@article{schafer_breslow_hohmann_hoffmann_2015, title={RELATIVE BARK THICKNESS IS CORRELATED WITH TREE SPECIES DISTRIBUTIONS ALONG A FIRE FREQUENCY GRADIENT}, volume={11}, ISSN={["1933-9747"]}, DOI={10.4996/fireecology.1101074}, abstractNote={AbstractThe probability of stem survival after fire is strongly influenced by energy allocation to bark because bark thickness affects heat transfer during fire. Greater relative investment in inner bark versus outer bark should also enhance survival because of greater moisture content of inner bark. We measured stem diameter, bark thickness, and habitat preference of five species typical of long-leaf pine savannas, and six species characteristic of adjacent wetlands (pocosins), and calculated relative bark thickness, the inner bark proportion, radial growth, and bark accumulation of each species. We hypothesized that savanna species have thicker bark and greater relative investment in inner bark than pocosin species, because fires occur more frequently in savannas than pocosins. As hypothesized, savanna species have relatively thicker bark than pocosin species. Relative bark thickness and the rate of bark accumulation were correlated with the mean location of a species along the pocosin-to-savanna gradient. However, the inner bark proportion did not differ between savanna and pocosin species. Our results indicate that relative bark thickness is likely the primary bark trait affecting fire-induced topkill and influencing the distribution of species along the pocosin-to-savanna gradient.}, number={1}, journal={FIRE ECOLOGY}, author={Schafer, Jennifer L. and Breslow, Bradley P. and Hohmann, Matthew G. and Hoffmann, William A.}, year={2015}, pages={74–87} }
 @article{schafer_breslow_hollingsworth_hohmann_hoffmann_2014, title={Size-dependent enhancement of water relations during post-fire resprouting}, volume={34}, ISSN={["1758-4469"]}, DOI={10.1093/treephys/tpu015}, abstractNote={In resprouting species, fire-induced topkill causes a reduction in height and leaf area without a comparable reduction in the size of the root system, which should lead to an increase in the efficiency of water transport after fire. However, large plants undergo a greater relative reduction in size, compared with small plants, so we hypothesized that this enhancement in hydraulic efficiency would be greatest among large growth forms. In the ecotone between long-leaf pine (Pinus palustris Mill.) savannas and wetlands, we measured stomatal conductance (gs), mid-day leaf water potential (Ψleaf), leaf-specific whole-plant hydraulic conductance (KL.p), leaf area and height of 10 species covering a range of growth forms in burned and unburned sites. As predicted, KL.p was higher in post-fire resprouts than in unburned plants, and the post-fire increase in KL.p was positively related to plant size. Specifically, large-statured species tended to undergo the greatest relative reductions in leaf area and height, and correspondingly experienced the greatest increases in KL.p. The post-fire increase in KL.p was smaller than expected, however, due to a decrease in absolute root hydraulic conductance (i.e., not scaled to leaf area). The higher KL.p in burned sites was manifested as an increase in gs rather than an increase in Ψleaf. Post-fire increases in gs should promote high rates of photosynthesis for recovery of carbohydrate reserves and aboveground biomass, which is particularly important for large-statured species that require more time to recover their pre-fire size.}, number={4}, journal={TREE PHYSIOLOGY}, author={Schafer, Jennifer L. and Breslow, Bradley P. and Hollingsworth, Stephanie N. and Hohmann, Matthew G. and Hoffmann, William A.}, year={2014}, month={Apr}, pages={404–414} }
 @article{schafer_breslow_just_hohmann_hollingsworth_swatling-holcomb_hoffmann_2013, title={Current and Historical Variation in Wiregrass (Aristida stricta) Abundance and Distribution Is Not Detectable from Soil delta C-13 Measurements in Longleaf Pine (Pinus palustris) Savannas}, volume={78}, ISSN={["1938-4386"]}, DOI={10.2179/12-021}, abstractNote={ABSTRACT Plant species distributions and transitions between vegetation types are determined by numerous factors, including disturbances such as fire. Documentation of past changes in the distribution and structure of fire-dependent ecosystems is necessary to assess the success of land management in maintaining historic vegetation types. In our study system—longleaf pine (Pinus palustris)-wiregrass (Aristida stricta) savannas and embedded wetlands (i.e., pocosins)—wiregrass is dependent on frequent burning. We used soil carbon (C) isotopes to test for past changes in the abundance of wiregrass and for shifts in the ecotone between savanna and pocosin in four sites at Fort Bragg, North Carolina. Wiregrass has a C4 photosynthetic pathway and therefore produces organic matter enriched in 13C compared to other dominant species in the community that have a C3 photosynthetic pathway. At each of the four sites, we measured profiles of soil δ13C to a depth of 1 m at four locations along the vegetation gradient from upland savannas to lowland pocosins. Surface soil δ13C, which reflects C inputs from current vegetation, did not differ along the gradient despite a decrease in wiregrass cover from savanna, where it is abundant, to pocosin, where it is absent. Enrichment of soil δ13C with depth was indistinguishable from effects of decomposition, indicating that past variation in the abundance and distribution of wiregrass was not detectable in our study sites. Our results suggest that wiregrass currently does not produce, and historically has not produced, enough biomass to influence soil δ13C values along the savanna-pocosin gradient.}, number={1}, journal={CASTANEA}, author={Schafer, Jennifer L. and Breslow, Bradley P. and Just, Michael G. and Hohmann, Matthew G. and Hollingsworth, Stephanie N. and Swatling-Holcomb, Samantha L. and Hoffmann, William A.}, year={2013}, month={Mar}, pages={28–36} }