INVESTIGADORES
KITZBERGER Thomas
artículos
Título:
Factors predisposing episodic drought-induced tree mortality in Nothofagus: site, climatic sensitivity and growth trends
Autor/es:
SUAREZ, M.L.; GHERMANDI, L.; KITZBERGER, T.
Revista:
JOURNAL OF ECOLOGY (PRINT)
Editorial:
BLACKWELL
Referencias:
Año: 2004 vol. 92 p. 954 - 966
ISSN:
0022-0477
Resumen:
1
Although climatic variability is a strong driving force for forest dynamics, drought-induced
mortality has generally received much less attention than other types of disturbance.
2
In 199899 northern Patagonia was affected by one of the most severe droughts of the
20th century, coinciding with a strong La Nina event, and this caused high mortality of
Nothofagus dombeyi
(coihue), the dominant tree species in Nahuel Huapi National Park.
3
Factors involved in determining this mortality of
N. dombeyi
were examined at both
patch and tree level. Radial growth characteristics of killed trees and survivors were
compared by dendrochronological analyses. Relationships between growth and climate
were investigated using response function analysis.
4
At the tree scale, individuals with variable growth were more prone to die from
drought than trees with more regular growth. Juveniles whose growth patterns showed
sensitivity to climate were particularly likely to die. However, among both killed trees
and survivors, older trees were less sensitive to climate.
5
Mean growth rate was a good predictor of mortality in adult trees, showing that trees
with slower growth rate were more susceptible to drought. Susceptible trees may have
been negatively affected by the drought that affected northern Patagonia in 195657.
6
These results underscore the importance of considering drought-induced tree
mortality as a non-random mechanism influenced by site, previous stress/disturbance
history, ontogeny, vigour, climatic sensitivity and physiology. Spatial patterns of extensive
full and partial crown dieback, which are evident in many temperate forests worldwide,
may reflect the superposition of these predisposing factors on strong/ repeated interannual
fluctuations of climate.