Bijdrage tot de kennis van den groei van Pseudotsuga taxifolia Britton in Nederland in verband met zijn beteekenis voor den Nederlandschen boschbouw

Development of the green Douglas fir in the Netherlands in different places with different methods of planting was studied by enquiry, personal research and from the literature. The climate and soil types seemed suitable. Game, insects and fungi caused little damage. The stands studied all derived from seed from north-west America but the exact origin was never known. This could explain differences in development and frost resistance. Planting of experimental forests was therefore advised with seed from different latitudes and heights above sea-level.Even on poorer soils the yield was much higher than the best stands of Scots pine, sometimes more than double. Wood production declined over 30 years much more than in Germany through lack of thinnings by too wide a spacing.Further advantages over Scots pine were better decomposition of needles, straighter stems, harder wood as measured by resistance to crushing through a higher porportion of summer wood and early formation of heart wood. A disadvantage was the severe self-pruning. Experience on planting and culture were discussed. Growth in length was strongly influenced by rainfall in the same year.