Rolland C. (1993).
Fonctionnement hydrique et croissance du Sapin (Abies alba Mill.) dans
les Alpes françaises. Dynamique des flux de sève, écophysiologie et
dendroécologie. Thèse de Doctorat, Juin 1993, Université Joseph
Fourier, Grenoble, France, 180 p.
- TITLE Water relations and growth
of the White Fir (Abies alba Mill.) in the French Alps. Sap flow
measurements, ecophysiology and dendroecology.
- LANGUAGE French
- SUBJECT Ecology, Tree growth, Response to
climate, Sap flow, Soil / Plant / Atmosphere, Climate
- KEY WORDS
- SPECIES Abies alba Mill.
- SITES Briançonnais, South-East of France,
Water relationships and growth of the White Fir (Abies alba Mill.) were
studied in field conditions in three forests on North facing slopes with
contrasting climates. These forests are located in the external Alps in
Chartreuse, where the climate is mild, rainy and humid, in the intermediate
Alps in Oisans, and in the internal Alps in Briançonnais, where the climate
is particularly dry. The number of stomata was shown to vary according to the
area. Next, the Soil-Plant-Atmosphere continuum was studied using soil water
potential measurements at different depths, leaf water potential measurements
on several trees and continuous recording of microclimatical factors such as
temperature, relative humidity, solar radiation and wind speed. The air vapour
deficit and potential evapotranspiration were then computed. Leaf water
potential was measured hourly during the day and weekly during the growing
season. Furthermore, a continuous recording of sap speed in four trunks was
carried out using a thermal method in the two most contrasting forests. Sap
speed and climate relationships were analysed daily and seasonally, before
calculating a mathematical model for sap speed and leaf potential. Finally, a
dendroecological study was carried out on the Fir in Briançon using a large
amount of core samples, to analyse the influence of age on basal area growth,
and to study the spatial variations of productivity. The influences of both
altitude and slope on the relationships between tree-rings and climate were
analysed using ring-widths measurements, and using also the number and sizes
of wood cells.