Treesearch

Color photographs as guides to assessing crown condition of oaks are provided. Use of crown condition for gypsy moth vulnerability rating and silvicultural treatments to minimize gypsy moth impacts are presented.

Rooting trials were established to evaluate rooting success of cuttings from mature and juvenile, grafted and ungrafted northern red oak (NRO). Buds from 4 mature NRO ortets and juvenile seedlings were grafted onto juvenile and mature rootstock. Cuttings were collected from the grafts and from juvenile and mature shoots developed in situ and subjected to a rooting trial. Of all treatments, cuttings from juvenile material rooted best. However, the rooting of cuttings from mature trees was also relatively successful. Rooting success of cuttings was significantly related to ortet genotype and...

The survival and growth of northern red oak (Quercus rubra L.) seedlings planted beneath a shelterwood in northern West Virginia were evaluated one year after planting. The use of 1.5 m (5 ft) tall TUBEX tree shelters on planted seedlings was also examined. The study was conducted on both excellent and good sites (site indices of 27 m (89 ft) and 22 m (74 ft) for northern red oak, respectively). The overstories on both sites were dominated by yellow-poplar (Liriodendron tulipifera L.), white oak (Quercus alba L.), and northern red oak. A replicated four-level split-plot experimental design...

Morphology, cultural characteristics, and pathogenicity of Rhizosphaera kalkhoffii from spruce (Picea spp.) showing premature needle loss in northern Minnesota and Wisconsin were investigated. Pycnidiospores from needles, conidia of the Hormonema-like synanamorph, and pycnidiospores produced in culture were similar for Colorado blue, Engelmann, Norway, and white spruce collections and isolates. Pycnidiospores from black spruce needles were smaller than those from Colorado blue or white spruce (P < 0.05). colony diameters at 14 days were similar on four different spruce needle extract agars...

Artificial regeneration of northern red oak is difficult to achieve in the Lake States. A replicated study was established in northern Wisconsin in 1990 to determine the effect of overstory density and understory competition on the performance of bareroot and containerized northern red oak seedlings on a dry-mesic site. The relationship between seedling performance and the number of first-order lateral roots was also tested. Seedling performance was evaluated under three overstory densities - clearcut, 25%, and 50% crown covers - in combination with (or without) understory vegetation...

A model that uses forest stand characteristics to estimate the likelihood of gypsy moth (Lymantria dispar) defoliation has been developed. It was applied to recent forest inventory plot data to produce susceptibility ratings and a map showing defoliation potential for counties in Pennsylvania and six adjacent states on new frontiers of infestation.

In 1991 and 1992, we observed gypsy moth defoliation of oak regeneration in clearcuts of varying sizes and ages. We established plots in the surrounding mature forests to document ambient gypsy moth population levels and placed subplots within the clearcuts designed to examine the effect of location relative to the clearcut edge. We found that the levels of defoliation on oak regeneration in the clearcuts closely approximated that of the adjacent mature forests. Clearcut age seemed to have little effect on rate of defoliation, but larger clearcuts (> 25 acres) had somewhat lower average...

A model for predicting gypsy moth defoliation in central hardwood forests based on stand characteristics was evaluated following a 5-year outbreak in Pennsylvania and Maryland. Study area stand characteristics were similar to those of the areas used to develop the model. Comparisons are made between model predictive capability in two physiographic provinces. The tested model was inconsistent in its predictive capacity. In the Ridge and Valley province of Maryland, model predictions overestimated actual stand level defoliation. In the Appalachian Plateau of Pennsylvania, the same model...