Treesearch

We used computer simulations to test the efficacy of multivariate statistical methods to detect, quantify, and map spatial variability of forest stands. Simulated stands were developed of regularly-spaced plantations of loblolly pine (Pinus taeda L.). We assumed no affects of competition or mortality, but random variability was added to individual tree characteristics. The purpose of simulating stands without these complex interactions was to provide a controlled situation to measure the efficacy of our methods. We examined redundancy analysis, partial redundancy analysis, and spatially...

Predicting the effects of silvicultural choices on tree regeneration has traditionally been difficult with the tools currently available to foresters. In an effort to improve this, we have developed a simulation framework based on hypotheses of stand dynamics for several species found in the Missouri Ozarks. This framework includes separate modules for establishment, growth, and mortality. Within the establishment module, empirical parameters are used to stochastically simulate regeneration establishment following a variety of harvest-based silvicultural manipulations. A pre-disturbance...

Site index is the most common metric of site productivity in loblolly pine plantations. Generally applied as a constant for a particular stand, it provides an overall measure of a site’s ability to grow trees. It is well known, however, that even the most uniform stands can have considerable variation in site index due to soil factors that influence microsite, variation in genetics from tree to tree, or the uneven application of silvicultural treatments. To better account for such variability, input options to the PTAEDA (version 4.1), an individual tree growth and yield model, were...

Information provided by growth and yield models is the basis for forest managers to make decisions on how to manage their forests. Among different types of growth models, whole-stand models offer predictions at stand level, whereas individual-tree models give detailed information at tree level. The well-known logistic regression is commonly used to predict tree survival probability. In addition to the maximum likelihood approach, a new approach called CDF regression was introduced here to estimate parameters of the tree survival equation. Each of the two above approaches was evaluated as...

Increasingly, fire managers are using natural ignitions in conjunction with prescribed burns to restore and maintain fire-adapted ecosystems. Increased fuel loading from fire suppression and increasing drought indices associated with climate change, however, may cause natural ignitions to burn with greater intensity and severity. Managers must weigh risk factors versus benefits before allowing a lightning ignition to burn under these conditions. During the severe drought of 2011, the Ouachita National Forest had more lightning ignitions than any year in recorded history. While most were...

An updated whole stand growth and yield system for planted longleaf pine (Pinus palustris) was developed from permanent plot data collected annually over a 13 to 16 year period. The data set consists of 15 intensively managed longleaf pine plantations that are located in Lee, Worth, Mitchell, and Baker counties in southwest Georgia. Stand survival, dominant height, basal area and cubic foot volume yield models were developed for both low and high planting densities. Model prediction error remained low for both planting density classes. Yield models are an improvement over those published...

In the shelterwood-burn technique, a moderate- to high-intensity growing-season prescribed fire is essential to achieve desired oak regeneration goals. These levels of fire intensity are dependent on the increased fuel loadings created by the preceding first removal cut. However, the loadings of forest fuels and their fluctuation during implementation of the shelterwood-burn technique have not been studied. From 1994 to 1997, three mature uncut oak stands, three oak shelterwoods, and three burned oak shelterwoods in central Virginia were examined to determine fuel loadings before, during,...

Mastication is an increasingly common fuels treatment that redistributes ‘‘ladder’’ fuels to the forest floor to reduce vertical fuel continuity, crown fire potential, and fireline intensity. Despite its widespread adoption, it remains unclear how mastication impacts fuels, fire behavior, or plant communities across Southeastern forest ecosystems. We evaluated these effects by reviewing studies conducted across Southeastern pine forests. Mastication is typically applied to reduce fire hazard prior to reintroducing fire to long-unburned sites and to promote desired herbaceous groundcover...

Forest Inventory and Analysis (FIA) data were summarized for southeastern U.S. counties which had their centroids within coastal watersheds (8-digit HUCs).

Longleaf pine (Pinus palustris Mill.) forests are fire-dependent ecosystems because frequent surface fires prevent other species from being recruited into the canopy. The successful recruitment of longleaf pine has been attributed mainly to its unique fire adaptation – the grass stage. It is commonly believed that, while in the grass stage, longleaf pine seedlings build carbon reserves in the taproot, and this reserve is then mobilized to support fast height growth so that the apical meristem can quickly elevate above flame height. Based on this perception, we hypothesize that when...