4 Georgia State College of Agriculture. 



the intolerant class. As a rule representatives of the tolerant class 

 are to be found on northern slopes, in coves of the mountains and 

 in the shade of other trees. Intolerant trees, on the other hand, 

 occupy southern and western slopes, the tops of hills and ridges, 

 and old fields. They quickly die if they become over-topped. 

 Between the extremes of tolerance is a class known as "moderately" 

 tolerant. Thus chestnut often occurs in the shade of poplar and 

 oak, but never in the shade of hemlock. 



Table of Tolerance. 



Tolerant Moderately tolerant Intolerant 



Dogwood Loblolly Pine Cypress 



Hemlock White Pine Shortleaf Pine 



Maple Chestnut Yellow Poplar 



White Cedar Red Oak (shade when Sassafras 



Black Gum young only) Hickory 



Beech Black Walnut Black Locust 



Basswood (Linden) Sycamore Longleaf Pine 



Trees which grow naturally in the shade of the forest usually 

 die when transplanted to the open, while trees grown in the open 

 never survive transplanting to the dense forest. If planting is to 

 be done in the forest, part of the old trees must be removed. 



Moisture. Water constitutes a raw product in the manufacture 

 of food, acts as a medium for the transportation of soil salts and, 

 through transpiration from the leaves, tends to equalize extremes 

 of temperature. Only a small portion of the total amount of water 

 absorbed by the roots is utilized in the manufacture of food, the 

 greater portion being transpired through the small openings (stom- 

 ata) in the leaves. A small amount of water is transpired through 

 the bark, but the amount is practically constant for winter and 

 summer. On the other hand the loss through the leaves is greatest 

 in summer during the period of growth, and very low in winter 

 after the leaves have fallen. During hot, dry weather a large 

 deciduous (hardwood) tree may transpire several barrels of water 

 per day. In winter, after the leaves have fallen, the same tree may 

 not transpire more than a quart or two. Where the ground freezes 

 solid in winter small trees often die because the roots cannot absorb 

 enough water from the soil to balance the amount transpired. This 

 is known as "winter-killing." 



The amount of water present in the soil is an important factor 

 in the distribution of trees, certain trees demanding considerable 

 water while others are able to survive on little. Too much water, 

 however, has much the same effect as too little, since a soil filled 

 with water (saturated) has no room for air which is also necessary 

 to the roots. If the level of ground water comes near the surface, 

 none but a few of the shallow-rooted trees will thrive, for the tap- 

 rooted trees demand a deep soil and a level of ground water at 

 considerable depth. Few trees will thrive in a swamp where the 

 surface of the ground is under water. If the surface water be 



