A model for simulating photosynthesis in plant communities

In this paper, the amount of photosynthesis accomplished by a canopy of leaves is predicted from the properties of individual leaves. Theories are developed for the penetration of direct and diffuse sunlight through a foliage composed of many layers of leaves, each having known orientation, area, reflection and transmission characteristics. From this, the illumination of each leaf at a particular time of day (sun elevation) and thus its photosynthesis, is determined. Hourly observations are summed for estimates of daily photosynthesis by plant communities. An immense number of calculations are required in such a model, but an IBM 7044-type computer can complete them in about six seconds. Solutions to a number of real and hypothetical problems are presented. These provide new insights into the photosynthetic behavior of plant communities.