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1.
Modern timber management practices often influence forage production for elk (Cervus elaphus) on broad temporal and spatial scales in forested landscapes. We incorporated site-specific information on postharvesting forest succession and forage characteristics in a simulation model to evaluate past and future influences of forest management practices on forage values for elk in a commercially managed Douglas fir (Pseudotsuga menziesii, PSME)-western hemlock (Tsuga heterophylla, TSHE) forest in western Washington. We evaluated future effects of: (1) clear-cut logging 0, 20, and 40% of harvestable stands every five years; (2) thinning 20-year-old Douglas fir forests; and (3) reducing the harvesting cycle from 60 to 45 years. Reconstruction of historical patterns of vegetation succession indicated that forage values peaked in the 1960s and declined from the 1970s to the present, but recent values still were higher than may have existed in the unmanaged landscape in 1945. Increased forest harvesting rates had little short-term influence on forage trends because harvestable stands were scarce. Simulations of forest thinning also produced negligible benefits because thinning did not improve forage productivity appreciably at the stand level. Simulations of reduced harvesting cycles shortened the duration of declining forage values from approximately 30 to 15 years. We concluded that simulation models are useful tools for examining landscape responses of forage production to forest management strategies, but the options examined provided little potential for improving elk forages in the immediate future.  相似文献   

2.
Forecasts of future resource states are central to resource management planning. Many simulation models and planning tools are used to produce such forecasts and apply knowledge of resource change dynamics as key input. Consistency among knowledge sources is therefore important to avoid knowledge ambiguity and uncertainty in resource forecasts and management plan outcomes. Using Ontario's boreal forest landscape as a case study, this paper examined two knowledge sources of forest resource change, practitioner expertise and research studies, commonly applied in plans and policies for large forest landscapes. The two knowledge sources were quantitatively compared by constructing networks of forest cover change for both sources and determining their agreement in structure and transition times. Some networks agreed well, indicating little knowledge ambiguity and comparatively low uncertainty if they were used to forecast forest landscapes. Other networks showed low agreement, thus indicating higher knowledge ambiguity and a dilemma of choice for forest landscape planners who may have to select from these knowledge sets. It is suggested that knowledge disagreements may be widespread in knowledge-driven management planning of many natural resource types and their causes similar. These disagreements signal areas of knowledge uncertainty, where resource planners must address resulting uncertainty of management outcomes and research should focus on improving resource change knowledge.  相似文献   

3.
Air pollution, harvesting practices, and natural disturbances can affect the growth of trees and forest development. To make predictions about anthropogenic impacts on forests, we need to understand how these factors affect tree growth. In this study the effect of disturbance history on tree growth and stand structure was examined by using a computer model of forest development. The model was run under the climatic conditions of east Tennessee, USA, and the results compared to stand structure and tree growth data from a yellow poplar-white oak forest. Basal area growth and forest biomass were more accurately projected when rough approximations of the thinning and fire history typical of the measured plots were included in the simulation model. Stand history can influence tree growth rates and forest structure and should be included in any attempt to assess forest impacts.  相似文献   

4.
Many factors influence forest landowner management decisions. This study examines landowner decisions regarding participation in ecosystem management activities, such as a landscape corridor cutting across their private lands. Landscape corridors are recognized worldwide as an important tool in biodiversity conservation. For ecosystem management activities to occur in areas dominated by a multitude of small private forest landholdings, landowner participation and cooperation is necessary. Data from a survey of landowners combined with an analysis of their land's spatial attributes is used to assess their interest in ecosystem management. Results suggest that spatial attributes are not good predictors of an owner's interest in ecosystem management. Other factors such as attitudes and opinions about the environment are more effective in explaining landowner interest. The results have implications for any land manager using GIS data and implementing ecosystem management activities on private forestland.  相似文献   

5.
Landscape spatial patterns have increasingly been considered to be essential for environmental planning and resources management. In this study, we proposed a hierarchical approach for landscape classification and evaluation by characterizing landscape spatial patterns across different hierarchical levels. The case study site is the Red Hills region of northern Florida and southwestern Georgia, well known for its biodiversity, historic resources, and scenic beauty. We used one Landsat Enhanced Thematic Mapper image to extract land-use/-cover information. Then, we employed principal-component analysis to help identify key class-level landscape metrics for forests at different hierarchical levels, namely, open pine, upland pine, and forest as a whole. We found that the key class-level landscape metrics varied across different hierarchical levels. Compared with forest as a whole, open pine forest is much more fragmented. The landscape metric, such as CONTIG_MN, which measures whether pine patches are contiguous or not, is more important to characterize the spatial pattern of pine forest than to forest as a whole. This suggests that different metric sets should be used to characterize landscape patterns at different hierarchical levels. We further used these key metrics, along with the total class area, to classify and evaluate subwatersheds through cluster analysis. This study demonstrates a promising approach that can be used to integrate spatial patterns and processes for hierarchical forest landscape planning and management.  相似文献   

