Geography of Pinus elliottii Engelm. and Pinus palustris Mill. leaf life-spans in the southeastern USA

Aim Past studies have investigated differences in leaf life-spans between deciduous and evergreen species. Environmental controls such as light, temperature, and nutrient and moisture availability explain differences in leaf life-spans between species. This study examined intraspecific leaf life-spans across climate and nutrient gradients within the geographical range of Pinus palustris Engelm (longleaf pine) and Pinus elliottii Mill. (slash pine). Location Five study areas in the southeastern United States were selected along the north-south geographical range of Pinus elliottii and Pinus palustris. Methods Leaf life-span was calculated based on stand inventories and annual litterfall totals for each site, and allometric relationships between d.b.h. and foliar biomass. Results Leaf life-span of P. elliottii ranged from 1.28 to 1.95 years between sites. Leaf life-span of P. palustris varied by nearly a factor of 5 between the study site with the lowest and highest value (0.58-2.49 years). ANOVA indicated that leaf life-spans of P. elliottii were not significantly different among sites. In contrast, ANOVA indicated a significant difference for P. palustris leaf life-spans among sites (P < 0.05). The Tukey multiple comparisons tests showed that 2 study areas were the only pair of P. palustris sites with a significant difference in leaf life-spans. Main conclusions The geographical variation in leaf life-spans between two species illustrates the different phenotypic responses to environmental controls. The variation in leaf life-spans by individuals of P. palustris across a geographical range illustrated in this study suggests that P. palustris may exhibit a greater phenotypic plasticity than P. elliottii.