Canadian Forest Service Publications

Conversion of total leaf area to projected leaf area in lodgepole pine and Douglas-fir. 1998. Barclay, H.J. Tree Physiology 18: 185-193.

Year: 1998

Issued by: Pacific Forestry Centre

Catalog ID: 4911

Language: English

CFS Availability: Order paper copy (free)

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Abstract

Three definitions of leaf area index (LAI) in the literature have no predictable relationship with each other. Factors were derived for converting total LAI to projected LAI of horizontal leaves and to projected LAI for inclined leaves of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.) and coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) to allow comparison of results from different studies. An algorithm was derived to allow determination of these factors based on twig angles and the angles that the foliage subtends with the twig. Allowances were made for both the vertical and horizontal components of projection. The value of the factor for converting total LAI to projected LAI for inclined leaves was 0.229 + 0.0032 for lodgepole pine and 0.230 + 0.0037 for Douglas-fir Sensitivity analysis established that this conversion factor was more sensitive to differences in vertical angles of the twigs than to twig rotation or foliar arrangement on the twig.