TY - JOUR
T1 - Stand-scale tree mortality factors differ by site and species following drought in southwestern mixed conifer forests
AU - Kane, Jeffrey M.
AU - Kolb, Thomas E.
AU - McMillin, Joel D.
N1 - Funding Information:
We thank the many people who provided field and lab assistance over the course of the study: B. Dechant, D. Carlson, D. Kennedy, M. McKinney, A. Coble, M. Gaylord, C. Erikson, and C. West. We received helpful editorial and analysis comments from J. Berrill, M. DeSilva, S. Eyes, G. Koch, A. Livingston, P. van Mantgem, K. Waring and three anonymous reviewers on earlier drafts. A Science Foundation of Arizona Fellowship and a McIntire-Stennis grant to the School of Forestry, Northern Arizona University funded this research, with supplemental support provided by scholarships from Achievement Rewards for College Scientists Program and by Kay and Irene Haffen.
PY - 2014/10/15
Y1 - 2014/10/15
N2 - Impacts of drought on tree mortality in high-elevation mixed-conifer forests of southwestern U.S. are poorly understood. A recent extended and severe drought in the region provided an opportunity to investigate the patterns and factors associated with tree mortality in this forest type. Specifically, we quantified mortality that occurred between 1995 and 2008 of four tree species, white fir (Abies concolor), limber pine (Pinus flexilis), trembling aspen (Populus tremuloides), and Douglas-fir (Pseudotsuga menziesii), in mixed-conifer forests over three sites in northern Arizona within 84, 0.02. ha plots. We found: (1) varied but substantial tree mortality (4-56% by basal area) in most species between 1996 and 2006 in association with recent severe and prolonged drought; (2) tree mortality differed among sites and species with aspen and white fir having the most mortality (>30% by basal area); (3) relationships between tree mortality and most climatic factors (e.g. temperature, precipitation, Palmer Drought Severity Index) were lagged 1-4. yr; (4) bark beetle attack and intraspecific tree basal area were consistently and positively related to tree mortality for most species and sites, whereas topographic and other stand characteristics were less consistently related to mortality. Results show that aspen, Douglas-fir, and white fir were more vulnerable to recent drought-associated mortality than limber pine. Associations between tree mortality and intraspecific basal area support further evaluation of treatments that reduce intraspecific competition within stands to lower risks of tree mortality in southwestern mixed conifer forests.
AB - Impacts of drought on tree mortality in high-elevation mixed-conifer forests of southwestern U.S. are poorly understood. A recent extended and severe drought in the region provided an opportunity to investigate the patterns and factors associated with tree mortality in this forest type. Specifically, we quantified mortality that occurred between 1995 and 2008 of four tree species, white fir (Abies concolor), limber pine (Pinus flexilis), trembling aspen (Populus tremuloides), and Douglas-fir (Pseudotsuga menziesii), in mixed-conifer forests over three sites in northern Arizona within 84, 0.02. ha plots. We found: (1) varied but substantial tree mortality (4-56% by basal area) in most species between 1996 and 2006 in association with recent severe and prolonged drought; (2) tree mortality differed among sites and species with aspen and white fir having the most mortality (>30% by basal area); (3) relationships between tree mortality and most climatic factors (e.g. temperature, precipitation, Palmer Drought Severity Index) were lagged 1-4. yr; (4) bark beetle attack and intraspecific tree basal area were consistently and positively related to tree mortality for most species and sites, whereas topographic and other stand characteristics were less consistently related to mortality. Results show that aspen, Douglas-fir, and white fir were more vulnerable to recent drought-associated mortality than limber pine. Associations between tree mortality and intraspecific basal area support further evaluation of treatments that reduce intraspecific competition within stands to lower risks of tree mortality in southwestern mixed conifer forests.
KW - Abies concolor
KW - Drought
KW - Pinus flexilis
KW - Populus tremuloides
KW - Pseudotsuga menziesii
KW - Tree death
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U2 - 10.1016/j.foreco.2014.06.042
DO - 10.1016/j.foreco.2014.06.042
M3 - Article
AN - SCOPUS:84905435045
SN - 0378-1127
VL - 330
SP - 171
EP - 182
JO - Forest Ecology and Management
JF - Forest Ecology and Management
ER -