Winter Sowing for Production of 1.0 Douglas-fir Planting Stock
Effects of early sowing on emergence and growth of Douglas-fir were examined in the Humboldt Nursery on California's north coast. In a 1979 study, seeds from coastal and inland regions of western Oregon and northern California were chilled 30 or 90 days at 10C and sown in March and May. Chilling seeds for 90 days resulted in greater speed and amount of seedling emergence in cool soil (March) and greater speed of emergence in warm soil (May). March sowing captured at least six additional weeks early in the potential growing season and resulted in 1-0 seedlings that were large enough to outplant. Top dry weight was increased by 63 to 106 percent and root dry weight after pruning, by 24 to 82 percent, depending on seed source. In a 1985 study, seeds of coastal and inland sources were chilled 90 days and sown in January, February. March. April, and May. Sizes of the resulting 1-0 seedlings defined sowing windows that were wide open in February and closed in late April. Relative stem volumes in the February through May sowings were 7.5. 4.2, 2.9. and 1.0, and the cull percentages, 14, 21, 38, and 82. respectively. Humboldt Nursery can efficiently produce 1-0 Douglas-fir for the Pacific slope by sowing fully chilled seeds in winter and early spring.
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Author(s): James L. Jenkinson, James A. Nelson
Publication: National Nursery Proceedings - 1986
Event:
Combined Western Forest Nursery Council and Intermountain Nursery Association Meeting
1986 - Tumwater, WA
