ISSN:
1432-1254
Source:
Springer Online Journal Archives 1860-2000
Topics:
Geography
,
Physics
Notes:
Abstract The transpiration of an isolated Scots pine (P. sylvestris), determined by weighing, was related to stomatal resistance and environmental factors. The tree had been sheared to 1.5 m diameter at the base and 1.8 m high. The transpiration (2.97 MJ for 12h) was rather constant throughout the day and similar in shape to direct beam radiation incident upon the side of a cone. Transpiration rates calculated with the gradient equation duplicated measured values when vapor density gradients (obtained from measured needle temperature), measured stomatal resistance, and characteristic width of 3 mm in aerodynamic resistance were used in the calculations. Net radiation (Q*) for the tree was calculated by replacing the direct beam component of measured net radiation with the direct beam component incident upon a cone. The sensible heat flux, calculated with needle temperatures, was large (50.8 MJ) and nearly equal to Q* (53.85). The resulting Bowen ratio was 17. Transpiration calculated with a modified Penman-Monteith type equation simulated measured values.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02250571
