@article{sumnall_raigosa-garcia_carter_albaugh_campoe_rubilar_alexander_cohrs_cook_2025, title={Assessing Methods to Measure Stem Diameter at Breast Height with High Pulse Density Helicopter Laser Scanning}, volume={17}, ISSN={["2072-4292"]}, DOI={10.3390/rs17020229}, abstractNote={Technological developments have allowed helicopter airborne laser scanning (HALS) to produce high-density point clouds below the forest canopy. We present a tree stem classification method that combines linear shape detection and model-based clustering, using four discrete methods to estimate stem diameter. Stem horizontal size was estimated every 25 cm below the living crown, and a cubic spline was used to estimate where there were gaps. Individual stem diameter at breast height (DBH) was estimated for 77% of field-measured trees. The root mean square error (RMSE) of DBH estimates was 7–12 cm using stem circle fitting. Adapting the approach to use an existing stem taper model reduced the RMSE of estimates (<1 cm). In contrast, estimates that were produced from a previously existing DBH estimation method (PREV) could be achieved for 100% of stems (DBH RMSE 6 cm), but only after location-specific error was corrected. The stem classification method required comparatively little development of statistical models to provide estimates, which ultimately had a similar level of accuracy (RMSE < 1 cm) to PREV. HALS datasets can measure broad-scale forest plantations and reduce field efforts and should be considered an important tool for aiding in inventory creation and decision-making within forest management.}, number={2}, journal={REMOTE SENSING}, author={Sumnall, Matthew J. and Raigosa-Garcia, Ivan and Carter, David R. and Albaugh, Timothy J. and Campoe, Otavio C. and Rubilar, Rafael A. and Alexander, Bart and Cohrs, Christopher W. and Cook, Rachel L.}, year={2025}, month={Jan} }
 @article{carter_albaugh_sumnall_grossman_campoe_cook_rubilar_maier_coates_defeo_et al._2025, title={Crown complementarity rather than crown selection contributes to stem complementarity in genetic mixtures of<i> Pinus</i><i> taeda</i> L}, volume={126}, ISSN={["1873-6238"]}, DOI={10.1016/j.actao.2025.104058}, journal={ACTA OECOLOGICA-INTERNATIONAL JOURNAL OF ECOLOGY}, author={Carter, David R. and Albaugh, Timothy J. and Sumnall, Matthew and Grossman, Jake J. and Campoe, Otavio C. and Cook, Rachel L. and Rubilar, Rafael A. and Maier, Chris A. and Coates, T. Adam and Defeo, Julia and et al.}, year={2025}, month={Mar} }
 @article{garrido-ruiz_rubilar_bozo_pincheira_zapata_jara_cook_carter_albaugh_campoe_2025, title={Potential of high- or low-solubility calcium to correct stem sinuosity in fast-growing Pinus radiata D. Don}, volume={55}, ISSN={["1179-5395"]}, DOI={10.33494/nzjfs552025x395x}, abstractNote={Background: Pinus radiata D. Don is widely planted in Chile due to its fast growth and adaptability to various soil types and environmental conditions. However, the species is prone to stem sinuosity due to factors such as genetics, environmental stresses including nutrient availability, and management practices. This study assessed the efficacy of either low- or high-solubility calcium (Ca) additions in reducing stem sinuosity in young radiata pine plantations grown on Andisols. Methods: We compared growth and stem sinuosity of a 3-year-old pine plantation subject to two types of Ca sources: agricultural low-solubility crushed lime (ag-lime), and finely ground pelletised high-solubility lime (pell-lime), applied at three concentrations (300 kg Ca ha-1, 600 kg Ca ha-1, 1,200 kg Ca ha-1) alongside a control. Results: Our findings revealed that both calcium sources increased the soil Ca content post-application but was only significant for the highest concentration in each case (1,200 Kg Ca ha-1). The soil Ca availability rate was higher in pell-lime treatments. Agricultural lime had no effect on growth, whereas two of the pell-lime treatments increased the basal area, the lowest concentration increased the cumulative diameter at the root collar, and the highest concentration reduced tree height. Interestingly, while pell-lime did not mitigate stem sinuosity in 3-year-old pine trees, ag-lime reduced stem sinuosity severity although this result was not correlated with soil Ca content. Notably, the ag-lime treatment at 600 kg Ca ha-1 was most effective, decreasing the proportion of severely deformed trees from 32% to 14%. Conclusions: The application of both low-solubility calcium (ag-lime) or high-solubility calcium (pell-lime) calcium increased the soil Ca content. Ag-lime treatments showed no adverse impact on stand growth and led to a reduction in stem sinuosity being the most effective treatment applying 600 kg Ca ha-1. Pell-lime treatments had mixed effects on growth: diameter at root collar (DRC) and basal area increment (BAI) increased, and height decreased. Pell-lime treatments did not reduce stem sinuosity. Our results suggests that stem sinuosity might be more closely associated with deficiencies in trace metals like Cu and Mn rather than Ca content alone.}, journal={NEW ZEALAND JOURNAL OF FORESTRY SCIENCE}, author={Garrido-Ruiz, Claudia and Rubilar, Rafael and Bozo, Daniel and Pincheira, Matias and Zapata, Alvaro and Jara, Oscar and Cook, Rachel and Carter, David and Albaugh, Timothy and Campoe, Otavio}, year={2025}, month={Feb} }
