Browsing by Author "Vanclay, Jerome K."

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Estimating Sustainable Timber Production from Tropical Forests
(1996) Vanclay, Jerome K.
"Natural forests in the humid tropics differ from temperate and plantation forests in several ways: there may be many tree species; many of these may occur infrequently; there may be a large range of tree sizes and shapes present; tree ages may be unknown and indeterminate; and despite the luxuriant appearance some rainforests, growth rates may be relatively low. This has many implications for timber harvesting and yield estimation and means that most of the estimation techniques devised for even-aged single-species forests cannot be used. "A timber harvest represents the culmination of many years of growth, even in 'fast growing' plantations. Thus, unlike the farmer of annual crops, the forest manager must consider the distribution of the harvest over time. Several 'rules-of-thumb' for estimating the annual allowable cut are examined, with special emphasisgiven to the selection of the cutting cycle, to growth and harvesting models, and to inventory and monitoring systems. Strengths and weaknesses of cutting cycle analysis are discussed, and are contrasted with the more sophisticated yield scheduling systems. "Tools, techniques and information sources for estimating timber yields are reviewed. Yield calculations should make full use of existing information, including data from old surveys and casual inspections. Remote sensing and geographic information systems offer several interesting possibilities for yield estimation, particularly for sensitivity testing, but are not without limitations. A check list and extensive references are given."
Modelling Interactions amongst People and Forest Resources at the Landscape Scale
(2003) Vanclay, Jerome K.; Sinclair, Fergus L.; Prabhu, Ravi
"FLORES, the Forest Land Oriented Resource Envisioning System, is a framework to facilitate quantitative modelling of ecological, economic and social issues at the landscape scale. This issue of Small-scale Forest Economics, Management and Policy describes the evolution of FLORES from a concept to a series of models calibrated for diverse locations, and documents the lessons learned."
On the Nature of Keystone Species: A response to: Khanina. 1998. 'Determining Keystone Species'
(1999) Vanclay, Jerome K.
"There is an unfortunate tendency to nominate large and conspicuous creatures as likely keystone species playing pivotal roles in ecosystems. Particular favorites in the tropics include fig trees (Ficus spp.), large apes, and colorful birds, but such claims are rarely supported by empirical evidence. Khanina (1998) follows this trend, suggesting that 'only trees can be considered as keystone species of forest communities (detritus ecosystems).'"
Scientific Research or Advocacy? Emotive Labels and Selection Bias Confound Survey Results: A response to: Costanza. 2000. 'Visions of Alternative (Unpredictable) Futures and Their Use in Policy Analysis'
(2000) Vanclay, Jerome K.
"Robert Costanza presents four compelling visions of the future, but the language he uses to describe them is emotive and value-laden and may bias the survey results. The descriptions and analogies used may evoke responses from the survey participants that reveal more about their reactions to the description than their attitudes toward a given scenario. It is hypothesized that the use of more neutral language may lead to more support for the scenario involving 'self-limited consumption with ample resources" that Costanza calls "Big Government.' If this hypothesis is correct, then the skeptic's policy that Costanza appears to prefer has the additional advantage of always leading to the favored outcome, regardless of the state of the world."
Technologies for Sustainable Forest Management: Challenges for the 21st Century
(1997) Sayer, Jeffrey A.; Vanclay, Jerome K.; Byron, R.N.
"Technology will help to address the challenges for sustainable forestry in the 21st century. Some of the challenges will include the shift of production from native forest to plantations in areas of comparative advantage, more efficient processing delinking end-use products from raw wood characteristics, increased demand, better information technologies to support decision makers, and more options for conserving biodiversity. Definitions of sustainability will vary in time and space as society’s expectations and aspirations change, so there can be no 'silver bullet' to ensure sustainability. However, progress may be facilitated with a systematic approach to forest management embracing the usual planning cycle: formulation of objectives, preparation of a strategy, planning, implementing, monitoring, and reappraisal. This requires a good understanding of each particular situation. Managers need good resource assessment and decision support systems; they must foster stakeholder participation in decisions, costs and benefits; and ensure effective procedures to resolve conflicts. Within an appropriate system, technical advances such as better machines and new implements may help to make a difference, but will not in themselves ensure sustainability. The important technologies for sustainable forestry are those that foster better communication between stakeholders and allow informed decisions spanning scales from the gene to the ecosystem. This remains an important challenge for forest managers in their search for sustainability."