Longleaf Pine Stands Research Articles

Currently Available Site Index Equations That Use On-Site Tree Measurements for Naturally Regenerated Longleaf Pine in Its Historical Range

The longleaf pine (Pinus palustris P. Mill.) forest type occupied a much greater area in the United States prior to the arrival of Europeans, estimated to be around 37.2 million hectares. This area has been greatly reduced, and these ecosystems now occupy only about 1.2 to 1.6 million hectares. However, there has been a great interest in the restoration of this forest type mainly due to concerns about the loss of ecosystem services associated with these forests; the improved seedling quality and yield potentials bolster those efforts. Beyond that, existing stands are actively managed through different types of practices, including thinnings, prescribed burns often to manipulate the vegetation of other species, and the various timings of clearcuts. Thus, managers need tools to estimate site quality and ultimately productivity. A commonly used measure of site quality is site index, or the height of some defined dominant portion of the stand at a standardized base or index age. The primary objectives are to summarize the 16 existing equations to estimate site index and dominant height in naturally regenerated longleaf pine stands and to examine and visually compare their predicted behavior across a range of site quality and age conditions. Important considerations when using site index of anamorphism and polymorphism as well as base-age invariance are reviewed. Biologically, polymorphism is often considered advantageous since for many species differences in site quality not only result in different asymptotic dominant heights, but also varying rates in their approach to the asymptote. Of the 16 equations examined, only nine of them were polymorphic in nature, but all equations were base-age invariant. There is not an individual equation that is clearly superior because, for instance, it is either anamorphic in nature, is polymorphic but developed based on anamorphic curves, fit using data obtained from temporary plots, or it is limited geographically. Given these limitations, others can use this publication as a reference to determine which equation they feel is best for their particular situation.

Differential effects of fire regime and site conditions on bark beetles (Coleoptera: Curculionidae) in a longleaf pine (Pinus palustris Mill.) ecosystem

Longleaf pine (Pinus palustris Mill.) ecosystems in the southeastern U.S. are fire-driven. Frequent prescribed fire or lack thereof through shifts in fire regimes may have consequences for tree health and associated herbivorous subcortical beetles (Coleoptera: Curculionidae). Yet, interactions between these ecologically and economically important beetles and prescribed fire in the southeastern U.S. are not well documented. We assessed the effects of various fire regimes, specifically of frequent fire, fire exclusion, and fire reintroduction, on bark and root-feeding beetles in mature longleaf pine stands in two edaphic types (mesic and xeric) in southwestern Georgia. We employed an information theoretic statistical approach to determine the effects of site conditions, as defined by both soil properties and stand structure, and prescribed burning on trap catches of subcortical beetles by species. We trapped a total of 141,611 beetles, indicating that subcortical beetles are abundant in this ecosystem. While the highest trap catches for three Ips beetle species were in the xeric fire-exclusion treatment, catches of I. grandicollis (Eichhoff) were similar at both sites for the fire-exclusion treatment. For the fire-exclusion treatment, I. avulsus (Eichhoff) and I. calligraphus (Germar) catches were 2–10 times higher at the xeric than mesic sites. Orthotomicus caelatus (Eichhoff) and Dendroctonus terebrans (Olivier) catches were 1.1–2.4 times higher in frequent-fire than fire-exclusion treatments. Root-feeding weevils, Pachylobius picivorus (Germar) and Hylobius pales (Herbst), exhibited opposite trends with catches higher and lower in burned treatments, respectively. Ips calligraphus were positively associated with percent basal area of understory trees, indicating this species may benefit from fire exclusion. Ips avulsus catches were negatively correlated with total basal area, suggesting this species may benefit from more open habitats like those facilitated by frequent fire. We conclude that both soil properties and stand conditions interact with the fire regime to differentially affect the catches of southeastern bark and root-feeding beetle species in a longleaf pine ecosystem.

