a large volume of HR unless soil texture allowed large water potential gradients to occur, as was the case at the sandy site (S). At the Piedmont site (P) characterized by a shallow clay-loam soil, HR was low but not negligible, representing up to 10% of T. In the absence of HR, it was predicted that at the C, S and P sites, annual GPP would have been diminished by 19, 7 and 9%, respectively. Under future climate conditions HR was predicted to be reduced by up to 25% at the C site, reducing the resilience of trees to precipitation deficits. The effect of HR on T and GPP was predicted to diminish under future conditions by 12 and 6% at the C and P sites, respectively. Under future conditions, T was predicted to stay the same at the P site, but to be marginally reduced at the C site and slightly increased at the S site. Future conditions and N fertilization would decrease T by 25% at the C site, by 15% at the P site and by 8% at the S site. At the C and S sites, GPP was estimated to increase by 18% and by >70% under future conditions, respectively, with little effect of N fertilization. At the P site, future conditions would stimulate GPP by only 12%, but future conditions plus N fertilization would increase GPP by 24%. As a consequence, in all sites, water use efficiency was predicted to improve dramatically with future conditions. Modeling the effect of reduced annual precipitation indicated that limited water availability would decrease all carbon fluxes, including NEE and respiration. Our simulations highlight the interactive effects of nutrients and elevated CO(2), and showed that the effect of N fertilization would be greater under future climate conditions.}, number={6}, journal={TREE PHYSIOLOGY}, author={Domec, Jean-Christophe and Ogee, Jerome and Noormets, Asko and Jouangy, Julien and Gavazzi, Michael and Treasure, Emrys and Sun, Ge and McNulty, Steve G. and King, John S.}, year={2012}, month={Jun}, pages={707–723} }
 @article{noormets_mcnulty_domec_gavazzi_sun_king_2012, title={The role of harvest residue in rotation cycle carbon balance in loblolly pine plantations. Respiration partitioning approach}, volume={18}, ISSN={["1354-1013"]}, DOI={10.1111/j.1365-2486.2012.02776.x}, abstractNote={Abstract}, number={10}, journal={GLOBAL CHANGE BIOLOGY}, author={Noormets, Asko and McNulty, Steve G. and Domec, Jean-Christophe and Gavazzi, Michael and Sun, Ge and King, John S.}, year={2012}, month={Oct}, pages={3186–3201} }
 @article{mcculloh_meinzer_sperry_lachenbruch_voelker_woodruff_domec_2011, title={Comparative hydraulic architecture of tropical tree species representing a range of successional stages and wood density}, volume={167}, ISSN={["0029-8549"]}, DOI={10.1007/s00442-011-1973-5}, abstractNote={Plant hydraulic architecture (PHA) has been linked to water transport sufficiency, photosynthetic rates, growth form and attendant carbon allocation. Despite its influence on traits central to conferring an overall competitive advantage in a given environment, few studies have examined whether key aspects of PHA are indicative of successional stage, especially within mature individuals. While it is well established that wood density (WD) tends to be lower in early versus late successional tree species, and that WD can influence other aspects of PHA, the interaction of WD, successional stage and the consequent implications for PHA have not been sufficiently explored. Here, we studied differences in PHA at the scales of wood anatomy to whole-tree hydraulic conductance in species in early versus late successional Panamanian tropical forests. Although the trunk WD was indistinguishable between the successional groups, the branch WD was lower in the early successional species. Across all species, WD correlated negatively with vessel diameter and positively with vessel packing density. The ratio of branch:trunk vessel diameter, branch sap flux and whole-tree leaf-specific conductance scaled negatively with branch WD across species. Pioneer species showed greater sap flux in branches than in trunks and a greater leaf-specific hydraulic conductance, suggesting that pioneer species can move greater quantities of water at a given tension gradient. In combination with the greater water storage capacitance associated with lower WD, these results suggest these pioneer species can save on the carbon expenditure needed to build safer xylem and instead allow more carbon to be allocated to rapid growth.}, number={1}, journal={OECOLOGIA}, author={McCulloh, Katherine A. and Meinzer, Frederick C. and Sperry, John S. and Lachenbruch, Barbara and Voelker, Steven L. and Woodruff, David R. and Domec, Jean-Christophe}, year={2011}, month={Sep}, pages={27–37} }
