Treesearch

Faced with multiple objectives, national forest managers and planners need a means to solicit and analyze public preferences and values. A conjoint ranking survey was designed to solicit public preferences for various levels of timber harvesting, wildlife habitats, hiking trails, snowmobile use, and off-road-vehicle (ORV) access on the Green Mountain National Forest. The survey was completed by 76 respondents during public involvement meetings. An ordered probit model was used to estimate linear and quadratic main effects. Respondents preferred moderate levels of timber harvesting and...

Our research requires determinations of total elemental concentrations of forest soils. The lack of certified forest soil reference materials led us to develop internal reference samples. Samples were collected from three soil horizons (Oa, B, and C) at three locations having forested, acidic soils similar to those we commonly analyze. A shatterbox was used to homogenize the nine samples. The Radiation Laboratory of the University of Massachusetts, Lowell completed neutron activation analyses (NA) on our samples. Our laboratory performed five digestion procedures: microwave [nitric acid...

A long-term study initiated in 1989 at the West Virginia University Forest contrasted the effects of silvicultural treatments on the development of gypsy moth (Lymantria dispar L.) outbreaks and their impacts. The area is a relatively susceptible Quercus spp./mixed hardwood forest. Egg mass densities, survivorship, and mortality from natural enemies differed little between stands that were treated silviculturally and those that were not. However, stands that were thinned had less overstory mortality than unthinned stands despite incurring comparable levels of defoliation.

We present prediction models for estimating tree mortality resulting from gypsy moth, Lymantria dispar, defoliation in mixed oak, Quercus sp., forests. These models differ from previous work by including defoliation as a factor in the analysis. Defoliation intensity, initial tree crown condition (crown vigour), crown position, and species grouping classes were highly significant in categorical analysis of variance for mortality. Heavy defoliation intensity was shown to have a strong, consistent influence in increasing the probability of tree mortality. Classification and Regression Tree...

In northeastern U.S. forests there is considerable variation in susceptibility (defoliation potential) and vulnerability (tree mortality) to gypsy moth (Lymantria dispar [L.]). Thinning has been suggested as a way to reduce susceptibility and/or vulnerability. We evaluated how thinning affected the dynamics of gypsy moth populations by experimentally thinning half of each of eight oak-mixed hardwood stands in the Central Appalachians. Population dynamics of gypsy moth were monitored using yearly counts of egg masses, numbers of larvae hatching per mass, estimates of larval density, and...

Tropical forests are the most species-rich forests in the world. As many as 225 tree species per hectare have been reported in these ecosystems, values that are equivalent to almost finding a different tree species every other tree encountered in the forest. Under some conditions, tree species richness decreases in tropical forests. For example, Hart et al. (1989) reported that forests in Africa that were dominated by a single species had on average 18 tree species per 0.5 ha. Fewer species still are normally found in freshwater forested wetlands. Values in these systems range from 1 to 23...

Two species of imported fire ants were introduced into the U.S. at Mobile, Alabama. The black imported fire ant, Solenopsis richteri Forel, was introduced around the early 1900's while the red imported fire ant, Solenopsis invicta Buren entered in the late 1930' or early 1940's. The red imported fire ant is the most widespread of the two and presents the greatest problem. From Mobile, these fire ants have spread naturally by such means as mating flights, and floating of colonies on rivers and streams after floods. Most importantly, the ant has spread artificially by the aid of man during...

Oak wilt, a fungal disease of all oak species, continues to be the primary cause of oak mortality in Minnesota. The oak type covers over 650,000 acres in Minnesota and is made up of six species. Forest industry adds $1 billion to the state's economy by harvesting and utilizing oak. In our communities, oak is our most valuable shade tree providing energy conservation, beauty, sound and visual protection, and wildlife habitat. Since 1987, surveys have identified just over 6,000 infection centers in 19 southeastern counties. Most of the disease is concentrated in the urban areas of the Twin...

Dogwood anthracnose, caused by the fungus Discula destructiva was found in the Southern United States in 1987. Since that time millions of flowering dogwoods have been killed and disfigured by this disease. As soon as the disease was discovered a group of state and federal personnel formed a working group to develop an action plan for dealing with the disease. Collaboration was the key word from the beginning of the working group. A key to the success of the working group was a spirit of cooperation with out concern for who was going to get credit. Each time the working group met informatio...