Treesearch

To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for sugar maple. Eleven types of external defect indicators and associated defects that are particularly difficult to evaluate are illustrated and described.

To properly classify or grade logs or trees, one must be able to correctly identify defect indicators and assess the effect of the underlying defect on possible end products. This guide assists the individual in identifying the surface defect indicator and shows the progressive stages of the defect throughout its development for yellow-poplar. Twelve types of external defect indicators and associated defects that are particularly difficult to evaluate are illustrated and described.

On 18 September 1989 Hurricane Hugo defoliated large forested areas of northeastern Puerto Rico. In two severely damaged subtropical wet forest sites, a mean of 1006-1083 g/m2, or 419-4 51 times the mean daily input of fine litter (leaves, small wood, and miscellaneous debris) was deposited on the forest floor. An additional 928 g/m' of litter was suspended above the ground. A lower montane rain forest site received 682 times the mean daily fine litterfall. The concentrations of N and P in the hurricane leaf litter ranged from 1. 1 ro 1. 5 and 1. 7 to 3. 3 times the concentrations of N and...

The electrical conductivity of stream water draining from an unmanaged and undisturbed control watershed has been increasing rather steadily, about 0.03 mS m-1 yr-1, since 1971. During this period, NO–3 and Ca2+ concentrations increased and were shown to mathematically account for the ionic contribution to conductivity; therefore, they are believed to be primarily responsible for the increase. However, the percentage of conductivity explained by the two ions was different over time. The percentage of conductivity attributable to NO–3 increased in a pattern very similar to concentration. In...

Breeding bird populations in six habitats in Columbia. MD. were studied to develop procedures suitable for measuring bird use of residential areas and to identify habitat characteristics that define the distribution of various common bird species. A procedure to measure bird use based on 4-min transect counts on plots measuring 91 m × 91 m proved better than point counts. Transect counts reduced many of the problems associated with counting birds in urban areas, such as varying noise and visibility. Eighty percent of observations were recorded in the first 4 min. Habitat measurement...

Small mammal distribution was examined in poletimber and sawtimber stands of four forest cover types in northern New England: northern hardwoods, red maple, balsam fir, and red spruce-balsam fir. During 1980 and 1981, eight stands on the White Mountain National Forest, NH, were sampled with four trap types (three sizes of snap traps and one pit-fall) for 16 000 trap-nights. Trapping was conducted during four 5-day periods in June and July. A total of 1206 individuals of seven species - Blarina brevicauda (short-tailed shrew), Sorex cinereus (masked shrew), Sorex fumeus (smokey shrew),...

Winter bird communities were compared in three suburbs over 5 years: MT, a 70-year-old area of large houses and planted mature trees, primarily oaks (Quercus) and elms (Ulmus); YT, a 15-year-old area also built upon former open agricultural land with young planted trees, primarily maples (Acer); OP, a 15-year-old area in which houses were built within a second-growth oak-pine (Quercus-Pinus) woodland. Winter bird surveys were conducted each year for 5 years (1976-1980) during January. The total number of species across suburban types was 32; total abundance was higher (P<0.05) in MT and YT...

Patterns of carbon allocation and mycorrhizal colonization were examined in loblolly pine seedlings from two half-sib families exposed to three ozone treatments (charcoal-filtered air, ambient air + 80 ppb 03 , and ambient air + 160 ppb 03) and three rain pH levels (5.2, 4.5, and 3.3) for 12 weeks in open-topped chambers in a field setting. No statistically significant effects of ozone or rain pH were detected on biomass, root:shoot ratios, or carbon allocation; some consistent patterns were observed, however. Coarse root starch concentrations and mycorrhizal infection varied significantly...

Glueline continuity is very critical in standard-size hardwood blanks because the blanks are cut up into small furniture parts, and a small gap in the glueline of a blank may extend across the whole part—or a gap may appear as a crack in the final product. Strength is not a critical factor. The objective of this study was to determine if a gap in a glueline can be detected by mechanical means. Furniture manufacturers want to be sure that any blank that they buy will have continuous gluelines. Every blank should be nondestructively tested, and all blanks with a defective glueline should be...

A two-dimensional second-order turbulence-closure model based on Mellor-Yamada level 3 is used to examine the nocturnal turbulence characteristics over Rattlesnake Mountain in Washington. Simulations of mean horizontal velocities and potential temperatures agree well with data. The equations for the components of the turbulent kinetic energy (TKE) show that anisotropy contributes in ways that are counter to our intuition developed from mean flow considerations: shear production under stable conditions forces the suppression of the vertical component proportion of total TKE, while potential-...