 @article{aspinwall_king_domec_mckeand_isik_2011, title={Genetic effects on transpiration, canopy conductance, stomatal sensitivity to vapour pressure deficit, and cavitation resistance in loblolly pine}, volume={4}, ISSN={1936-0584}, url={http://dx.doi.org/10.1002/eco.197}, DOI={10.1002/eco.197}, abstractNote={Abstract}, number={2}, journal={Ecohydrology}, publisher={Wiley}, author={Aspinwall, Michael J. and King, John S. and Domec, Jean-Christophe and McKeand, Steven E. and Isik, Fikret}, year={2011}, month={Jan}, pages={168–182} }
 @article{aspinwall_king_mckeand_domec_2011, title={Leaf-level gas-exchange uniformity and photosynthetic capacity among loblolly pine (Pinus taeda L.) genotypes of contrasting inherent genetic variation}, volume={31}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tpq107}, abstractNote={Variation in leaf-level gas exchange among widely planted genetically improved loblolly pine (Pinus taeda L.) genotypes could impact stand-level water use, carbon assimilation, biomass production, C allocation, ecosystem sustainability and biogeochemical cycling under changing environmental conditions. We examined uniformity in leaf-level light-saturated photosynthesis (A(sat)), stomatal conductance (g(s)), and intrinsic water-use efficiency (A(sat)/g(s) or δ) among nine loblolly pine genotypes (selected individuals): three clones, three full-sib families and three half-sib families, during the early years of stand development (first 3 years), with each genetic group possessing varying amounts of inherent genetic variation. We also compared light- and CO(2)-response parameters between genotypes and examined the relationship between genotype productivity, gas exchange and photosynthetic capacity. Within full-sib, half-sib and clonal genotypes, the coefficient of variation (CV) for gas exchange showed no consistent pattern; the CV for g(s) and δ was similar within clonal (44.3-46.9 and 35.5-38.6%) and half-sib (41.0-49.3 and 36.8-40.9%) genotypes, while full-sibs showed somewhat higher CVs (46.9-56.0 and 40.1-45.4%). In contrast, the CVs for A(sat) were generally higher within clones. With the exception of δ, differences in gas exchange among genotypes were generally insignificant. Tree volume showed a significant positive correlation with A(sat) and δ, but the relationship varied by season. Individual-tree volume and genotype volume were positively correlated with needle dark respiration (R(d)). Our results suggest that uniformity in leaf-level physiological rates is not consistently related to the amount of genetic variation within a given genotype, and δ, A(sat) and R(d) were the leaf-level physiological parameters that were most consistently related to individual-tree and genotype productivity. An enhanced understanding of molecular and environmental factors that influence physiological variation within and between loblolly pine genotypes may improve assessments of genotype growth potential and sensitivity to global climate change.}, number={1}, journal={TREE PHYSIOLOGY}, author={Aspinwall, Michael J. and King, John S. and McKeand, Steven E. and Domec, Jean-Christophe}, year={2011}, month={Jan}, pages={78–91} }
