Treesearch

Sodium fluoroacetate (compound "1080") and, to a lesser extent, red lead and zinc phosphide, have been suggested for use as rodent repellents in direct seeding. On the basis of a small test in 1950 on the Stanislaus Experimental Forest in California, none of these chemicals appears effective as repellents even though all three are effective as poisons.

A new type of protective screen for seed spots has attracted the attention of foresters on the Pacific coast. This screen is cylindrical in form, 4 inches long, about 1 inch in diameter, and is formed from 8-mesh hardware cloth. Foresters have named this protective device a "K-screen". K-screens appeal to the forester because they are relatively cheap, can be pre-loaded with seed and germinating medium before being transported to the field, can be placed quickly, and may not need to be removed from the seed spot. To protect the seed from rodents, the tops of the screens are pinched...

Activity in pine breeding has increased throughout the temperate forest regions of the world since the Institute of Forest Genetics issued its first summary of pollen collection dates in 1947. Cooperation between pine breeders has increased at the same time. The information most essential for conducting cooperative breeding operations are the dates of pollen collection (which also approximate the dates at which the bagging of flower buds to control pollination should be done) for various species at various localities. This publication, adding four years' data to the note issued in 1947,...

This report assembles the results of a number of small exploratory studies on the extraction, storage, and viability testing of pollen of several species of pines. These studies indicate clearly the need for more knowledge of the physiology of pollen — particularly of the relation between atmospheric humidity at the time of pollen shedding and the subsequent reactions of the pollen to environmental conditions.

This study was designed to obtain thermal conductivity of som common forest fuels which hitherto had defied such efforts because of their shape, size, or structure. Dry leaves and decayed. wood (punk) were modified so that conductivity measurements could be made by a thin plate uni-directional heat flow calibration stand, Resultss of these measurements are compatible with a linear relationship between thermal conductivity and specific gravity, established by MacLean, and indicate that conductivities of most common forest fuels may be determined from their specific gravities, MacLean's...

Forest fuels are heterogeneous mixtures of a number of green and dead woody substances. Most common are leaves, grass, conifer needles, moss, bark, and wood. As a result of past fires, an area may also contain some charcoal. With the exception of charcoal, these materials are in various stages of decay or decomposition. Logs, limbs, and decayed wood in an advanced stage of decay are referred to as punk. Mixtures of decayed needles, leaves, and grass are usually called duff.

Records of permanent sample plots and extensive observations by forest management research workers indicate that tree selection methods of cutting in sugar pine-fir types have not favored the establishment of sugar pine reproduction. Since sugar pine is a highly prized lumber producing species in the California region, special measures to preserve or increase its place in the stand were made part of an experimental logging project on the Stanislaus Experimental Forest in 1948 and 1949. This project was a combination field test and demonstration of unit area control, a silvicultural system...

Epicormic branches have developed on white fir (Abies concolor) one to two years after part of the live limbs were removed in a pruning experiment. The appearance of an average of six epicormic sprouts per tree raises some doubt as to the desirability of planting this species.

Reducing logging damage to reproduction and residual stands is an important part of harvesting the old-growth forests of California. Much of the over mature timber: is on areas with an acceptable stocking of advance growth. When the old trees are harvested, the advance growth is scarred, deformed, broken, or killed outright. Insects and disease attack the broken and scarred trees, and the quantity and quality of wood grown for the next harvest is reduced. Sometimes the advance growth is so severely damaged that the stand must be regenerated. This is costly and of course extends the time...

There is a definite distinction between the basic concept of unit area control and the specific techniques or treatments used for specific units. Unit area control as a term was first used in connection with a cutting trial in the sugar pine-fir type; consequently, many foresters think the term refers merely to the technique used in sugar pine management, This is not the case, Applying silviculture unit areas is appropriate and desirable for other major types as well. So far, however, techniques have been developed only for pine and mixed-conifer types in the Sierra Nevada. The remainder...