bluuebunny/crossref_metadata_2025 huggingface dataset:
A Legal History of the Softwood Lumber Dispute (in a Nutshell)
Authors: Kennedy Kevin C.
Published: April 2024

In every close economic relationship, trade frictions will inevitably occur. The trade relationship between the United States and Canada is no exception. The two-decade long, Canada–U.S. softwood lumber dispute undoubtedly has been the most prominent, if not the most irritating, trade friction of all. The heart of the dispute is the different views in Canada and the United States as to what constitutes a countervailable government subsidy and the proper methodology for determining the amount of such a subsidy when one is found to exist. In the latest round in the softwood lumber dispute, Softwood Lumber IV, Canada and the United States have engaged in a series of parallel dispute settlement proceedings under North American Free Trade Agreement (NAFTA) and at the World Trade Organization. Canada insists that it has won the latest softwood lumber dispute by virtue of an Aug. 2005 decision by a NAFTA Extraordinary Challenge Committee. The United States is equally insistent that the matter remains open by virtue of the International Trade Commission (ITC)s injury determination issued in 2004. With both sides in the Softwood Lumber dispute taking a hard line, such an environment is hardly conducive to the negotiation of a mutually agreeable settlement between the parties. A negotiated resolution of a legal dispute is always better than a litigated one.
If America Had Canada's Stumpage System
Authors: Spelter Henry
Published: April 2024

The North American lumber market is integrated and, under normal conditions, provides unhindered access to all suppliers. North American log markets, in contrast, function on different principles: in one principle, a profit allowance for the wood processor plays a role in timber pricing, whereas in the other it is a byproduct of the give-and-take of arm's length market negotiations. Under the first system, markets are characterized by high elasticities of price transmission and, at times of market weakness, by low elasticities of product supply. Under the second system, the opposite of these benchmarks prevails. This can result in asymmetric supply responses in weak markets, to the detriment of U.S. producers. Whether this is a subsidy in the sense of conferring a direct financial contribution by the government or merely a more efficient pricing mechanism is beclouded by the dearth of market-based transactions. The challenge in the lumber dispute then is to devise a system of pricing in Canada that is more transparent in regard to the underlying valuation of timber.
Timber Sale Characteristics and Competition for Public Lands Stumpage: A Case Study from the Lake States
Authors: Leefers Larry A. , Potter-Witter Karen
Published: April 2024

The U.S. stumpage pricing system is often presented as a market-based approach that should be adopted by Canadian provinces. We compare four public agency stumpage pricing systems in the Lake States (Michigan, Minnesota, and Wisconsin) with many similar features, but their differences lead to diverse starting points in the stumpage pricing process. Further, comparisons between the Michigan Department of Natural Resources (MiDNR) and the USDA Forest Service indicate that there is considerably more competition for MiDNR sales. This is due to institutional differences between the agencies. We estimated hedonic pricing models for Lake States national forest and MiDNR timber sales to determine which sale and institutional characteristics influenced stumpage prices. The final models for stumpage price centered on species–product composition of sales, number of species and products, regional location, administratively set sale contract length, and sale timing, competition, and firm size. Empirical results illustrate that models within the same geographic region are not readily transferable to another ownership. This will complicate efforts for cross-border comparisons of hedonic pricing results. Importantly, the models do provide insights regarding the sign and significance of variables. We conclude that the U.S. systems are not readily adaptable to Canadian regions in which little competition exists.
Regional Stem Profile Model for Cross-Border Comparisons of Harvested Red Pine (Pinus resinosa Ait.) in Ontario and Michigan
Authors: Zakrzewski W.T. , MacFarlane D.W.
Published: April 2024

In recent years, considerable attention has been paid to the problem of increasing the comparability of wood valuation across different markets (e.g., stumpage prices), highlighted in the ongoing softwood lumber dispute between the United States and Canada. One major thrust is toward standardizing measurement systems across markets such that volume estimation is more consistent and versatile. As part of the Great Lakes Stem Profile Modeling Project, established to improve the local timber production process and to enable cross-border comparisons of timber volumes, here we present results of a fitting taper (stem profile) model for red pine (Pinus resinosa Ait.) growing in Michigan and Ontario, Canada. Red pine is an important commercial species in both regions. We developed a joint stem profile model that predicts individual tree volume for red pine in Michigan and Ontario with a standard deviation (SD) of error of 10%, demonstrating the feasibility of providing regionally valid stem profile models for major commercial tree species. The stem profile model was fitted as a system of simultaneous equations using a three-stage least-squares regression method. Predictions were evaluated using an equivalence test. We believe that developing statistically and legally defensible estimates of timber product volume across political borders, as exemplified by the regional stem profile model presented here, will improve communication among the trade partners, such as the United States and Canada, by reducing uncertainty created by a lack of comparable estimates.
Factors that Influence Administrative Appeals of Proposed USDA Forest Service Fuels Reduction Actions
Authors: Laband David N. , González-Cabán Armando , Hussain Anwar
Published: April 2024

