The aim of this thesis was to analyze the water dynamics of trees by using a dynamic modeling approach. The work is of cross-disciplinary nature: tree water issues which is a subject of whole plant physiology is examined by means of physics. From physical principles five different models were derived. First, to study the sap flow and the water pressure dynamics in the xylem of tree stem, the ef...

Knowing crop water uptake each day is useful for developing irrigation scheduling. Many technologies have been used to estimate daily use. Sap flow one of the that measure through stem a plant and uptake. sensor an effective direct method measuring use, but it relatively expensive requires frequent maintenance. Therefore, alternative methods, such as evapotranspiration based on FAO 56 Penman-Mo...

Stem CO(2) concentrations (stem [CO(2)]) undergo large temporal variations that need to be understood to better link tree physiological processes to biosphere-atmosphere CO(2) exchange. During 19 months, stem [CO(2)] was continuously measured in mature subalpine Norway spruce trees (Picea abies) and jointly analysed with stem, soil and air temperatures, sap flow rates, stem radius changes and C...

The heat pulse method is widely used to measure water flux through plants; it works by using the speed at which a heat pulse is propagated through the system to infer the velocity of water through a porous medium. No systematic, non-destructive calibration procedure exists to determine the site-specific parameters necessary for calculating sap velocity, e.g., wood thermal diffusivity and probe ...

Bamboo species-the only herbaceous trees-have unique structural and physiological characteristics that differ from those of other tree taxa. However, the role of night-time water use in bamboo is poorly understood and has rarely been investigated. We studied the day- and night-time sap flow response to culm age and rhizome structure in three age levels (juvenile, mature, and senescent) of Phyll...