TIGER for Estimating Basis is being developed for use in the 20 states that TIGER for Woodlands and Compartments serves - Connecticut, Delaware, Indiana, Iowa, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, New Hampshire, New Jersey, New York, Ohio, Pennsylvania, Rhode Island, Vermont, West Illinois, and Wisconsin. Although each state has some unique forest inventory characteristics that are reflected in the version developed for each state, the program looks and feels the same for each state.
Estimating basis of a woodlands for a time some years before an inventory of the woodland was done requires estimating the condition of the trees in the woodland some years ago. This is done by using the USFS growth models used to estimate growth and mortality for TIGER for Woodlands and Compartments and running them "backwards" so that trees become smaller in diameter and more numerous.