Chronic Exclusion of Fire in Longleaf Pine Stands of an Urban Interface: The University of West Florida Campus Ecosystem Study

The dependence of longleaf pine (Pinus palustris) ecosystems on fire is well-understood, and the anthropogenic alteration of fire cycles within its natural range has contributed to its decline. This has been increasingly exacerbated in areas of urban interfaces, wherein the use of prescribed fire can be problematic. The purpose of this study—the University of West Florida Campus Ecosystem Study—was to examine the effects of fire exclusion on longleaf pine in the unique urban interface of a university campus. This was an interconnected series of investigations on the main campus and three associated natural areas that comprised remnant longleaf stands following the cessation of widespread longleaf pine harvesting—120 years ago. This period of chronic fire exclusion allowed for a distinct shift in the stand structure and composition. The open, savanna-like structure of fire-maintained longleaf stands has transitioned into closed-canopy forests with the increased prevalence of southern evergreen oaks (especially live oak—Quercus virginiana) and Magnolia spp., resulting in the complete absence of longleaf regeneration. Fire exclusion also appeared to decrease soil fertility. The significant variation in the mean age of longleaf pine stems on the main campus; natural areas suggest that these natural areas were likely under separate ownership with contrasting land-use history prior to its purchase by the State of Florida for campus construction in 1963.

Wild Turkeys in Texas: Ecology and Management by William P. Kuvlesky Jr. et al.

Reviewed by: Wild Turkeys in Texas: Ecology and Management by William P. Kuvlesky Jr. et al. William D. Gulsby Wild Turkeys in Texas: Ecology and Management. By William P. Kuvlesky Jr., Leonard A. Brennan, José Alfonso Ortega-Santos, Damon L. Williford, Jason B. Hardin, Humberto L. Perotto-Baldivieso, Landon Fritz, Clayton D. Hilton, Fred C. Bryant, Stephan A. Nelle, Brandon M. Mitchell, and Nova Silvy. College Station: Texas A&M University Press, 2020. 232 pp. Figures, tables, maps, bibliography, index. $40.00 cloth. Texas is a large and ecologically diverse state, and home to the Rio Grande, Eastern, and Merriam's wild turkey subspecies. Accordingly, writing a book on the ecology and management of wild turkeys in Texas is a difficult task, but one I think the authors handled well. Part of their success is attributable to the team they assembled, which included academics, agency biologists, and private-sector biologists, each with complementary experience and skillsets. Although the book does an exceptional job providing state-specific information to wild turkey enthusiasts in Texas, it is also a welcome update to Dickson's (1992) book The Wild Turkey: Biology and Management. Specifically, its contents are broadly applicable to those working with any of the three subspecies discussed. This is particularly true for Eastern wild turkeys, as most research has focused on this subspecies; the text reflects that. Most importantly, the book serves as a collection of updated references the reader can use to dive deeper into topics they find relevant. As an academic currently working with wild turkeys, I discovered several relevant journal articles during my review. The chapters are structured well, with the first few covering taxonomy and evolution, life history, and the restoration efforts that led to the populations we enjoy today. Then the authors take a deeper dive into population and behavioral ecology, habitat requirements and management, and diseases and parasites. Of those chapters, I found the population ecology chapter the most useful, as it contained several tables and figures summarizing research findings from studies representing various geographic regions. Wild turkey managers will likely find the chapters on habitat requirements and management particularly helpful, as they discuss everything from water requirements to grazing, brush management, food plots, forest management, and roost site identification and preservation. The chapter on diseases and parasites provides a broad overview but does not dive very deep into any one pathogen. The text closes with chapters on working with private landowners, conservation, research priorities, and the future. These chapters should be especially useful to aspiring and early career wildlife professionals interested in working with turkeys or other wildlife. The text was well supported with relevant images throughout. I found particularly useful those depicting different species of plants important to turkeys, as well as those showing various habitat management techniques and desired vegetation conditions to meet turkey requirements. I had very few criticisms and noted only a couple errors. One was the statement that fire cannot occur more frequently than every three years in longleaf pine–dominated landscapes, which is not true, as some longleaf pine stands are burned annually. I think this may have been an issue with phrasing. Another was that Bermudagrass was referred to as a cool-season grass in one section, which it is not. Otherwise, I found the writing and information to be easy to follow and accurate. Overall, I highly recommend this book to anyone interested in hunting, managing, or researching wild turkeys in Texas or elsewhere. Having a single reference on the shelf with up-to-date information on all aspects of wild turkey ecology and management will come in handy for both new and veteran turkey enthusiasts. I have no doubt I will find myself referencing the book, or using it to identify additional sources of information, on a regular basis. [End Page 61] William D. Gulsby College of Forestry and Wildlife Sciences Auburn University Copyright © 2023 Center for Great Plains Studies