Using the database developed by the General Accounting Office on proposed fuels reduction actions on federal lands in 2001 and 2002, we conduct probit regression analysis to identify factors that significantly affect the likelihood of administrative appeal. The likelihood of appeal of a proposed fuels reduction action is significantly increased by (1) the size of area affected, (2) the number of proposed activities at the site, (3) when one of the stated purposes is commodity production (timber and sawlogs), (4) when one of the stated purposes is reduction of project-generated fuels, (5) implementation involves prescribed burning or mechanical thinning, and (6) the presence of at least one species of mammal at risk of extinction in the immediate vicinity of the site. Conversely, the likelihood of appeal is significantly reduced if (7) implementation is handled by Forest Service personnel or using a service contract, and (8) the proposed action is located in a Wildland–Urban Interface area. However, we also observe persistent regional effects, with fuels reduction proposals in Region 1 (3, 6, 8) characterized by a significantly higher (lower) likelihood of appeal than proposals in the other regions.
Landscape-Level Impact of Beech Bark Disease in Relation to Slope and Aspect in New York State
Authors: Munck I.A. , Manion P.D.
Published: April 2024

During the past 40 years, the beech bark disease complex has destabilized the beech component of New York State forests, but a selected portion of the American beech (Fagus grandifolia) population has attained a sustainable forest structure. The influence of slope and aspect in relation to beech bark disease on the sustainability of American beech populations was evaluated. There were differences in the proportion of American beech trees with signs of Neonectria spp. and beech scale (Cryptococcus fagisuga) on eastern and western aspects on slopes ≥16%. American beech populations on northern, northeastern, eastern, southeastern, and southern aspects on slopes ≥16% (23–29% of the sample) displayed diameter distributions that would sustain the current forest structure. In all other sites, observed percentage mortality in the large-diameter classes was higher than predicted, suggesting a future shift in forest structure toward lower densities of large trees in these sites.
Research and Development Operations and Foreign Expansion of Multinational Companies: Evidence from Forest Industry Microdata
Authors: Laaksonen-Craig Susanna , Uusivuori Jussi
Published: April 2024

This article examines the impacts of research and development on the mode of multinational expansion (exports versus foreign sales) by forest products companies, and the effects of firms' international strategy on the level of research and development investments. A theoretical model of imperfect competition between international companies is derived and company-level data representing Finnish forest industries are used. The results indicate that the firms' own research and development investments helped, at least during the 1980s, their foreign expansion by favoring the firms' exports rather than foreign sales. External research and development investments by other companies were substitutes for a firm's own investment on research and development in the 1980s, but this effect seems to have disappeared toward the 1990s. There have not appeared to be any significant spillover effects from the research and development activities across the firms.
Innovativeness in the North American Softwood Sawmilling Industry
Authors: Crespell Pablo , Knowles Christopher , Hansen Eric
Published: April 2024

The North American forest products industry has traditionally maintained a production orientation and a commodity mentality toward operations, with much of the industry following a low-cost strategy and concentrating on wood fiber recovery. The propensity to innovate (innovativeness) is important for maintaining firm competitiveness. To assess industry practices with respect to innovativeness, United States and Canadian softwood sawmills were surveyed. Respondents rated themselves more innovative with respect to manufacturing processes as compared to product and business systems innovations. Innovativeness and market orientation were found to be positively correlated. High- and medium-innovative mills were consistently different (e.g., more market-oriented, more structured new product development processes) from low-innovative mills.
Bootstrap Simulation and Response Surface Optimization of Management Regimes for Douglas-Fir/Western Hemlock Stands
Authors: Liang Jingjing , Buongiorno Joseph , Monserud Robert A.
Published: April 2024

A method was proposed to simulate forest stand growth, timber prices, and interest rates by distribution-free bootstrapping, and then optimize management controls for economic and ecological objectives by response surface analysis. The method was applied to Douglas-fir/western hemlock stands to predict the effects on economic and ecological objectives of management alternatives defined by the cutting cycle, C, the residual stand basal area, B, the diameter of the largest tree, D, and the ratio, q, of the number of trees in adjacent diameter classes. The effects were described with response surfaces, which were used to determine the best combinations of B, q, and C for each management criterion. Adjusting B, q, and C could control for 97 to 99% of the variability in the expected value of species diversity, size diversity, percentage of peeler logs, and basal area, and for 80 to 90% of the variability in land expectation value and annual production. Economic and ecologic criteria were generally most sensitive to the q ratio, the residual basal area, and the cutting cycle. Annual production was negatively correlated with tree size diversity and wood quality. There was no apparent conflict between stand diversity and wood quality.
Forest Volume and Biomass Estimation Using Small-Footprint Lidar-Distributional Parameters on a Per-Segment Basis
Authors: Aardt Jan A.N. van , Wynne Randolph H. , Oderwald Richard G.
Published: April 2024

