A large-scale coherent signal of canopy status in maximum latewood density of tree rings at arctic treeline in North America

• Published in: Global and planetary change Vol. 100; pp. 109 - 118
• Main Authors: Beck, Pieter S.A., Andreu-Hayles, Laia, D'Arrigo, Rosanne, Anchukaitis, Kevin J., Tucker, Compton J., Pinzón, Jorge E., Goetz, Scott J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.01.2013; Elsevier
• Subjects: arctic tundra; boreal forest; canopy; correlation; Earth sciences; Earth, ocean, space; Exact sciences and technology; high latitudes; Hydrology; Hydrology. Hydrogeology; latewood; latitude; Marine and continental quaternary; Normalized Difference Vegetation Index; remote sensing; snowmelt; Surficial geology; temperature; tree ring; treeline; North America; polar regions; Arctic region; high latitudes; remote sensing; Normalized Difference Vegetation Index; tree ring; boreal forest; arctic tundra; density; latitude; chronology; vegetation; North America; forests; high temperature; meltwater; tundra; correlation; productivity; temperature; tree rings
• ISSN: 0921-8181; 1872-6364
• DOI: 10.1016/j.gloplacha.2012.10.005

We compared tree-ring width (TRW) and maximum latewood density (MXD) chronologies to remotely sensed indices of productivity (NDVI) and snowmelt since 1981 and to the instrumental temperature record at four arctic treeline sites in North America. Our results show that at these sites, TRW chronologies reflect temperatures less consistently than the MXD chronologies do and that the NDVI does not correlate significantly with TRW at high-frequency, i.e. when comparing yearly values. In contrast, the MXD chronologies correlate positively and significantly with NDVI and temperature during the growing season at all sites. Neither TRW or MXD chronologies appeared consistently influenced by the annual timing of snowmelt. A comparison of tree-ring chronologies and temperatures since 1900 confirms that MXD has tracked growing season temperature at these treeline sites throughout the past century. A spatial evaluation of the correlations further reveals that each of the MXD chronologies investigated here reflects interannual variation in NDVI and growing season temperatures across a large geographic region. As a result, they collectively provide a spatially comprehensive record of historic early-season canopy status as well as growing season temperatures for the high latitudes of North America. ► MXD provides a more reliable temperature proxy at North American arctic tree line than ring widths do. ► The interannual signal in MXD matches that in satellite-observed greenness. ► Site-level MXD records reflect early growing season canopy status of large regions.