TY - JOUR
T1 - Stand-structural effects on Heterobasidion abietinum-related mortality following drought events in Abies pinsapo
AU - Linares, Juan Carlos
AU - Camarero, Jesús Julio
AU - Bowker, Matthew A.
AU - Ochoa, Victoria
AU - Carreira, J. Antonio
N1 - Funding Information:
Acknowledgments This study was supported by projects PP06-RNM-02183 (Consejería de Innovación y Ciencia, Junta de And-alucía) and REN2002-2003-09509 (Spanish Ministry of Science). J.J.C. is grateful for the support of ARAID and the Globimed network. Tree cutting was supported by the Consejería de Medio Am-biente, Junta de Andalucía, with the helpful collaboration of J. López Quintanilla. We thank Dr. E. Sánchez for insightful discussions and G. Sangüesa for valuable laboratory assistance. We also thank Ram Oren and two anonymous reviewers for their helpful comments. These experiments comply with the current laws of Spain.
PY - 2010/12
Y1 - 2010/12
N2 - Climate change may affect tree-pathogen interactions. This possibility has important implications for drought-prone forests, where stand dynamics and disease pathogenicity are especially sensitive to climatic stress. In addition, stand structural attributes including density-dependent tree-to-tree competition may modulate the stands' resistance to drought events and pathogen outbreaks. To assess the effects of stand structure on root-rot-related mortality after severe droughts, we focused on Heterobasidion abietinum mortality in relict Spanish stands of Abies pinsapo, a drought-sensitive fir. We compared stand attributes and tree spatial patterns in three plots with H. abietinum root-rot disease and three plots without root-rot. Point-pattern analyses were used to investigate the scale and extent of mortality patterns and to test hypotheses related to the spread of the disease. Dendrochronology was used to date the year of death and to assess the association between droughts and growth decline. We applied a structural equation modelling approach to test if tree mortality occurs more rapidly than predicted by a simple distance model when trees are subjected to high tree-to-tree competition and following drought events. Contrary to expectations of drought mortality, the effect of precipitation on the year of death was strong and negative, indicating that a period of high precipitation induced an earlier tree death. Competition intensity, related to the size and density of neighbour trees, also induced an earlier tree death. The effect of distance to the disease focus was negligible except in combination with intensive competition. Our results indicate that infected trees have decreased ability to withstand drought stress, and demonstrate that tree-to-tree competition and fungal infection act as predisposing factors of forest decline and mortality.
AB - Climate change may affect tree-pathogen interactions. This possibility has important implications for drought-prone forests, where stand dynamics and disease pathogenicity are especially sensitive to climatic stress. In addition, stand structural attributes including density-dependent tree-to-tree competition may modulate the stands' resistance to drought events and pathogen outbreaks. To assess the effects of stand structure on root-rot-related mortality after severe droughts, we focused on Heterobasidion abietinum mortality in relict Spanish stands of Abies pinsapo, a drought-sensitive fir. We compared stand attributes and tree spatial patterns in three plots with H. abietinum root-rot disease and three plots without root-rot. Point-pattern analyses were used to investigate the scale and extent of mortality patterns and to test hypotheses related to the spread of the disease. Dendrochronology was used to date the year of death and to assess the association between droughts and growth decline. We applied a structural equation modelling approach to test if tree mortality occurs more rapidly than predicted by a simple distance model when trees are subjected to high tree-to-tree competition and following drought events. Contrary to expectations of drought mortality, the effect of precipitation on the year of death was strong and negative, indicating that a period of high precipitation induced an earlier tree death. Competition intensity, related to the size and density of neighbour trees, also induced an earlier tree death. The effect of distance to the disease focus was negligible except in combination with intensive competition. Our results indicate that infected trees have decreased ability to withstand drought stress, and demonstrate that tree-to-tree competition and fungal infection act as predisposing factors of forest decline and mortality.
KW - Basal-area increment
KW - Climate change
KW - Competition
KW - Point-pattern analysis
KW - Structural equation modelling
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U2 - 10.1007/s00442-010-1770-6
DO - 10.1007/s00442-010-1770-6
M3 - Article
C2 - 20838816
AN - SCOPUS:78449240277
SN - 0029-8549
VL - 164
SP - 1107
EP - 1119
JO - Oecologia
JF - Oecologia
IS - 4
ER -