Landscape-scale disturbance and boreal forest birds: Can large single-pass harvest approximate fires?

Boreal forest birds have adapted to changes caused by natural disturbances such as fire and this adaptation forms the basis for the Natural Disturbance Paradigm (NDP) underlying recent proposed changes in forest harvesting practices in western Canada. To date, this paradigm has been evaluated primarily at the stand level and within conventional harvesting systems. The potential for improvements in avian conservation at the landscape scale by adopting the NDP approach is largely unknown. We examined the effects of landscape-scale disturbances on forest bird communities by contrasting richness and abundance of birds in (1) 16 single-pass harvest sites with residual forest patches, (2) 29 multi-pass harvest sites with residuals; and (3) 15 salvage-logged post-fire sites with variable harvest intensity. We contrasted bird communities in these treatments with those in unsalvaged post-fire sites of similar age. Post-fire sites were used to provide a metric of the Natural Range of Variation (NRV) to be expected in bird communities. Sites were surveyed for avian community composition and abundance 1–5 years post-disturbance. Redundancy analysis indicated that bird communities differed from the NRV in all of the harvest treatments. However, single-pass harvests provided a somewhat better fit to NRV than did multi-pass harvesting. Avian community similarity was influenced by non-linear responses to area harvested, amount of residual retention, residual composition and pre-disturbance forest composition. An optimization routine created from a General Linear Model, suggests that community similarity to NRV can be maximized by using single-pass harvests over multi-pass harvests, harvesting 66–88% of the timber in the planning unit, and retaining 5–19% of the disturbance area as live residual patches, with 50% of harvests having at least 9% of the area in residuals.     

A marginal cost analysis of trade-offs in old-growth preservation in Ontario

The paper examines the economic impacts of sustainable forest management (SFM) policies in Canada. Specifically, the marginal costs (MC) of old-growth preservation in an even-aged boreal forest in northeastern Ontario are examined under the condition that forest managers need to achieve multiple objectives for SFM. Furthermore, the trade-offs of old-growth preservation are estimated, allowing the levels of three specific SFM objectives to vary, namely, providing a consistent supply of timber in each period, meeting terminal volume targets at the end of the planning horizon, and maintaining a desired age structure of the forest. MCs are higher for harvesting regimes constrained by SFM objectives compared with that in which only profit maximization is considered. We observed that MCs for these three scenarios varied more when the area allotted for old-growth preservation is small. When the area of protected old-growth forest reaches about 66% of the maximum possible, the MCs are almost the same. All MCs are iso-elastic. The even-flow volume per period has the highest marginal cost among the three cases. If managers choose to provide terminal volume that is greater than or equal to the initial volume, instead of a lesser terminal volume, then old-growth forest can be preserved at no extra cost. The study emphasizes the need for integrated and simultaneous achievement of complementary goals of SFM for better economic return and minimization of the negative economic impact of SFM on the forestry sector.     

Structuring a landscape by forestland classification and harvest scheduling spatial constraints

Landscape environmental features, such as disturbance susceptibility, biological diversity and aesthetics, depend on the forest spatial structure and on the characteristics of its component stands. Strategies for forestland classification are key for managing for spatial heterogeneity as they provide the setting for the layout of land use activities. The design of management units boundaries may further contribute to meet specific spatial conditions. In this paper, two alternative land-classification strategies are presented. They are applied to one test forest with about 12,000 ha. The forest management is constrained by the definition of an exclusion period — the minimum number of years between clearcuts of adjacent management units. Land transformation and fragmentation by harvest scheduling over a temporal horizon with eight ten-year periods is analyzed within the framework of each strategy. Landscape mosaics in each planning period are characterized by spatial statistics, such as the number of patches, average patch area, and the amount and type of edge and interior space. Results from three test computer runs are discussed. They show that land classification has a substantial impact on the spatial dynamics of the forested landscape. They further suggest that timber opportunity costs are not sensitive to the strategy used to classify the land as long as a scheduling model is used to help in management planning.     

