Treesearch

Thirteen different host species for elm leaf beetle, Xanthogaleruca luteola (Muller), were assayed to determine their relative suitability. Species examined were Ulmus parvifolia Jacq., U. thomasii Sarg., U. laevis Pall., U. wilsoniana Schneid., U. americana L., U. japonica Sarg., U. pumila L., U. rubra Muhl., U. laciniata Mayr., U. glabra Huds., U. carpinifolia Gledisch, Zelkova serrata Makino, and '204,' a hybrid of U. carpinifolia x U. parvifolia. Suitability was determined by feeding adults excised foliage from a tree and measuring mortality and fecundity during a two wk period....

From 1982 to 1984, inflight smaller European elm bark beetles, Scolytus multistriatus, were captured on American elms, Ulmus americana, that were therapeutically pruned for Dutch elm disease control. Pruning wounds were treated with wound dressing or left untreated to determine effects of the treatments on beetle attraction. Significantly more beetles were captured at pruning sites than were captured away from pruning sites, regardless of treatment. No differences were detected in beetle captures at pruning sites with or without wound dressing. Male to female sex ratios were unaffected.

The streams tributary to acidic Cone Pond, pH 4.5-4.8, and circumneutral Black Pond, pH 5.3-6.4, in the White Mountains of New Hampshire, USA, were monitored for a year. The watersheds of these two ponds were characterized in terms of geology and stream hydrology. Chemical gradients and patterns in rock weathering and groundwater discharge explain many of the differences in mineral content and acidity of the streams. The rocks of Black watershed produced an average of ten times the equivalent of basic cations as rocks from Cone watershed. This is on the same order as the difference in...

Northern red oak, black oak, black cherry, and red maple seedlings were grown under light treatments ranging from 8 to 94% of full sunlight for 2 years. Growth was least at the lowest light level and total dry weight increased with increasing light. Total dry-weight rankings (largest to smallest) at all light levels were black cherry, northern red oak, black oak, and red maple. As light increased, allocation of biomass into leaves and stems decreased while branch biomass held constant except for black cherry, which increased. Allocation of biomass into roots increased significantly with...

Forest managers on new frontiers of infestation are searching for better ways to cope with the gypsy moth (Lymantria dispar). Presented herea are information and guidelines for remedial action to minimize future losses. Methods for assessing potential stand defoliation (susceptibility) and mortality (vulnerability), monitoring insect populations, and selecting action alternatives are discussed. With due consideration of management objectives, we address the primary concerns of managers who lack previous experience with the pest.

The purpose of this manual is to assist members of the National Vegetation Survey in recognizing air pollutant-induced injury and in identifying disease and insect damage that may be confused with air pollutant-induced injury to forest vegetation in the eastern United States. Ozone, sulfur dioxide, and, to a limited geographic extent, hydrogen fluoride, are all pollutants of concern in relation to forest vegetation; detailed descriptions of the injuries caused by these pollutants are presented herein. A second section of this manual has been prepared to assist the Survey in recognizing...

Analysis of three environmental variables affecting seedling growth of four half-sib white ash families was dominated by a three-way interaction between soil moisture stress, fescue leachate, and family. Of these, soil moisture stress contributed by far the most to the interaction and resulted in an average growth decline of 62%. Although fescue leachate appeared to be phytotoxic to ash seedlings, it had a lesser effect resulting in changes in height rankings among families. Seedling families which grew well under moisture stress also tended to be tallest in the presence of fescue leachate....

This paper discusses the crosscut-first rough mill with emphasis on the effects of lumber quality, cutting bills, and operator efficiency on yields. Adding a gang-rip-first option is recommended, which will use more of the lower grades of lumber while meeting the needs of the furniture and cabinet industries. Current research that indicates why gang ripping to glueline-quality edges should be effective is also discussed. A rough mill that uses log-run lumber (No.2 Common and Better) and allows a gang-rip-first or crosscut-first option is described.

Nursery root and shoot measurements and annual height, basal diameter and survival data for the 5 years after outplanting were used to describe black walnut growth variation in southern Illinois. At age 5 sapling height narrow-sense heritability was found to be 0.49 for 131 open-pollinated families from across the black walnut comercial range. Greatest height and diameter growth was from previously identified provenances within 200 miles south of the planting site; local sources also provided good results. Although the largest seedlings in the nursery tended to remain the largest throughout...

Tissue culture techniques have been used to obtain hybrid poplars with putative resistance to leaf spot caused by Septoria musiva from clones previously susceptible to the disease. Stem internode explants were used to obtain proliferating callus cultures. Adventitious bud formation and shoot proliferation were then induced. Elongated shoots were excised and rooted in a peat : perlite medium under high humidity. After acclimation, rooted plants were transferred to the greenhouse. Variant plants were selected among the regenerants using a leaf disc bioassay that rapidly distinguishes plants...