© 1990 Heron Publishing—Victoria, Canada
A method for reconstructing the development of the sapwood area of balsam fir
Marie R. Coyea (1), Hank A. Margolis (1) and Robert R. Gagnon (2)
1. Département des sciences forestières, Faculté de foresterie et de géomatique, Université Laval,
Sainte-Foy, Québec, Canada G1K 7P4 / 2. Service de la protection contre les insectes et les maladies, Ministère de l’Énergie et des Ressources du Québec, 5700, 4e
Avenue ouest, Edifice de l’Atrium, 3e étage, Charlesbourg, Québec, Canada G1H 6R1 / Received November 9, 1989
Summary
Leaf area is commonly estimated as a function of sapwood area. However, because sapwood changes to heartwood over time, it
has not previously been possible to reconstruct either the sapwood area or the leaf area of older trees into the past. In
this study, we report a method for reconstructing the development
of the sapwood area of dominant and codominant balsam fir (Abies balsamea (L.) Mill.). The technique is based on establishing a species-specific relationship between the number of annual growth rings
in the sapwood area and tree age. Because the number of annual growth rings in the sapwood of balsam fir at a given age was
found to be independent of site quality and stand density, the number of rings in sapwood (NRS) can be predicted from the
age of a tree thus: NRS = 14.818 (1 – e–0.031 age), unweighted R2 = 0.80, and NRS = 2.490 (1 – e–0.038 age), unweighted R2 = 0.64, for measurements at breast height and at the base of the live crown, respectively. These nonlinear asymptotic regression
models based only on age,
were not improved by adding other tree variables such as diameter at breast height, diameter at the base of the live crown,
total tree height or percent live crown.