6.
Towards a sustainable Russian forest sector   总被引:4,自引:0,他引:4  
Russia's forest resources are enormous, but despite almost ten years of transition, problems are still immense, in terms of commercial output and with respect to forest management. This article suggests that one way of changing the situation is to introduce community management of forests. Using the Swedish forest commons as an example, this article argues that such a change in property rights will provide an alternative to massive privatization of the forests and to the undesirable continuation or strengthening of state forest management. Finally, it is concluded that such an introduction of new property rights regimes will not provide the solution to the problems, but rather will contribute to the establishment of a better institutional framework in the Russian forest sector.  相似文献   

7.
As tensions among diverse forest‐use interests in Lithuania are on the rise, this study examines the actual resource availability, the underlying planning approaches and the pertinent policy arena. Two 5‐year cycles of sampling‐based forest inventory provide accurate data showing that the overall timber harvest/increment ratio (or utilization intensity) is 61%. Utilization intensity is similar in state and private forests. It could potentially be raised to 70‐80%, with due account for environmental values. Such an increase is inhibited by rigid routines of forest management planning, involving inflexible rotation ages and cutting norms. Age‐class analysis indicates that the current planning practice counters its underlying aim of achieving a long‐term even flow of timber. According to a survey of key forest stakeholders, those who directly benefit from forest utilization have a weak position in the policy arena, the dominant powers being vested in the national forestry authorities. State forest enterprises have to follow restrictive plans from above, private forest owners are constrained by stern regulations and suffer from the bad image caused by the persistent myth of overuse in private forests. More rational management of Lithuanian forests is hardly possible without major shifts in the institutional set‐up accompanied by transformation of the professional ideology.  相似文献   

8.
/ Spatially explicit models that combine remote sensing with geographic information systems (GIS) offer great promise to land managers because they consider the arrangement of landscape elements in time and space. Their visual and geographic nature facilitate the comparison of alternative landscape designs. Among various activities associated with forest management, none cause greater concern than the impacts of timber harvesting on the composition, structure, and function of landscape ecosystems. A timber harvest allocation model (HARVEST) was used to simulate different intensities of timber harvest on 23,592-ha hypothetical landscapes with varying sizes of timber production areas and different initial stand age distributions. Our objectives were to: (1) determine the relative effects of the size of timber production areas, harvest intensity, method used to extract timber, and past timber harvest activity on the production of forest interior and edge; and (2) evaluate how past management (in the form of different initial stand age distributions) constrains future timber production options. Our simulations indicated that the total area of forest interior and the amount of forest edge were primarily influenced by the intensity of timber harvest and the size of openings created by harvest. The size of the largest block of interior forest was influenced most by the size of timber harvests, but the intensity of harvest was also significant, and the size of nontimber production areas was important when harvests were numerous and widely dispersed within timber management areas, as is often the case in managed forests. Stand age-class distributions produced by past harvest activity limited the amount of timber production primarily when group selection was used, but also limited clear-cutting when recent harvest levels were high.KEY WORDS: Simulation modeling; Timber harvest; Historical context; Spatial context; Landscape pattern; Forest interior; Forest edge  相似文献   

9.
Ecosystem-based management (EBM) of forests is gaining acceptance for its focus on the maintenance of the long-term integrity of ecosystem processes, but climate change challenges this view because of its impacts on these very processes. We have therefore evaluated the robustness of EBM to projected climate change, considering the role of climate on forest growth and fire regime in a boreal forest of eastern Canada. A climate sensitive growth index model was calibrated for three commercial species and used to project the evolution of merchantable volume for two climate scenarios (B1 and A2) under conventional and EBM strategies. Current burn rate and burn rates under future climate scenarios were also considered. Under the most extreme projected climate scenario, the periodic timber supply could be reduced by up to 79% through direct (growth reduction) and indirect (fire) effects. However, ecological indicators show that EBM is a more robust forest management strategy than conventional one demonstrating its adaptation potential to climate change at least in the short term.  相似文献   

10.
Recent advances in fire modeling permit quantitative estimations of fire behavior from quantitative inputs that describe the fuel array and conditions, such as weather and site data, under which it will burn. This paper describes the collection, analysis, and stratification of flammable forest fuels data for coniferous forest ecosystems in Montana and then illustrates the resource management application of these data in three areas: the development of the fire behavior model, a determination of the model's sensitivity to input errors as reflected by fire behavior prediction errors, and the development of a fire hazard simulator (TAROT). A new integrated stand simulator, GANDALF, is highlighted.Conclusions center on the need to integrate fire management into the land management planning decision-making process.This work was supported by a USDI National Park Service contract to Gradient Modeling, Inc., a nonprofit research foundation devoted to ecologic research and resource management applications, and by cooperative aid agreements between Gradient Modeling, Inc. and the USDA Forest Service, Intermountain Forest and Range Experiment Station, Northern Forest Fire Laboratory (Fire in Multiple Use Management, R, D, and A Program).  相似文献   

