Excerpt from Age-Class Structure of Old Growth Ponderosa Pine/Douglas-Fir Stands and Its Relationship to Fire History We chose 1900 as a basis for characterizing bistori cal stand conditions because studies in ponderosa pine/ fir forests generally indicate a disruption in the his torical pattern of frequent fires shortly after that time (arno Results of such comparative analyses can be influenced by the year chosen to represent his toric or presettlement conditions. The bias associ ated with using a single year to typify historic condi tions is offset somewhat by sampling several stands with different disturbance histories, as we did. Also, records of fire history in ponderosa pine forests of western Montana show a consistent pattern of frequent fire fiom 1900 back to about 1500; beyond that thresh old few living trees are available to sample (arno 1976; Barrett and Arno Stand structure comparisons might be made for several different dates prior to 1900, but the quality of projected stand information declines for earlier dates because of decay and effects of past fires in consuming dead trees. About the Publisher Forgotten Books publishes hundreds of thousands of rare and classic books. Find more at www.forgottenbooks.com This book is a reproduction of an important historical work. Forgotten Books uses state-of-the-art technology to digitally reconstruct the work, preserving the original format whilst repairing imperfections present in the aged copy. In rare cases, an imperfection in the original, such as a blemish or missing page, may be replicated in our edition. We do, however, repair the vast majority of imperfections successfully; any imperfections that remain are intentionally left to preserve the state of such historical works.