摘要:

Given the character of the manufacturing (emissions levels and composition of output), we find that approximately $28 billion worth of manufacturing value added is made possible by the carbon uptake service provided by Canadian forests in 1986, with no corresponding increase in emissions. Thus, forests play the role of a “free factory.” The above figure may also be expressed per Mt of carbon uptake, as approximately $937 million. Then, based on estimates of carbon uptake provided by forestry ecologists, we impute a value of the non-market service of carbon uptake that forests provide. The calculation of such a value contributes to the determination of the value of forests as social capital. This value must then be incorporated in the model that determines the optimal harvesting decision. Without this value, the social cost of forests is seriously underestimated, which would lead to over-exploitation of forest resources.

ISSN:1054-9811    

DOI:10.1300/J091v05n01_01

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Preserved wilderness in Saskatchewan has value to both the users and to non-users. To determine such values, a study of Saskatchewan residents' level of willingness-to-pay (WTP) for wilderness preservation was carried out. Results suggest that 58% of sample non-aboriginal and only 7% of aboriginal respondents were satisfied with the current level of wilderness and wildlife protection in the province. Their reasons for preserving wilderness areas varied but protection of water quality, air quality, and wildlife habitats topped the list. The estimated annual WTP to ensure current wilderness protection prevails was approximately $61 per household for the non-aboriginal sample, and $80 for the aboriginal sample, which amounts to a value of $ 100 per hectare.

ISSN:1054-9811    

DOI:10.1300/J091v05n01_02

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Tropical forests are very rich in biological diversity and form an important economic and ecological resource. This biodiversity is of great value for communities living in or near these forests as a ready source of subsistence and cash income, and for the world at large as a source of tropical timber and non-timber products and a repository of genetic and chemical information. However, this biological complexity is diminishing rapidly. We analyze the main human (anthropogenic) actions causing loss of tropical forest biodiversity along with the strategies of management for forest biodiversity. Not only is the biophysical component important in management for biodiversity, but the action participation and support of local people, the national government and international cooperation as a whole, arc essential for an effective and sustainable development of tropical forests. This integrated development strategy ensures that socio-economic and environmental benefits are provided for present and future generations.

ISSN:1054-9811    

DOI:10.1300/J091v05n01_03

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

With the new emphasis in land management agencies (particularly the USDA Forest Service) on ecosystem management, new attention is being paid to measurements of biological diversity (biodiversity). Forest managers faced with incorporating the maintenance of biodiversity into their analyses, plans, and decisions need reliable, quantitative biodiversity measures. Deciding which measures to use requires land managers to understand why biodiversity is valued, which components of diversity are of most value, and how to measure these components feasibly. In this paper, the values associated with biodiversity and the principal indices available to forest managers are reviewed. Attention is drawn to the differing emphases of biodiversity indices-species richness, heterogeneity, and evenness-and to how diese differences address different values. Potential applications for these indices in forest management plans-including ways to use habitat models to approximate biodiversity-are also discussed.

ISSN:1054-9811    

DOI:10.1300/J091v05n01_04

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The purpose of this study was to examine the pattern and changes in forest cover types over the last two decades on three landscape level physiographic provinces of the state of Alabama, USA: (i) The Great Appalachian Valley Province, (ii) The Blue Ridge Talladega Mountain Province, and (iii) The Piedmont Province. Studies of spatial patterns of landscapes are useful to quantify human impact, predict wildlife effects or describe various landscape features. A robust landscape index should quantify two distinct components of landscape diversity: composition and configuration. Composition refers to both the total number of “patch” types (i.e., forest cover types) and their relative proportions in the landscape, whereas configuration refers to the spatial pattern of patches in the landscape. The U.S. Forest Service conducts periodic surveys of forest resources nationwide from plots distributed on a 3 mile by 3 mile (4.8 km by 4.8 km) grid randomly established within each county using forest inventory and analysis survey data stratified by physiographic province, a relative contagion (RC) diversity value and its variance were calculated for each province for the survey years 1972, 1982, and 1990. One-way analysis of variance was used for hypothesis testing of RC values across time and between provinces. A view of each landscape at each point in time was generated with GIS software using Thiessen or proximal polygons of the forest cover types identified at each survey point on the landscape.

