THE CONTINUING POPULATION DECLINE OF TORREYA-TAXIFOLIA ARN

Torreya toxifolia is a federally endangered dioecious conifer endemic to ravine bluffs along the east side of the Apalachicola River in Gads den and Liberty Counties, Florida and Decatur County, Georgia (plus on e outlying population in Jackson County, Florida). Torreya taxifolia e xperienced a catastrophic population decline, presumably fungal in ori gin, in the late 1950's. Within 10 years virtually no adults remained in the wild, a situation that persists to the present. Size measuremen ts of trees indicate that the mean length of the longest stem is less than one meter. In a census population of over 100 trees, 10% died in four years, mostly from small size classes. Extension of terminal buds along the primary stem was infrequent, with only 47% of all trees exp eriencing any growth in length during the four year census period. Wit h 32% of all trees losing their primary stem during the census interva l, the mean size of individuals within the population is decreasing. M ost individuals are multi-stemmed and continue to carry symptoms of di sease. Although no causative agent for the decline has been identified , the most prevalent symptoms of disease are needle spots, needle necr osis and stem cankers. Growth fate does not appear to be strongly rela ted to habitat or the incidence of disease symptoms, although stem mor tality was higher among trees with heavy foliar pathogen loads. With n o sexually mature trees and no seed production, this species faces con tinued decline.