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1.
This study attempts to identify and associate the perceivedforest and rural quality of life values that people hold inrural areas in order to form a basis for improving forest managementdecision-making. The perceived forest and rural values of twodistinct local stakeholder goups are summarized from a surveyundertaken in the rural community of Konitsa. The empiricalevidence suggests that the respondents associate quality ofrural life mainly with the attractiveness of nature and landscapeas well as a sense of community life. In particular, multi-purposeforestry remains not only an issue within the scientific communityand forest policymakers but also is espoused widely by the localcommunity. The analysis identified certain value preferencepatterns between contemporary rural values and major forestvalues; it acknowledged forests as an integrative part of people'sinteraction with the living conditions in Konitsa. The natureof these preference patterns shows that there may be opportunitiesfor enhancing forest contributions to rural development whichevolve from a purely productive-based practice into a styleof forestry to improve environmental public goods, strengthencommunity stability, create amenity forests, and enhance thequality of life in the broader sense. Local forest decision-makersshould consider not only the socio-economic environment or thedynamic of the area but also the perceived standard of livingin the area. The study observed the dissonance between currentforest practices and local expectations. It implies that anintegrated and ecosystem-based forest strategy should be adoptedto evaluate more accurately the contributions of forestry tolocal demands and rural well-being, be open and democratic andlay claim to involvement at the local level.  相似文献   

2.
Saproxylic beetles are highly sensitive to forest management practices that reduce the abundance and variety of dead wood. However, this diverse fauna continues to receive little attention in the southeastern United States even though this region supports some of the most diverse, productive and intensively managed forests in North America. In this replicated three-way factorial experiment, we investigated the habitat associations of saproxylic beetles on the coastal plain of South Carolina. The factors of interest were forest type (upland pine-dominated vs. bottomland hardwood), tree species (Quercus nigra L., Pinus taeda L. and Liquidambar styraciflua L.) and wood posture (standing and downed dead wood, i.e., snags and logs). Wood samples were taken at four positions along each log and snag (lower bole, middle bole, upper bole and crown) ∼11 months after the trees were killed and placed in rearing bags to collect emerging beetles. Overall, 33,457 specimens from 52 families and ≥250 species emerged. Based on an analysis of covariance, with surface area and bark coverage as covariates, saproxylic beetle species richness differed significantly between forest types as well as between wood postures. There were no significant interactions. Species richness was significantly higher in the upland pine-dominated stand than the bottomland hardwood forest, possibly due to higher light exposure and temperature in upland forests. Although L. styraciflua yielded more beetle species (152) than either Q. nigra (122) or P. taeda (125), there were no significant differences in species richness among tree species. There were also no relationships evident between relative tree abundance and observed or expected beetle species richness. Significantly more beetle species emerged from logs than from snags. However snags had a distinct fauna including several potential canopy specialists. Our results suggest that conservation practices that retain or create entire snags as opposed to high stumps or logs alone will most greatly benefit saproxylic beetles in southeastern forests.  相似文献   

3.
The first steps in developing an agroforestry extension and training program involve compilation, synthesis, and analysis of current knowledge on existing practices. Equally important is to understand the perceptions of landowners and professionals of agroforestry as a land use option. No systematic effort has been made to assess these critical issues in the southeastern United States. Therefore, needs assessment surveys were developed following an analysis of major demographic issues that frame land use in the region and synthesis of information obtained from informal site visits and interviews with people engaged in resource and land use in the Atlantic and Gulf Coastal Plain. Surveys of extension professionals and landowners were then undertaken in the states of Alabama, Florida, and Georgia to represent the southeastern region. In addition to getting insights into the perceived benefits and concerns about agroforestry practices, the surveys indicated that the extent of alley cropping, forest farming and silvopasture practiced by landowners was less than anticipated, and that the prominence of windbreaks was overlooked by professionals. Managed riparian forest buffers or streamside management zones and windbreak technologies were the most widely used forms of agroforestry in the study area, although landowners did not recognize influence of agroforestry practices on quality or quantity of water among benefits of highest importance to them. Multistrata patio- or home gardens were also a prominent landowner-practice and acknowledged by professionals. These survey results can be useful for developing a relevant agroforestry extension and training program in the subtropical Southeast and may be of interest to agroforestry efforts in other similar settings. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

