Effects of plantation and juvenile spacing on tree and stand development.
| Authors: | J. Harry G. Smith, Donald L. Reukema |
| Year: | 1986 |
| Type: | Scientific Journal |
| Station: | Pacific Northwest Research Station |
| Source: | In: Oliver, Chadwick Dearing; Hanley, Donald P.; Johnson, Jay A., eds. Douglas-fir: stand management for the future: Proceedings of a symposium; 1985 June 18-20; Seattle, WA. Contribution no. 55. Seattle: College of Forest Resources, University of Washington. 239-245. |
Abstract
The aim of this paper is to summarize current knowledge of effects of initial spacing and respacing of plantations and natural stands on early growth until the time of first commercial entry—for coastal Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), concentrating on conclusions that can be drawn from the literature and the authors' own studies.General results of initially close spacings, with or without subsequent thinning, are well known (Evert 1971, 1973, 1984, Hamilton and Christie 1974, Sjolte Jorgensen 1967), and interest in spacing is increasing. The high costs of stand establishment, limited markets for small trees, ability of technologists to make good use of fast-grown wood, inability to grow clear Douglas-fir except by pruning, and the premiums for large logs and trees have strengthened the view that wider spacings are economically preferable (Smith 1958, 1980, Smith and Kennedy 1983).
To manage stands so that landowner's goals are achieved efficiently, forest managers must set target tree sizes for the products likely to be desired in the future. These tree sizes can be translated into desired numbers of trees per acre (or per ha), and thus into spacing. Fortunately, there can be flexibility in a manager's efforts to control stand development by numbers of trees, basal area, or average dbh. Targets established should allow efficient use of the resources available.