Modeling Survival, Yield, Volume Partitioning and Their Response to Thinning for Longleaf Pine Plantations

Carlos Gonzalez-Benecke,Daniel Leduc,Lisa Samuelson,Wendell Cropper,Timothy Martin,Salvador Gezan

doi:10.3390/f3041104

Carlos Gonzalez-Benecke, Daniel Leduc + Show 4 more

Open Access

https://doi.org/10.3390/f3041104

Copy DOI

Abstract

Longleaf pine (Pinus palustris Mill.) is an important tree species of the southeast U.S. Currently there is no comprehensive stand-level growth and yield model for the species. The model system described here estimates site index (SI) if dominant height (Hdom) and stand age are known (inversely, the model can project Hdom at any given age if SI is known). The survival (N) equation was dependent on stand age and Hdom, predicting greater mortality on stands with larger Hdom. The function that predicts stand basal area (BA) for unthinned stands was dependent on N and Hdom. For thinned stands BA was predicted with a competition index that was dependent on stand age. The function that best predicted stand stem volume (outside or inside bark) was dependent on BA and Hdom. All functions performed well for a wide range of stand ages and productivity, with coefficients of determination ranging between 0.946 (BA) and 0.998 (N). We also developed equations to estimate merchantable volume yield consisting of different combinations of threshold diameter at breast height and top diameter for longleaf pine stands. The equations presented in this study performed similarly or slightly better than other reported models to estimate future N, Hdom and BA. The system presented here provides important new tools for supporting future longleaf pine management and research.

Highlights

Longleaf pine (Pinus palustris Mill.) once dominated forests in the southeast U.S, occupying about36 million ha prior to European settlement [1]
Non-linear versions of the models presented in Equation 6 (BA) and 8 (VOL) were evaluated, but these resulted in no improvement in model performance, natural logarithm-transformed response variables were used
Bringing existing longleaf pine stands under management and restoring longleaf pine stands from degraded or otherwise converted forest stands is a priority for a number of land management entities in the southeastern U.S [37,38]

Summary

Introduction

Longleaf pine (Pinus palustris Mill.) once dominated forests in the southeast U.S, occupying about36 million ha prior to European settlement [1]. Longleaf pine (Pinus palustris Mill.) once dominated forests in the southeast U.S, occupying about. There are only about 1.2 million ha of longleaf pine stands left [2], extending along the Gulf and Atlantic Coastal Plains from Virginia, south into central Florida, and north into the Piedmont and mountains of northern Alabama and Georgia [2]. In order to improve stand management planning, researchers, managers and landowners need reliable information about stand dynamics and development. As forest management decisions are based on information about current and future resource conditions, forest growth and yield modeling plays an important role by quantifying and summarizing relationships observed in field studies, and by providing stand projections under alternative management scenarios. Whole-stand-level growth and yield models predict future yields as a function of previous stand-level attributes such as age, stand density and site quality [3]

Objectives

Methods

Results

Conclusion