Prescribed fire in longleaf pine ecosystems: fire managers’ perspectives on priorities, constraints, and future prospects

BackgroundProjected trajectories of climate and land use change over the remainder of the twenty-first century may result in conditions and situations that require flexible approaches to conservation planning and practices. For example, prescribed burning is a widely used management tool for promoting longer-term resilience and sustainability in longleaf pine ecosystems of the southeastern United States, but regional stressors such as climatic warming, changing fire conditions, and an expanding wildland-urban interface may challenge its application. To facilitate the development of fire management strategies that account for such changes, we surveyed nearly 300 fire managers to elicit information on the criteria used for prioritizing burn sites, current burning practices and constraints, and expectations for changes in burning opportunities, including those pertaining to climate change and urban growth.ResultsRespondents noted that their most common criteria for selecting longleaf pine stands for burning were fire history, ecosystem health, and fuel reduction, with the presence of threatened and endangered species also given priority by public land managers. Many respondents (38%) cited recent burn frequencies that fall short of historic burn intervals. Barriers to burning included legal, institutional, and managerial constraints, such as proximity to human developments, public concerns, and risk aversion, as well as environmental and resource constraints, including weather, air quality restrictions, and lack of personnel, equipment, or funding. Roughly half of all respondents expect that opportunities to burn will be reduced over the next 30 years, particularly during the growing season. Fire manager perceptions of factors that will limit prescribed burning in the future include a similar suite of constraints, many of which will be affected by projected regional changes in land use and climate.ConclusionsOn an organizational level, burn window availability and resource limitations constrain prescribed burning practices. More broadly, policy and legal frameworks coupled with trends in urbanization and climate change are expected to interact with operational constraints to challenge managers’ abilities to implement landscape-scale burning strategies and achieve restoration goals. Additional research and engagement with fire managers are needed to investigate opportunities for introducing policy flexibility, leveraging shared management interests, and developing creative solutions to expand burning opportunities.

Hidden Costs of Fire Exclusion in Longleaf Pine Forests Linked to Duff And Carbon Management

Abstract The reintroduction of fire to long-unburned pine ecosystems is a silvicultural tool to restore their ecological and economic value. However, if prescribed fire is used after long periods of fire exclusion, high amounts of duff consumed during fire can result in tree stress and mortality. Prescribed burning with a focus on managing duff has therefore been recommended for mitigating negative impacts on overstory trees when fire is reintroduced. We modeled the economic outcomes of different forest management scenarios related to burning for duff management in even-aged longleaf pine stands. We considered five management scenarios in which we varied prescribed fire use, thinnings, mortality rates, and salvage logging. Our findings indicate that burning for duff management without and with thinnings can be considered the most economically viable strategy ($1593/ha–$966/ha).