Leakage of forest harvest changes in a small open economy: case Norway

The effect of changes in roundwood harvests in Norway on the harvests in rest of the world is examined using a global forest sector model. About 60–100% of the harvest change in Norway is offset by an opposite change in the rest of the world. Such leakage rates vary over time, wood category, background scenario, and the size of the harvest change. Asymmetries between the effects of increasing and decreasing the harvests also exist. Hence, the magnitude of leakage rate is case specific, though considerable. Under tightening wood supply there is less need/room to respond to harvest increase/decrease in Norway with incremental/reduced harvests elsewhere. When the use of global forest resources intensifies with increasing wood demand in the future, leakage rates can be smaller than today. It is important to account for harvest leakage in order to avoid overestimating the climate benefits of policies that decrease or increase roundwood harvests. For instance, for full carbon sequestration benefits of increasing harvests for harvested wood products, creating fresh additional demand for these products should be prioritized. Else the origin of raw material and the place of production for these products may change instead of their stock.     

Comparing different forest zoning options for landscape-scale management of the boreal forest: Possible benefits of the TRIAD

Forest management has been criticised in the last 20 years for its negative impact on the native species, structures and functions of the forest. Of many possible alternatives proposed to minimize these effects, the functional zoning (or TRIAD) approach is gaining popularity in North America. The goal of this approach is to minimize the negative environmental impacts of forestry while maintain timber supply by dividing the forest into three broad land-use zones: (1) conservation, (2) ecosystem management, and (3) wood production. In this study, we used a spatially explicit landscape model to simulate the effects of fire and six different forest management scenarios on a boreal mixedwood forest management unit in central Quebec. The management scenarios examined included the current practices scenario, a scenario proposed by the provincial government, and four TRIAD scenarios varying in the amount of forest allocated to each of the three zones. For each scenario, we examined the harvest volume, percentage old-growth forest or old forest managed to favour old-growth attributes, and effective mesh size of forest patches by 20-year age classes. With more area set aside for conservation and high-retention partial cut harvesting techniques designed to maintain the attributes of old-growth stands, all TRIAD scenarios resulted in higher percentages of stands with old-growth attributes than the current practices scenario and the government proposed scenario, and two of the four TRIAD scenarios also resulted in higher harvest volume over the long term. All forest management scenarios resulted in significantly lower effective mesh size than the fire-only scenario, but this difference was not as pronounced for the four TRIAD scenarios as for the current practice and government proposed scenarios. We conclude that the TRIAD approach has the potential to minimize some of the negative impacts of forestry on the landscape, while maintaining timber supply over the long term.     

Improving long-term management plans for a forest plantation in Tanzania,using linear programming

Long-term planning for the management of multiple-species plantation forests can be a difficult undertaking, particularly when the forests have been created by afforestation over several decades so that the age-class structure of the compartments is seriously unbalanced. A time-staged linear-programming model is developed to assist forest managers in such situations. The model is expressly designed to be small enough to permit solutions with microcomputers of the type available to forest managers even in many developing countries. Investigations with the model for a forest project in Tanzania indicate that such models must be formulated to explicitly consider the structure of the forest at the planning horizon. Otherwise, harvesting schedules that seem to satisfy all of the forest manager's requirements during the planning horizon may lead to disastrously unbalanced harvesting patterns beyond the planning horizon.     

