TREES PER ACRE 123 



clay soils than is the use of the spike, as the spike com- 

 presses the clay on all sides ; but it must be remembered 

 that the roots start to grow in fine soil put in the hole, and 

 by a later period the compressed clay will have regained its 

 normal pressure owing to the action of earth worms, etc. 



However, on really stiff clays, planting in pits is usually 

 preferable ; and, of course, large trees must also be planted 

 in pits. 



The Number of Trees per Acre. 



This will vary according to the distance apart at which 

 the lines are made, and also according to the disposition of 

 the trees in the lines. 



There are various methods of arranging the disposition 

 of the trees over the area, but more commonly the trees are 

 arranged by "squares" or by "equilateral triangles." In 

 the latter case, each tree is the same distance apart from all 

 its neighbours, but the lines are nearer together than the 

 distance from tree to tree. In the former case, the lines are 

 the same distance apart each way, but the trees are not the 

 same distance apart from all their neighbours. 



The triangle system is a little more difficult to carry out, 

 and it requires relatively a greater number of trees per acre, 

 but close canopy is sooner formed, and natural pruning is 

 much better effected. 



To calculate the number of trees for " square " planting : 

 Divide the number of square feet per acre by the square of 

 the distance apart from tree to tree. 



Thus, for 4 feet planting, 



43' 5 = 2722 trees per acre. 

 4x4 



To calculate the number of trees per acre for "triangle " 

 planting : Divide the number of square feet per acre by the 

 square of the distance apart from tree to tree, and multiply 

 the result by 1-155. 



Thus, for 4 feet planting, 



x " I55 = 3 ' 43 ' 



