Miscommunication and confusion about longleaf pine growth: Using 40 years of real data to characterize long-term stand development

Background/Question/Methods

If you answer yes to any of the following questions, then you need, or should be interested in a longleaf pine (Pinus palustris Mill.) growth model. Are you interested in knowing how your trees are growing?  Have you been told that site index is a static number? Are you interested in knowing how many trees per hectare you want, or how many to plant? Do you think all older trees grow slowly and stagnate? Are you interested in knowing how natural mortality may affect your stand?  Do you want to know how different tree densities could affect ground cover? Are you interested in knowing how long it could take to grow a potential cavity tree for a red-cockaded woodpecker? Would you be happy to learn that there has been an increase in longleaf pine growth over the past 2 decades compared to the previous 2 decades? Have you been told that existing models or models for other species will be “good enough”? Due to misconceptions and too much miscommunication about longleaf pine, an effort has been underway using 40 years of longleaf pine growth data to develop models that provide accurate growth information.

Results/Conclusions

Growth models provide valuable information for the development of management plans and proper valuation of long-rotation longleaf stands.  The demands of the longleaf community are greater than those for other species due to the broad geographic range, differences in stand origin (natural vs. plantation), long-rotation management options, potential inclusion of multiple thinnings, habitat management treatments, and unique longleaf characteristics such as the grass-stage. Models are being developed from the U.S. Forest Service Regional Longleaf pine Growth Study (RLGS) which was initiated in 1964.  This study has been examining naturally-regenerated stands where plots have been maintained across a range of ages, site indices and densities.  Current model development is using the strong foundation of past modeling efforts to create models that are adaptable to these different situations.  These include the use of breast-height age, accounting for stand age structure when appropriate, and development of variable-density models to account for thinning and different sources of mortality.  Models are also being structured so they are useful foundations for inclusion of modifiers that can address regional differences and a diversity of management options.