Treesearch

One-year-old yellow-poplar seedlings were treated with acid mist at pH 2.5, 3.5, 4.5, and 5.5 either alone or in combination with 0.1 ppm 03, S02, and NO2 or NO2 plus S02. After 4 and 8 weeks of treatment, height, leaf area, and leaf and new shoot weight were determined and growth analysis variables calculated. Height, leaf area, and dry weight decreased with increasing acidity in seedlings treated with acid mist alone. Similar, but smaller reductions occurred in seedlings treated with SO2 and acid mist, but no differences were found in seedlings fumigated with NO2, NO2 plus SO2, or ozone...

In north-central West Virginia, previously unmanaged 60-year-old cherrymaple stands were thinned to 60 percent relative stand density. Thinning reduced mortality, redistributed growth onto fewer, larger stems, and increased individual tree growth. Five-year periodic basal-area growth per acre was 1.2 times greater in thinned stands than in unthinned stands. Periodic basal-area growth of,individual trees was greater in thinned stands than in controls: 3.0 times for all stems and 1.3 times for dominants and codominants. Relative stand density in the thinned stands increased 1.6 percent annually.

GR02 is an individual tree, distance-independent simulation model for predicting tree and stand growth over time. It performs five major functions during each run: (1) updates diameter at breast height, (2) updates total height, (3) estimates mortality, (4) determines regeneration, and (5) updates crown class.

Average survival, 7-year stem diameter, and stem diameter growth differed significantly among 34 black walnut families planted in West Virginia. Average total height, height growth, and diameter at breast height were not significantly different among families. Families were from seed collected in West Virginia, Pennsylvania, North Carolina, and Tennessee. The 7-year results indicated that although survival was significantly different among families, differences in height growth were not well enough defined to recommend sources for planting.

Describes the distribution of sawtimber trees by diameter at breast height (d.b.h.) and grade for eight hardwood species in upland oak stands of Pennsylvania. The proportion of trees by d.b.h. and grade revealed differences between species. The quality of northern red oak, white oak, and yellow-poplar appeared inherently better than that of red maple, chestnut oak, and a group of other hardwoods. Grade predictions by size and species allow more precise timber appraisals and enable managers to evaluate alternative management strategies more accurately.

In 1981, a study was initiated to measure the effects of low-level trampling (100 to 200 tramples) on selected vegetation on Hurricane Island, Maine. Low levels of trampling are representative of general recreational use patterns on most Maine islands. The study was designed to compare percent survival of common island species when subjected to low-level trampling, to observe treadway formation, and to monitor recovery. The quadropod photographic technique was used to monitor changes in area coverage of species. Climatic conditions on Hurricane lsland appear to favor rapid plant recovery....

This study reports the effects of recreational use on the water quality of an Adirondack lake. Phosphates, nitrates, conductivity, fecal coliform, transparency, and temperature were regularly measured over a period of 2 years and related to the recreational use that the lake received during that time. An adjacent lake, which was not visited by recreationists, served as a control. There was no apparent relationship between water quality and fluctuations in use at any of the sampling sites. There was also no significant variation in water quality between sites even though the use between the...

Adult survival of first-instar red oak borer larvae, Enaphalodes rufulus (Haldeman), implanted into red oak trees, Quercus rubra L., was 4 times greater when the larvae were protected from predators. Nitidulids, ants, and woodpeckers accounted for 40 to 60 percent of the mortality in unprotected larvae. Most mortality in protected larvae occurred from unknown causes during the first overwintering period.

Knowing what gypsy moth likes to eat can aid forest managers in making cost-effective control decisions. A recent 5-year study of defoliation in central Pennsylvania gives an up-to-date index of host species preferences. Chestnut oak is the most preferred species. Following in relatively close order are the other oaks and aspen. Hardwood species that rank low on the preference list are yellow-poplar, yellow birch, black locust, striped maple, ash, and black gum.

Regressions are given for predicting age from diameter for 10 different species of trees or shrubs in old-growth northern hardwood and spruce-fir stands.