© 1997 Heron Publishing—Victoria, Canada
Crown architecture of Abies balsamea from four canopy positions
Daniel W. Gilmore (1) and Robert S. Seymour (2)
1. Canadian Forest Products Limited, Postal Bag 100, Grande Prairie, Alberta T8V 3A3, Canada / 2. Department of Forest Ecosystem Science, College of Natural Resources, Forestry and Agriculture, University of Maine, Orono,
ME 04469-5755, USA / Received August 4, 1995
Summary
Data collected from four distinct canopy positions from each of 39 Abies balsamea (L.) Miller trees were used to construct models to describe the cumulative leaf area distribution within the crown and to
predict the needle mass of individual branches, the average branch angle, branch diameter, branch length, and crown radius
per whorl, and the average number of living branches per whorl. We tested the hypotheses that regression models are equal
among canopy positions and that a model to predict branch needle mass is valid at the northern and southern extremes of the
central climatic zone of Maine. Canopy position had an effect on the models constructed to predict needle mass, branch angle,
branch diameter, branch length, crown radius, and the number of living branches per whorl. However, compared with an expanded
model that incorporated parameters calculated for each crown class, there was only a small loss in model precision when a
general model constructed from data pooled from all crown classes was used to predict needle mass, branch angle, and branch
diameter. Regression equations unique to each crown class were needed to predict crown shape and leaf area distribution in
the crown satisfactorily. Our branch needle mass model, which was constructed from data collected at the southern extreme
of the central climatic zone of Maine, consistently underestimated needle branch mass when applied to the northern extreme
of the central climatic zone.
Keywords:
balsam fir, branch angle, crown shape, foliage distribution, Maine, needle mass, projected leaf area.
