Forests Of Alabama Research Articles

Open conversations: Finding ways to improve communication between family forest landowners and consulting foresters

Alabama is comprised of 23 million acres of forestland, of which family forest landowners (FFLs) own 56 % of that acreage. Therefore, FFLs are vital to maintaining the quality and diversity of Alabama's forests. However, FFLs possess varying attitudes towards management, value their land for different reasons, and have differing management objectives. In addition, FFLs are comprised of diverse backgrounds, own vastly different acreages, and fall within differing income brackets, all of which have been shown to affect management usage. This research aims to assess consulting foresters and FFLs in Alabama to learn why FFLs are hesitant to use consulting foresters for land management. It also aims to educate FFLs and consulting foresters in Alabama on better communicating their needs, services, and benefits. To study these two groups, a set of interviews and two surveys were used to collect perceptions, experiences, and needs. While consulting foresters are willing to work with smaller acreage, there are still constraints preventing management, and cost was mentioned by both groups. Still, FFLs are interested in consulting foresters' services, but many do not actively market FFLs. As a result, FFLs are unaware of the different types of forestry professionals, causing competition for consulting foresters who must be registered. Both consulting foresters and FFLs need to become more active in organizations, and consulting foresters need to adopt newer marketing techniques, while FFLs should seek more educational opportunities and opportunities to interact with consulting foresters directly.

Tradeoffs in longleaf pine conservation: Prescribed fire management increases exotic ambrosia beetle abundance in pine-hardwood forests

Exotic woodboring insects, including some ambrosia beetles (Coleoptera: Curculionidae, Scolytinae, and Platypodidae), are threatening native forests worldwide. Longleaf pine (Pinus palustris Mill.) forest is an endangered habitat in the southeastern United States. One of the most important actions necessary for its conservation is prescribed fire, which maintains its savanna structure. However, prescribed fire is a forest disturbance, possibly creating new niches for colonization by exotic insects. The interaction between prescribed fire and exotic ambrosia species is understudied, especially in highly fire-dependent ecosystems. We carried out a two-year experiment in mixed longleaf pine forests in Alabama, USA. We compared ambrosia beetle communities in recently burned and unburned sites. We found that more than 66 % of total individuals in longleaf pine forests, regardless of fire management, were exotic species. Moreover, exotic ambrosia beetles were more abundant in burned stands, whereas native species showed no difference between burned or unburned stands. Fire management influenced stand species composition for native but not exotic ambrosia beetles. These results indicate that trade-offs exist in managing fire-dependent ecosystems, especially in the Anthropocene era, which is associated with rampant biological invasions. Fire is important to preserve the longleaf pine habitat, but it simultaneously acts as a disturbance, increasing the population density of those exotic species taking advantage of the presence of stressed or dying trees.

Changes in bark properties and hydrology following prescribed fire in Pinus taeda and Quercus montana

AbstractIn the eastern United States, the use of prescribed fire as a silvicultural technique to manage for desirable upland tree species is increasing in popularity. Bark physical properties such as thickness, density, and porosity have known associations with fire tolerance among species. These physical properties simultaneously influence rainfall interception and canopy storage and thus are of interest across a range of disciplines. Furthermore, while these characteristics are innate to a species, it is unknown whether repeated exposure to fire facilitates physical change in bark structure and whether these changes are consistent among species. To answer these questions, bark samples were collected from mature pine (Pinus taeda L.) and oak (Quercus montana Willd.) trees from sites across the Bankhead National Forest in Alabama, USA under three different burn regimes: 3‐year cycle, 9‐year cycle, and no fire. Samples were analysed in the laboratory for bulk density, porosity, water storage capacity, and hygroscopicity (the amount of atmospheric water vapour absorbed by bark during non‐rainfall conditions). Drying rates of saturated samples under simulated wetting conditions were also assessed. Oak bark had higher bulk density, lower porosity, and dried slower than pine bark. Interestingly, bark from both species had lower bulk density, higher porosity, greater water storage capacity, and dried faster in stands that were burned every 3 years compared to other fire regimes (p < 0.001). In summary, this study demonstrates that prescribed fire regimes in an eastern US forest alter bark structure and thus influence individual tree control on hydrological processes. The increase in bark water storage capacity, coupled with faster bark evaporation times may lead to less water inputs to the forest floor and drier overall conditions. Further investigation of this fire‐bark‐water feedback loop is necessary to understand the extent of these mechanisms controlling landscape‐scale conditions.

