Long-term effects of fire and fire-return interval on population structure and growth of longleaf pine (Pinus palustris)

2010 ◽  
Vol 40 (7) ◽  
pp. 1410-1420 ◽  
Author(s):  
Chelcy R. Ford ◽  
Emily S. Minor ◽  
Gordon A. Fox

We investigated the effect of fire and fire frequency on stand structure and longleaf pine ( Pinus palustris P. Mill.) growth and population demography in an experimental research area in a southwest Florida sandhill community. Data were collected from replicated plots that had prescribed fire-return intervals of 1, 2, 5, or 7 years or were left unburned. Experimental treatment burns have been ongoing since 1976. Plots were sampled to estimate species distribution, stand structure, and longleaf pine density in four developmental stage classes: grass, bolting, small tree, and large tree. Tree-ring growth measurements in combination with burn history were used to evaluate the effects of fire and fire-return interval on basal area increment growth. Fire-return interval impacted stand structure and longleaf pine population structure. Our results suggest that recruitment from the bolting stage to later stages may become adversely affected with very frequent fires (e.g., every 1 or 2 years). Although adult tree productivity was negatively impacted during fire years, tree growth during years between fire events was resilient such that growth did not differ significantly among fire-return intervals. Our study shows that the longleaf pine population as a whole is strongly regulated by fire and fire-return interval plays a key role in structuring this population.

1980 ◽  
Vol 4 (2) ◽  
pp. 77-79
Author(s):  
Robert C. Sparks ◽  
Norwin E. Linnartz ◽  
Harold E. Harris

Abstract Pruning and thinning a young natural stand of longleaf pine (Pinus palustris Mill.) in southwest Louisiana had little influence on height. However, diameter growth was reduced substantially as pruning intensity or stocking rate increased up to 25-percent live crown and 200 stems per acre, respectively. Improved diameter growth at lower stocking rates was not sufficient to equal the total basal area increment of 200 trees per acre.


2012 ◽  
Vol 49 (No. 9) ◽  
pp. 395-402 ◽  
Author(s):  
W. Keith Moser ◽  
Yu Chui Kwan

We examined the impacts of variation in overstory structure and burning regime on understory vegetation in the longleaf pine (Pinus palustris Mill.) forest of the Okefenokee National Wildlife Refuge in southeastern Georgia, U.S.A. On sandy upland sites surrounding the Okefenokee Swamp and on islands, we established five randomly-located 0.04-ha plots within each of six study areas. The plots varied in overstory density, past management and fire regime. We measured overstory tree size of longleaf pines in the 0.04-ha plots and percent cover of ground cover species in five 1-m2 subplots nested within each 0.04-ha plot. We also calculated diversity indices for the ground cover species. There was no significant relationship between overstory basal area and any diversity measure. Even at the subplot level, there was no significant relationship observed between the diversity measures and distance to the nearest tree, presumably a surrogate for overstory density. The diameter (DBH) of the nearest tree exhibited a slight influence over the Shannon Index, and the nearest tree’s height was significantly related to evenness in each subplot. There were varied relationships between individual species and fire regime or nearest tree measurements. There was a definite, but statistically insignificant, trend of decreasing diversity with increasing years since the last burn. Height of the nearest tree positively influen­ced evenness, probably reflecting the influence of stochasticity and amount of needle deposition (influencing fire behavior) over a wide area. Within the generally equal fire-return interval across sites, individual fire-events and site-specific behavior apparently influence understory diversity. It is not surprising that the last burn would affect species richness, even more so than the number of growing-season burns, other studies support this observation. The presence of obligate seeding and (clonal) sprouting as dominants in the ground cover suggests that the fire-return interval is not regular. The cycling of fire-return intervals, even within the manage­ment-prescribed 2- to 4-year range, and the variation by microsite appear to provide sufficient variability of disturbance to create diversity in the ground-level cohort. Site-specific relationships between particular species and the nearest tree suggest that even a narrowly-prescribed fire management regime can provide sufficient diversity.


2001 ◽  
Vol 25 (3) ◽  
pp. 122-130 ◽  
Author(s):  
James D. Haywood ◽  
Finis L. Harris ◽  
Harold E. Grelen ◽  
Henry A. Pearson

Abstract From 1962 through 1998, 20 prescribed burns were applied in a natural stand of longleaf pine (Pinus palustris Mill.) to determine the effects of various fire regimes on the forest plant community. The original longleaf seedlings regenerated from the 1955 seed crop and were growing in a grass-dominated cover when the study began. By 1999, prescribed burning in March and May resulted in a significantly greater stocking of longleaf pine (203 trees/ac) than on the unburned and July burned treatments (72 trees/ac) (α = 0.05). Fire arrested the growth of natural loblolly pine (P. taeda L.) and hardwoods, but loblolly pines and hardwoods of at least 4 in. dbh added 70 ft2/ac of basal area on the unburned plots. Thus, total woody basal area was significantly greater on the unburned (117 ft2/ac) and May burned (132 ft2/ac) treatments than on the July burned treatment (66 ft2/ac); basal area was intermediate on the March burned treatment (97 ft2/ac). Pine volume was 4,315, 2,870, 2,652, and 1,970 ft3 inside-bark/ac on the May burned, March burned, unburned, and July burned treatments, respectively, but these differences were not statistically significant (P = 0.06). There was only 11 lb/ac of herbaceous plants on the unburned plots. Herbaceous plants averaged 993 lb/ac on the three burned treatments, with pinehill bluestem (Schizachyrium scoparium var. divergens [Hack] Gould) being the most common herbaceous plant. We believe the chief influence of burning in this natural longleaf pine forest was not on pine yield but how fires influenced overall stand structure and species composition. South. J. Appl. For. 25(3):122–130.