 @article{domec_2011, title={Let's not forget the critical role of surface tension in xylem water relations}, volume={31}, ISSN={["0829-318X"]}, DOI={10.1093/treephys/tpr039}, abstractNote={The widely supported cohesion–tension theory of water trans -port explains the importance of a continuous water column and the mechanism of long-distance ascent of sap in plants (Dixon 1914, Tyree 2003, Angeles et al. 2004). The evapora-tion of water from the surfaces of mesophyll cells causes the air–water interface to retreat into the cellulose matrix of the plant cell wall because the cohesion forces between water mol -ecules are stronger than their attraction to air. As a result, the interface between the gas and liquid phases places the mass of water under negative pressure (tension). This pulling force is then transmitted to soil water via a continuous water column since the strong hydrogen bonding of the water molecules also allows water to stay liquid under tension (Oertli 197 1). Related to these cohesive forces is surface tension, which characterizes how difficult it is to stretch the surface of a liquid.Most laboratory and field studies dealing with xylem cavita-tion and embolism repair assume that surface tension is equal to that of pure water and constant within and between species. Although surface tension is a crucial parameter in xylem water movement, few studies have tested whether this parameter dif -fers from that of pure water (Bolton and Koutsianitis 1980). In this issue, the study by Christensen-Dalsgaard et al. (2011) looked at the instantaneous surface tension of xylem sap extracted from branches of three tree species and its change over time. Using the pendant-drop method, they showed that in all three species studied, the instantaneous sap surface ten-sion was indeed equal to that of pure water. However, in one species,}, number={4}, journal={TREE PHYSIOLOGY}, author={Domec, Jean-Christophe}, year={2011}, month={Apr}, pages={359–360} }
 @article{sun_caldwell_noormets_mcnulty_cohen_myers_domec_treasure_mu_xiao_et al._2011, title={Upscaling key ecosystem functions across the conterminous United States by a water-centric ecosystem model}, volume={116}, ISSN={["2169-8961"]}, DOI={10.1029/2010jg001573}, abstractNote={[1] We developed a water-centric monthly scale simulation model (WaSSI-C) by integrating empirical water and carbon flux measurements from the FLUXNET network and an existing water supply and demand accounting model (WaSSI). The WaSSI-C model was evaluated with basin-scale evapotranspiration (ET), gross ecosystem productivity (GEP), and net ecosystem exchange (NEE) estimates by multiple independent methods across 2103 eight-digit Hydrologic Unit Code watersheds in the conterminous United States from 2001 to 2006. Our results indicate that WaSSI-C captured the spatial and temporal variability and the effects of large droughts on key ecosystem fluxes. Our modeled mean (±standard deviation in space) ET (556 ± 228 mm yr−1) compared well to Moderate Resolution Imaging Spectroradiometer (MODIS) based (527 ± 251 mm yr−1) and watershed water balance based ET (571 ± 242 mm yr−1). Our mean annual GEP estimates (1362 ± 688 g C m−2 yr−1) compared well (R2 = 0.83) to estimates (1194 ± 649 g C m−2 yr−1) by eddy flux-based EC-MOD model, but both methods led significantly higher (25–30%) values than the standard MODIS product (904 ± 467 g C m−2 yr−1). Among the 18 water resource regions, the southeast ranked the highest in terms of its water yield and carbon sequestration capacity. When all ecosystems were considered, the mean NEE (−353 ± 298 g C m−2 yr−1) predicted by this study was 60% higher than EC-MOD's estimate (−220 ± 225 g C m−2 yr−1) in absolute magnitude, suggesting overall high uncertainty in quantifying NEE at a large scale. Our water-centric model offers a new tool for examining the trade-offs between regional water and carbon resources under a changing environment.}, journal={JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES}, author={Sun, Ge and Caldwell, Peter and Noormets, Asko and McNulty, Steven G. and Cohen, Erika and Myers, Jennifer Moore and Domec, Jean-Christophe and Treasure, Emrys and Mu, Qiaozhen and Xiao, Jingfeng and et al.}, year={2011}, month={May} }
