Patching up the gap : sapling dynmaics of longleaf pine patches in a southwest Georgia forest
No Thumbnail Available
Authors
Meeting name
Sponsors
Date
Journal Title
Format
Thesis
Subject
Abstract
Natural regeneration of longleaf pine (Pinus palustris Mill.) often develops as discrete, aggregated patches within uneven-aged stands. While longleaf pine regeneration dynamics have been well-studied over the past few decades, few studies have considered the growth and mortality of saplings within such patches. Our objectives were to: 1) determine the age demographics of saplings within patches, 2) model the relationship between sapling age and diameter, and 3) evaluate the potential influence of climate, competition, and prescribed fire on sapling diameter growth. We stem-mapped trees on six plots, each of which encompassed a 0.76- ha area, within a 121.4-ha harvest area at The Jones Center at Ichauway to determine how competition based on spatial position and tree size influenced sapling growth. We also destructively sampled a subset of saplings on three of the six plots, taking a cross section of each cut sapling 25 cm above groundline. We then used tree ring analysis, regression modeling, and distance-weighted size ratio indices to address objectives 2 and 3. We determined that our sapling patches were relatively even-aged with some variation in the time that trees emerged from the grass stage. Timing of emergence from the grass stage was a primary factor influencing sapling growth within our patches, with the largest saplings being the earliest to emerge from the grass stage. Competition among saplings, which was based on distance and size of competitors, was correlated with reductions in sapling growth. We also detected a weak facilitative effect of hardwood neighbors on sapling growth. Prescribed fire was correlated with sapling growth reductions, but tolerance to fire increased as saplings grew in radial size, suggesting that young longleaf pine trees transition from fire susceptibility to fire resilience during the sapling stage.
Table of Contents
DOI
PubMed ID
Degree
M.S.