Treesearch

Stem analyses showed polymorphic patterns of height growth for each species and for different levels of site quality. New site index curves are presented that show better height growth in later years than predicted by older harmonized site index curves.

Summarizes the incidence of white-pine weevil, eastern pine-shoot borer, and eastern gall rust in a Lake States jack pine seed source study.

Relates the type and frequency of limbs and limb-related defects in the first two logs of five hardwood species to residual basal area 15 years after initial cutting. Also discusses other tree characteristics influenced by stand density and the applicability of present silvicultural guides to improve stem quality.

Realistic dynamic loading requirements for tree- or log-harvesting machines were determined. The study showed that dynamic forces and moments four times as great as those required statically can occur in the field.

Presents site-index comparisons for the following forest species in northern Minnesota: quaking aspen, paper birch, basswood, red oak, black ash, jack pine, red pine, white pine, white spruce, black spruce, balsam fir, white-cedar, and tamarack. Shows site-index relationships among these species by using site-index ratios and species-comparison graphs.

Describes virgin plant communities in the Boundary Waters Canoe Area. Data from all vegetative components of 106 virgin upland stands were used to construct a community classification through a combination of agglomerative clustering and principal components analysis. Discusses the relation of communities to their environment and to past wildfires.

Black walnut seedlings grown in a clay loam and sandy soil were subjected to two soil moisture regimes and three fertility levels. Fertilization increased growth only under most conditions. Under draught, fertilization retarded growth in the sand. Nitrogen was the element primarily responsible for the greater growth under moist conditions.

A sediment budget was constructed from 3 years of measurements on a pool and riffle stream. Total sediment load increased five times along a 26-mile length of stream; most sediment came from 204 eroding banks. Three-fourths of the total sediment load was sand size. The area of streambed covered with sand decreased downstream, indicating that the transporting capacity of the stream exceeded sediment supply. Complete streambank stabilization would reduce the sediment load by about half and probably result in streambed composition changes beneficial to trout.

From a study of campground use in 1967 and 1968 relationships were determined between the intensity of use and 74 onsite and location characteristics. Campers were interviewed to learn what factors influenced their choice of a particular campground. Recommendations to management and topics for further research are discussed.

Reports research at the Forest Genetics Institute in Rhinelander, Wisconsin, since its beginning in 1957. Describes the physical plant, study objectives, and work program. The latter includes studies of seed source, inheritance in white spruce, disease and insect resistance, interspecific hybridization, radiation genetics and radiobiology, vegetative propagation, cell biology, and tree improvement.