 @article{sun_noormets_gavazzi_mcnulty_chen_domec_king_amatya_skaggs_2010, title={Energy and water balance of two contrasting loblolly pine plantations on the lower coastal plain of North Carolina, USA}, volume={259}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2009.09.016}, abstractNote={During 2005–2007, we used the eddy covariance and associated hydrometric methods to construct energy and water budgets along a chronosequence of loblolly pine (Pinus taeda) plantations that included a mid-rotation stand (LP) (i.e., 13–15 years old) and a recently established stand on a clearcut site (CC) (i.e., 4–6 years old) in Eastern North Carolina. Our central objective was to quantify the differences in both energy and water balances between the two contrasting stands and understand the underlining mechanisms of environmental controls. We found that the LP site received about 20% more net radiation (Rn) due to its lower averaged albedo (α) of 0.25, compared with that at the CC (α = 0.34). The mean monthly averaged Bowen ratios (β) at the LP site were 0.89 ± 0.7, significantly (p = 0.02) lower than at the CC site (1.45 ± 1.2). Higher net radiation resulted in a 28% higher (p = 0.02) latent heat flux (LE) for ecosystem evapotranspiration at the LP site, but there was no difference in sensible heat flux (H) between the two contrasting sites. The annual total evapotranspiration (ET) at the LP site and CC site was estimated as 1011–1226 and 755–855 mm year−1, respectively. The differences in ET rates between the two contrasting sites occurred mostly during the non-growing seasons and/or dry periods, and they were small during peak growing seasons or wet periods. Higher net radiation and biomass in LP were believed to be responsible to the higher ET. The monthly ET/Grass Reference ET ratios differed significantly across site and season. The annual ET/P ratio for the LP and CC were estimated as 0.70–1.13 and 0.60–0.88, respectively, indicating higher runoff production from the CC site than the LP site. This study implied that reforestation practices reduced surface albedos and thus increased available energy, but they did not necessarily increase energy for warming the atmosphere in the coastal plain region where soil water was generally not limited. This study showed the highly variable response of energy and water balances to forest management due to climatic variability.}, number={7}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Sun, G. and Noormets, A. and Gavazzi, M. J. and McNulty, S. G. and Chen, J. and Domec, J. -C. and King, J. S. and Amatya, D. M. and Skaggs, R. W.}, year={2010}, month={Mar}, pages={1299–1310} }
 @article{noormets_sun_mcnulty_gavazzi_chen_domec_king_amatya_skaggs_2010, title={Energy and water balance of two contrasting loblolly pine plantations on the lower coastal plain of North Carolina, USA (vol 259, pg 1299, 2010)}, volume={260}, number={1}, journal={Forest Ecology and Management}, author={Noormets, A. and Sun, G. and McNulty, S. G. and Gavazzi, M. J. and Chen, J. and Domec, J. C. and King, J. S. and Amatya, D. M. and Skaggs, R. W.}, year={2010}, pages={169–169} }
 @article{domec_king_noormets_treasure_gavazzi_sun_mcnulty_2010, title={Hydraulic redistribution of soil water by roots affects whole-stand evapotranspiration and net ecosystem carbon exchange}, volume={187}, ISSN={["1469-8137"]}, DOI={10.1111/j.1469-8137.2010.03245.x}, abstractNote={
            Commentary p 3
          }, number={1}, journal={NEW PHYTOLOGIST}, author={Domec, Jean-Christophe and King, John S. and Noormets, Asko and Treasure, Emrys and Gavazzi, Michael J. and Sun, Ge and McNulty, Steven G.}, year={2010}, pages={171–183} }
 @article{noormets_gavazzi_mcnulty_domec_sun_king_chen_2010, title={Response of carbon fluxes to drought in a coastal plain loblolly pine forest}, volume={16}, ISSN={["1365-2486"]}, DOI={10.1111/j.1365-2486.2009.01928.x}, abstractNote={Abstract}, number={1}, journal={GLOBAL CHANGE BIOLOGY}, author={Noormets, Asko and Gavazzi, Michael J. and Mcnulty, Steve G. and Domec, Jean-Christophe and Sun, Ge and King, John S. and Chen, Jiquan}, year={2010}, month={Jan}, pages={272–287} }
 @article{domec_schaefer_oren_kim_mccarthy_2010, title={Variable conductivity and embolism in roots and branches of four contrasting tree species and their impacts on whole-plant hydraulic performance under future atmospheric CO2 concentration}, volume={30}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tpq054}, abstractNote={Anatomical and physiological acclimation to water stress of the tree hydraulic system involves trade-offs between maintenance of stomatal conductance and loss of hydraulic conductivity, with short-term impacts on photosynthesis and long-term consequences to survival and growth. Here, we study the role of variations in root and branch maximum