Survival and height, diameter at breast height (dbh), volume, and crown growth of Douglas-fir and western redcedar in a mixed plantation were measured 14 years after planting. As expected, Douglas-fir had faster early growth than western redcedar and average dbh, volume, and crown area of the stand increased as the proportion of Douglas-fir in the stand increased. However, the average growth of Douglas-fir and western redcedar was not significantly different when grown in a pure stand compared to being grown in a mixed stand. Average growth of either species was also not significantly different at densities of 500, 1000, or 2000 stems per hectare. Consequently, at this young age, the effect of the species mixtures on growth was likely due to different early growth rates rather than from differences between interspecific and intraspecific competition. This experiment will help to determine the long-term outcomes of different stand mixtures in producing timber volume.
Key words: crown area, diameter growth, height growth, mixed species, volume.
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Updated September 06, 2007