The Course of Growth Response in Released White Spruce

Book excerpt: Weekly bole measurements at 4.5 feet in height were made on individual codominant white spruce trees released on one, two, three, and four sides, and on untreated controls. Results showed that after 10 years annual circumference growth was still significantly related to the degree of release. The growth trend was established the first year but significant differences in annual growth were not evident until the third year. The growth rate reached a maximum during the ninth year. Trees with three and four sides released outgrew controls and trees with one and two sides released by a 2 to 1 ratio. Seasonal growth usually started around May 10, peaked during the second week in June, and ceased around August 20. Trees released on three or four sides appeared to start growing earlier and cease growing several days later than the other trees. The length of the growing season ranged from 100 to 115 days.