Treesearch

Nitrogen fertilizers triggered germination of dormant Prunus pensylvanica L. seed naturally buried in the forest floor of 60-year-old Allegheny hardwood stands. Neither triple superphosphate nor muriate of potash applied with urea increased germination over that which occurred with urea alone. Rates as low as 56 kg/ha N from urea and calcium nitrate and 112 kg/ha N from ammonium sulfate stimulated germination. Nitrate was apparently responsible for breaking dormancy.

Resident populations of wild birds and caged quail, Colinus virginianus L., were evaluated to detect short-term effects from aerial applications of the nucleopolyhedrosis virus (NPV) of the gypsy moth. NPV in 2 formulations was sprayed on woodland plots in central Pennsylvania. Comparisons of prespray and postspray censuses of the common birds on the control and NPV-treated plots revealed no changes in populations of the wild birds that could be attributed to the NPV treatments. Data from 23 caged quail and 53 free-living birds showed no significant differences, or differences in trends,...

Five species of mammals and 3 species of birds passed polyhedral inclusion bodies (PIB) of the gypsy moth nucleopolyhedrosis virus (NPV) through their alimentary tracts in amounts great enough to kIll gypsy moth larvae. In bioassays. Opossums and raccoons passed roughly 5% of the PIB administered by intubation while white-footed mice, a short-tailed shrew, and southern flying squirrels passed 2.3, 1.8, and 0.05%, respectively. House finches and a red-winged blackbird passed close to 15% of the PIB administered, whereas mourning doves passed 0.05%. All the birds, as well as the shrew and...

A bioassay technique was used to estimate the concentrations of infectious gypsy moth nucleopolyhedrosis virus (NPV) that occur naturaIly in leaf, bark, litter, and soil samples taken from woodland plots in Connecticut and Pennsylvania. These concentrations were then compared to those in samples taken sequentially after treatment of these plots with NPV. Results indicated that NPV is a natural component of the host's habitat, persisting in high concentrations in soil, litter, and on bark for at least one year after natural epizootics. Activity of NPV in spray deposits on foliage and bark...

Black flies have been long-time residents of Maine and cause extensive nuisance problems for people, domestic animals, and wildlife. The black fly problem has no simple solution because of the multitude of species present, the diverse and ecologically sensitive habitats in which they are found, and the problems inherent in measuring the extent of the damage they cause. As a beginning to the understanding of the nature of the black fly problem, an inventory of black fly species and habitats was made throughout the state. Previous black fly surveys in Maine, Waters (1969) and Bauer (1977),...

It is well known that a new reproduction stand that follows complete overstory removal will contain oaks in proportion to the numbers and size of advance oak reproduction present before the overstory was removed. Furthermore, the individual advance oaks must be relatively large with well-established root systems before they will compete successfully and be dominant in the new stand. In oak stands that are now mature or nearly mature, surveys show oak advance reproduction may be inadequate to replace the stand for one of two reasons: (1) There are not enough oak reproduction stems; or ( 2)...

Small aluminum "boats" containing cotton saturated with lindane were glued to elytra of female red oak borers and locust borers and the beetles released into cages or onto trees. Males attempting to mate with booby-trapped females contacted the insecticide and died. However, females also became contaminated in mating attempts and soon died.

Tree volume tables and equations for eastern redcedar are presented for gross volume, cant volume, and volume of sawmill residue. These volumes, when multiplied by the average value per cubic foot of cants and residue, provide a way to estimate tree value.

Foliar nutrient concentrations in young balsam fir growing on strip clearcuts were assessed in relation to soil drainage and three methods of slash disposal. Concentrations of N, K, and Mn were higher for trees growing on well-drained soils than for trees growing on poorly drained soils. Mo concentrations were higher on poorly drained soils and all other measured nutrients were unaffected. Only foliar Fe was affected by the three methods of slash disposal

Insect damage was simulated by the removal of buds from black cherry trees to determine the effects on stem mortality and tree form. Black cherry was very sensitive to disbudding. All degrees of disbudding caused terminal deformities and stem deformity nearly always occurred after the terminal bud was destroyed. Shoot mortality usually occurred after half or more of the buds on the terminal branch were removed. The types of deformities are illustrated.