190 



Turning from the consideration of these lamentable results which have been ex- 

 perienced in the countries referred to, we present a paper setting forth the beneficial effects 

 upon the health of the community resulting from the preservation of a due proportion 

 of forest in every extended area. 



FORESTS AND HEALTH. 



A Paper read before the Forestry Congress, Cincinnati, April, 1882, 

 By Dan. Millikin, M.D., Hamilton, O. 



Mr. President : — When I attempt to discourse of the influence of forests on health, 

 I am embarrassed, not alone by the importance of the subject, but by the very magnitude 

 of the claim which 1 feel bound to make for the trees. My thesis is nothing less modest 

 than this. Trees conduce to health, and the more trees the -more health. 



Whence comes our health ? Firstly and chiefly it is an inheritance from sound 

 ancestors, next and secondly it comes from personal habits, thirdly it depends on climate, 

 fourthly it depends on the sanitary or insanitary state of one's home. 



It cannot be pretended that trees and forests have much to do with the physical 

 constitutions we have inherited from our ancestors, nor even, directly, with our personal 

 habits. It remains for me, therefore, to say something of the influence of trees upon 

 climate, and upon the sanitary condition of homes. 



The most obvious and beneficial modification of climate by forests is by the arrest of 

 winds. This action, I am sure, is everlooked by city-bred persons, and by many who 

 have led a rural life, but have not had their eyes unsealed. On a bleak and windy day 

 the beasts of the field may be found standing on the lee side of whatever trees are in their 

 range, and a little investigation in such humble company will show that even a single 

 tree standing in the cutting blast has an invisible wake of calm stretching away to a con- 

 siderable distance. A thiji over-grown hedge, through which one might almost walk, 

 will produce something like a calm in its neighbourhood, and an ordinary forest of decid- 

 uous trees absolutely arrests the wind near the earth. I bring up this topic first of all, 

 not to discuss the subject of wind-breaks, for that subject will be well discussed in this 

 Congress, but to remind you that a windy climate is, in general, a bad climate ; that wind 

 interferes with health as well as comfort ; that it pinches hearty persons, and is ruinous 

 to invalids ; that it interferes with good ventilation, and with the moderate uniform 

 warmth which should prevail in our houses. A windy climate is a climate of shivers, 

 and snufiles, and colds, and consumption. Therefore I say that the more trees the less 

 wind, and the more trees the more health. 



A less simple and obvious proposition is made when we say that forests modify 

 climate in the matter of temperature. We must confess in the beginning that the mean 

 annual average temperature of a wooded region will be about the same as if it were 

 stripped bare of trees. But mean annual averages have very little to do with health. 

 What concerns the physician and sanitarian most is the extent and the rapidity of the 

 oscillations of temperature, and in this matter, as in all things, the forest is conservative. 



For it has been positively ascertained that every tree has a certain body -heat, bred 

 by the chemical and vital processes which take place within its rind. This heat is greater 

 when vital processes are most active, but it is appreciable by the infallible thermometer 

 even when tree-life seems to be dormant in winter. For this reason alone — because each 

 tree is an actual generator of heat — the forest warms the air that sighs and whispers 

 through its branches. We have just noted the fact that comparative calm prevails in the 

 forest, and are hence prepared for a statement that when a cold storm descends upon a 

 region, the forest acts as a reservoir of warm air, which is slowly displaced and is given 

 up to mitigate the chill. Nor may we forget the stores of water which the forest holds 

 in its spongy soil, nor that this water has, of all things in nature, the highest capacity for 

 heat, and, once warmed, can give back more heat than an equal weight of any other sub- 

 stance. Bearing all this in mind, we say that in winter every breath from the woods is 

 warmed and tempered by the hoarded heat of summer. 