4.
Green-up, or adjacency, requirements are a common constraint in forestry. The American Forest and Paper Association has developed a Sustainable Forestry Initiative that includes a green-up constraint which limits the average clearcut opening to 48 ha for 3 years or until the average height of the regenerated trees is >1.4 m. In addition to constraining the average clearcut size, many forestry companies in the southeastern USA voluntarily limit their maximum clearcut size to between 60 and 90 ha. In this research, a heuristic algorithm was used to develop tactical forest plans that consider both the maximum and average clearcut sizes. Economic effects of the green-up constraints were estimated for situations where intensive management can reduce the length of the green-up time from 3 to 2 years on a 21 600 ha ownership in Georgia (USA). For a 60-ha maximum opening size, this reduction in green-up time from 3 to 2 years resulted in an additional US$ 66 600 in present net worth (PNW) over a 10-year analysis period. This corresponds to a US$ 10 per harvested ha, or a 0.8% increase in PNW. The benefit gained by reducing the length of the green-up period is less with a 90-ha maximum clearcut size, where PNW increases by US$ 45 600, or US$ 6.70 per harvested ha, a 0.5% increase. While the total volume per period was near the volume goal produced by a strategic forest plan, the spatial restrictions and the desire to maximize net present value resulted in lower volume of timber products (sawlogs and chip-and-saw logs) from older forest stands. A sensitivity analysis showed that an increase in price or yield further reduced the economic incentive for the reduction of the length of the green-up constraint. As price or volume decreased below expectations, however, the incentive to use intensive forest management practices to reduce the length of the green-up constraint became more attractive, since the differences between a 2-year and 3-year green-up time requirement may be large enough to pay for more intensive management practices.  相似文献   

5.
The main objective of this study was to assess the economics of alley cropping of loblolly pine (Pinus taeda L.) and switchgrass (Panicum virgatum) in the southern United States. Assuming a price range of switchgrass between $15 and $50?Mg?1 and yield of 12?Mg?ha?1 year?1, we investigated the effect of switchgrass production on the optimal forest management for loblolly pine stands under different stumpage prices. We considered the following potential scenarios: no competition between species for resources; reduced loblolly pine productivity due to competition with switchgrass; and reduced productivity of both species due to competition for nutrients, water and light. Findings also suggested that the optimal system would depend on the competitive interactions between switchgrass and loblolly pine crops, and the expected prices for each crop. Loblolly pine monoculture would be the most profitable option for landowners compared to intercropping systems with switchgrass below $30?Mg?1. However, when switchgrass prices are ??$30?Mg?1, landowners would be financially better off adopting intercropping if competitive interaction between crops were minimal. In order to realize higher economic returns for intercropping system, forest landowners must make some efforts in order to diminish the decline of productivity.  相似文献   

6.
South  David B.  Rose  Robin W.  McNabb  Ken L. 《New Forests》2001,22(1-2):43-58
Researchers in the United States have generally taken a ``segregated' approach to regeneration research. As a result, trials involving nurserytreatments are usually separated from trials involving site preparationtreatments. Researchers have concentrated on just the main treatmenteffects. Little effort has been placed on examining potential interactionsbetween nursery and site preparation treatments. Only a few nursery bysite preparation (NxSP) studies have been established. The profession hasgenerally assumed that gains from nursery and site preparation treatmentsare simply additive, or that the relative gains from nursery treatmentswould be insignificant when compared to intensive site preparationtreatments. Both of these assumptions may be incorrect.This review examines some of the NxSP interaction trials that have beenestablished in the United States during the last half of the 20thcentury. We predict that as rotation ages for plantations decrease, the needfor NxSP interaction trials will increase. NxSP interaction studies will berequired if researchers wish to include both nursery and site preparationtreatments in their early establishment models. To date, only a fewestablishment models have been developed in the United States.  相似文献   

7.
Shelterwood silviculture is commonly used to regenerate oaks in upland stands. However, competition from other species such as tulip-poplar (Liriodendron tulipifera) may deter oak regeneration when these traditional shelterwood techniques are used. The shelterwood-burn technique is a relatively new tool for regenerating oak-dominated stands on some upland sites while simultaneously minimizing undesirable hardwood intrusion with prescribed fire. Once successful oak regeneration has been achieved, three options are available which will result in different vegetative structure and composition within a stand and subsequently different habitats for songbirds. These options are: complete or partial canopy retention, post-harvest prescribed burning and complete canopy removal. Canopy retention, burning and removal treatments will create, respectively, two-age stands that are likely to harbor a diverse mixture of mature forest and early successional species; park-like woodlands with open woodland species; or early-successional habitats with shrubland species. We suggest that shelterwood-burn systems and the management options associated with them offer viable alternatives for managing both songbird and timber resources where oak-dominated stands are the desired goal in upland southeastern sites.  相似文献   

