Treesearch

Two-year growth and mortality rates were analyzed for 254 black locust, 199 southern magnolia and 27 London plane trees planted along a major boulevard extending from southern Berkeley through western inner-city Oakland, California. After the first two years, 34% of these newly planted trees were either dead or removed. The average annual mortality rate was 19% with no significant difference in mortality among the species or between years. Areas of lower socio-economic status exhibited the most tree mortality with pecent mortality most strongly correlated with percent unemployment (r=0.78)....

Height and diameter measurements were taken for silver, sugar and Norway maple street trees in Rochester and Syracuse, New York. Mature silver maples proved to be the tallest of the three species. Average sugar maple height was consistently taller than Norway maple height until diameters reached 28 inches. Average mature tree height for all three species level off in the mid to upper 70-foot range. Tree age estimates were derived from the literature. After about the age of 35 years, silver maples appear to dominate the maples in terms of tree height. Height-diameter and heightapproximate...

Callus cultures of elm (Ulmus americana L.) derived from Dutch elm disease susceptible, intermediate-resistant, and resistant genotypes were exposed to the culture filtrates of three pathogenic isolates of Ceratocystis ulmi, the causal agent of Dutch elm disease. Callus fresh weights, cell viability, and reactions of stem cuttings were determined after exposure to various concentrations of the filtrates. Calli from the susceptible elm failed to increase in fresh weight and lost viability after exposure to media containing culture filtrate. Calli from the resistant and the intermediate-resis...

Air pollution and acidic deposition can influence forest tree growth and survival by causing ionic imbalances in the rooting zone. Altered nutrient status suppresses tree growth and weakens its immune system. Internal infections spread more quickly in response to weakened tree defenses. As adverse conditions persist, many trees die and the survivors are less healthy. Changes in concentrations and composition of ions within tree tissues are useful indicators of changes in vital processes affecting tree growth and survival. Ion chromatography is a useful method for measuring the concentration...

This paper describes a fast reliable, and a sensitive technique for the separation and quantification of dansylated polyamines by high-performance liquid chromatography. Using a small 33 x 4.6 mm I.D., 3 ?m particle size, C18 reversed-phase cartridge column and a linear gradient of acetonitrile-heptanesulfonate (10 mM, pH 3.4), at a flow-rate of 2.5 ml/min, the retention time for different polyamines was: N8-acetyl-spermidine, 1.79 min; N1-acetylspermidine, 1.82 min; putrescine, 2.26 min; cadaverine, 2.43 min; heptanediamine, 2.83 min; spermidine, 3.42 min; and spermine, 4.41 min. With an...

Describes a distance-independent individual-free probability of survival model for the Northeastern United States. Survival is predicted using a sixparameter logistic function with species-specific coefficients. Coefficients are presented for 28 species groups. The model accounts for variability in annual survival due to species, tree size, site quality, and the tree's competitive position within the stand. Model performance is evaluated using the chi-square goodness-of-fit test. Results are presented for the calibration data and an independent validation set. The model has been incorporate...

Methodology is presented for conducting drive-line counts to obtain absolute numbers of deer within fairly small (1560 ha) areas. Planning and layout of the drive and the organization of persons who make up the drive-line teams are discussed. Procedures for maintaining proper spacing and alignment of drivers are described. On a drive of a 5.7-km2 estate enclosed by a 2.5-m-tall deer fence in northwest Pennsylvania, numbers of deer counted (78) were within one of an estimate derived from a standard deer pellet-group count. The key elements of a successful drive are organization and communica...

A regional sample of tree-ring measurements was used to determine average annual growth in trees of 10 major species in New England. There have been extended periods of decreasing growth rates in red spruce since about 1960 and in balsam fir since about 1965. The other eight species, which included sugar maple and white pine, showed constant or increasing growth rates through 1980. The decreases in growth rate in sampled red spruce and balsam fir were independent of physical site characteristics, elevation, and geographic location, indicating that regional factors are involved. Weather...

In this paper, the mixed economic base of a modernizing rural community is examined with emphasis on the interrelationships between personal use of natural resources and other sectors of the economy.

Analyses of remeasured plot data show that between the last two forest inventories of New England, compound rates of value change in timber stands averaged 4.2 percent and ranged from -26 to + 43 percent. Three key characteristics of stand condition (species composition, tree size, and stocking) can be used to estimate economic growth. For example, stands with (1) more than 10 square feet of basal area per acre in softwood species; (2) tree of average basal area less than 7 inches in diameter; and (3) more than 50 percent of total basal area in white pine have a 14.7-percent average rate...