Estimation of foliage denseness and foliage angle by inclined point quadrats

Abstract

The total area of foliage per unit area of land can be estimated from the number of contacts with foliage made by point quadrats inclined at appropriate angles, and the distribution of this foiiage area with height above ground be estimated by recording the heights at which the contacts occur. These estimates, unlike those based on vertical and horizontal quadrats, are not depressed by variability in foliage angle (inclination of foliage to the horizontal). The foliage angle can be estimated by comparing the numbers of contacts made by quadrats inclined at two different angles, but this estimate is less satisfactory than one based on vertical and horizontal quadrats. Accurate estimates of both foliage area and foliage angle can be obtained by using a combination of vertical, inclined, and horizontal quadrats. This paper also discusses the application of point quadrat methods to stems as well as leaves, and considers certain practical aspects of point quadrat use.