Assessing the influence of climate on cone production of longleaf pine forests
Longleaf pine (Pinus palustris Mill.) forests have been identified as a societal, economical, and ecological resource in the southeastern United States. One major factor inhibiting contemporary efforts to restore native forests is the sporadic cone production of longleaf pine. It is difficult to evaluate the climate contribution to seed production since the reproduction process is lengthy and complicated. Here, we utilize a quantitative method previously applied to understanding complex systems to assess the influence of climate on longleaf pine cone production at five long-term monitoring sites in the southeastern United States. Our results indicate that climatic factors (annual air temperature and annual precipitation) have a stronger influence on cone production than nonclimatic factors. However, the contribution of climate to cone production varied with time at each site. Greater contribution of climate was related to low cone production at three of five sites. However, the scaling relationship between climate and cone production is not statistically significant. The potential maximum cone production can be estimated by this method, such as 250 cones per tree for Blackwater River State Forest and 150 cones for Jones Center. Our results provide a new understanding of cone production in longleaf pine forests and can be utilized to identify stands with high natural regeneration potential.