Most direct seeding projects have been conducted from the air and follow site preparation primarily by fire. Severe depredations by seed eating mammals (primarily species of the white-footed deer mouse, Peromyscus) have largely limited direct seeding to areas of sufficient size to make chemical control of these animals practical. However, increased costs associated with planting together with the logistics involved in producing planting stock physiologically suited for planting during the short planting seasons of the higher elevations in the Cascades have stimulated an increased interest in the practicality of regenerating forests by direct seeding. Examples of devices currently being tested in direct seeding projects and studies include:

1. Seedbed scarification device employed in seeding Ocala and pine (Pinus Clausa var. clausa) in Florida. This device effectively scarifies the seed bed and covers seeds, reducing losses to rodents.

2. Plastic micro-shelters. Protect seeds from animal damage and stimulate early germination. Successful trials have been conducted in Scandinavia, Canada, the Rocky Mountains, and the Pacific Northwest. Plastic disintegrates by mid-summer as a result of ultra-violet radiation, obviating the necessity to remove the shelter after seed germination.

3. Direct seeding in seed spots prepared by the Brackekultivatorn. Hand seeding of pines following machine spot-scalping has been shown to be effective, but white and black spruce are not amenable to this method. Destruction of seeds by seed eating mammals is not a limitation to direct seeding in northern Ontario.

Hand Slashing

1. Equipment and effects of use. Tools commonly employed include power saws, axes, machetes and chain girdlers. Unlike the above site preparation methods, hand slashing is generally restricted to release of previously planted seedlings. Because the technique is concerned with essentially de-topping competing vegetation and does not disturb the soil, it has a minimal effect upon the environment.

2. Suitability for site preparation and limitations. Hand slashing is generally too expensive to be conducted on a broadcast basis over entire harvest units and so is restricted primarily to removing competing vegetation adjacent to seedlings of the crop species. The method has definite limitations in that many of the competing brush species will sprout vigorously after slashing; and that tree seedlings are frequently damaged when workers are unable to see them in dense brush; and that removal of the competing species often results in "solarization" of crop seedlings. The principal advantages of hand slashing are that this technique has a minimal immediate effect upon the environment and that it is non-controversial.

Readings

Cleary, Brian D., Robert D. Greaves, Richard K. Hermann. 1978. Regenerating Oregon's Forests. Oregon State University Extension Service. Corvallis, Oregon. Stewart, R.E. Chapter 7. Site Preparation, p. 100-108.

Lavender, D.P. & M. Newton. 1984. Forest Regeneration and Forest Health. IN Human Impacts on Forest, J. Parde & H. Oswald, eds. INRA, Paris, France. 512p.

Study Questions

l. How may a forester best minimize the requirements for site preparation?

2. Does it appear possible to control competing brush species in western Oregon with a single hand slash treatment?

3. Give two possible advantages and five possible disadvantages of mechanical scarification for site preparation.

4. When would you use scalping as a site preparation technique?

5. You are to log an area immediately adjacent to a stand of vigorous alder. The slope varies from 20 to 30 percent and the owner wishes to harvest to be done in late summer, early fall. Would you use moving cable or tractors for your logging system (assume the stand structure and existing roads are equally appropriate for either harvest method?) Why?