This study assessed a lidar-based, object-oriented (segmentation) approach to forest volume and aboveground biomass modeling. The study area in the Piedmont physiographic region of Virginia is composed of temperate coniferous, deciduous, and mixed stands. Segmentation objects, hierarchical in terms of area and ranging from 0.035 to 5.632 ha/object, were created using a lidar-derived canopy height model. Horizontal point (basal area) samples were used to calculate volume and aboveground biomass. Per-object lidar point (per return height and intensity) distributional parameters were extracted from small-footprint lidar. Adjusted R 2 and Mallow's Cp metrics were used to select models for the range of segmentation results. Selected variables included intensity-based and structurally related first through fifth return height parameters. Object-based modeling (adjusted R 2 = 0.58–0.79; various object sizes) resulted in distinct improvements over stand-based attempts (adjusted R 2 = 0.40–0.73; majority adjusted R 2 < 0.50). Adjusted R 2 and RMSE values for deciduous volume (0.59; 51.15 m3/ha) and biomass (0.58; 37.41 Mg/ha) were better than those found for another, plot-based study in the study area. Coniferous R 2 values for volume (0.66) and biomass (0.59) were lower than previous studies, which was attributed to variability within the relatively narrow volume range (6.94–50.93 m3/ha).
A Generalized Approach for Modeling and Localizing Stem Profile Curves
Authors: Trincado Guillermo , Burkhart Harold E.
Published: April 2024

The Max and Burkhart segmented taper equation was fitted using nonlinear mixed-effects modeling techniques to account for within- and between-individual variation in loblolly pine (Pinus taeda L.) stem profiles. Within- and between-tree residual variances and spatial autocorrelation between residuals were incorporated in the model with an error variance function and a continuous autocorrelation structure, respectively. However, most of the residual autocorrelation was accounted for by including random effects. Upper stem diameter measurements were used to estimate random effects parameters using an approximate Bayesian estimator, which localized stem profile curves for individual trees. The procedure was tested with an independent data set. Measures of precision and bias showed that upper stem diameter measurements and subsequent estimates of random effects improved the predictive capability of the taper equation mainly in the lower portion of the bole. The method can localize stem curves for trees growing under different site and management conditions. It also represents a general framework that can be applied to other taper equation forms, increasing their flexibility and efficiency in prediction for local conditions.
Carbon and Nitrogen Cycling in Southwestern Ponderosa Pine Forests
Authors: Hart Stephen C. , Selmants Paul C. , Boyle Sarah I. , Overby Steven T.
Published: April 2024

Ponderosa pine forests of the southwestern United States were historically characterized by relatively open, parklike stands with a bunchgrass-dominated understory. This forest structure was maintained by frequent, low-intensity surface fires. Heavy livestock grazing, fire suppression, and favorable weather conditions following Euro-American settlement in the late 19th century resulted in a dramatic increase in pine regeneration. Today, many of these forest stands have high stand densities with low understory production, and are susceptible to infrequent, stand-replacing fires. The primary objective of our study was to better characterize the contemporary carbon (C) and nitrogen (N) cycling processes in relatively unmanaged southwestern ponderosa pine stands. We then compared these ecosystem conditions with those of an adjacent stand that had received an ecological restoration treatment that included thinning and prescribed burning. Our results suggest that N availability and aboveground net primary productivity (ANPP) of trees in these forests are low compared to other forests. Restoration treatments decreased ANPP but increased the proportion of ANPP in woody tissues. These treatments also increased soil respiration, water availability, temperature, and net nitrification, but had no effect on net N mineralization and microbial N. We speculate that the understory response to restoration treatments is a key factor affecting the overall ecosystem response in these forests.
Spatial Patterns of Modern Period Human-Caused Fire Occurrence in the Missouri Ozark Highlands
Authors: Yang Jian , He Hong S. , Shifley Stephen R. , Gustafson Eric J.
Published: April 2024

The spatial pattern of forest fire locations is important in the study of the dynamics of fire disturbance. In this article we used a spatial point process modeling approach to quantitatively study the effects of land cover, topography, roads, municipalities, ownership, and population density on fire occurrence reported between 1970 and 2002 in the Missouri Ozark Highland forests, where more than 90% of fires are human-caused. We used the AIC (Akaike information criterion) method to select an appropriate inhomogeneous Poisson process model to best fit to the data. The fitted model was diagnosed using residual analysis as well. Our results showed that fire locations were spatially clustered, and high fire occurrence probability was found in areas that (1) were public land, (2) within 6 km to 17 km of municipalities, and (3) <500 m from roads where forests are accessible to humans. In addition, fire occurrence probability was higher in pine-oak forests on moderate (<25 degree) slopes and xeric aspects and at higher (>270 m) elevations, reflecting the effects of natural factors on fire occurrence. The results serve as a provisional hypothesis for expanding fire risk estimation to surrounding areas. The spatial scale of analysis (approximately 1 ha) provides new information to guide planning and risk reduction efforts.
Sediment and Wood Routing in Steep Headwater Streams: An Overview of Geomorphic Processes and their Topographic Signatures
Authors: May Christine
Published: April 2024

