bluuebunny/crossref_metadata_2025_split huggingface dataset:
Factors Influencing Modern Wildfire Occurrence in the Mark Twain National Forest, Missouri
Authors: Brosofske Kimberley D. , Cleland David T. , Saunders Sari C. 
Published: August 2019

Abstract
Understanding relative influences of ecological and anthropogenic factors on wildfire occurrence can assist decisionmakers in allocating fire management resources. We examined the influences of ecological and anthropogenic variables on probability of modern fire occurrence in the Mark Twain National Forest (MTNF), Missouri, using classification and regression tree (CART) and logistic regression analyses. Models were developed for five classes of fire size. Although CART distinguished some effects of fire size on results, logistic regression indicated a single model developed for all fires was sufficient for predictions. Ecological subsection was a dominating influence on fire occurrence for final CART and logistic models, highlighting the potential usefulness of ecosystem classification as a framework for considering factors influencing modern wildfires. Other influential predictors included ecosystem fire resistance; distance to roads, cities, and railroads; road density; mean October precipitation; elevation; median house value; and population density. Wildfires in the MTNF are caused overwhelmingly by arson, which, when combined with our results, suggests that arsonists may seek out flammable fuel types in remote areas with easy access. Within this general anthropogenic fire regime, we found a more subordinate effect of specific human variables (e.g., population density) on modern fire occurrence than did similar studies in the Upper Midwest, perhaps because our study area encompassed primarily federal forestlands with low population density.
How Planting Method, Weed Abatement, and Herbivory Affect Afforestation Success
Authors: Sweeney Bernard W. , Czapka Stephen J. , Petrow L. Carol A. 
Published: August 2019

Abstract
The success of upland and riparian afforestation depends on landowners making informed decisions about key factors such as the quality of seedlings (species, size, and root stock), planting technique, site preparation, weed and herbivore control, and planting pattern for the plantation. We show here that the short-term (1 year) and longer-term (3 year) effects on seedling survivorship and growth due to planting technique (dibble-bar versus auger) did not differ significantly for the five test species (red maple [Acer rubrum L.], eastern redbud [Cercis canadensis L.], green ash [Fraxinus pennsylvanica Marsh], sweetbay magnolia [Magnolia virginiana L.], and sweet gum [Liquidambar styraciflua L.]). Weed treatment (tree mats, initial herbiciding, and annual herbiciding) also failed to significantly increase seedling survivorship or growth, a result hypothesized to be caused by high moisture and nutrient content of soils on the site. In contrast, tree shelters significantly increased seedling survivorship and growth after 1 and 3 years. For some species, 3-year survivorship was up to fivefold higher with shelters. Long-term weed control increased survivorship of sheltered seedlings but decreased survivorship for those without shelters because of increased exposure to deer. For this site, successful afforestation depends more on protecting seedlings from herbivory with tree shelters than on either the method of planting or the method of controlling weeds.
Trends Among Family Forest Owners in Alabama, 1994–2004
Authors: Pan Yi , Zhang Yaoqi , Butler Brett J. 
Published: August 2019

Abstract
There are an estimated 432,000 family forest owners in Alabama and they control 67% of the State's forestland. About two-thirds owned less than 10 ac. and about 88% of the family forest owners have holdings of less than 50 ac; collectively, this group of owners with 1–49 ac of forestland own 15% of Alabama's family forestland. The corollary to this finding is that a majority (85%) of the state's family forestland is owned by the minority (12%) of owners who own 50 ac or more. Between 1994 and 2004, the amount of forestland owned by family forest owners with small (less than 10 ac) and large (more than 500 ac) forest holdings increased, while the total area of forestland owned by people with intermediate-size holdings, in general, decreased. Compared with 10 years ago, the number of family forest owners 45–54 years old is higher but they tend to own smaller parcels of forestland. During the same period, the number of owners 65 years or older decreased, but, on average, the size of their holdings increased. Recreation and investments have become more important objectives of ownership, whereas timber production as a primary ownership objective decreases. The probability of an owner having harvested trees, having a management plan, or having sought forest management advice increased as the size of the forest holding increased.
Historical Patterns of Forest Fertilization in the Southeastern United States from 1969 to 2004
Authors: Albaugh Timothy J. , Lee Allen H. , Fox Thomas R. 
Published: August 2019

