An espacement (planting density) trial was established in the Coastal Western Hemlock biogeoclimatic zone in 1988. Two species, yellow-cedar (Chamaecyparis nootkatensis) and western redcedar (Thuja plicata), were planted at densities of 240, 480, 720, 1090, 1680, and 2990 stems per ha (sph) at two sites for each species. After 21 years, height, diameter at breast height (dbh), height to the lowest live branch, and height to the base of the live crown were not significantly different across the treatments. However, general trends were becoming apparent. Height and dbh growth were slower at the denser spacings for western redcedar. For yellow-cedar, height and dbh growth were similar at all spacings except at the 2990 sph spacing, which showed slower growth. The effect of spacing was more pronounced on dbh than on height. There was a trend of an increasing height to the base of the live crown and height to the lowest live branch as density increased for western redcedar. There was no trend for height to the lowest live branch and to the base of the live crown for yellow-cedar. Future measurements on this trial may yield definitive results and provide guidance on managing western redcedar and yellow-cedar.
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Updated March 30, 2011