Headwater streams in steep terrain pose a significant challenge for the development of best management practices (BMP) in forested watersheds. There is an incomplete understanding of the processes that govern the input, storage, and transport of sediment and wood, and these processes differ geographically. At the upstream extent of the channel network, headwater streams represent a transition from hillslope to channel processes. At the downstream extent, many of these channels transition from mass wasting to fluvial process dominance. Large-scale sediment routing processes typically consist of debris flows, earth flows, and/or gully erosion. In the interval between episodic transport events, headwater streams can interrupt the delivery of sediment from hillslopes to larger river systems by storing large volumes of sediment and wood. Forest management guidelines typically identify headwater streams as occurring upstream of the distribution of fish; however, a topographically based designation of headwater streams could prove useful for identifying which erosional processes are dominant in a particular area. Broad-scale terrain analysis based on unique topographic signatures can be used to identify the spatial domain of different geomorphic landforms that govern headwater stream processes, how they may be affected by forest management, and to infer the type and severity of downstream disturbance.
Influence of Headwater Streams on Downstream Reaches in Forested Areas
Authors: MacDonald Lee H. , Coe Drew
Published: April 2024

The source areas of headwater streams typically compose 60% to 80% of a catchment. This, plus the typical increase in precipitation with elevation, means that headwater streams generate most of the streamflow in downstream areas. Headwater streams also provide other important constituents to downstream reaches, including coarse and fine sediment, large woody debris, coarse and fine organic matter, and nutrients. The relative importance of headwater streams as a source of these other constituents is highly variable because the amount and quality of each constituent can be modified by in-channel storage, dilution, biological uptake, diminution, and chemical transformations. Headwater sources of water, fine sediment, and fine particulate organic matter are more likely to be delivered to downstream reaches than coarse sediment, woody debris, nutrients, or an increase in water temperatures. The complexity and temporal variability of channel-hillslope interactions, in-channel processes, and downstream conditions makes it difficult to rigorously link upstream inputs and anthropogenic activities to the condition of downstream resources. These issues may preclude the use of adaptive management, particularly in larger basins, as adaptive management implicitly assumes that (1) downstream changes can rapidly be detected, (2) management will change rapidly in response to any adverse change, and (3) a management change will rapidly improve the affected resource. Since these assumptions may be difficult to satisfy—particularly in larger basins—the use of adaptive management must be carefully examined before it can be applied at the watershed scale.
Riparian Buffer and Density Management Influences on Microclimate of Young Headwater Forests of Western Oregon
Authors: Anderson Paul D. , Larson David J. , Chan Samuel S.
Published: April 2024

Thinning of 30- to 70-year-old Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands is a common silvicultural activity on federal forest lands of the Pacific Northwest, United States. Empirical relationships among riparian functions, silvicultural treatments, and different riparian buffer widths are not well documented for small headwater streams. We investigated buffer width and density management effects on riparian microclimates of headwater streams in western Oregon. Spatial variations in stand density, canopy cover, and microclimate were measured along transects extending from stream center upslope into thinned stands, patch openings, or unthinned stands, with riparian buffers ranging from <5 m up to 150 m width. For treated stands, summer mean daily air and soil temperature maxima increased, and mean daily humidity minima decreased with distance from stream. Microclimate gradients were strongest within 10 m of stream center, a distinct area of stream influence within broader riparian areas. Thinning resulted in subtle changes in microclimate as mean air temperature maxima were 1 to 4°C higher than in unthinned stands. With buffers 15 m or greater width, daily maximum air temperature above stream center was less than 1°C greater, and daily minimum relative humidity was less than 5% lower than for unthinned stands. In contrast, air temperatures were significantly warmer within patch openings (+6 to +9°C), and within buffers adjacent to patch openings (+3°C) than within unthinned stands. Buffers of widths defined by the transition from riparian to upland vegetation or topographic slope breaks appear sufficient to mitigate the impacts of upslope thinning on the microclimate above headwater streams.
Vertebrate Assemblages Associated with Headwater Hydrology in Western Oregon Managed Forests
Authors: Olson Deanna H. , Weaver George
Published: April 2024

We characterized headwater stream habitats, fish and amphibian fauna, in and along 106 headwater stream reaches at 12 study sites within managed forest stands 40 to 70 years old in western Oregon. Headwater stream types in our sample included perennial, spatially intermittent, and dry reaches. We captured 454 fish of three species groups and 1,796 amphibians of 12 species. Using canonical correlation, nonmetric multidimensional scaling ordination, and generalized linear models, we identified species and assemblages associated with reach hydrologic type (e.g., perennial, intermittent, dry), stream size, gradient, and substrate composition. Our findings of torrent salamander (Rhyacotriton species) occurrences in spatially intermittent streams, and patchy and infrequent occurrences of Cottus fish (sculpins) and coastal tailed frogs (Ascaphus truei Stejneger) suggests these taxa warrant consideration during headwater management for retention of locally distinct biotic resources.
Structures Linking Physical and Biological Processes in Headwater Streams of the Maybeso Watershed, Southeast Alaska
Authors: Bryant Mason D. , Gomi Takashi , Piccolo Jack J.
Published: April 2024

We focus on headwater streams originating in the mountainous terrain of northern temperate rain forests. These streams rapidly descend from gradients greater than 20% to less than 5% in U-shaped glacial valleys. We use a set of studies on headwater streams in southeast Alaska to define headwater stream catchments, link physical and biological processes, and describe their significance within watersheds. We separate headwater stream systems into four units that have distinct hydrologic and geomorphic processes that link terrestrial processes to aquatic systems. Headwater streams collect, process, and transport material downstream. Physical and biological processes in headwater streams are complex and closely tied to terrestrial processes. Steps and step pools formed by large wood are keystone structures that link physical processes to biological processes and increase channel complexity. Large and coarse wood debris dams form in-channel step structures and act as valves that regulate the downstream flow of material. A large amount of inorganic and organic sediment is stored in step structures, which may be biological hotspots in headwater streams. Step pools formed by large woody debris are critical habitat for Dolly Varden (Salvelinus malma), juvenile coho salmon (Oncorhynchus kisutch), steelhead (O. mykiss), and cutthroat trout (O. clarkii) in reaches with gradients from less than 4% to those greater than 10%. Landslides and debris flows are the dominant channel-altering processes in headwater streams and remove the step profile. Management activities that increase the number and frequency of channel disturbance events in headwater streams can have important and long-term consequences throughout a watershed.
Modeling Pulpwood Trade within the United States South
Authors: Polyakov Maksym , Teeter Lawrence
Published: April 2024

Interregional trade of roundwood products is an important factor of regional roundwood markets. Until now, regional and subregional forest sector models did not account for the spatial aspects of roundwood markets. This article explores ways to model interregional trade of roundwood products. It compares the performance of different specifications of a gravity model (the model widely used in the analysis of international trade) and a fixed gravity coefficient model (common in regional input-output analysis) to forecast pulpwood trade between the states of the United States South. The gravity model estimated using nonlinear least-squares with fixed effects (NLS FEM) and the fixed gravity coefficient model (FGCM) showed the best results. Another important result of this study is the finding that the fixed gravity coefficients for pulpwood trade in the United States South are temporally stable. This suggests the possibility of using the FGCM for modeling roundwood trade in the absence of time series data.
Comparison of Methods to Estimate Reineke's Maximum Size-Density Relationship Species Boundary Line Slope
Authors: VanderSchaaf Curtis L. , Burkhart Harold E.
Published: April 2024

Maximum size-density relationships (MSDR) provide natural resource managers useful information about the relationship between tree density and average tree size. Obtaining a valid estimate of how maximum tree density changes with changes in average tree size is necessary to describe these biological relationships accurately. This article examines three methods to estimate the slope (b) of the MSDR species boundary line across a range of planting densities: ordinary least-squares (OLS), first-difference model, and the linear mixed-effects model. For this article, stability refers to the extent to which parameter estimates do not change when the range of planting densities in the fitting data set changes. When using data from a planting density trial consisting of planting densities ranging from 6,727 to 747 seedlings per hectare, mixed-effect models produced the most stable estimates of b while OLS resulted in the least stable estimates. MSDR boundaries have been defined as either (1) those that describe the boundaries of individual stands (MSDR dynamic thinning line) or (2) those that describe MSDRs common across all sites for a particular species in a certain geographical region (MSDR species boundary line). A further refinement of the MSDR species boundary line is proposed by defining two MSDR species boundary lines, labeled here as I and II. Although both MSDR species boundary lines are positioned above all observations, one MSDR species boundary line, II, has a slope that can be considered the population average of all MSDR dynamic thinning lines; the other species boundary line (I) has a slope that results from positioning the boundary above all observations without accounting for self-thinning patterns of individual stands. A mixed-effects analysis was used to estimate the slope of MSDR species boundary line II.
Modeling Tree Recruitment with Zero-Inflated Models: The Example of Hardwood Stands in Southern Québec, Canada
Authors: Fortin Mathieu , DeBlois Josianne
Published: April 2024

In recruitment modeling, the response variable is a count and its distribution is often characterized by an excess number of zeros. As a result, standard distributions of probabilities, such as Poisson, are inappropriate. A common approach in forestry consists of using two-part conditional models. These models have two distinct components aimed to predicting the occurrence and abundance of recruitment, respectively. For such data, zero-inflated models might provide a more adequate framework by combining the two components into a joint distribution of probabilities. In this article, a conditional model is compared with two different zero-inflated models, namely, a zero-inflated Poisson (ZIP) and a zero-inflated discrete Weibull (ZIdiW) model. The three models were calibrated using a data set provided by permanent sample plots located in hardwood stands. Parsimony criteria (the Akaike information criterion and the Bayesian information criterion) and diagnostic plots were used to perform the comparison. The results show that the ZIdiW model has the best fit. The flexibility of the Weibull function and the possibility of obtaining a more parsimonious model are two advantages related to the use of a ZIdiW model in recruitment modeling.
Ice Damage in Loblolly Pine: Understanding the Factors That Influence Susceptibility
Authors: Aubrey Doug P. , Coleman Mark D. , Coyle David R.
Published: April 2024