Abstract
Based on historical forest fertilization survey records, over 16 million ac were fertilized in the southeastern United States from 1969 to 2004, with the peak forest fertilizer application in 1999, when 1.59 million ac were fertilized. The 1999 applications were largely on loblolly pine (Pinus taeda L.; 91%) in established stands (78%) and included both nitrogen and phosphorus, typically as urea and diammonium phosphate fertilizers, respectively. On a tonnage basis from 2000 to 2004, the average amount of forest-applied urea and diammonium phosphate represented 2.5% of those materials applied in the United States. The number of acres fertilized approximately doubled every 2 years from 1991 through 1999. This increase can be attributed to a shift in forest production interests to the southeastern United States at a time when research results were showing positive biological and economic responses to nitrogen and phosphorus applications in midrotation southern pine stands. Common application rates for nitrogen and phosphorus were 200 and 50 lb elemental nitrogen ac−1and 25 and 50 lb elemental phosphorus ac−1 for stands >2 years old and ≤2 years old, respectively. In 1994, application of elements other than nitrogen and phosphorus, including potassium, boron, and magnesium, began in response to newly available research results. Boron was applied to 30% of the total number of acres fertilized in 2004, likely because boron, when applied with urea, may reduce nitrogen volatilization.
What do Louisiana and Mississippi Nonindustrial Private Forest Landowners Think about Forest Certification?
Authors: Perera Priyan , Vlosky Richard P. , Hughes Glenn , Dunn Michael A. 
Published: August 2019

Abstract
Nonindustrial private forest (NIPF) landowners own the majority of timberlands in the southern United States. As forest certification becomes more prevalent, it is important to understand the implications for NIPF landowners. This study, conducted in 2005–2006, reveals how well NIPF landowners in Louisiana and Mississippi understand forest certification, willingness to pay to become certified, and general perceptions about the certification process and implementation requirements. We surveyed 1,200 randomly selected NIPF landowners from each state that owned 10 ac or more of timberland in 2005. A total of 591 usable surveys resulted in an overall adjusted response rate of 30%. Forty percent of respondents believe certification is necessary on public lands. However, their lowest level of agreement is with the need for certification on private forestlands. Respondents believe certification in the United States is driven by environmental nongovernmental organizations rather than by demand in the marketplace. Private landowner organizations and approved professional foresters are the most trusted entities to administer and monitor certification. Results also suggest that respondents are generally not averse to having certifiers monitor their forest management activities; however, a majority are unwilling to bear the cost of certification.
An Improved Tree Height Measurement Technique Tested on Mature Southern Pines
Authors: Bragg Don C. 
Published: August 2019

Abstract
Virtually all techniques for tree height determination follow one of two principles: similar triangles or the tangent method. Most people apply the latter approach, which uses the tangents of the angles to the top and bottom and a true horizontal distance to the subject tree. However, few adjust this method for ground slope, tree lean, crown shape, and crown configuration, making errors commonplace. Given documented discrepancies exceeding 30% with current methods, a reevaluation of height measurement is in order. The sine method is an alternative that measures a real point in the crown. Hence, it is not subject to the same assumptions as the similar triangle and tangent approaches. In addition, the sine method is insensitive to distance from tree or observer position and can not overestimate tree height. The advantages of the sine approach are shown with mature southern pines from Arkansas.
Tree Biomass Equations for Naturally Regenerated Shortleaf Pine
Authors: Sabatia Charles O. , Lynch Thomas B. , Will Rodney E. 
Published: August 2019