 @article{hackman_cook_strahm_carter_woodley_garcia_albaugh_rubilar_campoe_2024, title={<i>Pinus</i><i> taeda</i> carryover phosphorus availability on the lower Atlantic Coastal Plain}, volume={555}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2024.121701}, abstractNote={Phosphorus (P) fertilizer that remains in the soil after harvest and into the subsequent rotation is referred to as carryover P. Carryover P is not well understood in loblolly pine (P. taeda) silviculture, especially on highly P responsive sites, where this effect could potentially have the greatest benefit to land managers. Our study aims to determine the duration of the P carryover effect and the magnitude of response to soil P as it relates to previously applied P fertilizer rates from the previous rotation. To address this knowledge gap, we studied two highly weathered sites on the lower Atlantic coastal plain: a somewhat poorly drained Spodosol and a poorly drained Alfisol over three years from pre- to post-harvest. Two years post planting, carryover fertilizer treatments resulted in a 13% increase in height for the 121 kg P ha-1, a 15% for the 81 kg P ha-1, and a 17% increase for the fertilized 40 + 45 kg P ha-1 treatments compared to the control for the Alfisol. Spodosols appeared to respond to any additional fertilization compared to the control group regardless of rate. Importantly, we found that O horizon mass and P content from the first rotation, approximately seven years before harvest, exhibited a positive linear relationship with one-year-old heights in the Spodosol and one- and two-year-old heights in the Alfisol. These findings shed light on the importance of the O horizon characteristics and its potential as an indicator for tree growth in subsequent rotations.}, journal={FOREST ECOLOGY AND MANAGEMENT}, publisher={Elsevier BV}, author={Hackman, Jacob and Cook, Rachel and Strahm, Brian and Carter, David and Woodley, Alex and Garcia, Kevin and Albaugh, Timothy and Rubilar, Rafael and Campoe, Otavio}, year={2024}, month={Mar} }
 @article{sumnall_carter_albaugh_cook_campoe_rubilar_2024, title={Evaluating the Influence of Row Orientation and Crown Morphology on Growth of <i>Pinus taeda L</i>. with Drone-Based Airborne Laser Scanning}, volume={6}, ISSN={["2643-6515"]}, DOI={10.34133/plantphenomics.0264}, abstractNote={The tree crown’s directionality of growth may be an indicator of how aggressive the tree is in terms of foraging for light. Airborne drone laser scanning (DLS) has been used to accurately classify individual tree crowns (ITCs) and derive size metrics related to the crown. We compare ITCs among 6 genotypes exhibiting different crown architectures in managed loblolly pine ( Pinus taeda L. ) in the United States. DLS data are classified into ITC objects, and we present novel methods to calculate ITC shape metrics. Tree stems are located using (a) model-based clustering and (b) weighting cluster-based size. We generated ITC shape metrics using 3-dimensional (3D) alphashapes in 2 DLS acquisitions of the same location, 4 years apart. Crown horizontal distance from the stem was estimated at multiple heights, in addition to calculating 3D volume in specific azimuths. Crown morphologies varied significantly ( P < 0.05) spatially, temporally, and among the 6 genotypes. Most genotypes exhibited larger crown volumes facing south (150° to 173°). We found that crown asymmetries were consistent with (a) the direction of solar radiation, (b) the spatial arrangement and proximity of the neighboring crowns, and (c) genotype. Larger crowns were consistent with larger increases in stem volume, but that increases in the southern portions of crown volume were consistent with larger stem volume increases, than in the north. This finding suggests that row orientation could influence stem growth rates in plantations, particularly impacting earlier development. These differences can potentially reduce over time, especially if stands are not thinned in a timely manner once canopy growing space has diminished.}, journal={PLANT PHENOMICS}, author={Sumnall, Matthew J. and Carter, David R. and Albaugh, Timothy J. and Cook, Rachel L. and Campoe, Otavio C. and Rubilar, Rafael A.}, year={2024}, month={Oct} }