11.
Forest ecosystems may be actively managed toward heterogeneous stand structures to provide both economic (e.g., wood production and carbon credits) and environmental benefits (e.g., invasive pest resistance). In order to facilitate wider adoption of possibly more sustainable forest stand structures, defining growth expectations among alternative management scenarios is crucial. To estimate the effect of tree size and spatial distributions on growth for forest structures commonly considered in uneven-aged forest stand management, large (0.2 ha+) plots were established in 14 uneven-aged ponderosa pine stands in eastern Montana. All study trees were stem-mapped and measured for diameter and 10-year sapwood and basal area increment. A generalized growth model was developed to predict both total and merchantable 10-year basal area increment for nine hypothetical stand structures [three diameter distributions (reverse-J, irregular, flat) × three spatial distributions (clumpy, partial clumpy, uniform)]. Results indicate that the size and spatial distributions of individual trees have a considerable effect on overall stand growth. The greatest total stand growth was in stands with reverse “J” shaped tree size distributions, while the greatest merchantable stand growth was in stands with “flat” diameter distributions and uniform spatial distributions. Through better comprehension of generalized uneven-aged stand growth dynamics, forest managers may better assess the effects of alternative stand structures on stand growth while providing forest stand structures that may be more resilient in a changing climate.  相似文献   

12.
Sustainability has become a major focus area within forest products industry. The European operational environment and national environmental steering in EU member states highlight the importance of sustainable development and the development of associated new management approaches to promote sustainability. This article reviews some key elements of sustainability management, covering examples of both Finnish forest products industry initiatives and public environmental steering at the European level. An assessment is made of the current situation and an outline of a future outlook for sustainability management, with special emphasis on bridging the gap between industry initiatives and environmental steering in the form of legislation, policies and strategies at the EU level.This study applied a hybrid approach comprising a review of EU sustainability initiatives, a policy and legal review and a questionnaire survey of forest industry actors. The results of the future outlook indicate that energy efficiency is perceived to be the most important focus area in addition to e.g. environmental and waste management and recycling. Less than half of the companies aim at applying sustainability management. Life-cycle management is also considered to be important whereas product-based approaches, climate change and local industrial symbiosis receive very little attention. All responding companies aim to integrate the principles of sustainability into their operations and most companies consider that life-cycle thinking, management and assessment are useful for them. Energy efficiency is identified as the most important focus area with energy and materials efficiency seen as the most crucial factors for the achievement of responsible competitive advantage and building of sustainable value-added. The findings indicate that sustainability and life-cycle management are not receiving enough management focus at the moment and neither is the industry receiving enough guidance at either the EU level or via national steering and regulatory frameworks.  相似文献   

13.
A model-based analysis of the effect of prescribed burning and forest thinning or clear-cutting on stand recovery and sustainability was conducted at Fort Benning, GA, in the southeastern USA. Two experiments were performed with the model. In the first experiment, forest recovery from degraded soils was predicted for 100 years with or without prescribed burning. In the second experiment simulations began with 100 years of predicted stand growth, then forest sustainability was predicted for an additional 100 years under different combinations of prescribed burning and forest harvesting. Three levels of fire intensity (low, medium, and high), that corresponded to 17%, 33%, and 50% consumption of the forest floor C stock by fire, were evaluated at 1-, 2-, and 3-year fire return intervals. Relative to the control (no fire), prescribed burning with a 2- or 3-year return interval caused only a small reduction in predicted steady state soil C stocks (< or =25%) and had no effect on steady state tree wood biomass, regardless of fire intensity. Annual high intensity burns did adversely impact forest recovery and sustainability (after harvesting) on less sandy soils, but not on more sandy soils that had greater N availability. Higher intensity and frequency of ground fires increased the chance that tree biomass would not return to pre-harvest levels. Soil N limitation was indicated as the cause of unsustainable forests when prescribed burns were too frequent or too intense to permit stand recovery.  相似文献   

14.
15.
The integration of socio-economic and environmental objectives is a major challenge in developing strategies for sustainable landscapes. We investigated associations between socio-economic variables, landscape metrics and measures of forest condition in the context of Portugal. The main goals of the study were to 1) investigate relationships between forest conditions and measures of socio-economic development at national and regional scales, 2) test the hypothesis that a systematic variation in forest landscape metrics occurs according to the stage of socio-economic development and, 3) assess the extent to which landscape metrics can inform strategies to enhance forest sustainability. A ranking approach and statistical techniques such as Principal Component Analysis were used to achieve these objectives. Relationships between socio-economic characteristics, landscape metrics and measures of forest condition were only significant in the regional analysis of municipalities in Northern Portugal. Landscape metrics for different tree species displayed significant variations across socio-economic groups of municipalities and these differences were consistent with changes in characteristics suggested by the forest transition model. The use of metrics also helped inform place-specific strategies to improve forest management, though it was also apparent that further work was required to better incorporate differences in forest functions into sustainability planning.  相似文献   

