THE IMPORTANCE OF SHKLTEU. 3'Jl 



Bat, importiint ;is llie liic(s already eliicidiiiod would seem to \k\ we shall 

 find inseparal)]y associated with Ihein, yet another fact scarcely less importani, 

 altiiough comparatively overlooked, doubtless because less amenable to merely 

 casual observation. 1 allude to the increased loss of heat, from the soil with 

 open exposure and free and rapid evaporation of moisture. 



It is well understood that in clear evenings the radiation of heat into space 

 yery rapidly reduces the temperature of the surface of the earth, but that the 

 intervention of clouds at once checks, and indeed, nearly arrests this radiation. 

 Well known as is this fact, it may not have occurred to all that the umbrngeous 

 covering of a forest may prove almost as eifective as a mantle of vapor, while 

 its influence can be had, even when the former shall fail of an appearanc(>. 



Our school-boy lessons have also taught us thai in the process of the evapora- 

 tion of a given amount of water from the surface of the earth it absorbs and 

 renders latent about tive and one-half times as much heat as would sullice to 

 raise that amount of water from the freezing to the boiling point, and it cannot 

 be assumed that such heat is returned to the surface with the return of this 

 moisture in the form of rain, for the reason that it is released from its imprison- 

 ment, in the atmosphere, in the process of the conversion of vapor into rain- 

 drops. 



From the facts above stated, the unavoidable inference would seem to be that 

 every acre of timber, whether spared or replanted, acts as a 



STORE HOUSE 



of reserved moisture and warmth, going to increase the fertility and general 

 temperature of the immediate locality, and acting as a check u[)onthe liability 

 to sudden frosts by contributing to the maintenance of a more perfect equilib- 

 rium of temperature. The cases in which moisture is already in excess, call 

 for the application of a distinct set of ideas, and, of course, are not to bo sub- 

 jected to the above course of reasoning. 



Thus far we have considered this sul)ject in a more or less general aspect; 

 although with reference to an ultimate application to the case of our own 

 State. 



There are believed to be few persons who now suppose that the great lakes 

 yield any very considerable share of the moisture which supplies the rainfalls of 

 this State, and, if there ever existed a plausible reason for such a siii'])ositiou, 

 the facts gathered up and systematized within the last few years under the 

 auspices of tiie Signal Bureau at Washington would seem ]iretty effectually to 

 set the subject before us in a new light. The tacts seem to be that these bodies 

 of water d.o not essentially, aifect the rainfall of the adjaciMit regions, while 

 they do operate as a means of equalizing temperatures, by storing up in their 

 depths the surplus heat of the warm season, and slowly imparting it to the 

 colder winds of winter as they pass over its surface. That wc enjoy tbe lienefits 

 of sueh equalization, instead of our sister State, Wisconsin, is due to the, to us, 

 Tery important fact that the prevailing winds are in our favor. It matters 

 Tery little to us, however, from what source our rainfalls may chance to be 

 derived, as our proximate interest consists in being able to assure to ourselves, 

 as it passes, such a share of it as shall prove adeciuate to our wants. If there 

 be real truth in the theory of the influence of timber growths upon the precip- 

 itation of rain as applied to Michigan, or even in that of its effects, upon tho 

 retention of heat and moisture, as heretofore stated, then it behooves us to 

 stay the ax, and substitute for it the spade of the planter in our older settled 