Re-Assembly of the Longleaf Pine Ecosystem: Effects of Groundcover Seeding on Understory Community, Fire Behavior and Soil Properties

Planting native groundcover is often recommended to restore the understory of longleaf pine stands in the southeastern United States, but the effectiveness of such restoration activities remains poorly evaluated. We conducted a study in 25-year-old longleaf pine plantation stands in Georgia, USA, to examine the effects of seeding native groundcover on understory characteristics, fire behavior and soil properties. In 2015, four stands were seeded with five warm-season C4 grasses and a legume and four served as controls. In Fall 2020, we sampled the understory and analyzed soils collected from these stands, and in Spring 2021, fire behavior was evaluated. A total of 120 species were recorded in the understory across the stands, with the seeded species average foliar cover of 15%. There were no significant differences in species richness and Shannon diversity index of the seeded and control stands but understory species composition changed significantly. Soil properties and fire behavior during the prescribed fire also did not differ significantly between treatments, however, mean flame residence time was higher in seeded stands (108 s). Agricultural legacies of elevated soil P and old-field indicator species were prominent across stands. Overall, seeding had a minor effect on longleaf pine ecological characteristics in five years.

Detecting historic tar kilns and tar production sites using high-resolution, aerial LiDAR-derived digital elevation models: Introducing the Tar Kiln Feature Detection workflow (TKFD) using open-access R and FIJI software

Significant declines in longleaf pine ecosystems during the last 150 years have motivated research and conservation programs focused on their restoration to perceived historical reference conditions. However, the ecological impacts of the historical naval stores industry on forest structure, fire regimes, and fuel conditions are not currently considered in reference conditions constructed from 18th, 19th, and 20th century sources. We present the Tar Kiln Feature Detection workflow (TKFD), an open-access, scripted, and replicable process developed in R and FIJI to identify archaeological tar kilns within high-resolution digital elevation models derived from aerial LiDAR datasets. The workflow is developed and validated on the entirety of the Francis Marion National Forest in coastal South Carolina. The TKFD has identified and measured over 2,700 tar kilns within our 420,000-acre study area and validation studies demonstrate a balanced identification accuracy of 90.6%. This is the most comprehensive dataset of tar production sites in North America and has implications for understanding the historical distribution of longleaf pine stands, anthropogenic impacts on fire and fuels, and the nature of these unique archaeological sites.

United States Forest Service Use of Forest Inventory Data: Examples and Needs for Small Area Estimation

Forest Inventory and Analysis (FIA) data provides robust information for the United States Forest Service’s (USFS) mid-to-broad-scale planning and assessments, but ecological challenges (i.e., climate change, wildfire) necessitate increasingly strategic information without significantly increasing field sampling. Small area estimation (SAE) techniques could provide more precision supported by a rapidly growing suite of landscape-scale datasets. We present three Regional case studies demonstrating current FIA uses, how SAE techniques could enhance existing uses, and steps FIA could take to enable SAE applications that are user-friendly, comprehensive, and statistically appropriate. The Northern Region uses FIA data for planning and assessments, but SAE techniques could provide more specificity to guide vegetation management activities. State and transition simulation models (STSM) are run with FIA data in the Southwestern Region to predict effects of treatments and disturbances, but SAE could support model validation and more precision to identify treatable areas. The Southern Region used FIA to identify existing longleaf pine stands and evaluate condition, but SAE techniques within FIA tools would streamline analyses. Each case study demonstrates a desire to have FIA data on non-forested conditions and non-tree variables. Additional tools to measure statistical confidence would help maximize utility. FIA’s SAE techniques could add value to a widely used data set, if FIA can support key supplements to basic data and functionality.

Can uneven-aged management improve the economic performance of longleaf pine?

Longleaf pine (Pinus palustris Mill.) is a keystone tree species in the Coastal Plain of the southern United States. To reverse habitat loss and restore critically important forest ecosystem services in this region dominated by private landownership, longleaf pine’s economic performance must be addressed. Uneven-aged forest management has been suggested as a viable alternative for longleaf pine, but evidence of its economic performance under uneven-aged versus even-aged management is lacking. Here, we compare the economic viability of three competing longleaf pine management scenarios — thinned even-aged, unthinned even-aged (conservation and non-conservation land objectives), and uneven-aged — considering timber and nontimber benefits. We find that managing existing uneven-aged longleaf pine forests with a 10-year cutting cycle is economically preferred to even-aged management for land conservation ($1643.9·ha−1 versus $1548.8 to $1641.6·ha−1). However, these estimates exclude costs associated with switching to uneven-aged management ($174.3 to $694.9·ha−1), which are considerable. Annual subsidies of between $5 and $22·ha−1 for 50 years would be required to offset costs of conversion to uneven-aged management. For establishment of new longleaf pine stands, an uneven-aged scenario would be the economically preferred management approach, providing higher economic gains ($176.9·ha−1) than unthinned, high-density even-aged management when the primary objective is timber production.

