Treesearch

A cbbl cellobiohydrolase gene was cloned and sequenced from the fungus Trichoderrna harzianum FP108. The cloning was performed by PCR amplification of T. harzianum genomic DNA, using PCR primers whose sequence was based on the cbbl gene from Tricboderma reesei. The 3' end of the gene was isolated by inverse PCR; attempts to clone regions upstream of the 5' end of the gene were unsuccessful. Sequence comparisons suggest that this gene is closely related to cbbl genes from other Trichoderma species. In particular, all catalytically important amino acids in the protein sequence deduced from...

The principal purpose of any classification is to relate common properties among different entities to facilitate understanding of evolutionary and adaptive processes. In the context of this volume, it is to facilitate ecosystem stewardship, i.e., to help support ecosystem conservation and management objectives.

One of the difficult challenges facing ecosystem management is the determination of appropriate spatial and temporal scales to use. Scale in spatial sence includes considerations of both the size area or extent of an ecosystem management activity, as well as thedegree of resolution of mapped or measured data. In the temporal sense, scale concerns the duration of both natural and human induced disturbances, duration and time intervals of successional trajectories, the appropriate planning horizon of future ativities and the length of any historical perpective.

Legume species distribution and abundance and selected environmental variables were quantified across a complex gradient (varying in both water-holding capacity and fertility) for frequently burned longleaf pine (Pinus palustris)-wiregrass (Aristida stricta) ecosystems. Legumes were present in all months; however, abundance peaked in June and was minimal after killing frosts in October. Legume species were prominent in the flora (43 species encountered) obiquitous (94% of 2- m2 subplots had at least one legume species), and abundant (nearly 120000 stems/ha). Although most species were...

This proceeding contains contributions from each author or group of authors who presented their current research at the bark beetle genetics workshop held 17-18 July 1998 on the campus of the University of Wisconsin in Madison, wisconsin, USA. This was the second meeting on this subject; the first was held in 1992. The subject of bark beete genetics is of growing, international interest; researchers from Austria, Hungary, and Mexico, as well as from across the United Stateshave contributed to this proceedings. The topics covered included molecular approaches to genetic analysis of bark...

Providing a balance among the various benefits and values derived from forest lands has always been a challenge for managers. Determining this balance will be an even greater challenge in the future as increasing human populations consume greater amounts of natural resources from a decreasing land base. Obviously, not all multiple uses are compatible. Past attempts to reduce conflict have resulted in separate land allocations such as natural areas, developed recreauon sites, nonmotorized and semi-prirmnve areas, research natural areas, botanical areas, and so on. Most often these designatio...

The study of forest landscape change requires an understanding of the complex interactions of both spatial and temporal factors. Traditionally, forest gap models have been used to simulate change on small and independent plots. While gap models are useful in examining forest ecological dynamics across temporal scales, large, spatial processes, such as seed dispersal, cannot be realistically simulated across large landscapes. To simulate seed dispersal, spatially explicit landscape models that track individual species distribution are needed. We used such a model, LANDIS, to illustrate the...

The purpose of this article is to give a personal perspective of the person of Gustave Malecot and a conceptual account of his contributions to the field of population genetics. Some essential biographical information is given, but more important are some insights he himself gave into his early career. I was privileged to have him share these insights with me over the past 5 years. There are also some mathematical formulations necessary to put his work into its conceptual as well as historical context. The structure is mostly chronological. At times this account borrows heavily from an...

LANDIS is a forest landscape model that simulates the interaction of large landscape processes and forest successional dynamics at tree species level. We discuss how object-oriented design (OOD) approaches such as modularity, abstraction and encapsulation are integrated into the design of LANDIS. We show that using OOD approaches, model decisions (olden as model assumptions) can be made at three levels parallel to our understanding of ecological processes. These decisions can be updated with relative efficiency because OOD components are less interdependent than those designed with...

Understanding disturbance and recovery of forest landscapes is a challenge because of complex interactions over a range of temporal and spatial scales. Landscape simulation models offer an approach to studying such systems at broad scales. Fire can be simulated spatially using mechanistic or stochastic approaches. We describe the fire module in a spatially explicit, stochastic model of forest landscape dynamics (LANDIS) that incorporates fire, windthrow, and harvest disturbance with species-level succession. A stochastic approach is suited to forest landscape models that are designed to...