Search Results (11)

The Elliott State Research Forest comprises 33,700 ha of temperate, Douglas-fir rainforest along North America’s Pacific Coast (Oregon, United States). In 2015, naturally regenerated stands at least 92 years old covered 49% of the research area and sawtimber plantations younger than 68 years another 50%. During the winter of 2015–2016, a forest wide inventory sampled both naturally regenerated and plantation stands, recording 97,424 trees on 17,866 plots in 738 stands. The resulting dataset is atypical for the area as plot locations were not restricted to upland, commercially harvestable timber. Multiage stands and riparian areas were therefore documented along with plantations 2–61 years old and trees retained through clearcut harvests. This dataset constitutes the only open access, stand-based forest inventory currently available for a large area within the Oregon Coast Range. The dataset enables development of suites of models as well as many comparisons across stand ages and types, both at stand level and at the level of individual trees. Full article

Hurricane and tornado events cause significant damage to high-value timber in the United States each year. Forest managers and landowners are keenly interested in finding solutions to salvage and repurpose these downed timbers before they cause pest infestations and fire outbreaks, completely losing their value or increasing processing costs. To better understand the wood quality of the downed timber, we used acoustic waves techniques as a nondestructive testing approach to assess the wood degradation rate of downed trees and determine the extent of fracture and voids in the damaged regions. We periodically monitored the acoustic velocity of the downed trees for 12 consecutive months using a time of flight (TOF) acoustic method. Acoustic measurements were conducted using three different techniques—longitudinal, transverse, and off-set methods. Wood density, age, and the diameter at breast height (dbh) class measurement for southern timber (chip-n-saw for dbh 8″–11″ and sawtimber with dbh 12″ and up) were used as the predictive parameters of the downed trees. The results indicated positive relationships between dbh class, stand age, and acoustic velocity measurement (R² > 65%). The TOF acoustic velocity was indicated to potentially separate higher-stiffness timber from lower-stiffness timber in a hurricane event for structural or non-structural applications. The regression coefficient from the repeated measurements indicated that both age and diameter class strongly impacted the acoustic properties of the downed trees (p-value ≤ 0.001). The sawtimber dbh class recorded a higher acoustic velocity compared to the chip-n-saw type. Fracture, voids, and massive decay in downed trees were detected beyond the visible inspection, features that often are identified by loggers in lower quality wood; however, TOF showed a weak response in picking up incremental deterioration due to changes in specific environmental factors that affected acoustic readings. This study showed that acoustic wave methods could potentially be used as a field evaluation tool for assessing the quality of downed trees. Full article

The southeastern United States is widely regarded as a leading region for intensively managed, short rotation pine forests. One drawback of this intensive approach is the production of more juvenile wood with lower quality properties that are less desirable for solid end uses. Improved construction sectors (e.g., housing) demand larger diameter sawtimbers. Delaying the final harvest allows for the production of larger diameter higher quality solid wood; however, this approach may incur additional costs to the landowner, which may disincentivize extending the rotation without additional monetary compensation. Sawmills are a primary consumer of pine sawtimber and exert a strong influence on stumpage prices. Therefore, understanding the importance of wood quality to sawmills is important for understanding price dynamics. To explore this aspect, we conducted a mail survey of softwood sawmills in the southeastern United States to determine willingness to pay price premiums for higher quality pine sawtimber. Most sawmills (57%) were willing to pay price premiums. The mean willingness to pay, estimated using a tobit regression, ranged from USD 4.22/ton to USD 12.98/ton. Sawlog size, procurement radius, sawlog grade, and the number of employees positively influenced sawmills’ willingness to pay a price premium for higher quality sawtimber, while sawmills’ processing capacity and the number of years in business had a negative impact. The results will be useful to landowners considering delaying the final harvest to grow large diameter sawtimber. Full article

This paper describes a new method for detecting individual tree stems that was designed to perform well in the challenging hardwood-dominated, mixed-species forests common to the northeastern U.S., where canopy height-based methods have proven unreliable. Most prior research in individual tree detection has been performed in homogenous coniferous or conifer-dominated forests with limited hardwood presence. The study area in central Pennsylvania, United States, includes 17+ tree species and contains over 90% hardwoods. Existing methods have shown reduced performance as the proportion of hardwood species increases, due in large part to the crown-focused approaches they have employed. Top-down approaches are not reliable in deciduous stands due to the inherent complexity of the canopy and tree crowns in such stands. This complexity makes it difficult to segment trees and accurately predict tree stem locations based on detected crown segments. The proposed voxel column-based approach has advantages over both traditional canopy height model-based methods and computationally demanding point-based solutions. The method was tested on 1125 reference trees, ≥10 cm diameter at breast height (DBH), and it detected 68% of all reference trees and 87% of medium and large (sawtimber-sized) trees ≥28 cm DBH. Significantly, the commission rate (false predictions) was negligible as most raw false positives were confirmed in follow-up field visits to be either small trees below the threshold for recording or trees that were otherwise missed during the initial ground survey. Minimizing false positives was a priority in tuning the method. Follow-up in-situ evaluation of individual omission and commission instances was facilitated by the high spatial accuracy of predicted tree locations generated by the method. The mean and maximum predicted-to-reference tree distances were 0.59 m and 2.99 m, respectively, with over 80% of matches within <1 m. A new tree-matching method utilizing linear integer programming is presented that enables rigorous, repeatable matching of predicted and reference trees and performance evaluation. Results indicate this new tree detection method has potential to be operationalized for both traditional forest management activities and in providing the more frequent and scalable inventories required by a growing forest carbon offsets industry. Full article

Forests are used to mitigate anthropogenic greenhouse gas (GHG) emissions through carbon offset programs, and forest management is generally accepted as “carbon neutral”. However, forest harvesting operations depend heavily on fossil fuels, so it would be remiss to broadly paint all forms of management as carbon neutral without empirical verification of this claim. Biomass feedstock, as a means to supplant fossil fuel consumption, has received the bulk of investigative efforts, as the carbon benefit of biomass is one of the most contentious among wood products, because it does not create long-term carbon storage. A life cycle assessment (LCA) was conducted on a winter shelterwood harvest occurring in the Adirondacks of upstate New York. Primary data were collected daily throughout the operation and used to model the impact attributed to producing clean chips and logs for delivery to a pulp mill and sawmill, respectively. This harvest produced 4894 Mg of clean chips and 527 Mg of sawtimber. We calculated that 39.77 and 25.16 kg of carbon dioxide equivalent were emitted per Mg of clean chips and sawtimber, respectively, with a total observed flow of GHG into the atmosphere between 206 and 210 thousand kilograms. The results contribute to our understanding of the global warming potential of implementing a forest harvest to produce raw materials for medium- and long-term carbon storage products such as paper and dimensional hardwood lumber. Full article

The objective of the study was to verify the applicability and usefulness of time series decomposition in analyzing the variability of timber prices and supply in Poland. The employed multiplicative model was the product of four components: cyclical, seasonal, and irregular fluctuations and the long-term trend. The elements of the time series were determined by means of the Census X11 method, while cyclicality was separated from the trend employing the Hodrick–Prescott filter. Data included quarterly information about the supply (volume) and prices (value) of the timber sold by the State Forests in the years 2005–2018. Analyses were performed for tree species with the greatest economic significance, that is, pine, oak, spruce, beech, birch, and alder, and for their most popular assortments: general purpose large-diameter timber (W0) and medium-diameter timber (S2A). Time series decomposition of quarterly timber production volume and prices revealed irregular, seasonal, and cyclic fluctuations. Within an annual time horizon, irregular fluctuations accounted on average for 6.7% and 28% of overall variability in timber prices and supply, respectively; they exhibited low amplitudes (+5%, −25%, respectively). Cyclical fluctuations were primarily found for prices and were characterized by substantial variations in cycle length (2–4 years) and change amplitude (3–27 Euros). Cyclical fluctuations in timber prices and supply were usually negatively correlated with each other: the upper turning points of price cycles fell near the lower turning points of supply cycles (with a shift of 1 to 3 quarters). The seasonality of prices was also inversely correlated with supply: quarters with low supply exhibited higher prices and vice versa. Seasonal fluctuations were more pronounced for timber supply (36%) as compared to timber prices (20.3%). Different seasonality patterns were found for hardwood and softwood. The lowest supply of softwood was found in the first quarter and the highest in the third quarter (spruce) or fourth quarter (pine). The supply of hardwood was the highest in the first quarter and the lowest in the third quarter. Full article

Understanding forestry practices cost is important for predicting the financial outcome of forest management activities. Assessing costs of practices that will be used in the future can be difficult and may result in over or underestimations of financial returns depending on the values used. We used historic real average rates of cost change for the southern United States to assess changes in the values of several loblolly pine plantation management scenarios over time through the use of discounted cash flow (DCF) analysis. Additionally, we analyzed the impact of certain practices cost changes on the financially optimal number of thinnings and rotation age. Findings indicated that declining costs for herbicide site preparation could all but offset the increasing costs of other practices and that a relatively slight increase in timber prices would more than compensate for increasing costs. Also, increasing thinning costs could exacerbate the effects of low sawtimber prices, further decreasing the viability of regimes with multiple thinnings. In the face of stagnant timber prices, the use of operator-select thinnings, and herbicide site preparation could stabilize the long-term financial value of plantation management. Full article

