FOREST INFLUKNCES. 

 Soil temperature* ( 'ontiuiied. 



Fiu.48. -Eftrrt.s .[' litter un soil temperature (littered surface bare). ( 11' O.) 



5 



-Jl. 



-2 



^5; 



WINTER. 



SPRING. 



SUMMER. 



AUTUMN. 



Depth of 0.8 inch. Depth of 4.C inches Depth of 0.3 inches. 



Via. 49. Difference of soil temperature, under sod, and bare surface (sod bare). Bccquerel's observations. 



1 



-Z' 



- 3 



-4" 



-5 



-6' 



- T 



WINTER. 



SPRING 



SUMMER. 



AUTUMN. 



Fro. 50. Under deciduous trees. 



FlO. 51,^Under evergreen trees. 



MINIMA. 



H. Doc. 181 21 



MAXIMA. 



FIG. 52. Under young forest (Lintzel). 



321 



