摘要:

This paper examines the premise, goals, and concepts of ecosystem management. Evidence and philosophy of traditional forestry do not support the premise that it (forestry) is environmentally destructive. The goals of ecosystem management-to maintain and enhance the quality of the environment on the global scale, and to meet current and future needs of an increasing human population-are highly desirable. It is doubtful, however, that they can be satisfied simultaneously. The absence of well-defined boundaries of ecosystems is another obstacle to their management. One of the primary objectives of ecosystem management is maintaining and increasing biodiversity. Besides technical problems, there is a conceptual difficulty: we still do not know what biodiversity is. Equating biodiversity with everything is enlightening, but not too helpful since it is not clear how to manage everything. Operationally both concepts (ecosystem and biodiversity) are meaningless. Even if we manage to define biodiversity and delineate ecosystems, it won't help much because ecosystem management is designed only to treat symptoms of environmental decline, rather than its cause.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_01

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Ecosystem management is a magnet for controversy, in part because some of its formulations rest on questionable assertions that are radically contested. These assertions are important to understanding much of the conflict surrounding ecosystem management and, therefore, deserve thoughtful discussion and vigorous debate. Unfortunately, the assertions usually receive little scrutiny because critics, supporters, and the public are, understandably, absorbed in the personal and societal consequences of implementing controversial public policy choices under the rubric of ecosystem management. Professional natural resource managers, typically operating from within government bureaucracies and professional organizations, tend to blunt debate over the critical assertions by depicting ecosystem management as an evolution of past management approaches. Others, usually from outside the traditional natural resource management professions, contend that ecosystem management is revolutionary, not evolutionary. In this more radical view, ecosystem management is much more than a mere reformulation of classic natural resource management. To accept such a radical view of ecosystem management, I propose that there are four necessary, but implicit assertions. None of the assertions is accepted without challenge: each has articulate supporters and detractors. My conclusion from evaluating the radically contested assertions and policy corollaries is that much, but not all, of what is alleged as a scientific basis for ecosystem management is an assertion of fundamental values or, at the very least, an expression of personal policy preferences.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_02

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Rapid growth in the world population threatens agricultural and forestry production. Currently, there are 6 billion people on earth, and we add a quarter million more each day. There are more than 3 billion people malnourished in the world at present-the largest number and proportion ever in history. Land, water and biological resources are being degraded at an alarming rate; this degradation has substantial negative impacts on food and forest production.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_03

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

This paper presents the yield comparisons from a wide range of silvicultural regimes when applied to nineteen United States National Forests in the Pacific Northwest. The objective is to highlight the range of yield, value and biological parameters that result given any one of these regimes is followed over the next 100 years. Many non-forestry professionals are pressing for no harvest or selection-type all-aged forest harvesting regimes in the Pacific Northwest. The question is, that if these regimes do not provide comparable wood volumes to clear-cutting, the public continues to demand wood products, and the wildlife and plant biodiversity is permanently altered, “Is this where we want to go?”.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_04

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Forest management has been conventionally based on two paradigms: (i) perpetuity of the forest based on the equilibrium between standing volume, standing volume increment and allowable cut; (ii) constrained optimisation of commodities (marketable or not). The latter, basically output-oriented, paradigm, has favoured simplifications of forest ecosystem structure and composition. The development of applied ecology has highlighted how dangerous such simplifications are for the ecosystems' functionality. In this perspective forest management on a natural basis is gaining growing recognition. Fundamental modifications of foresters' attitudes are required. Forest ecosysterns need to be perceived as entities with an intrinsic value and as complex, self-regulating, dynamically changing systems. A holistic and synthetic approach is required. Abandoning the strategy of forest normalisation, an adaptive management approach is needed to frame operational practices. This paper discusses: (i) the possible development of the theory of forest management on natural bases, and associated methodological fundamentals; (ii) the main guidelines for technical implementation of the proposed concepts; and (iii) case studies of Italian situations.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_05