Softwood chip-n-saw (CNS) is a relatively new stumpage product in the sawtimber- and pulpwood-dominated stumpage markets in the U.S. South. Based on a quarterly data series from 2003 to 2016, this study estimates the demand and supply models of the softwood CNS stumpage market in Louisiana. The two-stage least squares (2SLS) results reveal that own price elasticity of demand (PED) is price elastic, and the cross-price elasticity (XED)with sawtimber approaches unit elasticity. On the supply side, CNS is price inelastic in supply (PES), but more responsive to own price changesthan sawtimber quantity supplied. Further, severance tax increases are found to decrease the supply of CNS, indicating that suppliers are responsive to severance tax incidence. As the first empirical estimation of CNS, the findings should be of interest to those involved in the analysis of Southeastern stumpage markets. Full article

The South-Central United States, which includes the states of Louisiana, Mississippi, Texas, and Arkansas, represents an important segment of the softwood sawtimber market. By using the Seemingly Unrelated Regression (SUR) method to account for the linkage among the four contiguous timber markets, this study examines the dynamics of softwood sawtimber stumpage markets within the region. Based on quarterly data from 1981 to 2014, the findings reveal that both pulpwood and chip-and-saw (CNS) prices have a positive influence on the Texas and Arkansas sawtimber markets. Moreover, Granger-causality tests suggest that unidirectional causality runs from pulpwood and CNS markets to the respective sawtimber market. Compared to the pre-financial crisis period, sawtimber prices in these four states are 9%–17% lower in the recent years. Full article

We evaluated even- and uneven-aged silvicultural options for slash pine (Pinus elliottii Engelm.) using empirical data and the Forest Vegetation Simulator (FVS) model. Data were collected from a mature unthinned slash pine plantation in a flatwoods site in Florida, and used to simulate six scenarios of even- and uneven-aged silvicultural regimes applied to slash pine stands, including a no-action option. These alternative silvicultural regimes were evaluated for multiple benefits including timber production, carbon storage and stand structural diversity over a period of 100 years. None of the silvicultural regimes maximized all the benefits. While even-aged management options were more efficient in total merchantable timber production (9.78 to 11.02 m³·ha⁻¹·year⁻¹) and overall carbon stocks (3.05 to 3.47 metric tons·ha⁻¹·year⁻¹), uneven-aged management options created overall more complex stand structure (Stand Structural Diversity (computed from Shannon’s Indices values) = 1.92) and maintained a steady flow of yields, particularly sawtimber (34.29 to 58.46 m³·ha⁻¹ every 10 year) and aboveground carbon stocks (56.9 to 77.2 metric tons·ha⁻¹). Optimal achievement of multiple benefits across the landscape, therefore, may require maintaining an assortment of management strategies. Both even- and uneven-aged management options have the potential to improve production and carbon storage of pine forests and are a substantial improvement over no action. Full article

Regression models to predict stand size classes (sawtimber and saplings) and categories of species (hardwood and softwood) from fractal dimensions (FD) and Moran’s I derived from Landsat Thematic Mapper (TM) data were developed. Three study areas (Oakmulgee National Forest, Bankhead National Forest, and Talladega National Forest) were randomly selected and used to develop the prediction models, while one study area, Chattahoochee National Forest, was saved for validation. This study has shown that these spatial analytical indices (FD and Moran’s I) can distinguish between different forest trunk size classes and different categories of species (hardwood and softwood) using Landsat TM data. The results of this study also revealed that there is a linear relationship between each one of the spatial indices and the percentages of sawtimber–saplings size classes and hardwood–softwood categories of species. Given the high number of factors causing errors in the remotely sensed data as well as the Forest Inventory Analysis (FIA) data sets and compared to other studies in the research literature, the sawtimber–saplings models and hardwood–softwood models were reasonable in terms of significance and the levels of explained variance for both spatial indices FD and Moran’s I. The mean absolute percentage errors associated with the stand size classes prediction models and categories of species prediction models that take topographical elevation into consideration ranged from 4.4% to 19.8% and from 12.1% to 18.9%, respectively, while the root mean square errors ranged from 10% to 14% and from 11% to 13%, respectively. Full article