Effects of a Transpiration Retardant and Root Coating on Survival of Douglas-Fir Planting Stock
Experience shows that natural seeding cannot be relied upon to regenerate logged Douglasfir areas in California. Since artificial seeding is still new and uncertain, foresters probably will continue to rely on planting for several years to regenerate logged or burned forest land. Unfortunately, survival of Douglas-fir plantations has not been consistently satisfactory. We need to know how to obtain better results. Investigators, hoping to increase survival of planted trees, have tested transpiration retardants (2, 3, 4, 5).1 Results of their experiments have been inconsistent. In some trials transpiration retardants have slightly improved low survival rates, but results were still too poor to be acceptable. In other trials transpiration retardants decreased survival, while still other times field tests showed no differences in survival between treated and untreated trees. This study tested the effects of two relatively new products on planting stock survival and growth. The first, Rutex Foli-gard (formerly Rutex W-3), a transpiration retardant, was sprayed on seedling foliage; and the second, Rutex 59 (Hygrostat), a water absorbing material, was applied to seedling roots.
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Author(s): Douglass F. Roy
Publication: Tree Planters' Notes - Issue 79 (1966)