Treesearch

In the late 1970s, the outlook for conifer seedlings in new plantations in the Western United States was dismal&too many were dying or growing below the potential of the site. This situation was untenable, and a large study aimed at increasing the survival and growth of planted conifer seedlings was implemented. This was the National Administrative Study on Vegetation Management of which the California portion is reported here. This "study" was really a program on plantation release with 32 individual studies that resulted in more than 60 publications over a 25-year timeframe. The authors...

Over the past century, annual snowfall has increased across the ¡®snow-belt¡¯ region of the Upper Peninsula of Michigan, yet total annual precipitation has not changed, with potential impacts on hydrological processes and ecosystem composition. Using an integrated hydrochemical approach, we characterized groundwater discharge and quantified the contribution of snow- and rain-derived waters to groundwater for an old-growth riparian area within the Huron Mountains in northern Michigan. We then quantified the relative contribution of lateral, hillslope-derived groundwater and upstream lake...

In recent decades, intense droughts, insect outbreaks, and wildfires have led to decreasing tree growth and increasingmortality in many temperate forests. We compared annual tree-ring width data from 1,097 populations in the coterminous United States to climate data and evaluated site-specific tree responses to climate variations throughout the 20th century. For each population, we developed a climate-driven growth equation by using climate records to predict annual ring widths. Forests within the southwestern United States appear particularly sensitive to drought and warmth.We input 21st...

1. The introduction of trout to montane lakes has negatively affected amphibian populations across the western United States. In northern California’s Klamath–Siskiyou Mountains, introduced trout have diminished the distribution and abundance of a native ranid frog, Rana (=Lithobates) cascadae. This is primarily thought to be the result of predation on frog larvae. However, if trout feed on larval aquatic insects that are available to R. cascadae only after emergence, then resource competition may also affect this declining native amphibian. 2. Stomach contents of R. cascadae were compared...

In this article we explore the influence that a perceived connection between a natural resource management agency and individual citizens has upon conservation-related behaviors on public lands, offering an extension of psychology’s examination of environmental behaviors. Our emphasis is upon perceived value similarity and resulting trust between citizens and the USDA Forest Service, defined through the salient values similarity model. On the basis of a retrospective analysis of four studies examining public views on threatened and endangered species management on forest lands, we explore...

Research at the University of Costa Rica on potential biological control agents of Miconia calvescens was initiated in 2000. Although M. calvescens can be fairly common at certain sites, it is generally uncommon in Costa Rica and appears to be incapable of becoming established in forests with a closed canopy. Over fifty insect species have been identified as feeding on this plant, but most of these were excluded from further research because they are probably not sufficiently host-specific. Thus far we have focused our attention on six species that appear to be promising biological control...

We have made much progress in evaluating potential agents for biocontrol of miconia, and several appear likely to be suitable for future introduction to Hawaiÿi. Unfortunately, none of them is an obvious silver bullet. We face the challenge of prioritizing the existing candidates and inventing the combination of agents that will achieve our goals. Now is an opportune moment to reassess our goals for miconia biocontrol and strategize how we will combine biocontrol and other management tools to successfully manage this weed for the long term. Our goals and choices for biocontrol should take...

The native range of Miconia calvescens extends into southern Mexico, but no surveys of its natural enemies had previously been done in Mexico. In August 2006 we conducted a 2-week survey of the state of Chiapas to locate populations of Miconia calvescens and to identify insect and other natural enemy species present on it that might have potential as biological control agents. M. calvescens was found to be present in Chiapas, although at very low population densities. Seven locations were found in two separate areas, one east of the Lagunas de Montebello National Park, and the other in the...

New knowledge from wildlife-habitat relationship models is often difficult to implement in a management context. This can occur because researchers do not always consider whether managers have access to information about environmental covariates that permit the models to be applied. Moreover, ecosystem management requires knowledge about the condition of habitats over large geographic regions, whereas most research projects have limited spatial inference. For example, research has revealed much about the habitat of fishers (Martes pennanti) at various research sites in California, yet this...

This special issue of Forest Science features the national Fire and Fire Surrogate study (FFS), a niultisite, multivariate research project that evaluates the ecological consequences of prescribed fire and its mechanical surrogates in seasonally dry forests of the United States. The need for a comprehensive national FFS study stemmed from concern that information on the ecological effects of restoration treatments designed to improve current, unsustainable conditions in seasonally dry forests was lacking. Current conditions are the result of climate change and forest management practices...