Direct seeding of Sitka spruce (Picea sitchensis (Bong.) Carr.), lodgepole pine (Pinus Contorta Dougl. v. contorta) and Siberian larch (Larix sibirica Ledeb.), on scarified seed spots in southern Iceland, using various methods

摘要

Field experiments were established to study the potential of direct seeding of Sitka spruce, lodgepole pine and Siberian larch in southern Iceland. Five seeding methods were tried; control, covered with gravel, covered with pumice, pyramidal indentations and plastic cone. Spring- and autumn planting of one year old planting stock was also carried out for comparison. The results after two growing seasons are presented. Overall germination was 11,3% the first summer and 19,0% the second summer. Lodgepole pine had significantly highest germination or 41,3%. Sitka spruce, having 26.8% germination, and Siberian larch having 22,6% germination did not differ significantly from each other. The seeding method plastic cone gave the highest germination for all the species used, or 50,3%. Seedling mortality was high after the first winter, except in the plastic cone where more than 80% of the seedlings survived. The number of spots having at least one living seedling after two growth seasons was high in all seeding methods for lodgepole pine or 76,3-95,0% and for Sitka spruce or 71,3-86,3%. This result was however mainly explained by seedlings that germinated in the current growing season. For Siberian larch the number of the spots having one or more living seedlings was low for other seeding methods than plastic cone which gave 68,8%. No difference was found in seedling height between the methods control, covered with gravel, covered with pumice and pyramidal indentations. Survival of planted seedlings differed between planting times. Spring planting (28/6) was found more advantageous for Sitka spruce and lodgepole pine, but autumn planting (3/10) for Siberian larch. When the seeding methods were compared with planting after two growth seasons, it can be concluded that the method plastic cone was the only method tried which was compatible with planting. 45 refs, 9 figs, 14 tabs