Biophysical Processes and Primary Production 101 



the interception of radiation in the canopy, and by convecting this energy 

 warm the canopy air. The increased leaf temperatures increase trans- 

 piration, photosynthesis, biosynthesis and leaf expansion. Even in these 

 wet soils, the species show water stress, indicated by high leaf resistances, 

 and patterns of distribution related to soil water. Increased interception 

 in the canopy causes decreased absorbed energy at the moss and ground 

 surface, producing lower moss temperatures, lower soil temperatures 

 and shallower thaw depth. The latter two effects should reduce growth at 

 the stem base, growth of roots, and the amount of nutrients made 

 available by decomposition. Reduced nutrient uptake and reduced activi- 

 ty at the stem base should reduce leaf growth. This sequence of events 

 should have a stabilizing influence on foliage area index. The low foliage 

 area early in the growing season in the Carex-Oncophorus meadow, 

 relative to an evergreen shrub canopy with the same foliage area at peak 

 season, should increase soil thaw and nutrient availability and partially 

 compensate for the increased energy required to thaw waterlogged soils. 



