caa a22 4500 445383534 CHVBK 20180317143024.0 cr unu---uuuuu 170323e20110901xx s 000 0 eng 10.1007/s10021-011-9458-2 doi (NATIONALLICENCE)springer-10.1007/s10021-011-9458-2 Long-Term Tree Cover Dynamics in a Pinyon-Juniper Woodland: Climate-Change-Type Drought Resets Successional Clock [Elektronische Daten] [Michael Clifford, Neil Cobb, Michaela Buenemann] Woody vegetation has expanded in coverage over the past century in many places globally, exemplified by pinyon-juniper changes in the Southwestern United States. Extreme drought is one of the few non-management drivers besides fire that might reverse such cover changes, but this has not been well documented. Here, we assess 68years of tree cover dynamics across an elevation gradient of a pinyon-juniper woodland using aerial photographs (1936 and 1959) and QuickBird imagery (2004). Canopy cover increased 32% from 1936 to the onset of a major drought (2002). The largest relative increase in canopy cover occurred from 1936 to 1959 at the higher elevations, but these gains were eliminated by fires occurring from 1959 to 2002, during which time lower elevations with low canopy cover exhibited the greatest relative increases. The 2002-2004 drought reduced canopy cover by 55%, which eliminated gains in cover that occurred since 1936. Relative tree cover loss was highest at low elevations with low tree cover, but absolute tree cover loss was greater in areas of high tree cover, which increased with elevation. The loss of more than half of the canopy cover during a 2-year drought period was much greater than losses due to fire or possible increases due to historic land use (for example, grazing). These results suggest that regional-scale climatic influences may be more important than land use legacies in controlling tree cover of these and perhaps other semiarid woodlands over longer time scales—notable given that similar episodes of tree mortality are projected in coming decades with climate change. Springer Science+Business Media, LLC, 2011 drought nationallicence climate change nationallicence pinyon-juniper woodland expansion nationallicence aerial photographs nationallicence QuickBird nationallicence die-off nationallicence mortality nationallicence fire nationallicence grazing nationallicence elevation gradient nationallicence Clifford Michael Earth and Environmental Science Department, Lehigh University, 1 West Packer Avenue, 18015, Bethlehem, Pennsylvania, USA aut Cobb Neil Merriam-Powell Center for Environmental Research, Department of Biological Sciences, Northern Arizona University, Peterson Hall, Box 6077, 86011, Flagstaff, Arizona, USA aut Buenemann Michaela Department of Geography, New Mexico State University, MSC MAP, P.O. Box 30001, 88003, Las Cruces, New Mexico, USA aut Ecosystems Springer-Verlag 14/6(2011-09-01), 949-962 1432-9840 14:6<949 2011 14 10021 https://doi.org/10.1007/s10021-011-9458-2 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s10021-011-9458-2 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Clifford Michael Earth and Environmental Science Department, Lehigh University, 1 West Packer Avenue, 18015, Bethlehem, Pennsylvania, USA aut NATIONALLICENCE 700 1- Cobb Neil Merriam-Powell Center for Environmental Research, Department of Biological Sciences, Northern Arizona University, Peterson Hall, Box 6077, 86011, Flagstaff, Arizona, USA aut NATIONALLICENCE 700 1- Buenemann Michaela Department of Geography, New Mexico State University, MSC MAP, P.O. Box 30001, 88003, Las Cruces, New Mexico, USA aut NATIONALLICENCE 773 0- Ecosystems Springer-Verlag 14/6(2011-09-01), 949-962 1432-9840 14:6<949 2011 14 10021 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer