During March of 2002, a replacement series research trial was established on Vancouver Island combining western red cedar with red alder. Mixing these tree species makes ecological sense since shade intolerant alder normally has rapid height growth whereas cedar is much slower growing and shade tolerant. Alder also fixes nitrogen and may improve the growth of species in mixture. These two species were planted in four mixtures or proportions at a total density of 1600 stems per hectare varying the proportions from 100:0, 75:25, 50:50 and 0:100 cedar:alder. After 14 years, a comparison of the various mixed stands indicated that the largest stand volume was found in the pure alder mixture. Also, the largest cedar stand volume was achieved with a pure cedar mixture however, relative yield analysis showed a significant cedar growth increase under the 50:50 mixture. This result is not considered conclusive given the early age of this trial. Continued assessment of this mixedwood study will increase our understanding of the stand dynamics of cedar:alder mixtures.
Courtin, Paul, Harper, George. 2018. Assessment of a 14-year-old Mixed Western Redcedar:Red Alder Plantation in Southwestern British Columbia. Forests, Lands, and NR Operations. Extension Note (FLNRORD). EN121