Mortality predispositions of conifers across western USA.
New Phytol
; 229(2): 831-844, 2021 01.
Article
em En
| MEDLINE
| ID: mdl-32918833
ABSTRACT
Conifer mortality rates are increasing in western North America, but the physiological mechanisms underlying this trend are not well understood. We examined tree-ring-based radial growth along with stable carbon (C) and oxygen (O) isotope composition (δ13 C and δ18 O, respectively) of dying and surviving conifers at eight old-growth forest sites across a strong moisture gradient in the western USA to retrospectively investigate mortality predispositions. Compared with surviving trees, lower growth of dying trees was detected at least one decade before mortality at seven of the eight sites. Intrinsic water-use efficiency increased over time in both dying and surviving trees, with a weaker increase in dying trees at five of the eight sites. C starvation was a strong correlate of conifer mortality based on a conceptual model incorporating growth, δ13 C, and δ18 O. However, this approach does not capture processes that occur in the final months of survival. Ultimately, C starvation may lead to increased mortality vulnerability, but hydraulic failure or biotic attack may dominate the process during the end stages of mortality in these conifers.
Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Traqueófitas
Tipo de estudo:
Observational_studies
País/Região como assunto:
America do norte
Idioma:
En
Revista:
New Phytol
Ano de publicação:
2021
Tipo de documento:
Article