SOIL CONDITIONS. 23 



region, but that will support some form of tree growth. The 

 soil best adapted to all kinds of trees is one that is moderately 

 but evenly moist, porous, deep and well drained; yet with a 

 subsoil compact enough to transmit the subsoil water from 

 below upwards without its being so solid that it cannot be easily 

 penetrated by the roots. It does not matter about its being 

 stony if it has these qualities. On land that is -very wet in 

 this section, as the muskegs of northern Minnesota, which are 

 covered with Tamarack and Spruce, the trees never get to be 

 of large size. In the case of one Spruce grown on such land, 73 

 years was occupied in growing a tree i l /% inches in diameter, 

 and a Tamarack under similar conditions formed a diameter of 

 only i i-io 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 

 instance, land on which Black Walnut, Hard Maple, Hackberry 

 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 gen- 

 erally 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 I,and in Forests. The agri- 

 culturist aims to keep the soil porous, yet moderately compact, 

 that the roots may penetrate it easily and the subsoil waters 

 may be readily transmitted upwards to the roots of plants. He 

 aims to prevent 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 