The forest planning system in relation to the forest resource and forestry policies

The current forest planning system of Japan has been in place since the formulation of the Forest Law back in 1897. During this time, although addressing specified forests as demonstrated in the system for protection forests, in a more general sense, the execution of the forest planning system has placed forestry management at the core. In other words, it has instead been forest administration delivered in a manner relevant to forestry management. This trend is exhibited in, for instance, policies for the reorganization of common forest, the forest management planning system, forest owners associations, the proceeds-sharing reforestation system, cooperative silviculture management, and valley forestry revitalization; which have all been implemented.In this paper I review the results of these practices and explore the contemporary forest owners pattern of behavior. I also discuss the passive attitudes among forest owners, especially in comparison with the attitudes prevalent during the postwar reforestation era, continuing up to the 1960s, and the current tendency towards neglect in the afforested areas, as well as the increasing number of forest owners giving up forestry practice.In the postwar era (up to the 1960s), forestry had been following an upward trend of development that motivated forest owners to afforest, as this was the optimal choice for increasing the familys stocks for future generations (in the manner of holding an asset), and thus a rapid expansion of plantation forests resulted. By the 1970s, when domestic wood supply became less than a half of all domestic wood demand (it is still declining now), forest owners gradually began to lose interest in reforestation and care of the forest as a method of increasing assets. The current share of domestic wood supply in total consumption has dropped to 20%, and the annual cut volume is only 23% of the annual volume increment.Forests are as much a public property as they are private and, moreover, represent a globally significant resource. Active stewardship, such as materializing internationally agreed notions of sustainable forest management, promoting forest certification systems, and complying with the Kyoto Protocol, are now important issues, both domestically and internationally.The paradoxical gap between current forestry trends and public aspirations for forests is widening with each year, thus creating a grave social problem. I have been focusing on forestry revitalization as the primary step towards the resolution of this issue. As the logical basis for executing this policy, I review the relations between forest resource policies and forestry policies.At the same time, by reviewing the forest planning system and its developmental process, I sought to investigate what new policies would fulfill the need to realize the public functions of forests while revitalizing forestry, form the point of view of forestry policies and their influence on the forest planning system. I have concluded that there is a case for separating forest management from forest ownership in units of forest compartments; namely to establish an incorporative management system by which forest owners can invest in their stands.     

Modeling forest harvesting effects on landscape pattern in the Northwest Wisconsin Pine Barrens

Forest management shapes landscape patterns, and these patterns often differ significantly from those typical for natural disturbance regimes. This may affect wildlife habitat and other aspects of ecosystem function. Our objective was to examine the effects of different forest management decisions on landscape pattern in a fire adapted ecosystem. We used a factorial design experiment in LANDIS (a forest landscape simulation model) to test the effects of: (a) cut unit size, (b) minimum harvest age and (c) target species for management. Our study area was the Pine Barrens of northwest Wisconsin, an area where fire suppression has caused a lack of large open areas important for wildlife. Our results show that all three management choices under investigation (cut unit size, minimum harvest age and target species for management) have strong effects on forest composition and landscape patterns. Cut unit size is the most important factor influencing landscape pattern, followed by target species for management (either jack pine or red pine) and then minimum harvest age. Open areas are more abundant, and their average size is larger, when cut units are larger, target species is jack pine, and minimum harvest age is lower. Such information can assist forest managers to relate stand level management decision to landscape patterns.     

Spatial forest valuation: The role of location in determining attitudes toward payment for ecosystem services policies

Forests provide many benefits (e.g., esthetics, water purification, habitat, carbon sequestration) to humans when they are conserved. However, forest conservation efforts may conflict with other uses, particularly timber harvest. Incentives for forest conservation can be established through payment for ecosystem services (PES) policies. PES policies rely on forest valuation studies which traditionally have valued the whole forest, or characteristics of a forest. Methods that allow variability in estimated forest values over space can provide valuation information at a finer scale and aid in the optimization of PES policies. These spatially explicit values provide information critical to many policy decisions, particularly conservation prioritization and planning.Using moderate resolution satellite remote sensing (i.e., LandSat) and a forest use survey conducted in Kam Cha i, Thailand, methods to estimate forest product valuation for spatially heterogeneous plots are demonstrated. These estimates are produced using geographic information system (GIS) multicriteria decision analysis (MCDA). The MCDA method combines forest use data with associated travel costs and vegetation cover estimates to provide spatially explicit estimates of forest values. This information is then used to compare local use values against potential carbon credit values estimated from the literature. The results show that a majority of the forest plots have higher PES values than for local forest products. Some do not, however, which suggests a possible cause for resistance against potential PES policies implemented in these areas.     

