Modeling the dynamics of pressure propagation and diameter variation in tree sapwood.
A non-steady-state model of water tension propagation in tree stems was developed. The model is based on the cohesion theory and the assumption that fluctuating water tension driven by transpiration together with the elasticity of wood cause variations in the diameter of a tree stem. The change in xylem diameter can be linked to water tension in accordance with Hooke's law. The model was tested against field measurements of the diurnal change in xylem diameter at different heights in a 180-year-old Scots pine tree at Hyytiälä, southern Finland. Model predictions agreed well with measurements. The effect of tree dimensions on pressure propagation was examined with the model. The model outcomes were also consistent with results of several field measurements presented in the literature.
Perämäki
Martti
M
Department of Forest Ecology, University of Helsinki, P.O. Box 27, 00014 University of Helsinki, Finland. martti.peramaki@helsinki.fi
Vesala
Timo
T
Nikinmaa
Eero
E
D008954:Models, Biological; D028223:Pinus / Q000033:anatomy & histology / Q000502:physiology; D011312:Pressure; D014197:Trees / Q000033:anatomy & histology* / Q000502:physiology*; D014867:Water / Q000378:metabolism; D014934:Wood / Q000033:anatomy & histology* / Q000502:physiology*
D014867:Water