16.
A new environmental paradigm has emerged, reflecting a change in the public's understanding of resource sustainability. Forest policy makers need to be better informed about such changes to achieve economic, social, and environmental objectives in a manner that balances human needs and aspirations with ecosystem constraints. As an aid to this task, a forest resource accounting system based on the key concept of natural capital could help reshape forest policies to provide an even wider spectrum of benefits for both present and future generations by maintaining and enhancing the productive capacity of forest capital. Such a resource accounting system would provide a tool for integrating multidimensional information requirements in measuring the health of both forest ecosystems and economic systems. This paper outlines some of the features of this accounting system and proposes and framework that would integrate economic and ecological characteristics of natural resources. Forest resource accounting is urgently needed to achieve the sustainability goals of ecosystem management.  相似文献   

17.
Forest growth models are useful tools for investigating the long-term impacts of logging. In this paper, the results of the rain forest growth model FORMIND were assessed by a multicriteria decision analysis. The main processes covered by FORMIND include tree growth, mortality, regeneration and competition. Tree growth is calculated based on a carbon balance approach. Trees compete for light and space; dying large trees fall down and create gaps in the forest. Sixty-four different logging scenarios for an initially undisturbed forest stand at Deramakot (Malaysia) were simulated. The scenarios differ regarding the logging cycle, logging method, cutting limit and logging intensity. We characterise the impacts with four criteria describing the yield, canopy opening and changes in species composition. Multicriteria decision analysis was used for the first time to evaluate the scenarios and identify the efficient ones. Our results plainly show that reduced-impact logging scenarios are more 'efficient' than the others, since in these scenarios forest damage is minimised without significantly reducing yield. Nevertheless, there is a trade-off between yield and achieving a desired ecological state of logged forest; the ecological state of the logged forests can only be improved by reducing yields and enlarging the logging cycles. Our study also demonstrates that high cutting limits or low logging intensities cannot compensate for the high level of damage caused by conventional logging techniques.  相似文献   

18.
Two recent studies using tree aggregations to analyze forest age-structure stability and past forest structure are flawed. A better understanding of aggregation dynamics is needed before aggregation analysis is used in forest management.  相似文献   

19.
Mountainous forest areas are vitally important for water supply in dryland regions which suffer from high erosion risk and severe water shortage. Massive afforestation, mainly for erosion control, may reduce the water yield and threaten local water supply security. Moreover, many over‐dense forests due to a strict logging ban policy have produced remarkably negative impacts for both forests (e.g., low timber quality, restricted natural regeneration, and high stand instability) and water yield. To satisfy the rapidly increasing demands on water supply and other services, a practical approach for managing forest stands in a multifunctional way, which particularly addresses water yielding, is urgently required. For this purpose, we integrated the existing knowledge and experience, designed an “ideal” stand structure to represent multifunctional forest (MFF) and determined its key parameters (a ground coverage of >0.7, a canopy density around 0.7, and an H/DBH ratio (tree height [m] to the diameter at breast height [cm]) of <0.7). Moreover, a decision process for MFF stand management was recommended as: (1) investigating the site quality; (2) identifying the site‐specific main forest functions; (3) quantifying the stand structure; (4) diagnosing the stand structure by comparing with the “ideal” one; and (5) arranging the functions/structure‐oriented management measures. In this way, the water‐yielding function can be improved and meanwhile other forest functions can be promoted.  相似文献   

20.
Developing nature-based tourism in private lands calls for new mechanisms to consolidate the interests of the tourism industry, visitors, and landowners. This choice experiment study elaborates on the heterogeneity of visitors’ preferences and willingness to pay (WTP) for enhanced forest amenities and ecosystem services. The survey, targeting domestic and foreign tourists visiting the Ruka-Kuusamo area in Finland, considered four attributes: landscape quality, outdoor routes, forest biodiversity, and carbon sequestration. For observed heterogeneity, the visitors were grouped by their attitudes towards forest management. Unobserved heterogeneity in visitors’ choice behaviour and WTP was examined with the latent class model. While most visitors had environmentally friendly attitudes and were willing to pay, especially for enhanced landscape quality and biodiversity, considerable heterogeneity was revealed in terms of three segments with distinctive attitudes, choice behaviour and WTP. The variation in WTP has important implications for the design of a scheme of payments for environmental management.  相似文献   

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