SOIL CONDITIONS. 17 



be of large size. In the case of one Spruce grown on such 

 land, 73 years was occupied in growing- a tree H inches in 

 diameter and a Tamarack under similar conditions formed a 

 diameter of only 1 1-10 inches in 48 years. We also find that 

 growth is extremely slow on very dry land. On very open 

 porous land the water sinks quickly out of reach of the roots 

 and where the soil is too compact it cannot be penetrated by 

 the water or by the roots so that on such soils trees generally 

 suffer for moisture a part of the year. 



Relation Between Trees and Soils. The growth of trees and the 

 kinds growing on land are good though not infallible indexes 

 to the value of the soil for agricultural purposes. For in- 

 stance, land on which Black Walnut, Hard Maple, Haekberry 

 or Hickory grow to large size is of good quality for grasses, 

 grains and other agricultural crops while Black Oak is gener- 

 ally abundant on dry, gravelly ridges and sandy soil. Where 

 White Pine in this section is the prevailing tree the land is 

 generally of good quality. Norway Pine will endure more 

 drouth than the White Pine, outgrows it, and becomes the 

 prevailing tree on drier land, while the Jack Pine is the most 

 abundant on the very dry sandy lands of Northern Minnesota. 

 In the more humid climate of the eastern states the White 

 Pine grows on very sandy soils. 



Mechanical Condition of Land in Forests. The agriculturist aims 

 to keep the soil porous yet moderately compact that the roots 

 may penetrate it easily and the sub-soil waters may be readily 

 transmitted upwards to the roots of plants. He aims to pre- 

 vent the soil from becoming too compact and from the loss of 

 water from evaporation by cultivating the surface soil and to 

 keep out standing water by drainage. The forest grower can- 

 not rely upon such methods because they are too expensive or 

 entirely impracticable. He may indeed plow for his first 

 planting and cultivate the young trees but after a few years 

 cultivation will become impossible and the effects of the first 

 preparation will be lost. He must therefore attain his object 

 in another way, that is. by mulching the soil. The shading is 

 done at first by planting very closely so that the ground may 

 be protected as soon as possible from sun and wind. The 

 shade should be maintained well throughout the life of the 