Habitat Suitability Modeling of Rare Turkeybeard (Xerophyllum asphodeloides) Species in the Talladega National Forest, Alabama, USA

This study focused on the rare and threatened plant species eastern turkeybeard (Xerophyllum asphodeloides (L.) Nutt.) and its presence or absence in the Talladega National Forest in Alabama, USA. An ensemble suitable habitat map was developed using four different modeling methods (MaxEnt, Generalized Linear Model, Generalized Additive Model, and Random Forest). AUC evaluation scores for each model were 0.99, 0.96, 0.98, and 0.99, respectively. Biserial correlation scores for models ranged from 0.71 (GLM) to 0.94 (RF). The four different models agreed suitable habitat was found to cover 159.57 ha of the land. The ground slope variable was the most contributive variable in the MaxEnt and RF models and was also significant in the GLM and GAM models. The knowledge gained from this research can be used to establish and implement habitat suitability strategies across the Talladega National Forest and similar ecosystems in the southern United States.

Ensemble Species Distribution Model Identifies Survey Opportunities for At-Risk Bearded Beaksedge (Rhynchospora crinipes) in the Southeastern United States

Locating additional occurrences of at-risk species can inform assessments of their status and conservation needs (including potential legal protections). The perennial bearded beaksedge (Rhynchospora crinipes) ranges from Mississippi to North Carolina, but known occurrences are limited. Because of the species' apparent rarity, a model to identify areas with suitable habitat conditions for the species will allow conservationists to effectively prioritize and allocate scarce surveying resources. We used known occurrence records, a suite of environmental datasets, and four species distribution modeling techniques (generalized additive, GAM; maximum entropy, MaxEnt; generalized boosted, GBM; and weighted ensemble) to generate maps to inform surveys for R. crinipes. The ensemble approach improved predictive performance (AUC-PR = 0.95) compared to other techniques (individual model AUC-PR ranged from 0.7 to 0.8). We also obtained quantitative insights on the species' habitat relationships, including the likelihood of R. crinipes's presence near Atlantic white cedar (Chamaecyparis thyoides) habitat and floodplains, which is consistent with prior field observations. The ensemble model indicated that 3.6% of the study area could be suitable habitat, but only 0.38% had high suitability. Small stream riparian habitats and Atlantic swamp forests in Alabama, Florida, and Georgia had the highest proportion of suitable areas. Prioritizing surveys in areas with model-indicated high habitat suitability is expected to reveal additional R. crinipes occurrences. We suggest surveying efforts for other at-risk species may benefit from using an ensemble modeling approach to identify and prioritize survey areas and improve ecological knowledge of these species.

Temporal patterns of pollen shedding for longleaf pine (Pinus palustris) at the Escambia Experimental Forest in Alabama, USA

Longleaf pine is an important tree species in the southeastern United States and studying the temporal patterns of pollen shedding is crucial to a better understanding of its phenology and seed production. In this study, field observation data on the timing of pollen shedding from 1958 to 2013 were analyzed with reference to local weather conditions. Our results indicated that the time of peak pollen shedding after January 1 (TPPS) ranged from 53 days (about February 22) to 95 days (around April 5). There was no significant trend of decreasing TPPS. The number of days with the maximum air temperature above 0 °C was close to the TPPS. The accumulated maximum daily air temperature for the TPPS approximated an average of 1,342 °C. The TPPS declined with an increase in the average air temperature during winters. The time of 80% accumulated pollen density (TAPD) varied from 5 to 32 days, with an average of 13 days. Taylor’s power-law was evident in the TAPD data, with the time group of 10–15 days having an interval time of 2 years. Winter weather was not correlated with the TAPD. These results provide new information concerning the pollen phenology for longleaf pine trees.