 @article{sumnall_carter_albaugh_platt_host_cook_campoe_rubilar_2024, title={Evaluating the transferability of airborne laser scanning derived stem size prediction models for <i>Pinus taeda</i> L. stem size estimation to two different locations and acquisition specifications}, volume={45}, ISSN={["1366-5901"]}, DOI={10.1080/01431161.2024.2370499}, abstractNote={Airborne laser scanning (ALS) datasets are used widely for estimating forest biometrics. The transferability of predictive models among ALS acquisitions is a topic of research due to differences in timing, flight parameters, equipment specifications, environmental conditions, and processing methods. The transferability of predictive models therefore is subject to uncertainty. This paper presents an evaluation of the transferability of models for the estimation of stem volume and diameter at breast height (DBH) based on individual tree crown size and competitive neighbourhood metrics derived for managed loblolly pine (Pinus taeda) and slash pine (Pinus elliottii) forest in the Southern USA. Two predictive models types were tested: multiple linear regression (MLR) and Rand Forest (RF). We also evaluated the inclusion of additional training data to model development. Models were able to be transferred to other locations with similar structural and management conditions as the original training dataset with little decrease in accuracy, specifically unthinned stands, despite different ALS acquisitions (Plot stem volume: R2 0.7–0.8; NRMSE 10–12%; mean DBH: R2 0.4–0.7; NRMSE 10–17%; plot basal area: R2 0.7–0.8; NRMSE 12%). Increases in structural differences between the training and test data, driven by age or thinning status, introduced unacceptable levels of uncertainty (Stem volume: R2 0.4–0.7; NRMSE 12–16%; mean DBH: R2 0.4–0.5; NRMSE 18–20%; plot basal area: R2 0.5–0.6; NRMSE 22–40%). Generally, RF models most accuracy estimated DBH, and MLR for stem volume. Improvements to estimate accuracy can be achieved through the addition of relatively small datasets, representing features which were not present in the original data. ALS's ability to provide accurate and near-complete inventories of forests hold a great deal of potential for forest management. The existence of a transferable model that can be used across different acquisitions represents a saving in terms of cost and time, we would argue that future research is therefore warranted.}, number={16}, journal={INTERNATIONAL JOURNAL OF REMOTE SENSING}, author={Sumnall, Matthew J. and Carter, David R. and Albaugh, Timothy J. and Platt, Erik and Host, Trevor and Cook, Rachel L. and Campoe, Otavio C. and Rubilar, Rafael A.}, year={2024}, month={Aug}, pages={5267–5294} }
 @article{cook_fox_allen_cohrs_ribas-costa_trlica_ricker_carter_rubilar_campoe_et al._2024, title={Forest soil classification for intensive pine plantation management: "Site Productivity Optimization for Trees" system}, volume={556}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2024.121732}, abstractNote={Forest productivity and response to silvicultural treatments are dependent on inherent site resource availability and limitations. Trees have deeper rooting profiles than agronomic crops, so evaluating the impacts of soils, geology, and physiographic province on forest productivity can help guide silvicultural management decisions in southern pine plantations. Here, we describe the Forest Productivity Cooperative's "Site Productivity Optimization for Trees" (SPOT) system which includes: texture, depth to increase in clay content, drainage class, soil modifiers (i.e., surface attributes, mineralogy, and additional limitations such as root restrictions), geologic formations, and physiographic province. We quantified the total area for each SPOT code in the native range of loblolly pine (Pinus taeda L.), the region's most commercially important species, and used a remotely-sensed layer to quantify SPOT code areas in managed southern pine (approximately 14 million ha). The most common SPOT code in the native range is also the most planted, a B2WekoGgPD (fine loamy, shallow depth to increase in clay, well-drained, eroded, kaolinitic, granitic, Piedmont soil), spanning 1.1 million ha total, but only 12% in managed southern pine. However, the SPOT code with the greatest percentage of managed southern pine (61%; a D4PoioAmAF, spodic, deep to increase in clay, siliceous, middle Atlantic Coastal Plain, Flatwoods soil) was the 20th most common in the native range with 474,662 ha. We used machine learning and data from decades of "Regionwide" trials to assess the variable importance of SPOT constituents, climate, planting year, and N rate on site index (base age 25 years) and found that planting year was the most important variable, showing an increase of 17 cm site index per year since 1970, followed by maximum vapor pressure deficit, and precipitation. Geology was the top-ranking SPOT variable to explain site index followed by physiographic province. The Regionwide trials represent 72 unique SPOT codes (out of over 10,000 possible in the pine plantations) and approximately one million ha (or about 7% of all soils identified as supporting managed pine). To extrapolate site index values outside of the unique soil and geologic conditions empirically represented, we created a predictive model with an R2 of 0.79 and an RMSE of 1.38 m from SPOT codes alone. With this extrapolation, the Regionwide data predicts 10.5 million ha, or 74%, of all soils under loblolly pine management in its native range. Overall, this system will allow managers to assess their current site productivity, and recommend silvicultural treatments, thus, providing a framework to optimize forest productivity in pine plantations in the southeastern US.