Historical Stem Development of Northern White-Cedar (Thuja occidentalis L.) in Maine

摘要

We used stem analysis to quantify early height and diameter growth rates of 80 northern white-cedar trees (17.4-55.0 cm dbh) harvested in 2005 and 2006 in central and northern Maine. It took an average of 42 years (range, 9-86 years) for sampled trees to grow from stump height to sapling size, 96 years to grow to pole size (range, 28-171), 140 years to grow to sawtimber size (range, 54-238), and 170 years to reach shingle-stock size (range, 81-317). Approximately 80% of sampled trees had initial growth suppression followed by release, suggesting they originated as advance regeneration. The mean period of initial suppression exceeded 60 years, and some trees responded to release after nearly 200 years. Although growth rates were generally slow, the variability observed suggests the potential for northern white-cedar both to withstand prolonged periods of suppression and to grow rapidly under favorable conditions. Observed patterns suggest that this species might respond well to uneven-aged or shelterwood silvicultural systems; foresters are recommended to encourage advance regeneration and emphasize protection of the residual northern white-cedar understory during harvest operations.