Water-use efficiency (WUE) is critical in determining the adaptation and productivity of plants in water-limited areas, either under the present climate or future global change. Data on WUE are often highly variable and a unifying and quantitative approach is needed to analyse and predict WUE for different environments. Hsiao has already proposed a set of paradigm equations based on leaf gas ex...

In situ optical meters are widely used to estimate leaf chlorophyll concentration, but non-uniform chlorophyll distribution causes the opticalmeasurement to vary widely among species for the same chlorophyllconcentration. Over 30 studies have sought to quantify the in situ/in vitro (optical/absolute) relationship, but neither chlorophyll extraction normeasurement techniques for ...

Understanding seasonal changes in photosynthetic characteristics of canopy leaves is indispensable for modeling the carbon balance in forests. We studied seasonal changes in gas exchange characteristics that are related to the temperature dependence of photosynthesis in canopy leaves of Quercus crispula Blume, one of the most abundant species in cool-temperate forests in Japan. Photosynthetic r...

The hydrological recovery of watersheds from disturbances such as ®re and harvest can change the magnitude and distribution of ̄ow paths as the canopy regenerates. The spatial distribution of net water input to the soil±topography system is mediated by vegetation patterns through the processes of interception, evapotranspiration and snowmelt. We have previously described RHESSys, a distributed ...

Tropical hyperseasonal savannas provide a rare example of a tropical climax community dominated by graminoid species. Species living in such savannas are frequently exposed to excess heat and light, in addition to drought and waterlogging, and must possess traits to avoid or tolerate these stress factors. Here we examine the contrasting heat and light stress adaptations of two dominant savanna ...

The vegetation and microclimate of a stunted ridge-top cloudforest on Mt. Koroturanga (l210m), Taveuni, Fiji (Lat. l7 °S, Long. 180°) is described. Canopy heights decreased from about 30 m at sea level to 10m at 1140m altitude and to 3-7m on the ridge and upper windward slopes . The stunted trees were of low height for their stem diameter, and had abundant epiphytic bryophytes. The upper windwa...

The estimation model was constructed to estimate the evapotranspiration and canopy interception from the forest stand using the parameters showing the forest structure such as stem density, tree height and leaf area index. This model is expected to have the ability to estimate the effect of forest management such as stem thinning and leaf amount control. Comparing the calculated rate by this mo...

In arid and semiarid regions most of the solar radiation penetrates through the canopy and reaches the ground, and hence the turbulent exchange coefficient under canopy Cs becomes important. The use of a constant Cs that is only appropriate for thick canopies is found to be primarily responsible for the excessive warm bias of around 10 K in monthly mean ground temperature over these regions in ...

Hatf ie ld , J. L., Reg ina to , R. J. a n d Idso, S. B., 1984. Eva lua t ion of c a n o p y t e m p e r a t u r e e v a p o t r a n s p i r a t i o n mode l s over var ious crops. Agric. For. Meteorol . , 32: 41-53 . C a n o p y t e m p e r a t u r e s , w h e n m e a s u r e d r emo te ly , o f fe r a m e t h o d of e s t ima t ing evapo t r a n s p i r a t i o n wi th surface energy ba lance...

Recent global-scale analyses indicate that climate variability affects net carbon storage but regard temperature and precipitation to be the main contributors. Seasonal and interannual variation in light availability may also limit CO(2) uptake. As an experimental test of light limitation by cloud cover during tropical rainy seasons and by the unusually heavy cloud cover associated with La Niña...