hydraulic specific conductivity (k(s-max)) under high and low soil moisture in determining whole-tree hydraulic conductance (K(tree)) and in mediating stomatal control of gas exchange in four contrasting tree species growing under ambient and elevated CO₂ (CO₂(a) and CO₂(e)). We hypothesized that K(tree) would adjust to CO₂(e) through an increase in root and branch k(s-max) in response to anatomical adjustments. However, physiological changes observed under CO₂(e) were not clearly related to structural change in the xylem of any of the species. The only large effect of CO₂(e) occurred in branches of Liquidambar styraciflua L. and Cornus florida L. where an increase in k(s-max) and a decrease in xylem resistance to embolism (-P₅₀) were measured. Across species, embolism in roots explained the loss of K(tree) and therefore indirectly constituted a hydraulic signal involved in stomatal regulation and in the reduction of G(s-ref), the sap-flux-scaled mean canopy stomatal conductance at a reference vapour pressure deficit of 1 kPa. Across roots and branches, the increase in k(s-max) was associated with a decrease in -P₅₀, a consequence of structural acclimation such as larger conduits, lower pit resistance and lower wood density. Across species, treatment-induced changes in K(tree) translated to similar variation in G(s-ref). However, the relationship between G(s-ref) and K(tree) under CO₂(a) was steeper than under CO₂(e), indicating that CO₂(e) trees have lower G(s-ref) at a given K(tree) than CO₂(a) trees. Under high soil moisture, CO₂(e) greatly reduced G(s-ref). Under low soil moisture, CO₂(e) reduced G(s-ref) of only L. styraciflua and Ulmus alata. In some species, higher xylem dysfunction under CO₂(e) might impact tree performance in a future climate when increased evaporative demand could cause a greater loss of hydraulic function. The results contributed to our knowledge of the physiological and anatomical mechanisms underpinning the responses of tree species to drought and more generally to global change.}, number={8}, journal={TREE PHYSIOLOGY}, author={Domec, Jean-Christophe and Schaefer, Karina and Oren, Ram and Kim, Hyun S. and McCarthy, Heather R.}, year={2010}, month={Aug}, pages={1001–1015} }
 @article{domec_palmroth_ward_maier_therezien_oren_2009, title={Acclimation of leaf hydraulic conductance and stomatal conductance of Pinus taeda (loblolly pine) to long-term growth in elevated CO2 (free-air CO2 enrichment) and N-fertilization}, volume={32}, ISSN={["1365-3040"]}, DOI={10.1111/j.1365-3040.2009.02014.x}, abstractNote={ABSTRACT}, number={11}, journal={PLANT CELL AND ENVIRONMENT}, author={Domec, Jean-Christophe and Palmroth, Sari and Ward, Eric and Maier, Chris A. and Therezien, M. and Oren, Ram}, year={2009}, month={Nov}, pages={1500–1512} }
 @article{domec_noormets_king_sun_mcnulty_gavazzi_boggs_treasure_2009, title={Decoupling the influence of leaf and root hydraulic conductances on stomatal conductance and its sensitivity to vapour pressure deficit as soil dries in a drained loblolly pine plantation}, volume={32}, ISSN={["1365-3040"]}, DOI={10.1111/j.1365-3040.2009.01981.x}, abstractNote={ABSTRACT}, number={8}, journal={PLANT CELL AND ENVIRONMENT}, author={Domec, Jean-Christophe and Noormets, Asko and King, John S. and Sun, Ge and McNulty, Steven G. and Gavazzi, Michael J. and Boggs, Johnny L. and Treasure, Emrys A.}, year={2009}, month={Aug}, pages={980–991} }
 @article{domec_warren_meinzer_lachenbruch_2009, title={SAFETY FACTORS FOR XYLEM FAILURE BY IMPLOSION AND AIR-SEEDING WITHIN ROOTS, TRUNKS AND BRANCHES OF YOUNG AND OLD CONIFER TREES}, volume={30}, ISSN={["2294-1932"]}, DOI={10.1163/22941932-90000207}, abstractNote={The cohesion-tension theory of water transport states that hydrogen bonds hold water molecules together and that they are pulled through the xylem under tension. This tension could cause transport failure in at least two ways: collapse of the conduit walls (implosion), or rupture of the water column through air-seeding. The objective of this research was to elucidate the functional significance of variations in tracheid anatomical features, earlywood to latewood ratios and wood densities with position in young and old Douglas-fir and ponderosa