Abstract
Aboveground tree-level and branch-level biomass component equations were fitted by nonlinear seemingly unrelated regression, for even-aged naturally regenerated shortleaf pine (Pinus echinata Mill.) in southeastern Oklahoma. Data were obtained from 46- to 53-year-old trees growing in stands that had previously been thinned to densities ranging from 50% of full stocking to overstocked unthinned stands. Stand density affected some of the parameter estimates for trees growing in thinned stands versus unthinned stands. Equations based on dbh alone gave biomass estimates that were not significantly different from those obtained with equations based on dbh, height, and/or crown width. The fitted tree-level biomass component equations were additive in the sense that predictions for biomass components were constrained by the estimation process to sum to total tree biomass. These equations can be used to estimate aboveground tree or tree component biomass for naturally regenerated shortleaf pine in the dbh range of 7–40 cm in southeastern Oklahoma and have potential for application in other shortleaf pine growing areas.
The SOHARC Model System for Growth and Yield of Southern Hardwoods
Authors: McTague John Paul , O'Loughlin David , Roise Joseph P. , Robison Daniel J. , Kellison Robert C. 
Published: August 2019

Abstract
A system of stand level and individual tree growth-and-yield models are presented for southern hardwoods. These models were developed from numerous permanent growth-and-yield plots established across 13 states in the US South on 9 site types, in even-aged (age classes from 20 to 60 years), fully stocked, naturally regenerated mixed hardwood and mixed hardwood-pine stands. Nested plots (⅕ and ac) were remeasured at 5-year intervals. The system of permanent plots was established and maintained by private and public members in the North Carolina State University Hardwood Research Cooperative. Stand level models are presented for dominant height, survival, basal area prediction and projection, and the ingrowth component. Individual tree diameter growth and tree height models were constructed for the most common species: sweetgum, tupelo, yellow-poplar, blackgum, and red maple. All other species were grouped according to growth dynamics into four species groups using cluster analysis. A ranking variable was incorporated into the individual tree growth models to account for competition.
Separating Duff and Litter for Improved Mass and Carbon Estimates
Authors: Chojnacky David , Amacher Michael , Gavazzi Michael 
Published: August 2019

Abstract
Mass and carbon load estimates, such as those from forest soil organic matter (duff and litter), inform forestry decisions. The US Forest Inventory and Analysis (FIA) Program systematically collects data nationwide: a down woody material protocol specifies discrete duff and litter depth measurements, and a soils protocol specifies mass and carbon of duff and litter combined. Sampling duff and litter separately via the soils protocol would increase accuracy of subsequent bulk density calculations and mass and carbon estimates that use them. At 57 locations in North Carolina, Virginia, and West Virginia, we measured depth, mass, and carbon of duff and litter separately. Duff depth divided by total depth varied from 20% to 56%, duff was 1–4 times denser than litter, and the calculated median carbon-to-mass ratio for hardwood duff (0.37) was less than that for litter (0.45). Using FIA depth measurements, we calculated mass from (1) our mean density values, (2) a mass versus depth regression model we developed, and (3) published density values. Model mass calculations were lower than those using our mean densities, possibly because the latter ignore density differences with layer thickness. Our model could provide valuable mass and carbon estimates if fully developed with future FIA data (duff and litter separated).
Technical Note: Afforestation in North Mississippi on Retired Farmland Using Pinus echinata: First-Year Results
Authors: Kushla John D. 
Published: August 2019

Abstract
In March 2005, 1-0 bareroot shortleaf pine was planted on retired fields of the Mississippi Agriculture and Forestry Experiment Station near Holly Springs, Mississippi. Objectives of the study were to evaluate (1) subsoiling and (2) herbaceous weed control (HWC) on 1st-year seedling survival and size. Treatments were replicated three times in a randomized complete block design. The subsoiling treatment was completed in December 2004. The HWC treatment was 4-oz Arsenal AC + 2-oz Oust XP product per sprayed acre applied in a 4-ft band over the row in April 2005. In addition, mowing was completed three times between rows during the first growing season. First-year seedling measurements were completed by March 2006 on seedling survival, groundline diameter (GLD), and total height. Subsoil tillage did not have a significant effect on 1st-year survival, diameter, or height. HWC had a significant effect on shortleaf GLD but not survival or height.
Technical Note: Patterns of Urban Forest Debris from the 2004 and 2005 Florida Hurricane Seasons
Authors: Staudhammer Christina L. , Escobedo Francisco , Luley Christopher , Bond Jerry 
Published: August 2019