Analysis of fire frequency on the Talladega National Forest, USA, 1998-2018

Fire is an essential ecological process and management tool for many forested landscapes, particularly the pine (Pinus spp.) forests of the southern USA. Within the Talladega National Forest in Alabama, where restoration and maintenance of pine ecosystems is a priority, fire frequency (both wild and prescribed) was assessed using a geographical process applied to a fire history database. Two methods for assessing fire frequency were employed: (1) a simple method that utilised the entire range of years acknowledged in the database and (2) a conservative method that was applied only the date of the first and last fires recorded at each location. Analyses were further separated by (a) method of mean fire return interval calculation (weighted by area or Weibull) and (b) fire season interval with analyses conducted on growing season and dormant season fires. Analyses of fire frequency for national forest planning purposes may help determine whether a prescribed fire program mimics ecological and historical fire frequencies and meets intended objectives. The estimated fire return interval was between ~5 and 6.5 years using common, straightforward (simple) methods. About one-third of the forest receives no fire management and about half of the balance has sufficiently managed fuels.

Dynamics of forest composition and growth in Alabama of USA under human activities and climate fluctuation

ABSTRACT Integrated analysis of forest dynamics under both anthropogenic influence and climatic change is crucial to indicating emergent patterns and meeting objectives of climate change mitigation. In this study, a long-term forest inventory data (1960s-2010s) in Alabama, USA were analyzed for patterns in relation to human activities and climate fluctuation. The results indicated that the species (or species groups) composition in Alabama’s forests was significantly different between all reported times, except for 2012–2015 based on Simpson’s index. Eastern hemlock trees declined dramatically. The overall forest communities became less homogeneous. Positive or negative correlation existed in the abundance of many species. The distribution of tree abundance along diameters for tree species followed exponential models. Both annual tree mortality and net growth rate increased from the 1960s. The total volume of growing stock increased from 14.4 million cubic feet in 1963 to 39.5 million cubic feet in 2016. The average volume of growing stock per acre also increased linearly with annual average air temperature, but not with annual precipitation. Based on the patterns of Alabama’s forests under climate fluctuation and human activities, some suggestions on developing strategies for the sustainability of Alabama forest were discussed.

Linking hypothesized causal factors to aboveground biomass growth in forests of Alabama and the eastern United States

Aim of study: We analyzed the hypothesized causal effects of relative density, density, height, species richness, species diversity, temperature, precipitation, and slope on above ground biomass growth (AGBG).Area of study: Eastern region of the USA.Materials and methods: We used the USDA Forest Service’s Forest Inventory and Analysis (FIA) database. A total of 2554 plots from all stand ages, regardless of disturbance history, were selected from the state of Alabama and 967 plots of stand age under 30 years and no prior disturbance were selected from the eastern US. We analyzed the data using descriptive statistics and structural equation modeling.Main results: Relative stand density exhibited a strong positive direct effect on AGBG, especially in the young forests (path coefficient 0.79), but a weaker indirect effect through species richness/diversity. Tree height influenced positively AGBG directly and indirectly through relative density and species richness. The effect of temperature and slope was greater than the effect of species richness/diversity on AGBG in the young forests of the eastern US.Research highlights: For the forests of the eastern US, greater tree species diversity did not appear to result in neither greater nor lower productivity. The diversity-productivity relationship was negative in forests of Alabama, however, where prior management likely resulted in removal of select dominant trees from valuable species (i.e., high-grading).

Microbial and organic matter patterns in a prescribed burned and thinned managed forest ecosystem

