USING HISTORICAL PHOTOGRAPHY TO DOCUMENT LANDSCAPE CHANGE IN A GLACIAL FJORD: REVISITING SITES FROM THE EARLY 20TH CENTURY

Forest succession in Glacier Bay in Southeast Alaska has been studied and photographed for almost ninety years. This continuous record is unprecedented in high-latitude areas thanks to the efforts of researchers such as William S. Cooper, who began to photograph and study the vegetation of Southeast Alaska in 1916. Over the years, his efforts were aided by the observations and specimens collected by scientists and explorers, including Bradford Washburn. These long-term studies are extremely valuable for scientists and resource managers seeking to understand the processes of vegetation change in one of the most dynamic environments in Alaska. The objective of this study is to develop a better understanding of vegetative succession in areas that have recently opened up to colonization. Understanding variations in succession can aid resource managers in predicting changes in forest composition under different climactic conditions. Data from this study will be useful in understanding how areas which have been subjected to wildfires, tsunamis, landslides or other extreme events recover from significant perturbations. Cooper's work continued for more than a half-century, but no systematic inventory had been made of these sites in several decades. This study reoccupied these sites, compared current species assemblages with previous findings, and analyzed trends on sites throughout the bay. Cooper's field notes and papers were analyzed to determine the locations of the original sites, which were reoccupied and photographed. Vegetation data was collected from each site and changes quantified as to species composition and density. Understanding the connections that have occurred since the early 20th century between primary succession and the current vegetation are being used to develop a conceptual model that contributes to predicting future changes to vegetation and promoting an understanding of how climate change can affect vegetation.