The University of West Florida campus ecosystem study: the college/university campus as a unit for study of the ecology of longleaf pine

College and university campuses comprise a unique urban interface. Property used to establish the University of West Florida (UWF) in Pensacola, Florida, contained numerous ecological features, including natural areas with remnant longleaf pine stands that had undergone recovery from extensive regional logging. The two most prominent of these were studied to quantify the effects of chronic fire exclusion on longleaf pine stands. We addressed these questions: (1) how does composition and structure vary between areas? (2) how do soil characteristics vary between areas and change under fire exclusion? (3) what is the size structure of longleaf pine on the UWF campus? (4) how does the status of longleaf pine at the UWF campus compare to campuses of other colleges/universities within the nature range of longleaf pine? Fifteen 0.04 ha circular plots were established in each area to assess composition and structure and sample mineral soil. All live stems ≥2.5 cm diameter at breast height (DBH) in each plot were identified to species and measured for DBH to the nearest 0.1 cm. Mineral soil was taken to a 5-cm depth, air dried, and analyzed for pH, organic matter, cation exchange capacity, extractable macro- and micronutrients, and extractable aluminum. Basal area and density were closely similar between the natural areas, as was canopy dominance (live oak and longleaf pine), but with contrasting sub-dominant species. Soil analyses revealed no significant differences between natural areas, but suggested that fire exclusion decreased soil organic matter and fertility with establishment of hardwood species. Diameter structure of longleaf pine contrasted sharply between natural areas and with the main campus, suggesting different land-use history. The wide array of approaches to longleaf pine ecology by colleges/universities within its natural range indicates the importance of establishing a longleaf pine consortium to coordinate information.

A history of recurrent, low-severity fire without fire exclusion in southeastern pine savannas, USA

The reintroduction and maintenance of historical surface fire regimes are primary goals of ecological restoration across many open, pine-dominated ecosystems in North America. In the United States, most of these ecosystems experienced long periods of fire exclusion in the 20th century, leaving few locations to serve as reference sites for ecological conditions associated with a continuous history of recurrent, low-severity fire. Here, we present a tree-ring perspective of uninterrupted surface fire activity from three pine savanna sites in the Red Hills Region of northern Florida and southwestern Georgia, USA. Our sites include two old-growth stands of longleaf pine (Pinus palustris): the Wade Tract on Arcadia Plantation and the Larkin Tract on Millpond Plantation. We also sampled the largely second-growth mixed pine savannas of Tall Timbers Research Station. Documentary records for burning at these sites are limited to recent decades and are often incomplete, although regional land-use traditions and scattered historical records indicate frequent fire may have persisted through the 20th century to present day. Fire-scarred cross sections from externally-scarred stumps, dead trees, and live trees provided tree-ring evidence of frequent fires occurring from the beginning of our fire-scar record in the late 19th century onward. Both fire frequency and seasonality were relatively consistent throughout time and among sites. Biennial and annual fire intervals were the most common. Most fire scars occurred in the dormant and early-earlywood portions of the rings, indicating that these fires were human-set fires during the months of January to mid-April, before the main lightning-fire season. Our findings regarding post-settlement fire frequency are consistent with previous estimates of fire frequency during earlier centuries, resulting from lightning and Native American ignitions. We recommend that our sites be used as reference sites for restoration as they are among the relatively few areas in the United States with a continuous history of frequent low-severity fire without 20th century fire exclusion.

