摘要:

This literature review is based on data on amounts of plant nutrients in trunk biomass, other biomass, litter, humus and soil in tropical rain forest ecosystems obtained from 24 publications. These data were compared with corresponding figures for 29 randomly selected temperate coniferous stands and 14 randomly selected temperate deciduous forests stands.

ISSN:1054-9811    

DOI:10.1300/J091v07n01_01

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Local knowledge by rural villagers about forest resources extraction, production and marketing needs increased focus in planning sustainable and gender-sensitive forest management internationally. Local villagers should be encouraged to express resource management alternatives and gain new technical knowledge to improve understanding and utilization of alternative forest resources (AFRs). Forestry workers and villagers involved in management and use of local forests should strive for increased appreciation of local AFR knowledge and enhanced knowledge of market conditions. Indigenous management technologies should be part of all forest planning activity.

ISSN:1054-9811    

DOI:10.1300/J091v07n01_02

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The environmental effects of population growth have been debated by foresters, demographers, geographers, and economists alike (Rudel 1994). Yet no consensus has been reached on its relationship with deforestation (WCED 1987, WB 1992, Kummer and Sham 1994, Palo 1994). “Among twenty-one representatives of the nations comprising the World Conference on Environment and Development (1987), there was unanimous agreement on all issues concerning environment, with two exceptions-the causal significance of population growth, and what to do with Antarctica” (Shaw, 1989). Some warn that population growth is accelerating deforestation (Bowonder 1982, Allen and Barnes 1985, Repetto and Gillis 1988, Ehrlich and Ehrlich 1990, and Rudel 1994), while others suggest that a focus on population obscures the socio-economic and political context of deforestation (Westoby 1978, Zinsmeister 1990, Kummer and Sham 1994, and Palo 1994). This paper describes a systems dynamic model of deforestation which provides a reconciliation of the two positions in the population debate. The number of people and their socio-economic conditions both have a significant impact on deforestation. As a result, besides addressing the population numbers, policies that impact the socio-economic conditions of the people for the people are needed if deforestation is to be delayed or forests are to be sustained.

ISSN:1054-9811    

DOI:10.1300/J091v07n01_03

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:1054-9811    

DOI:10.1300/J091v07n01_04

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The conversion of natural forests into managed forests raises concerns about sustained timber production and nature conservation. This study combined long-term inventory projections for some 84,000 ha of productive boreal mixedwood in Saskatchewan with fragmentation analysis. A spatially unrestricted clearcut harvesting regime was simulated for a I 00-year period (1984-2084). The current harvest rates of 1.5 m3ha−1per year could be sustained, but the age class distribution of the forest would markedly shift towards younger stands. Maximizing timber yields could raise harvest rates by 10%. These harvest rates would make it increasingly difficult to set aside permanently productive forest for ecosystem protection and alternative forest uses. A reduction of current harvest rates by at least 30% would support forest conservation. Spatial restrictions of the harvesting regime would be required to prevent forest fragmentation.

ISSN:1054-9811    

DOI:10.1300/J091v07n01_05

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

ISSN:1054-9811    

DOI:10.1300/J091v07n01_06

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

WATER RELATIONS OF PLANTS AND SOrLS. Kramer, Paul J. and John S. Boyer.New York: Academic Press, 1995,493pp., ISBN 0-12-425060-2.Reviewed by Graeme P. Berlyn.

ISSN:1054-9811    

DOI:10.1300/J091v07n01_07

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor