Treesearch

The quantitative description and simulation of the fundamental processes that characterize forest growth are increasing in importance in forestry research. Predicting future forest growth, however, is compounded by the various combinations of temperature, humidity, precipitation, and atmospheric carbon dioxide concentration that may occur. One method of integrating new management objectives and potential climate scenarios is to model ecosystems mechanistically. General application of ecosystem process models has been difficult. In particular, obtaining initial physiological parameters from...

The Shrub Sciences Laboratory celebrated its 25th anniversary with the symposium documented by these proceedings and a ceremony honoring people instrumental in its establishment: Mr. A. Perry Plummer represented Forest Service Research and Development and Dr. Howard C. Stutz represented Brigham Young University. The laboratory came into being because of the research foundation in Western shrub ecosystems generated by USDA Forest Service researchers and their colleagues and the need to carry on programmatic research in vast Western shrublands. Since establishment of the laboratory, dozens...

Winterfat (Ceratoides lanata) is a long-lived shrub with excellent drought tolerance and good to moderate tolerance for herbivory. It often occurs as near monocultures in deep finetextured soils of alluvial fans and valley bottoms. Winterfat communities are second only to those of shadscale (Atriplex confertifolia) in dominance of the 16 million ha of salt-desert shrublands found in Western North America. In spite of improved grazing practices, winterfat is declining in many areas of the Great Basin. The Eurasian summer annual, halogeton (Halogeton glomeratus), is well adapted to the soils...

A number of modeling tools are required to go from short-term treatments to long-term objectives expressed as desired future conditions. Three models are used in an example that starts with determining desired stand level structure and ends with the implementation of treatments over time at a landscape scale. The Multi-Aged Stocking Assessment Model (MASAM) is used for assessing sustainable stand structures. Simulating Vegetative Patterns and Processes at Landscape Scales (SIMPPLLE) is initially applied to assess risks from disturbance processes on the current landscape without management...

Lewis’s Woodpecker (Melanerpes lewis) has been characterized as a ‘‘burn specialist’’ because of its preference for nesting within burned pine forests. No prior study, however, has demonstrated the relative importance of crown-burned forests to this woodpecker species by examining its reproductive success in different forest types. We studied breeding Lewis’s Woodpeckers in cottonwood (Populus fremontii) riparian forest patches of Colorado and crown-burned ponderosa pine (Pinus ponderosa) forests of Idaho to compare their reproductive success, productivity, and potential source-sink status...

We thank Wilcock [this issue] and Millar and Rennie [this issue] for their keen interest in our work and for the opportunity to clarify our model framework and results. While they make many valuable suggestions and addendums to our research, many of their objections are based on misinterpretation of our thesis and extension of our findings beyond their intended scope. We hope that our responses will dispel these misconceptions and decrease the potential for misapplication of our research.

Shortgrass prairie of the southern Great Plains extends through much of eastern New Mexico. The area is semi-arid; annual precipi­tation ranges between 380 and 510 mm (Wright and Bailey, 1982). Little is known about the arthropod fauna in the grasslands of eastern New Mexico, especially about non-eco­nomic species, which make up the majority of arthropods. We present here state and county records for surface-active species collected from Union Co. in the northeastern corner of New Mexico. Arthropods were originally col­lected as part of a fire ecology study (Ford, 2000), which reports on...

We report range extensions for 16 flea species collected from 11 rodent species in 7 counties across northeastern and central New Mexico. Including the new records, 107 species of flea have now been documented from New Mexico (Appendix 1). Records from the New Mexico Environment Department Vector Control Program (NMED) indicate 33 of these flea species have tested positive as vectors of sylvatic plague (Yersinia pestis = Pasturella) in New Mex­ico (Appendix 1). Of the species that tested plague positive, 5 (Aetheca wagneri, Malaraeus sinomus, opisodasys (Oxypsylla) keeni, Orapsylla...

Research results indicate that the home and its immediate surroundings within 100-200 feet (30-60 meters) principally determines the home ignition potential during severe wildland-urban fires. Research has also established that fire is an intrinsic ecological process of nearly all North American ecosystems. Together, this understanding forms the basis for a compelling argument for a different approach to addressing the wildland-urban fire problem. It argues for residential compatibility with wildland fire rather than the necessary prevention of fire encroachment on the community.

Gap models are perhaps the most widely used class of individual-based tree models used in ecology and climate change research. However, most gap model emphasize, in terms of process detail, computer code, and validation effort, tree growth with little attention to the simulation of plant death or mortality. Mortality algorithms have been mostly limited to general relationships because of sparse data on the causal mechanisms of mortality. If gap models are to be used to explore community dynamics under changing climates, the limitations and shortcomings of these mortality algorithms must be...