Treesearch

Volcanoes have been part of the Earth’s history ever since it has had a solid surface. And, volcanoes have been a part of human culture for thousands of years. In some ways, our reactions to the magnitude of a volcanic explosion haven’t evolved as much as one might think. Ranging from ancient cultures who believed that victims should be sacrificed in response to volcanic eruption, to Harry Truman who stubbornly sacrificed himself during the most recent eruption in the continental United States, volcanoes have impacted our lives in many ways and will continue to do so in the future.

Data from volcanic ash-influenced soils indicates that soil pH may change by as much as 3 units during a year. The effects of these changes on soil chemical properties are not well understood. Our study examined soil chemical changes after artificially altering soil pH of ash-influenced soils in a laboratory. Soil from the surface (0-5 cm) and subsurface (10-15 cm) mineral horizons were collected from two National Forests in northern Idaho. Soil collections were made from two undisturbed forest stands, a partial cut, a natural bracken fern (Pteridium aquilinum [L.] Kuhn) glade, an approxima...

My purpose is twofold: to review key messages from previous speakers and to offer some concepts that may help you link recently acquired information. When Mt. Mazama erupted about 7,000 years ago, its airborne ash and pumice fell on a wide variety of existing soils. This Mazama tephra was a new parent material for soil development (fig. 1). At some locations, the original deposition was redistributed by: gravity, wind, water, plants, or animal activities, including those of humans. Soil at any specific location in the Inland West is a result of these soil-forming factors and their many...

A multiplicative and a semi-mechanistic, BWB-type [Ball, J.T., Woodrow, I.E., Berry, J.A., 1987. A model predicting stomatal conductance and its contribution to the control of photosynthesis under different environmental conditions. In: Biggens, J. (Ed.), Progress in Photosynthesis Research, vol. IV. Martinus Nijhoff, Dordrecht, pp. 221-224.] algorithm for calculating stomatal conductance (gs) at the leaf level have been parameterised for two crop and two tree species to test their use in regional scale ozone deposition modelling. The algorithms were tested against measured, site-specific...

The mountain pine beetle Dendroctonus ponderosae is a native species currently experiencing large-scale outbreaks in western North American pine forests. We sought to describe the pattern of genetic variation across the range of this species, to determine whether there were detectable genetic differences between D. ponderosae occupying different host trees in common localities, and to determine whether there was molecular evidence for a past demographic expansion. Using a combination of amplified fragment length polymorphism (AFLP) and mitochondrial sequencing analyses, we found evidence...

A spectacular forest in the center of the CCE cuts a 15- by 5-km swath along the Flathead River's South Fork around Big Prairie in the middle of the Bob Marshall Wilderness Area in Montana (Figure 13- 1). This wide valley bottom, which contains two patches (of about 1,000 ha each) of the last vestiges of the historic ponderosa pine ecosystem in the CCE, provides a local context and a case example for our discussion of fire dynamics in this chapter. The Big Prairie ponderosa pine (see Chapter 2 for scientific names not given in this chapter) ecosystem is a consequence of a special fire...

The smouldering combustion of peat and muck soil plays an important role in the creation and maintenance of wetland communities. This experimental study was conducted to improve our understanding of how moisture and mineral content constrain smouldering in organic soil. Laboratory burning was conducted with root mat and muck soil samples from pocosin and pond pine woodland wetlands common on the North Carolina coastal plain. The results of laboratory and prescribed burning were compared. Laboratory results showed that moisture and mineral content influenced sustained smouldering in root...

In this chapter, we present a case study intended to help crystallize for many readers, through use of an illustrative example, some of the important concepts developed in the preceding chapters. From an understanding of forest successional and disturbance processes, both natural and anthropogenic (Linke et al., Chapter 1, this volume), research questions were developed to compare and contrast the landscape patterns generated from fire and harvest disturbance. Remotely sense data are demonstrated as an appropriate source of relevant information (Coops et al., Chapter 2, this volume),...

Pacific salmon (Oncorhynchus spp.) have been central to the development of management concepts associated with evolutionarily significant units (ESUs), yet there are still relatively few studies of genetic diversity within threatened and endangered ESUs for salmon or other species. We analyzed genetic variation at 10 microsatellite loci to evaluate spatial population structure and genetic variability in indigenous Chinook salmon (Oncorhynchus tshawytscha) across a large wilderness basin within a Snake River ESU. Despite dramatic 20th century declines in abundance, these populations...

In this study, LIDAR snow depths, bare ground elevations (topography), and elevations filtered to the top of vegetation (topography + vegetation) in five 1-km2 areas are used to determine whether the spatial distribution of snow depth exhibits scale invariance, and the control that vegetation, topography, and winds exert on such behavior. The one-dimensional and mean two-dimensional power spectra of snow depth exhibit power law behavior in two frequency intervals separated by a scale break located between 7 m and 45 m. The spectral exponents for the low-frequency range vary between 0.1 and...