pine trees in terms of their consequences for the safety factors for tracheid implosion and air-seeding. For both species, wood density increased linearly with percent latewood for root, trunk and branch samples. However, the relationships between anatomy and hydraulic function in trunks differed from those in roots and branches. In roots and branches increased hydraulic efficiency was achieved at the cost of increased vulnerability to air-seeding. Mature wood of trunks had earlywood with wide tracheids that optimized water transport and had a high percentage of latewood that optimized structural support. Juvenile wood had higher resistance to air-seeding and cell wall implosion. The two safety factors followed similar axial trends from roots to terminal branches and were similar for both species studied and between juvenile and mature wood.}, number={2}, journal={IAWA JOURNAL}, author={Domec, Jean-Christophe and Warren, Jeffrey M. and Meinzer, Frederick C. and Lachenbruch, Barbara}, year={2009}, pages={101–120} }
 @article{scholz_bucci_goldstein_moreira_meinzer_domec_villalobos-vega_franco_miralles-wilhelm_2008, title={Biophysical and life-history determinants of hydraulic lift in Neotropical savanna trees}, volume={22}, ISSN={["1365-2435"]}, DOI={10.1111/j.1365-2435.2008.01452.x}, abstractNote={1. Ecological and physiological characteristics of vascular plants may facilitate or constrain hydraulic lift. Studies of hydraulic lift typically include only one or few species, but in species-rich ecosystems a larger number of representative species needs to be studied. 2. Measurements of sap flow in tap roots, lateral roots and stems, as well as stable isotope labelling techniques were used to determine the occurrence and relative magnitude of hydraulic lift in several individuals of nine co-occurring Brazilian savanna (Cerrado) tree species differing in life-history traits, and to assess physical and biological determinants of this process at the tree and ecosystem level. 3. The occurrence of reverse sap flow observed in deciduous and brevideciduous species during the dry season was consistent with hydraulic lift. The evergreen species did not exhibit reverse flow. Consistent with their ability to carry out hydraulic lift, the brevideciduous and deciduous species had both shallow and tap roots (dimorphic root systems), whereas the evergreen species had mostly deep roots (monomorphic root systems). 4. In the deciduous and brevideciduous species, the contribution of tap roots to transpiration increased substantially as the dry season progressed. Seasonal changes in the contribution of tap roots to transpiration were not observed in the evergreen species. 5. There was an inverse relationship between rates of reverse sap flow and seasonal loss of hydraulic conductivity in lateral roots, suggesting that hydraulic lift in Cerrado woody plants may help maintain the functionality of the lateral roots in exploring dry and nutrient rich superficial soil layers without directly enhancing the amount of water uptake. 6. Reverse sap flow in lateral roots of the deciduous and brevideciduous species increased asymptotically as the driving force for water movement from roots to the soil increased. This nonlinear relationship implies that additional sinks for water such as nocturnal transpiration and refilling of internal water storage tissues may compete for internal water resources during the dry season. 7. There appears to be a trade-off between greater year-round access to nutrients in the upper soil layers (deciduous and brevideciduous species) and a greater access to deep and more reliable water sources during the dry season (evergreen species), which has implications for whole-ecosystem water, carbon and nutrient balance in Neotropical savannas.}, number={5}, journal={FUNCTIONAL ECOLOGY}, author={Scholz, F. G. and Bucci, S. J. and Goldstein, G. and Moreira, M. Z. and Meinzer, F. C. and Domec, J. -C. and Villalobos-Vega, R. and Franco, A. C. and Miralles-Wilhelm, F.}, year={2008}, month={Oct}, pages={773–786} }