8.
Jordan  C.F. 《Agroforestry Systems》2004,61(1-3):79-90
Agroforestry Systems - Organic farming offers an alternative that can eliminate many of the environmental problems of conventional agriculture in the industrialized world. Instead of using...  相似文献   

9.
Public environmental and natural resource agencies have become increasingly diverse in mission and organization. Although holistic approaches for sustaining the physical attribute of large forest ecosystems have been advocated, attention has yet to focus on complementary organizational landscapes composed of integrated and co-ordinated public agencies. Results of a 2000 assessment of state agency conditions in the USA indicate that state government agencies affecting forest conditions are dispersed over all sectors and levels of state government; a state's lead forestry agency is often only a small piece in the puzzle of state agencies affecting forests; state agencies affecting forests engage primarily in forest resource use and management activities, yet some state agencies affect forest conditions by aggressively implementing responsibility for fisheries and wildlife, water pollutant management, and parks and recreation; consequences of fragmented state agency responsibility for forests are generally adverse, especially public confusion over agency roles and lack of integrated resource management; co-ordination among state agencies affecting forest conditions is modest and takes many forms; and the counterpart to state level agency diversity is the plethora of federal agencies that affect forest conditions, a situation that often deters state ability to integrate management of forests.  相似文献   

10.
In the south-east United States, 70% of the forest area is privately owned, by an estimated 5 M landholders. If ecosystem or landscape-level management is to work, cooperation across private ownerships is essential. As a first step in garnering cooperation among landowners, a mail survey was carried out to understand their characteristics, attitudes, beliefs and interest in ecosystem management. A specific area of the Coastal Plain of South Carolina, typical of rural forest-dominated areas of this region, was chosen as the study site. Forestry-related uses, specifically timber production, are the main reasons why over half the respondents own their land. Only one-third of the respondents are familiar with the concept of ecosystem management. However, about 70% are interested in learning more about joint management with other landowners. The major concerns about participating in joint management are loss of land and timber values. Most of the landowners who would participate in a landscape corridor system, for example, want to maintain control of their land rights and limit outside intervention in the process.  相似文献   

11.
Concerns over the effect of greenhouse gases and consequent international agreements and regional/national programs have spurred the need for comprehensive assessments of forest ecosystem carbon stocks. Down and dead woody (DDW) materials are a substantial component of forest carbon stocks; however, few surveys of DDW carbon stocks have been conducted at national-scales around the world. This study uses the DDW survey of the United States as a case study to examine the challenges of inventorying DDW at a national scale, reviews how dead wood carbon pools are currently estimated in the National Greenhouse Gas Inventory (NGHGI), and suggests opportunities for improving such inventories. The US currently estimates national DDW carbon stocks using models with standing live tree attributes as predictor variables, calibrated using preliminary DDW field estimates. In recent years, implementation of a national DDW inventory has resulted in inventory-based DDW estimates. National field-based DDW estimates follow the national patterns of DDW carbon dispersion seen in earlier model-based estimates. Although the current DDW inventory provides fairly repeatable measurements within a statistically defensible national sample design for producing national estimates of DDW carbon stocks, improving numerous aspects of the DDW survey would may improve the accuracy and precision of C estimates reported in the NGHGI.  相似文献   

12.
Wood-decaying fungi are essential for the functioning of forest ecosystems. They provide habitat for many other organisms and enable the regeneration of forests throughout the world. Since wood decomposition is a decisive process in nutrient recycling, soil formation and the carbon budget of forest ecosystems, it is receiving increasing attention from forest ecologists, pathologists and managers. Research has focussed on the factors driving the species-richness of wood-decomposing organisms and is moving on to analyse the effects of this species-richness on ecosystem functioning. Coarse woody debris (CWD) and its associated wood-decaying organisms have been drastically reduced in abundance and diversity by forestry and so these features often have potential as conservation indicators. Protective measures at a landscape level are needed for threatened wood-inhabiting fungi. These include restricting salvage operations in windthrow stands, actively encouraging the accumulation of deadwood in forests, and facilitating decay in standing trees by inoculating them with fungi. Here, we aim to collect and summarize recently produced work on deadwood ecology, pointing out research gaps and perspectives.  相似文献   