Effects of longleaf pine planting density and other factors on stand structure and associated wildlife habitat

The primary objective of many longleaf pine (Pinus palustris) restoration programs is to enhance or restore habitat for wildlife dependent on herbaceous plant communities. Because herbaceous cover is inversely related to canopy cover, restoration programs often place restrictions on longleaf pine planting density. However, the influence of planting density on understory plant communities has been inadequately evaluated. Therefore, we initiated a study to examine the relative influences of planting density and other factors on overall understory composition and forage availability for white‐tailed deer (Odocoileus virginianus) and northern bobwhite (Colinus virginianus) in nine longleaf pine stands throughout the Coastal Plain of Alabama during 2017–2018. We found that coverage of herbaceous plants decreased 3.5%, coverage of woody plants decreased 2.4%, and coverage of northern bobwhite forage plants decreased 1.9% for each 1 m2/ha increase in longleaf pine basal area. However, planting density was not a significant predictor of current basal area, nor coverage of any functional group of plants we examined, likely because current longleaf pine density averaged only 46% (range = 30–64%) of seedling planting density. We did not detect an effect of prescribed fire on stand condition or understory plant communities, likely due to variability in fire timing and frequency. Our findings related to planting density were likely a function of low longleaf pine survival, which is not uncommon. Because of this and the inherent variability in growth rates for young longleaf pine stands, restoration programs should consider placing greater emphasis on post‐planting monitoring and management than planting density.

Avian taxonomic and functional diversity in early stage of longleaf pine (Pinus palustris) stands restored at agricultural lands: variations in scale dependency

In agricultural landscapes, the longleaf pine initiative (LLPI) and the Bobwhite Quail Initiative (BQI) aim to restore longleaf pine forests and early successional habitats, respectively. The early stage of longleaf pine stands and grass and forb vegetation produced by a combination of both restoration programs (LLPI‐BQI) may form habitat conditions favorable to early successional bird species and other birds, increasing avian diversity. We investigated how the LLPI and BQI programs affected taxonomic and functional diversity of birds and abundance of early successional birds (grassland and scrub/shrub species), and what environmental characteristics were associated with the diversity and abundance of birds. Our study was performed at 41 fields in Georgia, United States, during 2001–2002 by considering environmental characteristics at two spatial scales: local‐scale vegetation features and restoration program type (LLPI or LLPI‐BQI) and landscape‐scale vegetation features and landscape heterogeneity. Functional evenness, species richness, and abundance of grassland and scrub/shrub species did not show a clear association with local‐ or landscape‐scale variables. Shannon‐Wiener diversity was slightly influenced by restoration program type (local‐scale variable) with higher value at LLPI‐BQI stands than at LLPI stands despite no significant differences in local vegetation features between those stands. Functional divergence was strongly positively associated with landscape‐scale variables. That is, niche differentiation increased with increasing shrub coverage within a landscape, reducing competition between abundant bird species and others. Our results suggest that although a combination of BQI and LLPI program may have a positive effect on avian taxonomic diversity, it is important to consider shrub vegetation cover within a landscape to improve functional diversity.

Changes in Tree Canopy, Understory Vegetation, and Fuel Composition after 10 Years of Restoration Management in an Old-Growth Mountain Longleaf Pine Forest

The Berry College Longleaf Pine Management Area (BCLPMA) harbors one of the few old-growth mountain longleaf pine (Pinus palustris) forests. Like many remnant longleaf pine forests, Berry College's stands have been fire-suppressed for decades. Since 2003, ∼160 ha of the BCLPMA has been managed using prescribed burns and herbicide injection of hardwoods with the goal of achieving an open, pine-dominated canopy, low duff, litter, and downed woody fuels, increased groundcover vegetation, and improved longleaf pine recruitment. Canopy tree structure was quantified using the point-quarter method in eight managed and five unmanaged stands in 2004 and 2014. Understory vegetation and downed woody fuels were estimated in a subset of these stands in 2003/2004 and 2015 using a plane-intercept method. Data from mountain longleaf pine stands in Alabama were included as external frequently burned and fire-suppressed references. Overall canopy and understory structure of managed stands has moved over time in the direction of frequently burned external reference stands. Longleaf pine basal area has been maintained and importance values have increased with management despite the loss of some canopy trees associated with duff smoldering after burning. Duff and litter levels have decreased substantially in managed stands, while understory plant cover (herbs, grasses, shrubs, vines, and small trees) has increased. Downed woody fuels, which have varied as a result of fire events, have generally dropped in managed stands, whereas longleaf pine recruitment has increased. Results show progress being made in restoring the vegetative structure to desired conditions and may inform analogous restoration projects throughout the mountain longleaf pine ecosystem.

Comparison of climate–growth responses of montane and piedmont longleaf pine (Pinus palustris Mill.) chronologies in North Carolina

Montane longleaf pine tree-ring chronologies exhibit fidelity to summer soil-moisture conditions. Multi-century climate reconstructions using longleaf pine can provide insights into the natural range of moisture variability. Longleaf pine (Pinus palustris Mill.) ring width is associated with temperature and precipitation throughout its range, yet intrasite comparisons of climate and ring growth are limited and have not examined interior (i.e., montane vs. piedmont) populations. Here, we investigated remnant stands of montane and piedmont longleaf pine in central North Carolina and compared their sensitivity to summer climatic variables during 1935–2015. Summer precipitation and PDSI were better associated with tree-ring chronologies developed from latewood growth from both the montane (r = 0.429 PDSI, r = 0.563 precipitation) and piedmont (r = 0.252, r = 0.441) chronologies while correlations with temperature variables were either weak (r = − 0.249 maximum temperature montane, r = − 0.229 piedmont) or not significant. We examined longleaf pine latewood sensitivity to late-summer (July–September) climate conditions, drought detection, and differences in radial growth during drought and non-drought periods and found greater sensitivity of the montane chronology to these metrics. Specifically, the montane chronology was more sensitive to drought detection identifying all 11 droughts that occurred during the 81-year study period, while the piedmont chronology identified only 6 of the 11. Further, while significant differences in radial growth existed between drought and non-drought years for both chronologies, the montane chronology exhibited considerably greater growth range between these favorable and unfavorable periods. These results indicate the use of montane longleaf pine is preferable when reconstructing precipitation variability and when coupled with remnant stump data provide an opportunity to reconstruct summer climate variability.

Identification of gas-phase pyrolysis products in a prescribed fire: first detections using infrared spectroscopy for naphthalene, methyl nitrite, allene, acrolein and acetaldehyde

Abstract. Volatile organic compounds (VOCs) are emitted from many sources, including wildland fire. VOCs have received heightened emphasis due to such gases' influential role in the atmosphere, as well as possible health effects. We have used extractive infrared (IR) spectroscopy on recent prescribed burns in longleaf pine stands and herein report the first detection of five compounds using this technique. The newly reported IR detections include naphthalene, methyl nitrite, allene, acrolein and acetaldehyde. We discuss the approaches used for detection, particularly the software methods needed to fit the analyte and multiple (interfering) spectral components within the selected spectral micro-window(s). We also discuss the method's detection limits and related parameters such as spectral resolution.

Foliage re-establishment of Pinus palustris Mill. saplings after spring or fall prescribed fire

Repeated fire is key to the viability of longleaf pine (Pinus palustris Mill.) ecosystems, but its acceptance as a management tool may depend on satisfactory longleaf pine growth. This is because longleaf pine establishment often has the dual-purpose of ecosystem restoration and stemwood production. Timely recovery of scorched foliage among longleaf pine seedlings and saplings supports maximum juvenile growth. We identified two means of foliage re-establishment in the growing season after prescribed fire regardless of the season of fire application. New foliage growth after spring or fall fire was correlated with un-scorched foliage biomass and the presence of lateral branches. After prescribed fire in spring, foliage biomass recovery also appeared to benefit from the mobilization of starch. The high carbon demand of foliage recovery after fall prescribed fire was associated with interruption of seasonal starch accumulation in the stem and taproot. The implication of low starch accumulation in stem and taproot tissues during the growing season after fall prescribed fire is unknown and warrants further investigation. Our results demonstrate a positive influence of residual foliage, lateral branches, and stored starch on timely foliage recovery of young longleaf pines after fire. Together with knowledge of longleaf pine development and fuel and climate conditions at the time of prescribed fire, this information will aid prescribed fire practitioners charged with maintaining longleaf pine stands of high vigor.

