NOAA/WDS Paleoclimatology - Dye - Huron Mountain Club-Rush Lake - TSCA - ITRDB MI024

Availability of high-quality primary ecological datasets like tree-ring growth is critical to the progress of ecological sciences. The International Tree-Ring Databank (ITRDB) is the premier public archive for interannual records of tree-ring growth (i.e., “chronologies”); however, there is currently a dearth of available chronologies that extend into the 21st century. In Michigan, none of the available records for eastern hemlock extends past 1983. Unfortunately, this reduces the availability of these chronologies for study of recent ecological and climatological change or for their integration with new environmental measuring technologies. In this paper, we fill part of this gap for northern Michigan and examine how our datasets can inform long-term studies of ecology-climate interactions in the Midwest region. We present multi-century Tsuga canadensis (L.) Carrière (eastern hemlock) tree-ring growth records for four sites in the Upper Peninsula of Michigan, U.S.A., covering the periods 1708–2015, 1754–2015, 1794–2015, and 1857–1995. We explore potential applications of these datasets by examining basic correlations between interannual growth on the one hand and regional temperature and Palmer Drought Severity Index (PDSI, an estimate of dryness) values on the other. At all four sites, growth is negatively correlated with previous summer and current spring temperature, while growth is positively correlated with previous summer PDSI at three of the four sites.