Silva Fennica : quarterly issues : 42(1) : sa421019.htm

Miina Rautiainen, Matti Mõttus, Pauline Stenberg & Sanna Ervasti. 2008.

Crown envelope shape measurements and models

Silva Fennica 42(1): 19–33

This paper addresses tree crown envelope shape modeling from the perspective of optical passive remote sensing. The aims are 1) to review the specific requirements of crown shape models and ground measurement techniques in optical remote sensing, and 2) to present preliminary results from empirical, parametric crown shape and volume modeling of Scots pine and Norway spruce applicable in Finland. Results indicated that the basic dimensions (maximum radius, its height and crown length) of tree crowns were better predicted for pines, but the profile shape of the upper part of the crowns varied more than in spruce. Pine crowns were also slightly less concave than spruce crowns. No regularities were observed concerning the lower part of the crowns. The asymmetry of crowns increased as a function of tree age for both species, spruce crowns being more asymmetric than pine crowns. A comparison of measured crown volume with several simple geometrical crown shape envelopes showed that using a cone as a crown shape model for Scots pine and Norway spruce underestimates crown volume most severely. Other crown envelope shape models (e.g. ellipsoids) rendered crown volumes closer to the measured volume and did not differ considerably from each other.

Keywords
crown profile, Scots pine, Norway spruce, reflectance model, remote sensing

Addresses
Rautiainen, Tartu Observatory, 61602 Tõravere, Estonia, and Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland; Mõttus, Tartu Observatory, 61602 Tõravere, Estonia; Stenberg, Department of Forest Resource Management, P.O. Box 27, FI-00014 University of Helsinki, Finland; Ervasti, City of Vantaa, Land Use and Environment / Green Area Unit, Kielotie 13, FI-01300 Vantaa, Finland. E-mail miina.rautiainen@helsinki.fi

Received 31 January 2007 Revised 12.10.2007 Accepted 22 October 2007
ISSN 0037-5330

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