Treesearch

A gram-negative bacillus, pathogenic for gypsy moth larvae, was characterized culturally, morphologically, and physiologically as a member of the Serratia group of the family Enterobacteriaceae. The microorganism lacked the pigmentation characteristic of the group but was generally distinguished from closely related members of the family by its inability to produce gas from glucose, inositol, glycerol, and cellobiose; its rapid liquefaction of gelatin; and its failure to ferment raffinose or arabinose. The microorganism displayed lecithinase, deoxyribonuclease, and chitinase activity. The...

The ED50 of a strain of Serratia marcescens for microinjected instar III and IV gypsy moth larvae was 7.5 and 14.5 viable cells, respectively. Percentage and rate of mortality were found to be highly variable among replicates of the same instar and between instars in free-feeding bioassays. Mortality in second instar larvae occurred before ecdysis, whereas practically no mortality occurred in third and fourth instars until the molting period. Neither Boivin endotoxin preparations nor culture filtrates were toxic to instar III larvae when administered per os or by microinjection. Histologica...

This booklet offers guidelines on how to care for trees to keep them healthy and to protect them from wounds. It also prescribes ways to prevent, recognize, and minimize damage by decay that most often sets in after tree wounding.

Northern white-cedar from 18 provenances was evaluated for total height in the nursery and for survival and total height in two field plantings in northern Wisconsin and in western Upper Michigan. There were significant differences among provenances in survival at one location and in height at both field locations 5 years after planting; there were no differences among provenances in height in the nursery. Total height was moderately, but significantly correlated between the plantings. The data suggest that there is significant genetic variation and genotype-environment interaction in...

Trees in a yellow birch progeny test began to bear seed when 7 years old and the proportion of fruiting trees increased in the following 2 years. Male catkins were produced at age 8 and the number of trees with males increased greatly the following years. Although there is much variation between and within families in earliness of flowering and in number of flowers and fruiting catkins, about one-third of the families have borne seed and 45 percent have produced males. The number of catkins per tree has ranged up to 429 for females, 196 for fruiting, and 1379 for males. Seed yield varied...

Leaf material from 21 nursery-grown Populus hybrid clones was analyzed for three nitrogen fractions (total N, soluble protein, and soluble amino acids) and three carbhydrate fractions (reducing sugars, total soluble sugars, and total nonstructural carbohydrates-TNC). In addition, nursery-grown green ash and silver maple, field-grown bigtooth and trembling aspen, and growth-room-reared eastern cottonwood were analyzed for comparison. The amounts of the various chemical fractions ranged widely among the Populus clones: total N from 2.14 to 3.86% dry weight, soluble protein 0.98 to 5.89%,...

A statistical and analytical report on the third forest survey of New Hampshire. Statistical findings are based on the remeasurement of 1/5-acre plots and new 10-point cluster plots. Trends in forest-land area, timber volume, annual growth, and timber removals are discussed; also timber-products output by forest industries, based upon a canvass of industries in 1973, and the importance of timber and forests to the State's economy and environment. The report includes a discussion of the outlook for timber supplies during the next 30 years, and forest management opportunities in the State....

Detailed study of the history of forest tree growth by tree-ring analysis is used to assess the effect of acid precipitation. The pattern and historical trends of acid precipitation deposition are compared with growth trends from mature forest stands in New Hampshire and Tennessee. No clear indication of a regional, synchronized decrease in tree growth was found. The residual variation of relative tree growth responses, after removal of variation due to weather, shows no recent time-dependent trend. Due to the unknown initiation-date of acid precipitation and to the large variation of tree...

This paper summarizes the results from current studies in Norway. One main approach is the application of artificial acid "rain" and of lime to field plots and lysimeters. Application during two growth seasons of 50 mm per month of "rain water" of pH 3 to a podzol soil increased the acidity of the humus and decreased the base saturation. The reduction in base saturation was mainly due to leaching of calcium and magnesium. Laboratory experiments revealed that decomposition of pine needles was not affected by any acid "rain" treatment of the field plots. Liming slightly retarded the decomposi...

The department of plant ecology and soils of the College of Forestry has been interested in the problem of the acid rain as an environmental factor since the discussion of this problem started in the late 1960's (0den 1968).