AbstractPrescribed burning and thinning were implemented in an Alabama forest (Bankhead National Forest) as a management strategy to control pest and disease outbreaks and also to increase forest productivity. However, using fire as a control mechanism in this forest may alter soil nutrient cycling, soil organic matter (SOM), and soil microbial populations. There is the need for continuous research on forest ecosystems to bridge knowledge gaps in our understanding of SOM transformations and microbial processes in a repeatedly burned forest ecosystems. The objectives of this study were to assess and document the impact of prescribed burning and thinning on soil labile organic matter fractions, microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN), potential carbon mineralized (PCM), enzymatic activity, and energy (ATP) potentials. Labile organic carbon was isolated using the density method, whereas enzyme activities were determined as described in Bottomley et al. (Methods of soil analysis: part 2—Microbiological and biochemical properties, Madison, Wisconsin, USA: Soil Science Society of America, 1994). Microbial biomass C and N (MBC and MBN) were determined using the fumigation‐incubation method. Treatment applications had some effects on MBC and MBN although these effects were not statistically significant (P ≤ 0.05). Light fraction carbon (LFC) and light fraction nitrogen (LFN) were significantly (P ≤ 0.05) affected by treatments. Irrespective of treatment, xylanase activity was the highest (3244 ± 327–5223 ± 567 μmol/g 24 h−1), whereas amylase activity was the lowest (12.57 ± 8.9–116 ± 42.8 μmol/g 24 h−1). Correlation analysis revealed that amylase, β‐glucosidase, and NAGase correlated with particulate organic carbon (POC), particulate organic nitrogen (PON), and LFC, whereas cellulase, xylanase, and invertase had no correlation with the labile organic matter fractions. Compared to the referenced treatment plot, burned and thinned plots had reduced MBC, MBN, and increased PCM although this was not statistically significant. Although enzyme activities within plots were significant, no significant enzyme activities between plots were observed except with amylase. The lack of statistical significance on microbial activities, MBC, and MBN support our hypothesis that prescribed burning and thinning temporarily affected microbial indices, and these parameters are expected to return to pretreatment levels after a period of time.

Testing Atmospheric Oxidation in an Alabama Forest

Abstract The chemical species emitted by forests create complex atmospheric oxidation chemistry and influence global atmospheric oxidation capacity and climate. The Southern Oxidant and Aerosol Study (SOAS) provided an opportunity to test the oxidation chemistry in a forest where isoprene is the dominant biogenic volatile organic compound. Hydroxyl (OH) and hydroperoxyl (HO2) radicals were two of the hundreds of atmospheric chemical species measured, as was OH reactivity (the inverse of the OH lifetime). OH was measured by laser-induced fluorescence (LIF) and by taking the difference in signals without and with an OH scavenger that was added just outside the instrument’s pinhole inlet. To test whether the chemistry at SOAS can be simulated by current model mechanisms, OH and HO2 were evaluated with a box model using two chemical mechanisms: Master Chemical Mechanism, version 3.2 (MCMv3.2), augmented with explicit isoprene chemistry and MCMv3.3.1. Measured and modeled OH peak at about 106 cm−3 and agree well within combined uncertainties. Measured and modeled HO2 peak at about 27 pptv and also agree well within combined uncertainties. Median OH reactivity cycled between about 11 s−1 at dawn and about 26 s−1 during midafternoon. A good test of the oxidation chemistry is the balance between OH production and loss rates using measurements; this balance was observed to within uncertainties. These SOAS results provide strong evidence that the current isoprene mechanisms are consistent with measured OH and HO2 and, thus, capture significant aspects of the atmospheric oxidation chemistry in this isoprene-rich forest.

Fine-particle water and pH in the southeastern United States

Abstract. Particle water and pH are predicted using meteorological observations (relative humidity (RH), temperature (T)), gas/particle composition, and thermodynamic modeling (ISORROPIA-II). A comprehensive uncertainty analysis is included, and the model is validated. We investigate mass concentrations of particle water and related particle pH for ambient fine-mode aerosols sampled in a relatively remote Alabama forest during the Southern Oxidant and Aerosol Study (SOAS) in summer and at various sites in the southeastern US during different seasons, as part of the Southeastern Center for Air Pollution and Epidemiology (SCAPE) study. Particle water and pH are closely linked; pH is a measure of the particle H+ aqueous concentration and depends on both the presence of ions and amount of particle liquid water. Levels of particle water, in turn, are determined through water uptake by both the ionic species and organic compounds. Thermodynamic calculations based on measured ion concentrations can predict both pH and liquid water but may be biased since contributions of organic species to liquid water are not considered. In this study, contributions of both the inorganic and organic fractions to aerosol liquid water were considered, and predictions were in good agreement with measured liquid water based on differences in ambient and dry light scattering coefficients (prediction vs. measurement: slope = 0.91, intercept = 0.5 μg m−3, R2 = 0.75). ISORROPIA-II predictions were confirmed by good agreement between predicted and measured ammonia concentrations (slope = 1.07, intercept = −0.12 μg m−3, R2 = 0.76). Based on this study, organic species on average contributed 35% to the total water, with a substantially higher contribution (50%) at night. However, not including contributions of organic water had a minor effect on pH (changes pH by 0.15 to 0.23 units), suggesting that predicted pH without consideration of organic water could be sufficient for the purposes of aqueous secondary organic aerosol (SOA) chemistry. The mean pH predicted in the Alabama forest (SOAS) was 0.94 ± 0.59 (median 0.93). pH diurnal trends followed liquid water and were driven mainly by variability in RH; during SOAS nighttime pH was near 1.5, while daytime pH was near 0.5. pH ranged from 0.5 to 2 in summer and 1 to 3 in the winter at other sites. The systematically low pH levels in the southeast may have important ramifications, such as significantly influencing acid-catalyzed reactions, gas–aerosol partitioning, and mobilization of redox metals and minerals. Particle ion balances or molar ratios, often used to infer pH, do not consider the dissociation state of individual ions or particle liquid water levels and do not correlate with particle pH.

