Effects of Low Levels of Dispersed Retention on the Growth and Survival of Young, Planted Douglas-Fir

Forests

Nicholas J. Smith¹ 

[1] Nick Smith Forest Consulting, 3332 Kite Way, Nanaimo, BC V9T 3Z2, Canada

关键词: sector sampling;    dispersed retention;    Douglas-fir;    variable retention;    stand growth;   

DOI  :  10.3390/f3020230

来源: mdpi

【 摘 要 】

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 (p < 0.05) 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. 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.

【 授权许可】

CC BY   
© 2012 by the authors; licensee MDPI, Basel, Switzerland.