Winter ice storms frequently occur in the southeastern United States and can severely damage softwood plantations. In January 2004, a severe storm deposited approximately 2 cm of ice on an intensively managed 4-year-old loblolly pine (Pinus taeda L.) plantation in South Carolina. Existing irrigation and fertilization treatments presented an opportunity to examine the effects of resource amendments on initial ice damage and subsequent recovery. Fertilized treatments showed more individual stem breakage, whereas nonfertilized treatments showed more stem bending; however, the proportion of undamaged trees did not differ between treatments. Irrigation did not influence the type of damage. Trees that experienced breakage during the storm were taller with larger diameter and taper and leaf, branch, and crown biomass compared with unbroken trees. One growing season after ice damage, relative height increases were significantly greater for trees experiencing stem breakage compared with unbroken trees; however, relative diameter increases were significantly lower for these trees. Relative diameter increases for broken trees were smaller for fertilized treatments compared with nonfertilized treatments. A reduction in wood strength was ruled out as the cause of greater breakage in fertilized trees; rather, fertilized trees had reached an intermediate diameter range known to be susceptible to breakage under ice loading.
Biomass Removal, Soil Compaction, and Vegetation Control Effects on Five-Year Growth of Douglas-fir in Coastal Washington
Authors: Ares Adrian , Terry Thomas , Harrington Constance , Devine Warren , Peter David , Bailey John
Published: April 2024

Sustainable forest production requires an understanding of the effects of site disturbance on tree growth and the consequences of soil amelioration and vegetation control practices. We assessed the impacts of biomass removals at harvest, soil compaction and tillage, and vegetation control on early growth of Douglas-fir in coastal Washington. Harvest treatments included removal of commercial bole only (BO), bole only up to 5-cm top diameter (BO5), total tree (TT), and total tree plus all legacy coarse woody debris (TTP). Vegetation control (VC) effects were tested in BO, while soil compaction (BO/SC) and compaction plus tillage (BO/SCT) were imposed in BO/VC. Five years after planting, biomass removal and soil compaction/tillage effects on tree growth were relatively small. At year 5, mean stem basal diameter in BO was greater than in TT, whereas mean height was similar in BO and BO/SC, but increased in BO/SCT. Control of competing vegetation markedly increased tree growth. At year 5, mean tree stem diameter at 1.3-m height (dbh) and height in BO/no vegetation control (NVC) were 34 mm and 308 cm, respectively, compared to 45 mm and 357 cm in BO/VC (P <0.01). Mean relative growth rate in stem diameter for trees in BO/VC was greater than in BO/NVC in years 2–4, but this trend reversed in year 5, suggesting that tree intraspecific competition may be greater in BO/VC than in BO/NVC. Vegetation control also increased second-flushing (i.e., the flushing of set buds in late summer) in years 4 and 5. Vegetation competition effects on tree growth appeared to be related to changes in available soil water rather than to competition for nutrients.
δ15N Patterns of Douglas-Fir and Red Alder Riparian Forests in the Oregon Coast Range
Authors: Scott Emily E. , Perakis Steven S. , Hibbs David E.
Published: April 2024

We used naturally occurring stable isotopes of N to compare N dynamics in near-stream and upslope environments along riparian catenas in N-fixing red alder (Alnus rubra) and Douglas-fir (Pseudotsuga menziesii) forests in the Coast Range of western Oregon. Based on the existing literature, we expected soil δ15N to be enriched closer to streams owing to inputs of isotopically heavy, marine-derived N by spawning salmon, higher rates of denitrification near the stream, or both. However, it has been unclear what effect red alder might have on soil δ15N patterns near streams. We found a consistent −1‰ δ15N signature in red alder foliage, and δ15N of total N in soils under red alder averaged 2.2‰ along sampling transects extending 20 m upslope from the stream. Surprisingly, δ15N of total N in soil under Douglas-fir was progressively depleted nearer to streams, opposite from the pattern expected from N losses by denitrification or N inputs from anadromous salmon. Instead, δ15N of total N in soil under Douglas-fir converged toward soil δ15N values typical of red alder sites. We consider that the historic presence of red alder may have contributed a legacy of lower soil δ15N nearer to streams on sites that are currently dominated by young Douglas-fir forest.
Differences in Spruce Budworm Defoliation among Balsam Fir and White, Red, and Black Spruce
Authors: Hennigar Chris R. , MacLean David A. , Quiring Dan T. , Kershaw John A.
Published: April 2024