Woody Regeneration in a Southern AppalachianQuercusStand Following Wind Disturbance and Salvage Logging

ABSTRACT In the eastern United States, the practice of salvage logging is common to reclaim economic losses and/or reduce fuel loading following a natural disturbance. A current hypothesis states that two disturbances in rapid succession (i.e., compounded disturbance) have a cumulative severity of impact and may displace the successional trajectory further than either disturbance occurring separately. On 20 April 2011, Bankhead National Forest in Alabama was affected by an EF1 tornado with accompanying straight-line winds. Much of the damage was salvaged, however adjacent disturbance in a Wilderness Area was not harvested. A unique set of conditions allowed for comparisons of woody regeneration within a single stand, reducing uncontrolled variables to test the compounded disturbance hypothesis at a fine spatial scale. After two growing seasons, species richness, species evenness, and Shannon diversity of seedlings and saplings did not significantly differ by disturbance class. We found seedling density si...

Comparison of carbon storage, carbon sequestration, and air pollution removal by protected and maintained urban forests in Alabama, USA

The Auburn University campus in Auburn, Alabama, USA, was the location for a case study to compare carbon storage, carbon sequestration, and air pollution (CO, O3, NO2, PM10, SO2) removal estimates between protected and maintained urban forests. Results were from a complete tree inventory and i-Tree Eco analysis of the 237 ha maintained and 5.5 ha protected areas of the campus. Trees in the maintained landscapes had an average diameter at breast height of 16.4 cm and basal area of 2.24 m2/ha when compared with 24.4 cm and 12.04 m2/ha for the protected area. The maintained landscapes were estimated to store 6652 kg of carbon per ha and sequester 291 kg/year/ha of carbon. The protected area was estimated to store 41,975 kg of carbon per ha and sequester 1758 kg/year/ha of carbon. Trees in the maintained areas removed 2970 kg/year of air pollution (12.5 kg/year/ha) compared with 560 kg/year for the protected area (102 kg/year/ha), which was 8 times the amount on a unit area basis compared with the maintained landscapes. The results demonstrate differences between maintained and protected forests and how important protected areas are in urban environments in enhancing carbon storage and sequestration and promoting air pollution removal.

Trends of forest inventory data in Alabama, USA, during the last seven decades

Summary Long-term time series of forest inventory information at a local scale could provide information about trends in local forest resource changes and be useful for testing some hypotheses about forestry development. Based on forest inventory data and related human population information in Alabama’s 67 counties for the past seven decades, the trend of forest resource change (e.g. area and resource composition) for Alabama was characterized as well as the complicated relationship between human population and commercial forest land at county level. These results indicate that (1) only two counties had increased human population and decreased commercial forest area, (2) commercial forest coverage increased in counties with a relatively poor economy and (3) counties with more commercial forest coverage had fewer roads. Therefore, long-term forest inventory information and other related data could uncover emergent trends of changing Alabama forest resources and may be helpful for local forest resource management and development.

Habitat relationships of reptiles in pine beetle disturbed forests of Alabama, U.S.A. with guidelines for a modified drift-fence sampling method

Abstract Understanding vertebrate habitat relationships is important to promote management strategies for the longterm conservation of many species. Using a modified drift fence method, we sampled reptiles and compared habitat variables within the William B. Bankhead National Forest (BNF) in Alabama, U.S.A from April 2005 to June 2006. We captured 226 individual reptiles representing 19 species during 564 total trap nights. We used canonical correspondence analysis to examine habitat associations for the reptiles sampled and we detected a distinct habitat gradient ranging from sites with greater litter depth and percent canopy cover to more open sites with greater woody, herbaceous, and coarse woody debris (CWD) coverage, and CWD volume. Little brown skinks Scincella lateralis and eastern worm snakes Carphophis a. amoenus were associated with sites with greater litter depth and canopy cover, whereas eastern fence lizards Sceloporus undulatus, copperheads Agkistrodon contortrix, and gray ratsnakes Pantherophis spiloides were associated with sites possessing greater CWD coverage and volume. We found that disturbances due to the southern pine beetle Dendroctonus frontalis were likely important for influencing reptile distributions through the creation of canopy gaps and fallen coarse woody debris. Compared to other studies, our modified drift-fence trap technique was successful for sampling larger snake species (66 snakes in 564 trap nights). We have also provided detailed schematics for constructing drift fence array and box traps used in this study.

Alabama Forest Products and the Potential Impacts of FTAA Price Changes

The Free Trade Area of the Americas FTAA will increase import competition for some forest product industries in Alabama but create export opportunities for others. Forest products loom large in the Alabama economy, both in terms of income and pollution. The present paper gauges the potential impacts of a range of price changes for forest products in an applied specific factors model of production. Pollution adjusts with forest product outputs. The potential impacts on outputs, capital returns, and pollution are substantial. Anticipated price changes also raise the wage and lower energy demand.

First Report of Leech Parasitism in the Amphibian Family Sirenidae

Macrobdella ditetra were found to take blood meals from the salamander Siren intermedia collected from Tuskegee National Forest in Alabama, U.S.A. This is a new host record for M. ditetra, the first record of leech parasitism in this family of salamanders, and only the second article reporting an ectoparasite from this family.

Quantifying Impacts of Land Ownership on Regional Forest NDVI Dynamics

Identifying the impacts of human activities on local and regional ecological processes is important for protecting essential ecological functions. In this study, the spatial and temporal dynamics of Normalized Difference Vegetation Index (NDVI) at three adjacent areas with different proportions of private land (6 percent, 20 percent and 55 percent) in the Bankhead National Forest in Alabama, USA from 1998 to 2004 were examined. The phase coupling, synchrony, and information entropy of NDVI at multiple temporal scales for each of these areas were examined. A higher proportion of private land (e.g., 55 percent) resulted in decrease of annual mean, coefficient of variance, seasonal maximum, and absolute value of rate of increase/ rate of decrease for NDVI values as well as increase in seasonal minimum NDVI and decrease in spatial coupling and synchrony of NDVI dynamics. Thus, a higher proportion of private land could affect regional NDVI dynamics in complex and ecologically significant ways.

Assessing rates of forest change and fragmentation in Alabama, USA, using the vegetation change tracker model

Forest change is of great concern for land use decision makers and conservation communities. Quantitative and spatial forest change information is critical for addressing many pressing issues, including global climate change, carbon budgets, and sustainability. In this study, our analysis focuses on the differences in geospatial patterns and their changes between federal forests and nonfederal forests in Alabama over the time period 1987–2005, by interpreting 163 Landsat Thematic Mapper (TM) scenes using a vegetation change tracker (VCT) model. Our analysis revealed that for the most part of 1990 s and between 2000 and 2005, Alabama lost about 2% of its forest on an annual basis due to disturbances, but much of the losses were balanced by forest regeneration from previous disturbances. The disturbance maps revealed that federal forests were reasonably well protected, with the fragmentation remaining relatively stable over time. In contrast, nonfederal forests, which are predominant in area share (about 95%), were heavily disturbed, clearly demonstrating decreasing levels of fragmentation during the time period 1987–1993 giving way to a subsequent accelerating fragmentation during the time period 1994–2005. Additionally, the identification of the statistical relationships between forest fragmentation status and forest loss rate and forest net change rate in relation to land ownership implied the distinct differences in forest cutting rate and cutting patterns between federal forests and nonfederal forests. The forest spatial change information derived from the model has provided valuable insights regarding regional forest management practices and disturbance regimes, which are closely associated with regional economics and environmental concerns.