Treesearch

Data gathered by automobile traverse were used to describe the urban heat of Akron, Ohio. Observations were made at 2100 or 2200 EST on four nights-17 April, 11 July, 10 October, and 2 January. Weather conditions not conducive to heat-island development were avoided. Temperatures in the center of the heat island were 6 to 14?F warmer than rural areas outside the city. The heat-island center was always over a mixed residential/commercial area. Topographic influences were apparent in the heat-island pattern.

The removal of particulate lead from the air by a roadside windbreak of white pine containing 8 rows of 25-year-old trees and 27 m in depth was studied. Knowledge of particulate trapping and retention was gained by atomic absorption spectrophotometry of the lead burden of foliage and twigs of various ages adjacent to and far from the road. The effectiveness of the windbreak was also shown by comparison of the lead content of the soil beneath the windbreak with that of an adjacent open, undisturbed field.

Taxes on forest properties and on income from timber disposal impose one of the most significant kinds of cost burden faced by owners of interests in forest lands. Local property taxes impose annual charges regardless of the level of management, and may even be increased by intensive practices. Federal and state income taxes are usually second in impact only to property taxes. Federal transfer and state death taxes can seriously endanger the continuity of management programs from one generation to another. Taxpayers can significantly reduce the impacts of these taxes by an awareness of the...

In a study of decay in yellow-poplar (Liriodendron tulipifera L.), red maple (Acer rubrum L.), sugar maple (Acer saccharum Marsh.), black gum (Nyssa sylvatica Marsh.), and ash (Fraxinus spp.) in the central hardwood region, decay was found in 57 of 148 study trees. Extent of decay, causal fungi, and method of entry are discussed. The relationship between tree age and diameter and decay is also examined.

Recent research has shown that prompt removal of diseased elms reduces the incidence of Dutch elm disease more than sanitation practice that allows diseased elms to remain standing into the dormant season. The key to prompt removal is repeated surveys to detect diseased elms as early as possible. Intensive sanitation can save more elms and cost less than the more conventional sanitation practice. A 3-year case history demonstrates savings of 25 percent in total cost and an additional 92 elms per thousand.

A statistical and analytical report on the third forest survey of Vermont by the USDA Forest Service. Statistical findings are based on the remeasurement of 1/5-acre plots and 10-point cluster plots. This report discusses and analyzes trends in forest-land area, timber volume, annual growth, and timber removals. 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 are also discussed. The report also includes a discussion of the outlook for timber supplies during the next 30...

Being downwind of eastern and midwestern industrial centers, the Hubbard Brook Experimental Forest offers a prime location to monitor long-term trends in atmospheric chemistry. Continuous measurements of precipitation chemistry during the last 10 years provide a measure of recent changes in precipitation inputs of hydrogen ion. The weighted average pH of precipitation during 1964-65 to 1973-74 was 4.14, with a minimum annual value of 4.03 in 1970-71 and a maximum annual value of 4.21 in 1973-74. The sum of all cations except hydrogen ion decreased from 51 μeq/l in 1964-65 to 23 μeq/l in...

Data collected since 1965 at a network of 9 stations in the northeastern United States show that precipitation is most acid in the growing season (May-September) and least acid in winter (December-February). For the Hubbard Brook station in New Hampshire, where the mean hydrogen ion content of precipitation ranges between 46 μeq/l in winter and 102 μeq/l in summer, the seasonal pattern in acidity correlates closely with seasonal differences in sulfur deposition from the atmosphere. As summer precipitation passes through the forest canopy, hydrogen ion concentrations are lowered by an...

Immature Lymantria dispar L. were collected from 6 geographically distinct populations over 2 years to determine correlations between parasitoid and disease incidences. Incidence of the nuclear polyhedrosis virus disease (NPV) was found to be positively correlated with incidences of the parasitoids Apanteles melanoscelus (Ratzeburg) and Parasetigena silvestris (Robineau-Desvoidy).

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...