Spruce budworm (Choristoneura fumiferana Clem.) outbreaks severely reduce growth and survival of balsam fir (Abies balsamea [L.] Mill.) and spruce (Picea spp. A. Dietr.) over much of eastern North America, resulting in major reductions in yield and disruption of harvest schedules. This is the first study to rigorously quantify defoliation differences among all four spruce budworm host tree species at a stand level. An extensive permanent sample plot data set, with more than 27,000 tree and 1,117 stand measurements from 1984 to 1992 in New Brunswick, Canada, revealed a clear and consistent hierarchy of host species defoliation susceptibility. Regardless of defoliation severity and other stand variables tested, white (Picea glauca [Moench] Voss), red (Picea rubens Sarg.), and black spruce (Picea mariana [Mill.] B.S.P.) had approximately 72, 41, and 28% as much defoliation as balsam fir, respectively. Balsam fir defoliation was a highly significant predictor of white, red, and black spruce defoliation. Of the variation in defoliation of red-black spruce hybrids, 34% was explained by balsam fir defoliation and an interaction with spruce hybrid index. This is the first model to quantify hybrid red-black spruce defoliation across a full range of severities. Quantitative models of stand-level defoliation differences among host species will improve spruce budworm stand impact forecasts and decision support prioritization of bioinsecticide or salvage operations and provide information to calibrate population-defoliation models for host species in mixed species stand types.
Characterizing Family Forest Owners: A Cluster Analysis Approach
Authors: Majumdar Indrajit , Teeter Lawrence , Butler Brett
Published: April 2024

For policy implementation to promote better stewardship on family forestlands, it is necessary to understand what motivates landowners. This study characterizes family forest owners in Alabama, Georgia, and South Carolina, based on their feelings about forest stewardship and their stated reasons for owning forestland. Multivariate cluster analysis suggests that family forest owners are, in fact, a diverse set of owners who can be grouped into three attitudinal types, namely, multiple-objective, nontimber, and timber. The multiple-objective ownership type was found to be the largest group (49.1% of respondents) with almost half the family forest owners in the sample population belonging to this category. Owners belonging to the timber cluster (29.4%) indicated only timber management and land investment as strong motivating factors behind their forestland ownership, whereas owners belonging to the nontimber cluster (21.5%) value the nonconsumptive uses of their forestland such as aesthetic values, biodiversity, recreation, and privacy.
An Integrated Approach to Evaluating the Economic Costs of Wildfire Hazard Reduction through Wood Utilization Opportunities in the Southwestern United States
Authors: Lowell Eini C. , Becker Dennis R. , Rummer Robert , Larson Debra , Wadleigh Linda
Published: April 2024

This research provides an important step in the conceptualization and development of an integrated wildfire fuels reduction system from silvicultural prescription, through stem selection, harvesting, in-woods processing, transport, and market selection. Decisions made at each functional step are informed by knowledge about subsequent functions. Data on the resource characteristics of small-diameter ponderosa pine (Pinus ponderosa Dougl. ex Laws.), harvest equipment productivity, lumber recovery, and net profit (loss) by level of fuels reduction achieved were collected from four 8.1-ha (20 ac) sites in northern Arizona. These data were used to develop a Windows-based, financial and engineering software program, the harvest cost-revenue (HCR) estimator, to identify the economic costs of wildfire fuel reduction treatments that may be used to evaluate cost per acre thresholds for logging contractors, appraise contract bid rates, or assess stumpage values for ponderosa pine stands in the southwestern United States. Application of the model illustrates variability in fuels reduction costs owing to the level of fuels reduction achieved, the volume of merchantable wood removed from different forest stands, and the availability of markets for removed material. Machine productivity helps predict differences in harvest costs but is secondary to market constraints and the volume of wood harvested.
Bivariate Distribution Modeling of Tree Diameters and Heights: Dependency Modeling Using Copulas
Authors: Wang Mingliang , Rennolls Keith , Tang Shouzheng
Published: April 2024

Models of diameter and height distributions play an important role in forest mensuration and inventory, and many models and fitting methods are available for fitting these distributions separately. Very few models and methods appropriate for fitting the joint distribution of diameters and heights are available. The S BB and distributions obtained using Plackett's method are the only appropriate models published in the forestry literature to date. A bivariate joint distribution can be represented in terms of its underlying marginals and a copula function that models the dependency structure. A copula is a function that joins or “couples” a multivariate distribution function to its one-dimensional marginal distributions. The copula approach provides a general way of constructing bivariate distributions, including previously used bivariate models. The basics of the copula representation, the most useful copula functions, and maximum likelihood estimation (MLE) of the copula function are introduced. The emphasis of this article is on the choice of copula function(s) appropriate for modeling the joint distribution of tree diameters and heights. Using an empirical dataset of 102 Chinese fir (Cunninghamia lanceolata Lamb.) plantation plots, we fit each of the copula functions that we considered to each sample-plot joint distribution of tree diameters and heights. A two-stage MLE approach with a nonparametric (empirical) approach to the marginal distributions is adopted. In this case study the normal copula proves to be the best for modeling the joint distribution (dependence) of tree diameters and heights.
Generalized Algebraic Difference Approach Derivation of Dynamic Site Equations with Polymorphism and Variable Asymptotes from Exponential and Logarithmic Functions
Authors: Cieszewski Chris J. , Strub Mike
Published: April 2024

