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Extensive Studies of Fertilizing and Thinning Coastal Douglas-fir and Western Hemlock: An Establishment Report

Author(s) or contact(s): L.M. Darling and S. A.Y. Omule
Source: Research Branch
Subject: Fertilization
Series: FRDA Report
Other details:  Published 1989. Hardcopy is available.


Nine hundred and forty permanent 0.05- to 0.10-ha plots were established in the Vancouver Forest Region by the B.C. Forest Productivity Committee in 1971-1975 to study the effects of thinning and/or fertilizing pure and mixed stands of immature Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) and western hemlock (Tsuga Heterophylla [Raf.] Sarg.). The core study examined the effects of various levels and combinations of thinning (0, 20, 35% live basal area removed) and nitrogen fertilization (0, 225, 450 kg N/ha) on tree growth. Subsidiary studies examined operational thinning or fertilization, and effects of thinning and fertilizing in juvenile stands. Tree diameters and heights were measured and pathological characteristics evaluated before and after treatment, and at 3-year intervals since establishment. Vegetation and soils were described for each installation, and weather stations were maintained at or near each installation for up to 8 years. This report, a collation of published and unpublished information, provides a summary of the methods of plot establishment and measurement.

FRDA Research Report 054 (303 KB)

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Updated July 24, 2015