3Y 



momvealtli and if po8si1)le the extent to wliicli AA^e would lie Justitied iu 

 devoting time and money to secure certain forestry regtilations. 



The soil of a forest is less susceptible to sudden variations in tempera- 

 ture than that of the fields outside, and consequently warms more slowly in 

 summer and its cooling is delayed in the winter. The summer effect is 

 much more marked than the winter effect. The mean annual temperature 

 of the forest soil is about 21 degrees lower than that outside. In the sum- 

 mer this cool soil will temper the air above it, start currents in the direc- 

 tion of adjoining fields and lower their temperature. 



The average annual evaporation within the forest is but fifty per cent, 

 of that in the open, and the difference between the two is greatest in 

 the summer when the saving for the forest is the largest and most needed. 

 About twelve per cent, of the precipitated water is evaporated in the year 

 from forest soil and forty per cent, from open fields, the presence of the 

 forest litter effecting a saving in some cases of seven-eighths of what 

 would otherwise evaporate directly. Much of this difference is due to the 

 looseness of forest soil and its poor capillarity that fails to draw the water 

 to the surface. That the forest serves as a windbreak, in preventing cur- 

 rents of air from rushing over adjoining fields and depriving them of their 

 moisture, is obvious to all. 



The extent to which the forest influences affect the adjoining fields, and 

 the distance to which this may be felt, depends on the nature of the 

 forest, its size, composition, age, exposure, undei'brush. elevation, prox- 

 imity of streams, etc. 



A collection of all of the published records of temperature and rain- 

 fall taken in the State has been studied, but they do not furnish such 

 data as would in any way bear on the problem in hand. The earliest rec- 

 ords were made in 1807 at but two points in the State. The central oflice 

 at Indianapolis was not organized until 1882 and its first publication was 

 iu 1884. In a half dozen places records were kept from 1872 to 1881 and 

 then discontinued. All of these stations were cities or towns and do not 

 afford data for the forests about. Certain it is that statistics to support 

 our claims are not forthcoming in Indiana, but our conditions are not 

 unlike those of other States from which these facts were gathered, and 

 the results are applicable to our own territory. 



The infiuence of the forests on the fertility or productiveness of our 

 land has been discussed from may points of view and it is liardly safe 

 to generalize in a matter so dependent on the controlling influences of local 



