328 



FORESTRY INVESTIGATIONS I". S. DEPARTMENT OF AGRICULTURE. 



I'm. 77. Vortical temperature, gradient in woo<ls, dcgruoa FahrnnliiMt. for 100 feet. 



FIG. 78 Vertical temperature gradients from observations above trees. 



EVERGREEN TREES. 



MEAN. MAXIMA. 



FIG. 79. Forest temperature, differences above trees from Fautrat's observations. 



