Relation Between Cone Production and Diameter Increment of Douglas Fir (Pseudotsuga Menziesii (Mirb.) Franco), Grand Fir (Abies Grandis (Dougl.) Lindl.), and Western White Pine (Pinus Monticola Dougl.)

Cone count records for a 28-year period on 80 Douglas fir, 14 grand fir, and 9 western white pine were statistically analyzed with the annual diameter increment to evaluate the relationship between cone and wood production. The width of annual rings was depressed only during the years of cone production, suggesting that carbohydrates used in cone development were supplied from current photosynthesis rather than from stored reserve. The initiation of reproductive buds did not appear to be dependent on the level of carbohydrates in a tree and the role of carbohydrates was probably only that of nutrition during cone development. Maturing cones did not exhibit any inhibitory effect on initiation of new flowering buds. Different species may require a different combination of climatic factors for initiation of flowering buds.