}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Cook, Rachel and Fox, Thomas R. and Allen, Howard Lee and Cohrs, Chris W. and Ribas-Costa, Vicent and Trlica, Andrew and Ricker, Matthew and Carter, David R. and Rubilar, Rafael and Campoe, Otavio and et al.}, year={2024}, month={Mar} }
 @article{beasley_carter_albaugh_enemo_hong_cook_campoe_rubilar_2024, title={Growth trends of loblolly pine age five or less in relation to soil type and management intensity}, volume={574}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2024.122355}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Beasley, Christen and Carter, David R. and Albaugh, Timothy J. and Enemo, David and Hong, Daniel S. and Cook, Rachel and Campoe, Otavio and Rubilar, Rafael}, year={2024}, month={Dec} }
 @article{lim_medvigy_maekelae_kim_albaugh_knier_blasko_campoe_deshar_franklin_et al._2024, title={Overlooked branch turnover creates a widespread bias in forest carbon accounting}, volume={121}, ISSN={["1091-6490"]}, DOI={10.1073/pnas.2401035121}, abstractNote={Most measurements and models of forest carbon cycling neglect the carbon flux associated with the turnover of branch biomass, a physiological process quantified for other organs (fine roots, leaves, and stems). Synthesizing data from boreal, temperate, and tropical forests (184,815 trees), we found that including branch turnover increased empirical estimates of aboveground wood production by 16% (equivalent to 1.9 Pg Cy}, number={42}, journal={PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA}, author={Lim, Hyungwoo and Medvigy, David and Maekelae, Annikki and Kim, Dohyoung and Albaugh, Timothy J. and Knier, Aubrey and Blasko, Robert and Campoe, Otavio C. and Deshar, Rashila and Franklin, Oskar and et al.}, year={2024}, month={Oct} }
 @article{rubilar_bozo_albaugh_cook_campoe_carter_allen_alvarez_pincheira_zapata_2023, title={Rotation-age effects of subsoiling, fertilization, and weed control on radiata pine growth at sites with contrasting soil physical, nutrient, and water limitations}, volume={544}, ISSN={["1872-7042"]}, DOI={10.1016/j.foreco.2023.121213}, abstractNote={Although short- and medium-term responses to early silvicultural treatments have been documented, few studies show productivity gains or losses throughout a rotation across a range of soil types and resource availability. We evaluated the rotation length productivity responses of radiata pine to subsoiling, fertilization, and weed control in dry sand (DS), red clay (RC), and recent volcanic ash (RV) soils representing a gradient of physical, nutrient, and water limitations. Stands were planted in 2000 in a split-plot factorial design, with soil preparation (subsoiling vs. shovel planting) as the main plot and fertilization at planting (B only vs. NPKB) and weed control (none vs. 2-year banded application) as factorial randomized treatment plots within the main plots. Annual diameter at breast height, height, survival, and cumulative volume responses were measured. The rotation-age results for cumulative volume showed that early gains from weed control were maintained through at least 15 years of age. At rotation age, weed control increased the cumulative volume at the DS site (56 m3/ha, 20% gain), and the response over time was maintained at the RC site (28 m3/ha, 8% gain), whereas the volume was reduced at the RV site (-36 m3/ha, 7% loss). Fertilization resulted in the greatest response at the RC site (29 m3/ha, 8% gain); there were small responses at the DS site (5 m3/ha, 2% gain) and negative responses at the RV site (-18 m3/ha, 4% loss). Interestingly, subsoiling resulted in null or negative responses at all sites, and negative effects increased over time, with volume responses ranging from −4 m3/ha (1% loss) and −27 m3/ha (7% loss) at the DS and RC sites, respectively, to −116 m3/ha (21% loss) at the RV site. Carrying capacity was reached at mid-rotation at the RV site and resulted in negative treatment effects at rotation age, suggesting the need for thinning or a younger harvest age at this site. Given the negative or null effects of soil preparation, a better understanding is needed for how this silvicultural treatment is affected by soil type and soil strength.}, journal={FOREST ECOLOGY AND MANAGEMENT}, author={Rubilar, Rafael and Bozo, Daniel and Albaugh, Timothy and Cook, Rachel and Campoe, Otavio and Carter, David and Allen, H. Lee and Alvarez, Jose and Pincheira, Matias and Zapata, Alvaro}, year={2023}, month={Sep} }