© 1992 Heron Publishing—Victoria, Canada
A rapid technique for recording and measuring the leaf area of conifer needle samples
John A. Kershaw, Jr. (1) and David R. Larsen (2)
1. Department of Forest Resources, University of New Brunswick, Bag Service Number 44555, Fredericton, NB E3B 6C2, Canada / 2. Faculty of Forestry, University of Joensuu, P.O. Box 111, SF-80101 Joensuu, Finland / Received March 16, 1992
Summary
An optical planimetric technique for measuring projected leaf area of conifer needle samples was developed that combines a
rapid field recording method with an inexpensive hand-held optical scanner. The field recording method utilizes strips of
diazo paper (blueprint paper), 10 × 28 cm, to make positive images of the needle samples. An analysis program calculates leaf
area from the output files produced by the hand-held scanner. The results from this system were compared with results from
a Li-Cor 3100 leaf area meter and from a digital camera-based image analysis system using both standard samples of known area
and needle samples from three conifer species. All three systems produced similar results in terms of means and variances.
The digital camera system typically had the lowest variances between successive measurements of the same sample. Most differences
among the systems were not statistically significant. The system presented in this paper is inexpensive, easy to use, and
provides a rapid and permanent method for recording and measuring the leaf area of conifer samples.
