74 



P. C. Miller et al. 



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FIGURE 3-2. Seasonal courses in 1971 of incoming solar irradiance, 

 300 to 3000 nm (B) and the ratio of simulated net photosynthesis to 

 incoming irradiance (A), the ratio of net photosynthesis to intercepted 

 irradiance (A '), and the ratio of intercepted to incoming irradiance (C). 

 Photosynthesis was calculated in terms of energy units, and the ratios 

 are dimensionless. 



ited strongly by the availability of photosynthetic tissue and intercep- 

 tion and absorption of solar radiation throughout most of the season 

 (Figure 3-2). Carboxylation data (Chapter 4) suggested a maximum 

 photosynthetic capability around mid-July, which, combined with a 

 maximum live foliage area index around the first day of August, should 

 have given peak community photosynthesis around or preceding the 

 first day of August. This trend was predicted by the simulations. 



VERTICAL DISTRIBUTION OF BIOMASS 

 AND CANOPY STRUCTURE 



The canopy structure affects the microclimate and soil temperature 

 by intercepting and emitting radiation and decreasing the vertical trans- 



