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Effects of Low Levels of Dispersed Retention on the Growth and Survival of Young, Planted Douglas-Fir
Nick Smith Forest Consulting, 3332 Kite Way, Nanaimo, BC V9T 3Z2, Canada
Vancouver Island University, 900 5th Street, Nanaimo, BC V9R 5S5, Canada
* Author to whom correspondence should be addressed.
Received: 11 March 2012; Accepted: 17 April 2012 / Published: 16 May 2012
Abstract: Three large-scale, experimental, dispersed residual tree sites established in coastal British Columbia, Canada were measured for planted Douglas-fir tree growth and survival five to six years after planting. The dispersed trees were predominantly large diameter (60 cm+) Douglas-fir left with a range of 0% to 30% of the original forest stand basal area (0 m2 ha−1 to 14 m2 ha−1). Two sites had 0%, 5% and 15% retention, while one site had 0%, 5%, 10% and 30% retention. The trees were measured in sector plots established to randomly sample the range of microsites in each treatment. There was no detectable difference between height and basal diameter growth or mortality rates between the retention treatments over the measurement period, except for a reduction of basal diameter growth at the 30% retention level (p < 0.05). Thus a statistically significant impact on growth was demonstrated for the 30% retention compared to the 0% retention level. We expected intermediate growth rates between the 0% and the other lower retention levels but were unable to demonstrate this due to the low statistical power of the test (10 observations) and high site variability for these very young trees.
Keywords: sector sampling; dispersed retention; Douglas-fir; variable retention; stand growth
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MDPI and ACS Style
Smith, N.J.; Beese, W.J. Effects of Low Levels of Dispersed Retention on the Growth and Survival of Young, Planted Douglas-Fir. Forests 2012, 3, 230-243.
Smith NJ, Beese WJ. Effects of Low Levels of Dispersed Retention on the Growth and Survival of Young, Planted Douglas-Fir. Forests. 2012; 3(2):230-243.
Smith, Nicholas J.; Beese, William J. 2012. "Effects of Low Levels of Dispersed Retention on the Growth and Survival of Young, Planted Douglas-Fir." Forests 3, no. 2: 230-243.