Abstract:
One of the largest problems facing the forester in the Pacific Northwest today is the economical, rapid rehabilitation of cut-over lands. Many of these cut-over lands are planted to Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco]. Previously, both aerial and spot seeding techniques have been evaluated for their efficiency in Douglas-fir regeneration. The depredations of the apparently ubiquitous seed-eating mammals, however, have precluded wider utilization of seeding techniques. Spot seeding of Douglas-fir is an aspect of artificial seeding that should be examined more closely because of the protection afforded against seed depredation and the creation of favorable microenvironmental conditions for germination. Using a shelter seeding system, several Finnish and Swedish experimenters have been successful in establishing plantations of Scots pine (Pinus silvestris L.), Norway spruce (Picea abies L. Karst.), and Siberian larch (Larix sibirica) under a variety of conditions. A cooperative study was undertaken by the Oregon State University Forest Science Department and the Eugene District Bureau of Land Management to test on a moderate site, under Pacific Northwest conditions, a shelter seeding system developed in Finland. Questions that were to be specifically addressed included the possible requirement for artificial shading and the shelter's ability to prevent seed depredation. Results showed that the shelters stimulated early germination. The disintegration of the shelters during exposure to summer ultraviolet radiation precluded the necessity for subsequent removal. The shelters did not prove to be an effective rodent barrier, however, until they were modified. Further system development will be necessary before the planting tool can be used operationally with Douglas-fir seed.