 @article{domec_pruyn_2008, title={Bole girdling affects metabolic properties and root, trunk and branch hydraulics of young ponderosa pine trees}, volume={28}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/28.10.1493}, abstractNote={Effects of trunk girdling on seasonal patterns of xylem water status, water transport and woody tissue metabolic properties were investigated in ponderosa pine (Pinus ponderosa Dougl. ex P. Laws.) trees. At the onset of summer, there was a sharp decrease in stomatal conductance (g(s)) in girdled trees followed by a full recovery after the first major rainfall in September. Eliminating the root as a carbohydrate sink by girdling induced a rapid reversible reduction in g(s). Respiratory potential (a laboratory measure of tissue-level respiration) increased above the girdle (branches and upper trunk) and decreased below the girdle (lower trunk and roots) relative to control trees during the growing season, but the effect was reversed after the first major rainfall. The increase in branch respiratory potential induced by girdling suggests that the decrease in g(s) was caused by the accumulation of carbohydrates above the girdle, which is consistent with an observed increase in leaf mass per area in the girdled trees. Trunk girdling did not affect native xylem embolism or xylem conductivity. Both treated and control trunks experienced loss of xylem conductivity ranging from 10% in spring to 30% in summer. Girdling reduced xylem growth and sapwood to leaf area ratio, which in turn reduced branch leaf specific conductivity (LSC). The girdling-induced reductions in g(s) and transpiration were associated with a decrease in leaf hydraulic conductance. Two years after girdling, when root-to-shoot phloem continuity had been restored, girdled trees had a reduced density of new wood, which increased xylem conductivity and whole-tree LSC, but also vulnerability to embolism.}, number={10}, journal={TREE PHYSIOLOGY}, author={Domec, Jean-Christophe and Pruyn, Michele L.}, year={2008}, month={Oct}, pages={1493–1504} }
 @article{meinzer_campanello_domec_gatti_goldstein_villalobos-vega_woodruff_2008, title={Constraints on physiological function associated with branch architecture and wood density in tropical forest trees}, volume={28}, ISSN={["0829-318X"]}, DOI={10.1093/treephys/28.11.1609}, abstractNote={This study examined how leaf and stem functional traits related to gas exchange and water balance scale with two potential proxies for tree hydraulic architecture: the leaf area:sapwood area ratio (A(L):A(S)) and wood density (rho(w)). We studied the upper crowns of individuals of 15 tropical forest tree species at two sites in Panama with contrasting moisture regimes and forest types. Transpiration and maximum photosynthetic electron transport rate (ETR(max)) per unit leaf area declined sharply with increasing A(L):A(S), as did the ratio of ETR(max) to leaf N content, an index of photosynthetic nitrogen-use efficiency. Midday leaf water potential, bulk leaf osmotic potential at zero turgor, branch xylem specific conductivity, leaf-specific conductivity and stem and leaf capacitance all declined with increasing rho(w). At the branch scale, A(L):A(S) and total leaf N content per unit sapwood area increased with rho(w), resulting in a 30% increase in ETR(max) per unit sapwood area with a doubling of rho(w). These compensatory adjustments in A(L):A(S), N allocation and potential photosynthetic capacity at the branch level were insufficient to completely offset the increased carbon costs of producing denser wood, and exacerbated the negative impact of increasing rho(w) on branch hydraulics and leaf water status. The suite of tree functional and architectural traits studied appeared to be constrained by the hydraulic and mechanical consequences of variation in rho(w).}, number={11}, journal={TREE PHYSIOLOGY}, author={Meinzer, Frederick C. and Campanello, Paula I. and Domec, Jean-Christophe and Gatti, M. Genoveva and Goldstein, Guillermo and Villalobos-Vega, Randol and Woodruff, David R.}, year={2008}, month={Nov}, pages={1609–1617} }
