ABSTRACT
All of the discussion of timber growth in earlier chapters has been in terms of net growth—that is, gross growth minus mortality. The Forest Service defines mortality as "Number or sound-wood volume of live trees dying from natural causes during a specified period." Although the formal definition does not go further, the text discussion clearly indicates that fire, insects, disease, and storms are the chief causes of mortality. The published sources of data include data on mortality as well as upon net growth, standing volumes, removals, etc.
