Crown Shape in Open- and Forest-Grown Balsam Fir and Black Spruce

Abstract

Crown-radius equations developed from measurements taken on open-grown balsam fir and black spruce were applied to forest-grown trees of the same species. For that part of the crown considered to be growing free of aerial competition, radii were estimated to within ±1.5 ft (±45.7 cm) at the 5% significance level. It was concluded that those portions of balsam fir and black spruce crowns estimated to be growing free of aerial competition are not significantly different from similar portions of open-grown trees of the same height and species. Coefficients and related statistics for the general crown-radius equation, CR = a1 L + a2LH + a3L2/H + a4L2, are given.