Treesearch

Many growth and yield simulators require a stand table or tree-list to set the initial condition for projections in time. Most similar neighbour (MSN) approaches can be used for estimating stand tables from information commonly available on forest cover maps (e.g. height, volume, canopy cover, and species composition). Simulations were used to compare MSN (using an entire database) with two stratified MSN approaches. The first stratified MSN approach used species composition to partition the population into two inventory type strata, and the second stratified MSN approach used average...

The Alsea Watershed Study (AWS) was the first long-term fisheries research project to address the effects of forestry operations on salmonid populations in the Pacific Northwest using a watershed approach. To this day it remains one of a very limited number of investigations that have provided long-term information on salmon and trout responses to forestry operations. These studies have had a significant impact on the development of state and provincial forest practices regulations. The initial results of the AWS, which demonstrated negative impacts of logging on salmonid spawning and...

A recent series of severe fire seasons in the United States has contributed to sharply rising wildfire suppression costs. These increasing costs have caught the attention of policymakers, but so far the responses have not focused clearly on the incentive structures that allow or encourage rising costs. We analyze the problem of rising suppression costs by examining the incentive structures faced by fire managers. Specifically, we examine the influence of wildfire suppression funding mechanisms on managers' behavior. The rationale for this approach is that fire managers have a good deal of...

We develop and test a conceptual model of wood dynamics in stream networks that considers legacies of forest management practices, floods, and debris flows. We combine an observational study of wood in 25 km of 2nd- through 5th-order streams in a steep, forested watershed of the western Cascade Range of Oregon with whole-network studies of forest cutting, roads, and geomorphic processes over the preceding 50 years. Statistical and simple mass balance analyses show that natural process and forest management effects on wood input, transport processes, and decomposition account for observed...

A recent four-part series in Arborist News outlined different appraisal processes used to value urban trees. The final article in the series described the three generally accepted approaches to tree valuation: the sales comparison approach, the cost approach, and the income capitalization approach. The author, D. Logan Nelson, noted that the sales comparison approach has the appeal of being based on observed market transactions. In this article, we outline the strengths and weaknesses of the sales comparison approach, define what type of value it estimates, and introduce the hedonic price...

Decline of yellow-cedar (Chamaecyparis nootkatensis((D. Don) Spach) has occurred on 200 000 ha of temperate rainforests across southeastern Alaska. Because declining forests appeared soon after the Little Ice Age and are limited mostly to low elevations (whereas higher elevation forests remain healthy), recent studies have hypothesized a climatic mechanism involving early dehardening, reduced snowpack, and freezing injury. This hypothesis assumes that a specific suite of microclimatic conditions occurs during late winter and declining cedar populations across the region have responded...

Environmental controls of stand-level tree transpiration (E) and seasonal patterns of soil water utilization were studied in five central Brazilian savanna (Cerrado) sites differing in tree density. Tree density of Cerrado vegetation in the study area consistently changes along topographic gradients from ~1,000 trees ha-1 in open savannas (campo sujo) at the lower end of the topographic gradient to >3,000 trees ha-1 in woodlands (cerradao) at the upper end of the gradient. Tree canopy resistance (rc) increased linearly with increasing daily mean air saturation deficit (D) at all sites, but...

Tree mortality is a poorly understood process in the boreal forest. Whereas large disturbances reset succession by killing all or most trees, background tree mortality was hypothesized to be affected by competition, ageing, and stand composition. We tested these hypotheses on jack pine (Pinus banksiana Lamb.) mortality using data from long-term repeatedly measured permanent sample plots collected between 1952 and 1989 in Ontario, Canada. The probability of mortality over a 5-year period was modeled using logistic regression with the maximum likelihood estimation employed for parameter...

Managers, regulators, and researchers of aquatic ecosystems are increasingly pressed to consider large areas. However, accurate stream maps with geo-referenced attributes are uncommon over relevant spatial extents. Field inventories provide high-quality data, particularly for habitat characteristics at fine spatial resolutions (e.g., large wood), but are costly and so cover relatively small areas. Recent availability of regional digital data and geographic information systems software have advanced capabilities to delineate stream networks and estimate coarse-resolution hydrogeomorphic...

This study uses a multiscale, multimethods approach to examine the effects of declining timber harvests on the well-being of forest communities in the Pacific Northwest as a result of the Northwest Forest Plan (the Plan). We found that the effects of declining timber harvests were variable and depended on the importance of the timber sector in a community in the late 1980s, the extent to which federal timber supported that sector, and the degree to which local residents depended on U.S. Forest Service jobs. In addition, we found that other goods, services, and opportunities associated with...