Fuel mass and stand structure after post-fire logging of a severely burned ponderosa pine forest in northeastern Oregon

Stand structure and fuel mass were measured before and after a post-fire logging operation conducted 2 years after the 1996 Summit Wildfire (Malheur National Forest), in a ponderosa pine-dominated forest in northeastern Oregon. Variables were measured both pre- and post-logging in four replicate units for each of three treatments [un-logged control, commercial harvest (most dead merchantable trees removed), fuel reduction harvest (most dead merchantable trees removed plus most dead trees >10 cm diameter)]. Post-fire logging resulted in a significant decrease in mean basal area, down to 46% pre-treatment level in commercial units, and down to 25% in fuel reduction units. Logging significantly reduced tree density, especially for the smallest (<22 cm diameter) and intermediate (23–41 cm) diameter classes. Fuel reduction units also had significantly fewer snags (dead trees >30 cm diameter—4 ha⁻¹), compared to both commercial (23 ha⁻¹) units and to un-logged controls (64 ha⁻¹) in the year following timber harvest. Logging did not change ladder height or tree species composition (% ponderosa pine, Douglas-fir and grand fir). Total woody fuel mass increased significantly in fuel reduction units when compared to controls, with the greatest difference among treatments occurring in the slash fuel (<7.6 cm diameter) component (mean of 6.2 Mg/ha for fuel reduction stands versus 1.3 Mg/ha for un-logged stands). Logging activity caused no change in the mass of the forest floor (litter or duff). Model projections of the fuel bed using the fire and fuels extension of the forest vegetation simulator (FVS–FFE) indicate that the disparity in slash fuel mass between fuel reduction and un-logged units would be sustained until about 15 years post-logging, but a re-burn of moderate intensity occurring during this time would likely kill all young trees, even in un-logged units, because of the influence of other components of the fuel bed, such as grasses and shrubs. Model projections of 1000-h fuels (woody fuels >7.6 cm diameter) indicate that standing structure in all stands would collapse quickly, with the result that un-logged stands would contain two- or three-fold greater masses at 25 and 50 years post-logging, leading to much higher consumption rates of fuel in the event of a re-burn in the same place. Variation in dead tree fall and decay rates did not change the relationship among treatments in 1000-h fuel loads, but changed the time at which treatment differences were projected to disappear. Despite treatment differences in heavy fuel accumulations over time however, FVS–FFE predicts no differences among treatments in mortality of young trees due to either moderate or high intensity fire occurring in the same place at 25, 50, or 100 years post-fire logging. The lack of a re-burn effect is in part due to the reliance on flame length as the primary mechanism leading to tree death in the fire effect models used by FVS–FFE. If tree death turns out to be caused more by root burning or cambial heating, the observed variations in 1000-h fuel loadings among treatments could be significant in the event of a future re-burn.     

Acidity in four coniferous forest soils after different harvesting regimes of logging slash

The soil acidity of four coniferous sites, two in S Sweden and two in N Sweden, were studied 7–9 years after clear‐felling. Each site had three different slash treatments; (a) all slash harvested, (b) only needles remaining, and (c) all slash remaining. Our results verify that harvesting of slash after clear‐cutting means an acidification of the organic horizon in acid forest soils. On plots subjected to full slash harvest the pH‐value of the forest floor was 0.2–0.4 units lower than that of slash‐covered ones, and at three of the four study sites the exchangeable acidity was significantly higher on the slash‐cleared plots. Plots with only needles remaining were generally intermediate in acidity. The change in exchangeable acidity corresponded to approximately 10% of the theoretically estimated proton load caused by slash harvesting. The rate of proton flux associated with whole‐tree harvesting varied between 7–65 meq m^‐3 yr^‐1, which roughly corresponds to the amounts deposited in precipitation. Harvesting of stems accounted for about one third and needles for one third of the proton load.     