The generalized algebraic difference approach (GADA) uses both: two-dimensional functions of explicit time and two-dimensional functions of explicit site to derive a single dynamic equation that is a three-dimensional function of explicit time and implicit site. In 2004 Cieszewski advanced dynamic site equations with polymorphism, and variable asymptotes (Cieszewski, C.J. 2004. GADA derivation of dynamic site equations with polymorphism and variable asymptotes from Richards, Weibull, and other exponential functions. PMRC Tech. Rep. 2004-5, p. 16.) were built with GADA using one general function of time T and two general functions of site X. The function of time is the exponential function Y = MTb , and the functions of site are the quadratic function Z = b1 + b2X + b3X 2 and the inverse half-saturation function Z = b1 + b2/(X + b3). We discuss the new dynamic equations based on five exponential substitutions (Richards, Gompertz, Korf, logistic, and log-logistic) and one new logarithmic model substitution in the exponential function of time and 10 special cases of the two functions of site corresponding to their different parameter values. The new dynamic equations presented offer breakthrough flexibility in modeling of the self-referencing dynamics with the exponential and logarithmic functions considered in this article.
A Geographically Weighted Regression Analysis of Douglas-Fir Site Index in North Central Idaho
Authors: Kimsey Mark J. , Moore James , McDaniel Paul
Published: April 2024

An analysis of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. glauca) site index (SI) was performed in north central Idaho using two forms of linear regression: standard multiple linear regression (MLR) and geographically weighted regression (GWR). The hypothesis was that the GWR model would provide better estimates of SI using edaphic, topographic, and climatic predictor variables than ordinary MLR. Elevation, volcanic ash depth, slope, and aspect were significantly correlated with Douglas-fir SI (R A 2 = 0.5). GWR accounted for an additional 29% of the variation in SI and reduced the error sum of squares by approximately 53%. The geographically weighted parameter estimates of the model intercept and elevation were nonstationary, which indicates that geographic location determines the influence of a variable on SI. Residual analysis from a MLR model showed large SI prediction error throughout the study area. This prediction error was significantly reduced using the GWR model. GWR shows promise for biological modeling.
Suppression Cost Forecasts in Advance of Wildfire Seasons
Authors: Prestemon Jeffrey P. , Abt Karen , Gebert Krista
Published: April 2024

Approaches for forecasting wildfire suppression costs in advance of a wildfire season are demonstrated for two lead times: fall and spring of the current fiscal year (Oct. 1–Sept. 30). Model functional forms are derived from aggregate expressions of a least cost plus net value change model. Empirical estimates of these models are used to generate advance-of-season forecasts. Cost forecasts involve estimation of suppression cost equations by geographical region based on a time series of historical data (1977–2006) of costs, a time trend, and climate variables, forecasts of the next season's suppression costs, by region and in total across all regions, and generation of suppression cost forecast probability distributions by region and in aggregate. The forecasts are also evaluated historically for their goodness of fit using cross-validation techniques. The two lead time forecast models are compared with the 10-year moving average of suppression costs, currently used as a budget request formula by the US Forest Service. Results show that the spring forecast of suppression costs is statistically no better than the fall forecast for predicting the coming season's costs. However, both the spring and fall forecasts significantly outperform the 10-year moving average, reducing forecast errors by approximately 60%.
Adjacency Branches Used To Optimize Forest Harvesting Subject to Area Restrictions on Clearfell
Authors: McNaughton Alastair J. , Ryan David
Published: April 2024

Consider a forest containing units of various sizes for which a maximum clearfell area has been specified along with an associated green-up time period. For such an application it is customary to use adjacency constraints to produce a harvesting plan. These constraints control the availability for harvest of specific units relative to the harvesting of certain adjacent units. However, such constraints are difficult to formulate and often precipitate major difficulties in the implementation of the solution algorithm. A new concept, a nuclear set, is introduced. This concept allows the unit-specific aspects of the problem to be analyzed in an insightful manner. Any adjacency violation can be detected in relation to these nuclear sets. Suitable adjacency branches can be implemented to remove these violations. The form of these branches derives from the same nuclear sets. A remarkably small number of these branches are required to obtain a feasible solution. These ideas are incorporated into a column generation and constraint generation model. This new forest harvesting model solves the clearfell area restriction problem in an exact sense. Results are included for numerical trials involving simulated data representing moderately sized applications with a planning horizon of up to one rotation. The output from these trials suggests that this algorithm is suitable for large commercial applications. Several applications of 1,600 units are solved over 25 time periods with multiple green-up.