Treesearch

Methods of mining and the effects on aquatic ecosystems of mine-caused sediment, changes in pH, and toxic heavy metals are described.

A new method has been developed for collecting, sorting, and interpreting gravel quality. Samples are collected with a tri-tube freeze-core device and dry-sorted by using sieves based on the Wentworth scale. An index to the quality of gravel is obtained by dividing geometric mean particle size by the sorting coefficient (a measure of the distribution of grain sizes) of a sample. The resulting number is called the "fredle index" and is proposed as a standard for evaluating the reproductive potential of spawning gravel.

Nitrogen and phosphorus were applied to young Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees to determine their effects on deer browsing and tree growth. Nitrogen (N) proauced measurable responses in browsing of terminal shoots and growth of trees the first year, but effects were mostly negligible 2 years after treatments. No responses to phosphorus (P) were detected. Nitrogen and N+P treatments increased the concentration of N in tree foliage the first year, but amount of moisture, ash, calcium, and P were not affected after 2 years.

Root pressure exudates collected from detopped seedlings of Douglas-fir, grand fir, noble fir, Pacific silver fir, ponderosa pine, lodgepole pine, and Engelmann spruce were analyzed for sugars, amino acids, organic acids, nitrogen, potassium, calcium, and magnesium. Sugar concentrations ranged from 0.10 percent to 5 percent, and included glucose, sucrose, fructose, and two unknowns, possibly rhamnose, and ribose. Amino acid concentrations ranged from 0.02 to 0.10 percent, and organic acids from 0.01 to 0.06 percent. Aspartic acid, glutamic acid and glutamine were the main amino acids in...

The length of flames of wildland fires is a relative indicator of fireline intensity and an important index to fire effects and difficulty of control. A technique for measuring flame height and flame-tilt angle for the purpose of calculating flame length is described. Laboratory tests determined the feasibility of using cotton string treated with ammonium phosphate fertilizers to measure flame height. Ammonium phosphate treatments with an effective P2O5 equivalent greater than 10 percent by weight prevented the string from sustaining combustion above the zone of contact with flames....

Two populations of Douglas-fir trees were screened for graft compatibility. Two-stage testing procedures were used with either high- or low-intensity screening in the first step. Of 303 trees, 16 (5 percent) were found to be 90- to 100-percent graft compatible and suitable for seed orchard use as rootstocks. High-intensity screening in the first stage was more effective than the low-intensity screening in detecting highly compatible trees. Trees proven to be 90- to 100-percent compatible after second stage screening were propagated as rooted cuttings and used as parents in controlled...

The average biomass of big sagebrush (Artemisia tridentata Nutt.), antelope bitterbrush (Purshia tridentata (Pursh) DC.), snowbrush ceanothus (Ceanothus velutinus Dougl. ex Hook.), and greenleaf manzanita (Arctostaphylos patula Greene) was 6.1, 5.1, 10.7, and 16.2 tons per acre (13.9, 11.3, 24.0, and 36.0 tonnes per hectare), respectively, for 100-percent shrub crown coverage. Biomass by fuel size class and category is tabulated for percentage of crown cover.

Traps baited with Seudenol + a-pinene caught 87 percent more eastern larch beetles, Dendroctonus simplex LeConte, than did tamarack logs infested with females. Male beetles responded to the synthetic attractant in greater numbers than females. Male beetles were not attracted to frontalin, a principal attractant of the closely related Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins. Attraction was reduced by 92 and 86 percent by addition of methylcylohexenone (MCH) and frontalin but by only 36 percent when trans-verbenol was added. This evidence partially supports the taxonomic...

Nine herbicides were compared for aiding establishment of four conifer species on upper-slope forest sites dominated by sedge and beargrass. Both glyphosate and a mixture of atrazine + dalapon produced substantial and consistent gains in survival of all four conifers after 3 years.

Pupal density of western spruce budworm, Choristoneura occidentalis Freeman, can be accurately estimated from 45-cm branch tips. Density on tips was representative of densities on entire branches. Mean pupal densities on branch tips are statistically different from lower, mid, and upper crowns (p = .07). Therefore, multi-crown sampling is required to precisely estimate the mean of populations similar to those used in this study.