Potential use of a spatially constrained harvest scheduling model for biodiversity concerns: Exclusion periods to create heterogeneity in forest structure

The objective of this paper is to investigate potential use of a spatially constrained harvest scheduling model for biodiversity concerns. Change in the degree of biodiversity is represented only by spatial characteristics of harvesting patterns of forest stands with different exclusion periods applied to adjacent forest stands. A spatially constrained harvest scheduling model called SSMART (Scheduling System of Management Alternatives foR Timber-harvest) is used for the analysis. It is one of the heuristics to solve a spatially constrained harvest scheduling problem by using the partitioning heuristic. The algorithm incorporated into SSMART is designed to seek a solution for a multicriteria problem with present net value maximum, meeting spatial feasibility and minimizing period-to-period harvest flow fluctuation, approximating even-flow constraints within the 0–1 integer programming framework. Our experimental analysis shows that the longer exclusion period, the less the harvest flow level and the total present net value are derived and the more heterogeneous the forest structure becomes in terms of the forest stand age distribution. It is also shown that the three exclusion period results in a stable forest stand age distribution over the time horizon for our experimental forest. This research supported by the Grants-in-Aid for Scientific Research (No. 09041071) from the Ministry of Education, Science, Sports, and Culture of Japan.     

An economic model of international wood supply,forest stock and forest area change

Abstract

Wood supply, the link between roundwood removals and forest resources, is an important component of forest sector models. This paper develops a model of international wood supply within the structure of the spatial equilibrium Global Forest Products Model. The wood supply model determines, for each country, the annual forest harvest, the annual change of forest stock and the annual change of forest area. The results suggest that global forest area would decline by 477 million ha between 1999 and 2030, with the largest decline in Asia and Africa. However, global forest stock would increase by 25 billion?m³, with the largest increase in Europe, and North and Central America. Higher global harvests and lower prices were predicted than those predicted in the past with exogenous timber supply assumptions.     

北京落叶松人工林全林分模型研建

以北京森林资源一类调查中侧柏的数据为基础,以Rechards方程为模版,通过spss统计建模工具进行拟合,建立了包括落叶松的树高模型、立地指数、林分密度、断面积指数、全林收获模型、林分生长模型在内的全林分模型。林分生长模型保持了与收获模型的相容性,在此基础上利用林分生长模型,可根据某一时期的林分收获量预知未来某一时期的林分蓄积。通过检验证明,此北京落叶松人工林全林分的林分生长模型有很强的适用性,为有关林业部门确定最优密度指数、立地指数等因子来改善落叶松的经营方式提供了依据。     

Carbon balance of forest stands,wood products and their utilization in South Korea

Forests provide wood products and feedstock for bioenergy and bio-based products that can mitigate climate change by reducing carbon emissions. In order to assess the effects of forest products on reducing carbon emissions, we analyzed the carbon balance for individual carbon pools across the forest supply chain over a long period of time. We simulated particular forest supply chain activities pertaining to even-aged management of pine stands in South Korea to demonstrate our methods. Two different rotation scenarios (i.e., 40 and 70 years) were assessed over the 280-year time horizon in terms of temporal changes in carbon stock in each carbon pool along the supply chain, carbon transfer between carbon pools, substitution effects, and delayed carbon release by wood products. We found that the average carbon stock level was higher for the 70-year rotation scenario, but the total amount of gain in carbon was higher for the 40-year rotation at the end of the time horizon. This study confirms that forest products and energy feedstock can both reduce carbon emissions and increase carbon storage. However, the complexity of carbon accounting along the supply chain warrants a thorough evaluation from diverse perspectives when it is used to assess forest carbon management options.     

