Stem characteristics on the lower log of 35-year-old western redcedar grown at several spacings

Abstract

Information on stem characteristics of western redcedar (Thuja plicata) grown in managed stands is quite limited. Stem characteristics are important because they influence the quality of logs and lumber produced. We measured branch diameter, number of branches, taper, and fluting severity on the first 5m log of stems grown at spacings of 1.8 to 4.6 m in a 35-yr-old spacing trial on the University of British Columbia Research Forest. Average branch diameter increased from 15 mm to 25 mm as tree spacing incrcased from 1.8 m to 4.6 m. Number of branches per unit of stem length was unaffected by spacing. Trees at wider spacings tended to be more tapered and have more butt swell than those at narrower spacings. At wider spacings, more trees showed fluting, and that fluting was more severe than at narrower spacings. However, most trees had no fluting or only mild fluting even at the 4.6 m spacing. Branch diameter, taper, and fluting were all related to stem diameter. Smaller diameter stems tended to have smaller branches, less taper, and were less likely to have severe fluting than large diameter stems. Branch diameter was larger at wider spacings even for trees of the same stem diameter.