2007 ◽  
Vol 31 (1) ◽  
pp. 28-38 ◽  
Author(s):  
John D. Shaw ◽  
James N. Long

Abstract We developed a density management diagram (DMD) for longleaf pine (Pinus palustris P. Mill.) using data from Forest Inventory and Analysis plots. Selection criteria were for purity, defined as longleaf pine basal area (BA) that is 90% or more of plot BA, and even-agedness, as defined by a ratio between two calculations of stand density index. The diagram predicts stand top height (mean of tallest 40 trees/ac) and volume (ft3/ac) as a function of quadratic mean diameter and stem density (trees/ac). In this DMD we introduce a “mature stand boundary” that, as a model of stand dynamics, restricts the size–density relationship in large-diameter stands more than the expected self-thinning trajectory. The DMD is unbiased by geographic area and therefore should be applicable throughout the range of longleaf pine. The DMD is intended for use in even-aged stands, but may be used for uneven-aged management where a large-group selection system is used. Use of the diagram is illustrated by development of density management regimes intended to create and maintain stand structure desirable for the endangered red-cockaded woodpecker (Picoides borealis).


2002 ◽  
Vol 32 (11) ◽  
pp. 1984-1991 ◽  
Author(s):  
Michael A Battaglia ◽  
Pu Mou ◽  
Brian Palik ◽  
Robert J Mitchell

Spatial aggregation of forest structure strongly regulates understory light and its spatial variation in longleaf pine (Pinus palustris Mill.) forest ecosystems. Previous studies have demonstrated that light availability strongly influences longleaf pine seedling growth. In this study, the relationship between spatial structure of a longleaf pine forest and spatial pattern of understory light availability were investigated by comparing three retention harvest treatments: single-tree, small-group, large-group, and an uncut control. The harvests retained similar residual basal area but the spatial patterns of the residual trees differed. Hemispherical photographs were taken at 300 stations to calculate gap light index (GLI), an estimate of understory light availability. Stand-level mean, variation, and spatial distribution of GLI were determined for each treatment. By aggregating residual trees, stand mean GLI increased by 20%, as well as its spatial variation. Spatial autocorrelation of GLI increased as the size of the canopy gaps increased and the gaps were better defined; thus, the predictability of GLI was enhanced. The ranges of detrended semivariograms were increased from the control to the large-group harvest indicating the spatial patterns of understory GLI became coarser textured. Our results demonstrated that aggregated canopy structure of longleaf pine forest will facilitate longleaf pine seedling regeneration.


2011 ◽  
Vol 28 (2) ◽  
pp. 92-96 ◽  
Author(s):  
Aaron R. Weiskittel ◽  
Laura S. Kenefic ◽  
Rongxia Li ◽  
John Brissette

Abstract The effects of four precommercial thinning (PCT) treatments on an even-aged northern conifer stand in Maine were investigated by examining stand structure and composition 32 years after treatment. Replicated treatments applied in 1976 included: (1) control (no PCT), (2) row thinning (rowthin; 5-ft-wide row removal with 3-ft-wide residual strips), (3) row thinning with crop tree release (rowthin+CTR; 5-ft-wide row removal with crop tree release at 8-ft intervals in 3-ft-wide residual strips), and (4) crop tree release (CTR; release of selected crop trees at 8×8-ft intervals). PCT plots had more large trees and fewer small trees than the control in 2008. There were no other significant differences between the rowthin and control. The rowthin+CTR and CTR treatments had lower total and hardwood basal area (BA) and higher merchantable conifer BA than the control. CTR also resulted in more red spruce (Picea rubens [Sarg.]) and less balsam fir (Abies balsamea [L.]) than the other treatments. Although stand structures for rowthin+CTR and CTR were similar, the percentage of spruce in CTR was greater. Although the less-intensive rowthin+CTR treatment may provide many of the same benefits as CTR, the latter would be the preferred treatment if increasing the spruce component of a stand is an objective. Overall, early thinning treatments were found to have long-term effects on key stand attributes, even more than 30 years after treatment in areas with mixed species composition and moderate site potential.


1993 ◽  
Vol 17 (1) ◽  
pp. 10-15 ◽  
Author(s):  
William D. Boyer

Abstract Well-stocked mature longleaf pine (Pinus palustris Mill.) stands were cut to five residual basal areas in 1957, namely 9, 18, 27, 36, and 45 ft² per ac, to observe the effect of stand density on seed production and seedling establishment. Seedlings, mainly from the 1955 or 1961seed crops, were established in treated stands. All pines on net 0.9 ac plots were remeasured in 1991 to determine the effect of residual pine density on development of the regeneration. Even the lightest residual overstory converted the structure of 29- to 35- yr-old ingrowth into the reverse-Jdiameter class distribution characteristic of uneven-aged stands. Four or six residual trees, now comprising 7 to 10 ft² basal area (ba)/ac, reduced ingrowth basal area to about half that of same-aged stands released from overstory competition. Merchantable volume of ingrowth under theselow residual densities averaged 40% of that in released stands. Mean annual per ac volume increment of ingrowth averaged 21 to 22 ft³ under the 9 ft² density but did not exceed 7 ft³ under any residual density above this. The potential impact of significant growth reductionsshould be taken into account when considering uneven-aged management methods for longleaf pine. South. J. Appl. For. 17(1):10-15.


2019 ◽  
Vol 11 (15) ◽  
pp. 1803 ◽  
Author(s):  
John Hogland ◽  
Nathaniel Anderson ◽  
David L. R. Affleck ◽  
Joseph St. Peter

This study improved on previous efforts to map longleaf pine (Pinus palustris) over large areas in the southeastern United States of America by developing new methods that integrate forest inventory data, aerial photography and Landsat 8 imagery to model forest characteristics. Spatial, statistical and machine learning algorithms were used to relate United States Forest Service Forest Inventory and Analysis (FIA) field plot data to relatively normalized Landsat 8 imagery based texture. Modeling algorithms employed include softmax neural networks and multiple hurdle models that combine softmax neural network predictions with linear regression models to estimate key forest characteristics across 2.3 million ha in Georgia, USA. Forest metrics include forest type, basal area and stand density. Results show strong relationships between Landsat 8 imagery based texture and field data (map accuracy > 0.80; square root basal area per ha residual standard errors < 1; natural log transformed trees per ha < 1.081). Model estimates depicting spatially explicit, fine resolution raster surfaces of forest characteristics for multiple coniferous and deciduous species across the study area were created and made available to the public in an online raster database. These products can be integrated with existing tabular, vector and raster databases already being used to guide longleaf pine conservation and restoration in the region.


2018 ◽  
Vol 11 (1) ◽  
pp. 1 ◽  
Author(s):  
Brooke McCalip ◽  
Brian P. Oswald ◽  
Kathryn R. Kidd ◽  
Yuhui Weng ◽  
Kenneth W. Farrish

Longleaf pine (Pinus palustris) savannas were once dominant across the southeastern U.S., including East Texas and parts of western and central Louisiana. The diverse understory associated with these historical savannas may occasionally be seen today, but not often in longleaf pine ecosystems. This project aimed to define east Texas site characteristics that are necessary to support these ecosystems with a dense and diverse herbaceous understory with little to no midstory cover. Fifty-nine plots across three study sites were established to evaluate the influence of overstory cover, basal area, aspect, elevation, and slope on the number of plant genera present. Forest structure and site characteristics had significant effects on the number of plant genera found. The number of genera increased with higher elevation and slope; as elevation increased, there was a decline in basal area and overstory cover, leading to a more diverse, understory layer. In order to re-establish and maintain a diverse, herbaceous understory in longleaf pine savannas, sites with more open canopies and on slopes with the most solar exposure should be given priority, particularly when planting desired understory species.


2000 ◽  
Vol 24 (2) ◽  
pp. 86-92 ◽  
Author(s):  
James D. Haywood ◽  
Harold E. Grelen

Abstract Prescribed burning treatments were applied over a 20 yr period in a completely randomized field study to determine the effects of various fire regimes on vegetation in a direct seeded stand of longleaf pine (Pinus palustris Mill.). Seeding was done in November 1968. The study area was broadcast-burned about 16 months after seeding. The initial research treatments were applied in 1973, and as many as 12 research burns were applied through 1993. Pines were measured in March 1995. Prescribed burning resulted in a greater stocking of longleaf pine (an average of 598 trees/ac) on treated plots than on unburned plots (30 trees/ac). However, on the burned treatments, longleaf pines were significantly smaller (2.5 ft3/tree of stemwood) than were the unburned trees (3.7ft3/tree of stemwood). Half of the treated plots were burned in early March, and the other half were burned in early May. Seasons of burning did not significantly influence longleaf pine stocking. However, use of fire in May resulted in significantly greater basal area (100 ft2/ac) and stemwood production (1,921 ft3/ac) than burning in March (59 ft2/ac and 909 ft3/ac). Fire effectively kept natural loblolly pine (P. taeda L.) seedlings from reaching sapling size, but loblolly saplings and poles dominated the unburned plots (710 trees/ac). When all pines were considered on all treatments, stocking ranged from 467 to 740 trees/ac, but stocking was not significantly different among treatments. The unburned plots had significantly greater total basal area (149 ft2/ac) and stemwood productivity (2,918 ft3/ac) than the burned treatments (82 ft2/ac and 1,459 ft3 /ac). Likewise, hardwoods that were at least 1 in. dbh were more common on unburned p lots (327 stems/ac) than on burned treatments (58 stems/ac). South. J. Appl. For. 24(2):86-92.


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