The Life Table Approach to Analysis of Insect Impact

To optimize present and future forest productivity, use, and value, the destructive as well as the constructive elements operating on a forest system must be regulated. Long-term quantitative data are needed for analyzing the relative importance of these interacting forces, and the life table provides a logical format for this purpose. Two types of life table are described, and the way each can be developed to account for insect impacts on forest stands is given. A typical life table of a white-pine stand, including damage and loss caused by the white-pine weevil, is presented and discussed. Several analytical procedures may be used to reveal, in turn, the critical age intervals and the factors or agents most important in determining yield and value. Life-table data of forest stands also can augment analytical schemes of forest regulation now in use.