Treesearch

Evaluates SILVAH, FIBER, NE-TWIGS, and OAKSIM, simulators commonly used in the northeastern United States, by comparing predicted stand development with actual stand development records for periods ranging from 15 to 50 years. Results varied with stand parameter, forest type, projection length, and geographic area. Except in the spruce-fir forest type where FIBER stands out as the best simulator, no single simulator is clearly superior to the others for all locations within a forest type. In general, FIBER, NE-TWIGS, and SILVAH performed best in the northern hardwood (beech-birch-maple)...

Beechnut production and losses were studied over a 6-year period in 41 northern hardwood stands ranging in age from 10 to 140 years in the White Mountains of New Hampshire. Beechnut production increased consistently with stand age or d.b.h. of dominant trees and percentage of basal area composed of beech. Losses to insects, rodents, and birds before the seed reached the ground ranged from 24 to 100 percent; insects caused the greatest losses. Good seed years occurred about every third year.

Survival of recently fallen northern red oak acorns after exposure to a cool fall burn was evaluated in northwestern Pennsylvania. Although no acorns were consumed by the fire, some were charred. Between 40 and 49 percent of the acorns in the litter were destroyed. The fire was not hot enough to kill Curculio larvae within the acorns. Burned acorns infested with Curculio that survived the fire had 20 percent lower germination rates than unburned acorns.

Examines the growth and survival of planted and natural red oak seedlings and seedlings from planted acorns within translucent tan tree shelters, fences, and unprotected controls under a shelterwood seed-cut stand. Seedlings planted within tree shelters and fences were inside tree shelters. Natural seedlings grew very little and their height inside and outside of tree shelters did not differ. Recommendations based on these results should improve results from the use of tree shelters.

As increased demands are placed on forest land for timber production, wildlife, esthetics, recreation, hunting, fishing, and other uses, owners of woodlots and forest land are looking for different ways to harvest or treat the stands to accomplish their objectives. The large clearcut harvest blocks that had been the standard for years with the forest industry are not always acceptable. The contemporary emphasis is on harvesting trees using partial and tree-selection cuts, thinnings, and group-selection methods. Group-selection involves taking small groups or clumps of trees in a somewhat...

Some growth and yield simulators applicable to central hardwood forests can be formulated for use in mathematical programming models that are designed to optimize multi-stand, multi-resource management problems. Once in the required format, growth equations serve as model constraints, defining the dynamics of stand development brought about by harvesting decisions. In large models representing forests with varying cover types equations from several unique simulators can be combined to account for individual stand growth. The inclusion of appropriate growth functions greatly enhances the...

Crown class, stem diameter, and sprout rank of 2067 red maples on medium quality sites were measured at 10-yr intervals between 1927-1987. Nominal stand age was 25 yrs in 1927. There was a progressive increase in the probability of an individual red maple ascending into the upper canopy and persisting in the upper canopy from suppressed through dominant crown classes between ages 25-85. While 41% of dominant red maples remained in the upper canopy for any 30-yr period, less than 10% of intermediate red maples ascended into dominant or codominant crown classes. Mortality rates were highest...

Changes in tree species composition and regeneration patterns were studied in 53 permanent vegetation plots located at two sites (Pioneer Forest and University State Forest) in oak-hickory forests of southeastern Missouri where mortality and decline of red oak species have been identified. The two sites also exhibited differing levels of decline and mortality. Between 1962 and 1991 the importance value (IV) of white oak at University State Forest increased from 20 to 56%, while that of black oak and, to a lesser degree, scarlet oak decreased. Over the same 28 year period, the IV of white...

When harvested, upland oak forests of northwestern Pennsylvania generally regenerate to new forests dominated by non-oak species. In 1988, the Northeastern Forest Experiment Station began to identify and learn to manipulate factors that limit the establishment and development of northern red oak (Quercus rubra L.) seedlings in second-generation stands on high-quality sites. The study includes three replications located within the Moshanon State Forest and four replications within the Allegheny National Forest on the unglaciated section of the Allegheny Plateau in northwestern Pennsylvania....

Forest vegetation of some loess bluff ravines in the Jackson Purchase Region of Kentucky was sampled. A total of 27 tree species comprised the mixed mesophytic association with Acer saccharum, Fagus grandifolia and Liquidambar styraciflua as the dominants. This assemblage of species agrees with that reported for the loess bluffs over 100 years ago. Basal area averaged 27.2 m?/ha; density 289.5 trees/ha; and diversity (H') ranged from 3.01-3.52. Species similarity was stronger between the forests of the loess bluffs and those of the Appalachians, but especially the dissected Illinoian till...