Timber harvesting as ongoing disturbance in a landscape of diverse ownership

Although the northeastern US includes extensive areas of aggrading forest, uncertainty regarding the intensity and pattern of forest harvesting hampers an understanding of important ecological processes and characteristics such as carbon and nitrogen storage, habitat quality, and forest dynamics, and impedes regional conservation and management planning. Due to the complex ownership pattern dominated by thousands of non-industrial private forest (NIPF) owners and the difficulty of detecting selective logging using remote sensing, details of the harvesting regime remain largely unknown to the scientific and policy communities. To examine the value of statewide regulatory data for Massachusetts as a unique source of this critical information, we analyzed 17 years of timber harvest data gathered for regulatory purposes for a 168,000 ha forested landscape in Massachusetts that is the focus of concerted conservation planning and intensive study of landscape and ecosystem pattern and process. The North Quabbin Region is heavily wooded with a complicated ownership pattern dominated by over 2500 NIPF owners, three state agencies, and diverse conservation and municipal holdings.

The extent and intensity of harvesting were surprising, with an annual disturbance rate of 1.5% and a mean intensity of 44.7 m³ ha⁻¹ (approximately one-fourth of average stand volume). The predominant form of harvesting was selective removal of commercially valuable tree sizes, grades and species (e.g., Quercus rubra and Pinus strobus). The spatial pattern of logging was random with regards to major physical, biological, or cultural factors. However, logging was strongly related to landowner class. NIPF owners control 60% of the forest area and were responsible for 64.1% of harvest area, but the highest logging intensity (volume per area harvested; 69.3 m³ ha⁻¹) among major landowners was conducted by the state agency responsible for managing southern New England’s largest conservation property, the watershed of Boston’s drinking reservoir.

This regime of chronic disturbance is occurring over the entire landscape and exerting a major influence on forest composition, dynamics, and habitat quality. However, dispersed selective harvesting is largely unnoticed by residents, is routinely overlooked by ecologists and conservationists, and would remain unrecognized in the absence of this previously unused regulatory data. These results identify the value of regional regulatory spatial information to estimate ecological trends and to assist in conservation planning. Given similarities among ownership and forest patterns for much of the northeastern US, we expect that the broad findings of this study to have regional application.     

Adaptive versus fixed policies for economic or ecological objectives in forest management

In the context of forest management, a fixed harvesting policy consists in trying to convert stands of trees to a chosen state at fixed intervals, regardless of the stand state and of the state of the market. In an adaptive policy, instead, the post-harvest state and the timing of the harvest depend on the stand and market states at the time of the decision. The objective of this study was to determine the practical gain from the theoretically superior adaptive policies. To this end, we compared optimal fixed and adaptive policies obtained with identical models and assumptions, and with data from the Douglas-fir/western-hemlock forests in the Pacific Northwest of the United States. In maximizing economic returns from harvests over an infinite time horizon, the net present value was 17 percent higher with an adaptive than with a fixed policy. It was 22 percent higher when the objective was to maximize annual harvest. The adaptive policy was even more superior with undiscounted, non-economic objectives, such as the area of spotted owl habitat (+37 percent gain), or the area of late-seral forest (+51 percent), but less so in maximizing the stock of high quality logs (+6 percent). The adaptive formulation also lent itself readily to multi-objective management.     

Spatial optimization by simulated annealing and linear programming

Forest management planning comprises selection among treatment alternatives in management units. A traditional linear programming (LP) approach may effectively account for a profit maximization objective combined with sustainability constraints, e.g. on the temporal distribution of harvest volume flows, cash‐flow, and net present value development, but it fails to account for spatial constraints, especially those associated with final felling. By applying a simulated annealing adjacency model based on net present value maximization and combined with an LP consequence computation model, it is possible to delineate optimal strategies of final felling scheduling. Evaluation is made of the trade‐off between (1) the incremental cost (determined by use of the LP model) of an optimal adjacency model solution, and (2) the potential damage cost resulting from adjacency characteristics such as windthrow and bark injuries. The decision support system may contribute significantly to reduce damage costs and may improve the reliability of forest management planning.