Direct response of tree growth to soil water and its implications for terrestrial carbon cycle modelling
Eckes‐shephard, Annemarie H. LU
; Tiavlovsky, Egor
; Chen, Yizhao
; Fonti, Patrick
and Friend, Andrew D.
(2021)
In Global Change Biology
27(1).
p.121-135
- Abstract
- Wood growth constitutes the main process for long‐term atmospheric carbon sequestration in vegetation. However, our understanding of the process of wood growth and its response to environmental drivers is limited. Current dynamic global vegetation models (DGVMs) are mainly photosynthesis‐driven and thus do not explicitly include a direct environmental effect on tree growth. However, physiological evidence suggests that, to realistically model vegetation carbon allocation under increased climatic stressors, it is crucial to treat growth responses independently from photosynthesis. A plausible growth response function suitable for global simulations in DGVMs has been lacking. Here, we present the first soil water‐growth response function and... (More)
- Wood growth constitutes the main process for long‐term atmospheric carbon sequestration in vegetation. However, our understanding of the process of wood growth and its response to environmental drivers is limited. Current dynamic global vegetation models (DGVMs) are mainly photosynthesis‐driven and thus do not explicitly include a direct environmental effect on tree growth. However, physiological evidence suggests that, to realistically model vegetation carbon allocation under increased climatic stressors, it is crucial to treat growth responses independently from photosynthesis. A plausible growth response function suitable for global simulations in DGVMs has been lacking. Here, we present the first soil water‐growth response function and parameter range for deciduous and evergreen conifers. The response curve was calibrated against European larch and Norway spruce in a dry temperate forest in the Swiss Alps. We present a new data‐driven approach based on a combination of tree ring width (TRW) records, growing season length and simulated subdaily soil hydrology to parameterize ring width increment simulations. We found that a simple linear response function, with an intercept at zero moisture stress, used in growth simulations reproduced 62.3% and 59.4% of observed TRW variability for larch and spruce respectively and, importantly, the response function slope was much steeper than literature values for soil moisture effects on photosynthesis and stomatal conductance. Specifically, we found stem growth stops at soil moisture potentials of −0.47 MPa for larch and −0.66 MPa for spruce, whereas photosynthesis in trees continues down to −1.2 MPa or lower, depending on species and measurement method. These results are strong evidence that the response functions of source and sink processes are indeed very different in trees, and need to be considered separately to correctly assess vegetation responses to environmental change. The results provide a parameterization for the explicit representation of growth responses to soil water in vegetation models. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/fab3792d-0d12-4c0b-9340-094aa793fce2
- author
- Eckes‐shephard, Annemarie H.
LU
; Tiavlovsky, Egor
; Chen, Yizhao
; Fonti, Patrick
and Friend, Andrew D.
- publishing date
- 2021-01-01
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Soil moisture, tree growth, Source-sink dynamics
- in
- Global Change Biology
- volume
- 27
- issue
- 1
- pages
- 121 - 135
- publisher
- Wiley-Blackwell
- external identifiers
-
- pmid:33065763
- scopus:85096802951
- ISSN
- 1354-1013
- DOI
- 10.1111/gcb.15397
- language
- English
- LU publication?
- no
- id
- fab3792d-0d12-4c0b-9340-094aa793fce2
- date added to LUP
- 2021-05-11 15:42:18
- date last changed
- 2022-04-27 01:57:10
@article{fab3792d-0d12-4c0b-9340-094aa793fce2,
abstract = {{Wood growth constitutes the main process for long‐term atmospheric carbon sequestration in vegetation. However, our understanding of the process of wood growth and its response to environmental drivers is limited. Current dynamic global vegetation models (DGVMs) are mainly photosynthesis‐driven and thus do not explicitly include a direct environmental effect on tree growth. However, physiological evidence suggests that, to realistically model vegetation carbon allocation under increased climatic stressors, it is crucial to treat growth responses independently from photosynthesis. A plausible growth response function suitable for global simulations in DGVMs has been lacking. Here, we present the first soil water‐growth response function and parameter range for deciduous and evergreen conifers. The response curve was calibrated against European larch and Norway spruce in a dry temperate forest in the Swiss Alps. We present a new data‐driven approach based on a combination of tree ring width (TRW) records, growing season length and simulated subdaily soil hydrology to parameterize ring width increment simulations. We found that a simple linear response function, with an intercept at zero moisture stress, used in growth simulations reproduced 62.3% and 59.4% of observed TRW variability for larch and spruce respectively and, importantly, the response function slope was much steeper than literature values for soil moisture effects on photosynthesis and stomatal conductance. Specifically, we found stem growth stops at soil moisture potentials of −0.47 MPa for larch and −0.66 MPa for spruce, whereas photosynthesis in trees continues down to −1.2 MPa or lower, depending on species and measurement method. These results are strong evidence that the response functions of source and sink processes are indeed very different in trees, and need to be considered separately to correctly assess vegetation responses to environmental change. The results provide a parameterization for the explicit representation of growth responses to soil water in vegetation models.}},
author = {{Eckes‐shephard, Annemarie H. and Tiavlovsky, Egor and Chen, Yizhao and Fonti, Patrick and Friend, Andrew D.}},
issn = {{1354-1013}},
keywords = {{Soil moisture; tree growth; Source-sink dynamics}},
language = {{eng}},
month = {{01}},
number = {{1}},
pages = {{121--135}},
publisher = {{Wiley-Blackwell}},
series = {{Global Change Biology}},
title = {{Direct response of tree growth to soil water and its implications for terrestrial carbon cycle modelling}},
url = {{http://dx.doi.org/10.1111/gcb.15397}},
doi = {{10.1111/gcb.15397}},
volume = {{27}},
year = {{2021}},
}