 @article{meinzer_woodruff_domec_goldstein_campanello_gatti_villalobos-vega_2008, title={Coordination of leaf and stem water transport properties in tropical forest trees}, volume={156}, DOI={10.1007/s00442-008-0974-5}, abstractNote={Stomatal regulation of transpiration constrains leaf water potential (Psi(L)) within species-specific ranges that presumably avoid excessive tension and embolism in the stem xylem upstream. However, the hydraulic resistance of leaves can be highly variable over short time scales, uncoupling tension in the xylem of leaves from that in the stems to which they are attached. We evaluated a suite of leaf and stem functional traits governing water relations in individuals of 11 lowland tropical forest tree species to determine the manner in which the traits were coordinated with stem xylem vulnerability to embolism. Stomatal regulation of Psi(L) was associated with minimum values of water potential in branches (Psi(br)) whose functional significance was similar across species. Minimum values of Psi(br) coincided with the bulk sapwood tissue osmotic potential at zero turgor derived from pressure-volume curves and with the transition from a linear to exponential increase in xylem embolism with increasing sapwood water deficits. Branch xylem pressure corresponding to 50% loss of hydraulic conductivity (P (50)) declined linearly with daily minimum Psi(br) in a manner that caused the difference between Psi(br) and P (50) to increase from 0.4 MPa in the species with the least negative Psi(br) to 1.2 MPa in the species with the most negative Psi(br). Both branch P (50) and minimum Psi(br) increased linearly with sapwood capacitance (C) such that the difference between Psi(br) and P (50), an estimate of the safety margin for avoiding runaway embolism, decreased with increasing sapwood C. The results implied a trade-off between maximizing water transport and minimizing the risk of xylem embolism, suggesting a prominent role for the buffering effect of C in preserving the integrity of xylem water transport. At the whole-tree level, discharge and recharge of internal C appeared to generate variations in apparent leaf-specific conductance to which stomata respond dynamically.}, number={1}, journal={Oecologia (Online)}, author={Meinzer, F. C. and Woodruff, D. R. and Domec, J. C. and Goldstein, G. and Campanello, P. I. and Gatti, M. G. and Villalobos-Vega, R.}, year={2008}, pages={31–41} }
 @article{domec_lachenbruch_meinzer_woodruff_warren_mcculloh_2008, title={Maximum height in a conifer is associated with conflicting requirements for xylem design}, volume={105}, ISSN={["0027-8424"]}, DOI={10.1073/pnas.0710418105}, abstractNote={Despite renewed interest in the nature of limitations on maximum tree height, the mechanisms governing ultimate and species-specific height limits are not yet understood, but they likely involve water transport dynamics. Tall trees experience increased risk of xylem embolism from air-seeding because tension in their water column increases with height because of path-length resistance and gravity. We used morphological measurements to estimate the hydraulic properties of the bordered pits between tracheids in Douglas-fir trees along a height gradient of 85 m. With increasing height, the xylem structural modifications that satisfied hydraulic requirements for avoidance of runaway embolism imposed increasing constraints on water transport efficiency. In the branches and trunks, the pit aperture diameter of tracheids decreases steadily with height, whereas torus diameter remains relatively constant. The resulting increase in the ratio of torus to pit aperture diameter allows the pits to withstand higher tensions before air-seeding but at the cost of reduced pit aperture conductance. Extrapolations of vertical trends for trunks and branches show that water transport across pits will approach zero at a heights of 109 m and 138 m, respectively, which is consistent with historic height records of 100–127 m for this species. Likewise, the twig water potential corresponding to the threshold for runaway embolism would be attained at a height of ≈107 m. Our results suggest that the maximum height of Douglas-fir trees may be limited in part by the conflicting requirements for water transport and water column safety.}, number={33}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Domec, Jean-Christophe and Lachenbruch, Barbara and Meinzer, Frederick C. and Woodruff, David R. and Warren, Jeffrey M. and McCulloh, Katherine A.}, year={2008}, month={Aug}, pages={12069–12074} }