The physiological status of Douglas fir seedlings and the field performance of freshly lifted and cold stored stock

摘要

The physiological status of Douglas fir seedlings in Ireland was followed from October to April each year from 1991-1995 and examined in relation to field performance in a farm-field trial established concurrently with the physiology work. A precise cold hardiness pattern was defined: the seedlings were less cold hardy in 1994/1995 than in other years, but the period of highest cold hardiness was from November to February each year. The roots of the seedlings were mitotically active throughout the winter in some years. The best time to plant freshly lifted stock was from November to December/January. Following cold storage until June, field performance was acceptable for seedlings lifted to the store from December/January to February.