Site Index

Site Index is a measure used by foresters to classify the productivity of a forest. Specifically, the site index is the average height of dominant and codominant trees at an index age, usually 50 years. Site index equations use two independent variables (stand age and site index) to predict the dependent variable (height). This is normally expressed as a 2D figure with age on the x-axis, height on the y-axis and multiple lines drawn to show the third dimension of site index. These traditional 2D figures can be misleading in that site index exists on a continuum, and not as discrete values. Consequently, site index is really a ‘curved plane’. This app displays the true ‘site index plane’ for a number of commercial tree species found in North America. The 3D figures from this app can be used to show the true relationship of stand age, site quality and average stand height. If an age and site index are entered the app will compute and display the predicted average stand height. All 3D figures can be yawed, pitched and rolled for better viewing.