Equations to describe crown allometry of Larix require local validation

Allometric equations were developed to describe crown attributes of three s pecies of open-grown Larix in Minnesota and compared with similar data from Maine and published works from Austria. No differences were detected in al lometric relationships to predict crown length, projected crown radius, and crown radius at different depths within the crown among tamarack, European larch, and hybrid European x Japanese larch grown in Minnesota. Small (<1 m within the range of data). but significant, differences in the prediction of crown length from total height were found between Minnesota and Maine. Allometric equations constructed from inventory data in Austria used a diff erent model form and predicted larger crown attributes then equations gener ated with data from Minnesota. Results underscore the necessity for forest managers to validate allometric equations locally. With exotic species, how ever, it may be necessary to use published works until local data and resou rces for validation can be obtained. Applications include usage in the cons truction of stocking charts, stand density diagrams, and the prediction of DBH and volume from crown shape using remote sensing data. (C) 2001 Elsevie r Science B.V. All rights reserved.