ISSN:1054-9811    

DOI:10.1300/J091v05n01_05

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Studies in eastern North America suggest that nest predation on forest songbirds increases with habitat fragmentation. However, the majority of these studies have been conducted in highly fragmented suburban/rural deciduous forest habitat, making generalization of the results difficult. The objective of this study was to examine artificial nest predation dynamics along a fragmentation gradient (farm woodlots, logged forest stands and contiguous forest) in the conifer dominated Boreal Mixedwood. Predation was significantly higher in farm woodlots (78.8% edge and 78.5% interior) than the forest interior in contiguous and logged areas (42.8% and 41.9%, respectively). Predation at logged edges (60.0%) was not significantly different from either the woodlots or the forest interiors. All land-uses showed a variety of avian and mammalian predators. Using timer nests, we determined that predation was highest immediately after sunrise, with a second peak around sunset. Census results suggest that farm woodlots have significantly more red squirrels and a very different corvid community than forested areas. Overall, fragmentation due to agriculture seems to have a far greater impact on nest predation in the Boreal Forest than does logging and is in part, due to changes in the predator community. Further work is required to confirm the relative importance of nest predators in different land-uses. Clarification of the impact that logged edges have is alsorequired.

ISSN:1054-9811    

DOI:10.1300/J091v05n01_06

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

For forests to be sustainable, viable populations of rare plants should be maintained. Where habitat management alone cannot conserve species threatened by human activity, micropropagation may advance species recovery. Micropropagation protocols were developed for Pacific Northwest endemics;Hackelia venusta, Douglasia idahoensis, Astragalusspecies, andCornus nuttallii.Mi-croshoots and seed were multiplied and rooted on nutrient media containing minimal levels of cytokinin and auxin growth regulators to maintain stable gene expression in plantlets. Acclimatized plant-lets were reintroduced to protected habitat or propagated for further environmental experiments. Micropropagation serves a useful off-site role in sustaining Pacific Northwest forests by maintaining viability of certain threatened rare plants.

ISSN:1054-9811    

DOI:10.1300/J091v05n01_07

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Fungal root pathogens are widespread and may cause substantial seedling losses in conifer nurseries. Furthermore, poor seedling survival and growth on reforestation sites results in reduced forest regeneration. Use of microbial inoculants for disease control and plant growth promotion has become an important endeavour. A microbial culture collection of 500 strains was assessed for biological control of fungal root pathogens and/or plant growth promotion of conifer seedlings. Seven of these strains showed significant suppres-sive effects on various soil-bome fungal pathogens. On Douglas fir, two strains, RAL3 and 64-3, reduced disease caused byFusariumby. 7-42% in repeated growth room assays. The same strains significantly increased healthy stand of white spruce seedlings inoculated withFusariumandPythiumin a conifer nursery, and increased the survival of bare-root white spruce seedlings planted on a reforestation site by 19-23%. Both strains also significantly increased new root and total plant dry weights. Strain RAL3 in commercial formulation maintained a viable population of about log 8-9 cfu/ml for over a year when stored at 5°C. Strain survival on seed varied with conifer species. No decreases in bacterial populations were observed on seeds of jack pine or Douglas fir after 37 to 44 days storage at 5°C, but decreases were observed on seeds of white spruce and Scots pine. This study has provided candidate beneficial microbial inocu-lants which offer promise for development of commercial inoculants for the forestry industry.

ISSN:1054-9811    

DOI:10.1300/J091v05n01_08

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:1054-9811    

DOI:10.1300/J091v05n01_09

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor