Treesearch

We presented a matrix growth model for an uneven-aged, oak-hickory forest in the Ozark Highlands of Missouri. The model was developed to predict ingrowth, growth of surviving trees, and mortality by diameter class for a five-year period. Tree removal from management activities is accounted for in the model. We evaluated a progression of models from a static, fixed parameter to a dynamic, function form. The model was based on data from 366 0.2-arce permanent plots, measured over seven five-year periods from 1957 to 1992. Variables used in development of the dynamic model incvluded basal...

Various approaches are available to minimize impacts on forest productivity during forest road building and timber harvesting activities. These approaches include a variety of practices and technologies. They include practices such as reducing road and trail development, using designated trails, and leaving slash at the stump on nutrient deficient sites. Technology options include low ground pressure machinery, tracked swing-to-tree feller-bunchers, small-scale equipmnnt, and portable wetlands and stream crossing structures. Increased application of these approaches will require additional...

Unlike annual floods, large floods affect plant species outside of bottomland ecosystems. We know little about the effects of catastrophic floods on upland plants because of the rarity of this type of disturbance. Here we report on mortality and vegetative recovery of upland longleaf pines (Pinus palustris) after a large flood. The flood top-killed most seedlings and advance regeneration, while most large pines survived. About one-half and one-third of affected seedlings and advance regeneration, respectively, recovered vegetatively through resprouting or reflushing. High rates of initial...

Mechanical wounding stimulates the accumulation of Pschi4 transcripts (encoding a putative extracellular chitinase) in pine trees. To gain insight into the transcriptional regulatory region(s) in this gymnosperm defense gene, the 5'-flanking region of Pschi4 was fused to the uidA reporter gene encoding -glucuronidase (GUS), and the construct was functionally tested for transient expression in onion and pine cells. As little as 200 bp of the upstream sequence was sufficient to promote activated transcription and nearly maximum levels of transient expression in onion cells. Similar results...

Perceptual range, or the distance at which habitat 'patches' can be perceived, constrains an animal's informational window on a given landscape. If such constraints are great, they may limit successful dispersal between distant habitat patches. On dark nights, nocturnal white-footed mice, Peromyscus leucopus, have surprisingly limited perceptual abilities regarding distant forested habitat. In fact, their ability to orient towards such habitat while travelling in a bare agricultural field indicates a perceptual range under 30 m. However, increasing illumination can increase perceptual...

Microclimate is the suite of climatic conditions measured in localized areas near the earth's surface (Geiger 1965). These environmental variables, which include temperature, light, windspeed, and moisture, have been critical throughout human history, providing meaningful indicators for habitat selection and other activities. For example, for 2600 years the Chinese have used localized seasonal changes in temperature and precipitation to schedule their agricultural activities. In seminal studies, Shirley (1929, 1945) emphasized microclimate as a determinant of ecological patterns in both...

Population genetics theory has dealt only with the spatial or geographic pattern of degrees of relatedness or genetic similarity separately for each point in time. However, a frequent goal of experimental studies is to infer migration patterns that occurred in the past or over extended periods of time. To fully understand how a present geographic pattern of genetic variation reflects one in the past, it is necessaly to build genealogy models that directly relate the two. For the first time, space-time probabilities of identity by descent and coalescence probabilities are formulated and...

Public attitudes, beliefs, and underlying values about roads on the U.S. national forests expressed in more than 4,000 on-line news stories during a 3-year period are analyzed by using computer methods. The belief that forest roads provide access for recreation was expressed most frequently, accounting for about 40% of all beliefs expressed. The belief that roads cause ecological damage was the second-most prominent belief. The volume and nature of media debate about forest roads changed in the third quarter of 1997 due to narrowly defeated proposals in the U.S. House of Representatives...

This paper describes a new approach for monitoring the social environment for natural resource management and policy, based on content analysis of online news media stories. Content analysis of the media has repeatedly been shown to produce results that are closely correlated with attitude surveys and opinion polls. Computer methods were used to analyse almost 30,000 online news stories about the US national forests for expressions of four broad categories of benefits and values. Recreation benefits and values were expressed more often than other categories, both at the national and...

Increasing awareness of the importance of scale and landscape structure to landscape processes and concern about loss of biodiversity has resulted in efforts to understand patterns of biodiversity across multiple scales. We examined plant species distributions and their relationships to landscape structure at varying spatial scales across a pine barrens landscape in northern Wisconsin, U.S.A. We recorded plant species cover in 1 X 1 m plots every 5 m along a 2575 m transect, along with variables describing macro- and micro-landscape structure. A total of 139 understory plant species were...