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

The information is presented on the independent state of Turkmenistan as a rich depository of unique biodiversity. Biodiversity in Turkmenistan is well-studied compared to many adjacent areas due to the unique historical and political circumstances. The long and complicated geological history of Turkmenistan has provided a diverse arena for the formation of local biodiversity and endemism of fauna and flora. Diverse mountain vegetation of the Kopetdagh Range-a depository of plant genetic diversity-is characterized in detail. Endangered species of large mammals (many in the IUCN Red Data Book) are listed and their current status is outlined. Suggestions are made for conservation of biodiversity in Turkmenistan.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_06

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Longleaf pine(Pinus palustrisMill.) ecosystems once occupied over 36 million hectares in the southeastern United States' lower coastal plain. These fire-dependent ecosystems dominated a wide range of coastal plain sites, including dry uplands and low, wet flatlands. Today, less than 1.3 million hectares remain, but these ecosystems represent significant components of the Region's cultural heritage, ecological diversity, timber resources, and present essential habitat for many animal and plant communities. Fire was an essential component of the original longleaf pine ecosystems. The landscapes were characterized by open stands of mature longleaf pine with a savanna-like understory that were biologically diverse. Recent improvements in the technology to artificially regenerate longleaf pine has stimulated interest in restoring longleaf pine on many sites. Long-term studies show that the frequent use of fire hastens initiation of height growth, reduces undesirable competing vegetation, and stimulates growth and development of the rich understory. So, fire is an important element in establishing the species and is critical to achieve and maintain the biologically diverse understory that is characteristic of the ecosystem.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_07

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Under the perspective of forest ecosystem management, landscape is interpreted as a functioning structure. From an inventory and monitoring operational point of view, such an approach implies wise use of geographic information systems and remote sensing techniques enabling a global view of the territorial mosaic. From a methodological point of view, landscape ecology theory may be used as the assessment framework. Remotely sensed data provide excellent opportunities for the involved analyses, using both vegetation density measures and spatial statistics. The objective of this paper was to assess landscape spatial heterogeneity using an analysis method based on Shannon's information theoretic entropy applied to satellite remotely sensed inputs of plant biomass. A forested mountainous landscape of Central Italy was examined as a case study. In this area, anthropogenic disturbance resulted as opposing the natural tendency of vegetation towards an horizontally homogeneous landscape giving way to a micro-heterogeneous structure composed of long-term stratification of small patches. The proposed analysis method proves to be simply refinable by more finely classifying land cover types to enable a more thoroughly landscape texture properties linkage to ecological processes.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_08

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

As population increases, the needs for products from the forest increase, along with the needs for recreation, wildlife, and esthetics. Although some of these products can also be produced by substitutes, such as plastic, steel, or aluminum, forest products have the desirable property of coming from a renewable resource, that is economically produced, and has positive environmental aspects. While use of forests for products does not preclude their use for recreation, and other nonproduct values, setting aside large tracts solely for recreation obviously can constrain total forest product yields. It is proposed that emphasis should be placed on intensive plantation management, or production forests, to significantly improve product flows to meet people's needs, while freeing other areas for alternative uses. Examples are given to show how genetically improved stock, seedling culture, site preparation, management of competing grass and hardwoods, fertilization, and thinning, can be used to increase product yields from intensively managed forests. The proposed forest management practices are also conducive to good wild life production, recreation, soil stability, and water quality.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_09

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor

摘要:

Management of tropical timber plantations is generally based on a single-product output, high-input model, often using an exotic species, that has been successfully used for plantation timber production in many temperate regions. This intensive model may be appropriate in areas designated solely for wood production but where the aim is to produce a wider range of conservation benefits and maintain more ecosystem functions, alternative plantation management approaches will be required. In this paper we describe some alternative management options for tropical forest plantations, incorporating ecosystem management concepts, that can potentially result in a wider range ecosystem benefits from tropical landscapes. Some of these practices have been used by plantation management agencies for some time. Others have been applied on a small scale or are still to be tested operationally. Options include: (1) consideration of the forest landscape and management of the matrix in which the plantation is established, (2) the use of native rather than exotic species, (3) using mixed species plantations rather than monocultures, (4) using the plantation to facilitate natural understorey regeneration, and (5) incorporating more structural and compositional diversity in plantations for wildlife habitat.

ISSN:1054-9811    

DOI:10.1300/J091v09n01_10

出版商:Taylor & Francis Group    

年代:1999

数据来源: Taylor