Abstract
Urban tree debris generation and damage resulting from seven hurricanes during the 2004 and 2005 Florida hurricane seasons was analyzed using a random sample of communities in highly affected counties. Woody debris amounts, rates, and costs for cleanup were quantified, as were the spatial patterns of damage across the state. Average debris volume per mile of street segment was 488 cubic yards, and cost of removal and disposal averaged $21.50 per cubic yard. Urban forest structure, community characteristics, and hurricane severity influenced debris and cost results. Spatial analyses indicated that debris results were clustered into northwest and southeast areas of the state, which represent two distinct ecoregions in Florida. Although southeastern Florida had much higher costs per cubic yard than the northwest, the debris volume per road mile was higher in the northwest portion of the state. On a per-mile basis, Hurricane Ivan was responsible for the greatest debris volume, and Hurricane Katrina was the most expensive. These results can be used to help communities plan for hurricane response and management activities and to estimate potential damage to their urban forest resource.
Dynamic Site Index Equation for Thinned Stands of Even-Aged Natural Longleaf Pine
Authors: Lauer Dwight K. , Kush John S. 
Published: August 2019

Abstract
A dynamic site equation derived using the generalized algebraic difference approach was developed for thinned stands of natural longleaf pine (Pinus palustris Mill.) in the East Gulf region of the United States using 40 years of measurements on 285 permanent plots. The base model predicts height growth of trees once they reach 4.5 ft and was fit using a varying parameter for each tree and global parameters that are constant for all 3,267 trees. Parameters were estimated in one step using the dummy variable approach and a first-order autoregressive error term to account for serial correlation. The final base-age invariant equation allows the user to specify the number of years required for trees to reach 4.5 ft in height.
Realizing the Economic Value of a Forested Landscape in a Viewshed
Authors: Poudyal Neelam C. , Hodges Donald G. , Fenderson John , Tarkington Ward 
Published: August 2019

Abstract
Existing literature on nonmarket valuation indicates an ambiguous value of the view of a forest due largely to the fact that these studies relied on inappropriate proxies or poor measures of forest view. The current study attempts to fill this gap by using GIS to measure the actual forest area that is visible from a house and then using a hedonic regression model to examine how its value is reflected in residential housing price. A spatial hedonic model of residential housing price was applied to housing sales data in a forested landscape located in the southeastern portion of Cheatham County and the adjacent Scottsboro-Bells Bend area of Davidson County, near Nashville, Tennessee. Results indicate that increasing the size of forest area visible from a house by 1 ac increased the house price by $30. The findings imply that residents place a significant value on and likely pay a price premium to preserve the view of a forest. Findings from this study could be useful in evaluating viewshed protection policies as a hedge against development pressures that threaten the forested landscapes and in designing market protocols for scenic view as an ecosystem service.
Prediction of Whole-Stem α-Cellulose Yield, Lignin Content, and Wood Density in Juvenile and Mature Loblolly Pine
Authors: Aspinwall Michael J. , Li Bailian , McKeand Steven E. , Isik Fikret , Gumpertz Marcia L. 
Published: August 2019

Abstract
Models were developed for predicting whole-stem α-cellulose yield, lignin content, and wood density in 14- and 20-year-old loblolly pine across three different sites. Also, the relationships between juvenile-, transition-, and mature-wood α-cellulose yield, lignin content, and wood density at breast-height and overall whole-stem wood property values were examined. Whole-stem wood property weighted averages were calculated by taking 12-mm core samples at breast height and at 2.4-m incremental heights up each tree, and breast-height wood property values were then used to predict whole-stem weighted averages. Despite large differences in growth across sites and both ages, whole-stem models based on whole cores taken at breast height were not significantly different among sites, and coefficients of determination (R2) were 0.87, 0.74, and 0.78 for α-cellulose, lignin, and wood density, respectively. Generally, whole-stem prediction models based on sections of wood at breast height were not significantly different among sites and were less effective than cores as predictors, explaining between 39 and 82% of the variation in whole-stem wood traits. The results of this study indicate that the relationship between breast height and whole-stem wood chemical properties (and density) is predictable and consistent across sites in both juvenile and mature loblolly pine.
Equations Relating Compacted and Uncompacted Live Crown Ratio for Common Tree Species in the South
Authors: Randolph KaDonna C. 
Published: August 2019

Abstract
Species-specific equations to predict uncompacted crown ratio (UNCR) from compacted live crown ratio (CCR), tree length, and stem diameter were developed for 24 species and 12 genera in the southern United States. Using data from the US Forest Service Forest Inventory and Analysis program, nonlinear regression was used to model UNCR with a logistic function. Model performance was evaluated with standard fit statistics (root mean squared error, mean absolute error, mean error, and model efficiency) and by comparing the results of using the observed and predicted UNCR values in secondary applications. Root mean squared error for the regression models ranged from 0.062 to 0.176 UNCR and averaged 0.114 UNCR across all models. Height to live crown base calculations and crown width estimations based on the observed and predicted UNCR values were in close agreement. Overall, the models performed well for the Pinus and Taxodium genera and several individual hardwood species; however, model performance was generally poor for the Acer, Quercus, and Carya genera.
Economic Potential of Agroforestry and Forestry in the Lower Mississippi Alluvial Valley with Incentive Programs and Carbon Payments
Authors: Frey Gregory E. , Mercer D. Evan , Cubbage Frederick W. , Abt Robert C. 
Published: August 2019

Abstract
Conversion of bottomland hardwood forests in the Lower Mississippi Alluvial Valley (LMAV) to agricultural land has caused a loss of ecosystem services. The primary approaches to reverse this have been the Wetlands Reserve Program and the Conservation Reserve Program, which provide financial incentives to landowners to reforest. However, other forest production regimes and forestry financing mechanisms will be necessary to meet reforestation goals. Using capital budgeting techniques, we estimated financial returns from eight agroforestry and seven forestry systems to compare to returns from agriculture on marginal and average lands in the LMAV, as an indicator for potential adoption. In all but a few cases, agriculture had higher returns than agroforestry and forestry, even on marginal lands, and this is especially true when considering federal agricultural payments. We then estimated the break-even carbon net revenue per metric ton that would create a large enough financial incentive to favor forestry or agroforestry systems over agriculture. Given prospective moderate prices from carbon credits from afforestation and reforestation activities and high costs for implementing those activities, a few forestry and agroforestry systems might have potential on marginal agricultural land in the LMAV, subject to requirements such as providing evidence that reforestation would not have taken place without carbon payments. Regimes that maintain a large carbon stock on site by avoiding clearcutting performed better under carbon markets.
Comparing the Use of Three Dendrometers for Measuring Diameters at Breast Height
Authors: Liu Shangbin , Bitterlich Walter , Cieszewski Chris J. , Zasada Michal J. 
Published: August 2019

Abstract
Three dendrometers are used to measure dbh. Two of the devices are the well-known and widely used d-tape and caliper. The third device is the lesser-known sector fork. In this study, measurements of dbh were collected from each dendrometer for each tree in nine plots, with each of the three plots nested in one of the diameter classes (small, medium, and large). The results from repeated-measures analysis of variance show that different dendrometers, the interaction between the dendrometer and diameter class, and the interaction between the dendrometer and plot significantly affected the dbh measurements. Statistically significant differences were detected in most of the comparisons of dbh measured by the three dendrometers. However, the actual mean differences and limits of agreement (Bland, J.M., and D.G. Altman. 1986. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1:307–310) were small enough to support the claim that the dbh measurements made by the three dendrometers agree well in measurements of the small and medium trees (in this study, dbh of <16 in.). Thus, these statistically significant differences are not biologically and/or practically important. For the large trees (dbh 16 in. or more), the dbh measured by d-tape and caliper still agreed well. The sector fork should be used cautiously in measuring large trees.