13.
National forest inventories provide information for strategic decisions in a large number of countries. In general, they cover a wide range of variables, from timber-related features to biodiversity and carbon sequestration. Often, it is difficult to decide the exact scope and design of this type of inventory; especially, it is difficult to decide the appropriate sample size. In planning inventories, trade-offs between cost and precision for core variables frequently are made; however, this approach does not fully acknowledge the fact that data typically are collected to form the basis for decisions. In theory, cost-plus-loss analysis provides a more holistic approach to inventory planning, since both inventory costs and losses due to information deficiencies in the decision-making processes are considered. However, whilst it is normally straightforward to determine cost functions, loss functions are difficult to establish; an important reason is that the linkages between data and decisions must be clearly understood. In this study, we explored the possibilities for using cost-plus-loss analysis in connection with determining the appropriate sample size of a national forest inventory. We used Sweden as a case and restricted the analysis to consider the use of data for determining sustainable harvesting levels. The results indicated that the number of plot clusters in Sweden should be in the order of 1,300–2,400 annually, whereas it is currently about 1,400. However, our main objective of the study was not to determine an exact answer for the case of Sweden, but rather to suggest pathways for how cost-plus-loss analysis could be used to support decisions related to determining the appropriate sample size of national forest inventories.  相似文献   

14.
Laurel wilt, caused by Raffaelea lauricola, is responsible for extensive mortality of redbay and other American members of the Lauraceae in the southeastern United States. Raffaelea lauricola is a mycangial symbiont of the redbay ambrosia beetle (Xyleborus glabratus), and the beetle and fungus were accidentally introduced from Asia. Branch dieback of camphortree (Cinnamomum camphora), an Asian member of the Lauraceae, has been occasionally observed in areas where laurel wilt has decimated redbay populations, and R. lauricola was isolated from such camphortrees. However, the role of X. glabratus and R. lauricola in this branch dieback remains unclear. Examination of camphortrees on Jekyll Island, Georgia showed that healthy‐appearing trees and those with branch dieback had been attacked by X. glabratus, but the trees with branch dieback had four times as many beetle attacks. Raffaelea lauricola was routinely isolated from discoloured xylem near beetle tunnels in healthy trees and those with dieback. Single‐point inoculations with R. lauricola on stems of mature, healthy camphortree trees failed to induce wilt‐like symptoms or branch dieback, although areas of discoloration were scattered throughout the xylem, and R. lauricola was reisolated irregularly at various heights in some inoculated trees. In growth chamber experiments, single‐point inoculations with R. lauricola resulted in systemic colonization but no wilt symptoms or branch dieback in camphortree saplings. In contrast, inoculations at multiple points along the stem (simulating multiple attacks by the vector) caused branch dieback and wilt‐like symptoms, including a brownish, diffuse discoloration of the xylem. Camphortree appears to be more resistant than American species of Lauraceae to the vascular wilt caused by R. lauricola. The fungus does colonize camphortrees systemically, however, and can apparently cause branch dieback. This suggests that the fungus may provide brood material for X. glabratus in Asia as it does in the southeastern United States.  相似文献   

15.
中国东南沿海混交海防林建设研究进展   总被引:1,自引:0,他引:1  
综述了我国东南沿海混交海防林的现状,目前混交林型海防林主要是木麻黄与湿地松、相思类树种与桉属等树种混交形成的混交林。通过分析比较不同混交林型的生长效果、防护效能和改土效果,提出合理的混交类型。此外还提出采用乡土树种与木麻黄混交,为建设混交林型的海防林体系提供更多的混交树种选择,为我国沿海防护林的管理、低效林的改造以及提高海防林的生态功能提供参考。  相似文献   

16.
There is a growing interest to take into account dry forests in planning sustainable development in arid and semi-arid sub-Saharan Africa. A mixed quantitative and qualitative research design involving various data collection tools was employed to examine the significance of dry forest income and associated conditioning factors in the context of pastoral and agro-pastoral production systems of southeastern Ethiopia. Income from livestock and dry forests were the first and second most important components of the total household income. Dry forest income accounts 34.8% and 35.2% of the total household income and 38% and 46% of the total household cash income in the Liben and Afdher Administrative Zones of Somali National Regional State, respectively. It was the largest income compared to all other incomes added together for 45% of the respondents. Most notably, for very poor households, dry forest income contributes up to 63% of their total income. Dry forest income levels varied significantly with occupation (P < 0.05), pastoralists generating more income than agro-pastoralists. Dry forest income enables 24% of households to remain above the poverty line, and it reduces income disparity by 13.7%. Moreover, dry forest income has become increasingly important for households' ex-ante risk and ex-post drought coping strategies. The number of youths per household (P < 0.001), access to extension services (P < 0.001), and being member of a cooperative (P < 0.05) significantly affected dry forest income levels in both Zones. Findings of this study could apply to similar dryland eco-regions in the Horn of Africa and contribute to enhance promotion of sustainable management of dry forests for integrated livelihood adaptation, biodiversity conservation and combating desertification. Further research is needed to quantify the contribution dry forests make to livelihoods through livestock production and to develop options that will guide policy making process to generate additional economic incentives for communities and countries to be engaged in sustainable management and use of dry forests.  相似文献   

17.
Changes in biomass and soil carbon with nitrogen fertilization were simulated for a 25-year loblolly pine (Pinus taeda) plantation and for three consecutive 7-year short-rotation cottonwood (Populus deltoides) stands. Simulations were conducted for 17 locations in the southeastern United States with mean annual temperatures ranging from 13.1 to 19.4 °C. The LINKAGES stand growth model, modified to include the “RothC” soil C and soil N model, simulated tree growth and soil C status. Nitrogen fertilization significantly increased cumulative cottonwood aboveground biomass in the three rotations from a site average of 106 to 272 Mg/ha in 21 years. The equivalent site averages for loblolly pine showed a significant increase from 176 and 184 Mg/ha in 25 years with fertilization. Location results, compared on the annual sum of daily mean air temperatures above 5.5 °C (growing-degree-days), showed contrasts. Loblolly pine biomass increased whereas cottonwood decreased with increasing growing-degree-days, particularly in cottonwood stands receiving N fertilization. The increment of biomass due to N addition per unit of control biomass (relative response) declined in both plantations with increase in growing-degree-days. Average soil C in loblolly pine stands increased from 24.3 to 40.4 Mg/ha in 25 years and in cottonwood soil C decreased from 14.7 to 13.7 Mg/ha after three 7-year rotations. Soil C did not decrease with increasing growing-degree-days in either plantation type suggesting that global warming may not initially affect soil C. Nitrogen fertilizer increased soil C slightly in cottonwood plantations and had no significant effect on the soil C of loblolly stands.  相似文献   

18.
19.
Background:With the loss of species worldwide due to anthropogenic factors,especially in forested ecosystems,it has become more urgent than ever to understand the biodiversity-ecosystem functioning relationship(BEFR).BEFR research in forested ecosystems is very limited and thus studies that incorporate greater geographic coverage and structural complexity are needed.Methods:We compiled ground-measured data from approx.one half mil ion forest inventory sample plots across the contiguous United States,Alaska,and northeastern China to map tree species richness,forest stocking,and productivity at a continental scale.Based on these data,we investigated the relationship between forest productivity and tree species diversity,using a multiple regression analysis and a non-parametric approach to account for spatial autocorrelation.Results:In general,forests in the eastern United States consisted of more tree species than any other regions in the country.The highest forest stocking values over the entire study area were concentrated in the western United States and Central Appalachia.Overall,96.4 % of sample plots(477,281)showed a significant positive effect of species richness on site productivity,and only 3.6 %(17,349)had an insignificant or negative effect.Conclusions:The large number of ground-measured plots,as well as the magnitude of geographic scale,rendered overwhelming evidence in support of a positive BEFR.This empirical evidence provides insights to forest management and biological conservation across different types of forested ecosystems.Forest timber productivity may be impaired by the loss of species in forests,and biological conservation,due to its potential benefits on maintaining species richness and productivity,can have profound impacts on the functioning and services of forested ecosystems.  相似文献   

20.
In this study, the overall utility of forest management alternatives at the forest management unit level is evaluated with regard to multi-purpose and multi-user settings by a multi-criteria analysis (MCA) method. The MCA is based on an additive utility model. The relative importance of partial objectives of forest management (carbon sequestration, ground water recharge, biodiversity, and timber production) is defined in cooperation with stakeholders. The forest growth model 4C (Forest Ecosystems in a Changing Environment) is used to simulate the impact of six forest management strategies and climate on forest functions. Two climate change scenarios represent uncertainties with regard to future climatic conditions. The study is based on actual forest conditions in the Kleinsee management unit in east Germany, which is dominated by Scots pine (Pinus sylvestris L.) and oak (Quercus robur L. and Quercus petraea Liebl.) stands. First, there is an analysis of the impact of climate and forest management on forest functions. Climate change increases carbon sequestration and income from timber production due to increased stand productivity. Secondly, the overall utility of the management strategies is compared under the priority settings of different stakeholder groups. From an ecological perspective, a conservation strategy would be preferable under all climate scenarios, but the business as usual management would also fit the expectations under the current climate due to high biodiversity and carbon sequestration in the forest ecosystem. In contrast, a forest manager in public-owned forests or a private forest owner would prefer a management strategy with an intermediate thinning intensity and a high share of pine stands to enhance income from timber production while maintaining the other forest functions.  相似文献   

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