The Collins Companies: forest management (page 8)

An Environmental Softwood Forest

The following are common insects that damage trees on CAF:

Round Head Wood Borers
Flat Head Wood Borers
Western Pine Bark Beetle
Jeffery Pine Bark Beetle
Mountain Pine Bark Beetle
Douglas-fir Bark Beetle
Red Turpentine Bark Beetle
Carpenter Ants
Ponderous Wood Borer
Pine Butterfly Moth

Cone Beetles
Cone Moths
Emarginate Ips
Western Pine Engraver
Calif. Five-spined Ips
Fir Engraver
Doug-fir Tussock Moth
Ponderosa Pine Tip Moth
Pine Reproduction Weevil
Wood Termites

Chip/Thinning
Cuttings made in immature stands or clumps of trees in order to stimulate growth of the remaining trees and to increase the total yield of useful material from the stand are termed "thinnings." If the material from the cutting is manufactured into "chips" suitable for pulp (paper) or hog fuel (burning in a co-generation plant), then the combination of the two become what is called a "chip/thinning" forestry operation.

The chip/thinning program on the Collins Almanor Forest has been in progress since 1986 when 85 acres were treated. This operation will normally treat about 1,000 acres each year on the Forest. The 1,000 acres treated will produce approximately 20,000 bone dry tons (BDT) of chips to be used at the Collins Pine Company’s 12 megawatt co-generation powerhouse.

This program not only provides fuel to the powerhouse, but also provides a great value to our forest management program. Surplus trees are removed for the purpose of concentrating the potential wood production of the stand on a fewer number of selected trees. The total yield of the stand is increased by the utilization of trees that would otherwise die of suppression. The value and yield of the final crop trees is increased by virtue of the fact that the favored trees grow more rapidly than they would without thinning and are healthier.

The trees we select to chip are surplus, dead, or deformed. They are primarily white fir, under 12 inches in diameter (DBH). The feller-buncher (tree cutting machine with large scissors like attachments and arms to hold bunches of trees cut) operators are instructed to space the trees under 12 inches DBH from a minimum of 15 feet to a maximum of 18 feet. We have found, for these diameters, this is the ideal spacing for the growth rates we want on the remaining trees and at the same time allow for additional natural regeneration of ponderosa pine and sugar pine. Our target diameter growth rate is 6 to 10 annual rings per inch of wood grown.

Surprisingly, tree spacing does not effect height growth, but has a tremendous influence in diameter growth. As an example, for a tree to reach 30"DBH can take as little as 60 years, or it can take 300 years or more. It depends on the spacing of trees as much as the soil quality. Trees that are too close together are severe competitors with each other. Close spacing of trees less than 12 inches DBH has been the situation on a considerable portion of the ownership prior to 1985.

The close spacing of trees is due to the fact that the species most likely to be perpetuated after the removal of a tree in the single-tree selection system are those that are more shade tolerant, or trees that prefer shade. White fir has those characteristics and will dominate the understory of the forest if not treated. Historically, natural wildfire would destroy the white fir understory creating nearly pure pine stands throughout the Sierra Nevada. With the suppression of wildfire, white fir has gradually begun to dominate the forest again. The chip/thinning operation actually resembles what fire did historically, but under a much more controlled process.

Not all acres are treated by chip/thinning on the forest. There are some areas that are not economically feasible to operate on at this time, either because the size of the trees is too small or the ground is too steep. Also, those areas of special concern, such as riparian habitat along stream courses, or those areas designated for wildlife, are not treated. Emphasis is given to protecting wildlife travel corridors through the chip/thinning operation by designating areas to be left natural.

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