HE-PLANTING FORESTS IN MOUNTAINS. 187 



that trees may thrive, the quality of the soil, both the 

 mineral and physical, should well be heeded. The mix- 

 ture of the soil and the proportions in which it con- 

 tains the principal component parts of the soil, viz., clay, 

 sand and lime is as every farmer knows very impor- 

 tant. But still more important are the physical con- 

 ditions of the soil. Very favorable conditions are: 

 depth, friability, moisture and the capacity of the soil 

 for absorbing and retaining warmth and gases. If you 

 find besides these qualities a good humus at the surface, 

 you can be sure to raise the most fastidious trees. Elm, 

 maple and ash require the best soil. Less pretentious 

 are : oak, beech and other nut-bearing trees, the bass- 

 wood or linden, fir, etc. Still more readily are satisfied : 

 larch, hemlock, spruce, hornbeam, locust, alder, willow, 

 poplar, aspen, cedar, etc., and the least demands are 

 made by the pines and even by some kinds of the birch 

 and alder. 



If in selecting the kind of trees, attention is given to 

 these hints, we may be pretty safe to successfully grow 

 forest-trees on a proper place in the mountains. But 

 considering the very great difference which often exists 

 in near-by situated mountain localities, we may still 

 be safer in our selection if we raise those kinds which 

 have grown with success before on that spot or its 

 neighborhood. But even this rule does not always hold 

 good, especially where an area for a long time has been 

 denuded of vegetation and become barren owing to the 

 exposure of the winds and the sun. In such case 

 nature often demands a rotation* in the kinds of trees, 



* The doctrine of " rotation " in the culture of forests has been lately 

 very rudely shaken up by theoretical reasons as well as by practical 

 observations. In regard to the former, reference is had to the differ- 

 ence between the growth of grains and that of trees, by which it is 

 claimed that woodlands, through the undisturbed tree-growth, will al- 



