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Temperature and water potential co‐limit stem cambial activity along a steep elevational gradient
Author(s) -
Cabon Antoine,
Peters Richard L.,
Fonti Patrick,
MartínezVilalta Jordi,
De Cáceres Miquel
Publication year - 2020
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.16456
Subject(s) - tracheid , turgor pressure , xylem , environmental science , cambium , picea abies , atmospheric sciences , phenology , botany , wood production , larch , biology , ecology , forest management , physics
Summary Efforts to develop mechanistic tree growth models are hindered by the uncertainty of whether and when tree growth responses to environmental factors are driven by carbon assimilation or by biophysical limitations of wood formation. In this study, we used multiannual weekly wood‐formation monitoring of two conifer species ( Larix decidua and Picea abies ) along a 900 m elevational gradient in the Swiss Alps to assess the biophysical effect of temperature and water potential on wood formation. To this end, we developed a model that simulates the effect of water potential on turgor‐driven cambial division, modulated by the effect of temperature on enzymatic activity. The model reproduced the observed phenology of tracheid production, as well as intra‐ and interannual tracheid production dynamics of both species along the elevational gradient, although interannual model performance was lower. We found that temperature alone explains the onset of tracheid production, yet water potential appears necessary to predict the ending and the total amount of tracheids produced annually. We conclude that intra‐annual cambial activity is strongly constrained by both temperature and water potential at all elevations, independently of carbon assimilation. At the interannual scale, biophysical constraints likely interact with other factors.