Vertical distribution and persistence of soil organic carbon in fire-adapted longleaf pine forests

Longleaf pine (Pinus palustris Miller) forests in the southern United States are being restored and actively managed for a variety of goals including: forest products, biodiversity, C sequestration and forest resilience in the face of repeated disturbances from hurricanes and climate change. Managed southern pine forests can be sinks for atmospheric CO2 in forest biomass; however, the persistence of biomass in the environment or in forest products is limited, thus making soil C the primary long-term pool. Little is known about the size of extant soil C pools, residence time of soil C or the role that frequent burning plays in C stabilization in longleaf pine ecosystems. We sampled soil from a chronosequence of longleaf pine stands ranging in age from 5 to 87years to quantify the vertical distribution of soil organic carbon (SOC) stocks; both oxidizable (SOCOX) and oxidation resistant (SOCR) fractions, pyrogenic carbon (PyC) and the mean residence time (MRT) of SOC and its associated fractions. SOC stocks (0–1m) ranged from 44.1 to 98.1 (x¯=77.0) Mg C ha−1, and no effect of stand age or biomass accumulation on SOC stocks was detected. Soil C accumulation was associated with elevated clay and extractable Fe contents. While SOC concentration declined with soil depth, the proportion of SOCR in SOC increased with depth. PyC was a minor component of soil C, representing 5–7% of SOC and the proportion was not depth dependent. The MRT of SOC was hundreds of years near the surface and many thousands of years at depth. Though SOCR was less abundant than SOCOX, SOCR MRT was an order of magnitude greater than SOCOX MRT and had a strong influence on bulk SOC MRT. The majority of the PyC was in the less persistent SOCox and not associated with long-term C storage in soil. Despite the flow of C from biomass in the form of decay products, litter fall, root turnover and pulses of PyC, these soils preserve little of recent inputs, which may be rapidly oxidized, lost to the atmosphere from periodic fires or, in the case of PyC, may be transported out of the system via erosion. Our results indicate that these soils were not strong sinks for atmospheric CO2, especially when compared to C accumulation in biomass.

Preliminary observations on effects of using different stocking rates of meat goats to control understory vegetation in longleaf pine stands

The use of goats for clearing longleaf pine (Pinus palustris Mill.) stand undergrowths has potential as an alternative tool to prescribed burning. Objectives of the experiment were to determine the effects of using different stocking rates of meat goats on understory plant biomass height and quantity, understory crown cover density, animal productivity, soil characteristics and damage to pine trees. A 4.86 ha of 8–9 years old longleaf pine stands with 1112 trees/ha was divided into twelve 0.40 ha at Tuskegee, AL. The understudy vegetation contained many volunteer tree species with Broomsedge (Andropogon virginicus L.) being the predominant grass cover. Fifty-four mature Kiko wether goats (initial BW = 48.5 ± 2.5 kg) were allocated randomly to four treatments (0, 3, 6, 9 goats/0.4 ha) with three replications per treatment for 83 days in 2013 according to a completely randomized block design. The data was analyzed using the GLM procedure of SAS. The tree damage was monitored. Results showed that both initial and the final soil bulk density and soil compaction, plant biomass heights and quantity were not significantly different (P > 0.05) among treatments. Average daily BW gains were not significantly different (P = 0.76) but daily gains were close to zero. The combined final crown cover density percent at 2.0 m decreased linearly (P < 0.05) with increasing stocking rates. The tree damage was minimal even at the highest stocking rates. The results suggest that goats have potential to manage understory vegetation under longleaf pines.