INTRODUCTION. 15 
of a few feet or rods in width around the farm; and while 
they afford shelter and protection they will also become 
a source of revenue and profit. It is always best to plant 
the young trees near together at first, and then thin out 
as they grow. These annual thinnings, even where the 
object is to allow the main crop to grow to a large size, 
will more than pay for all the care and cost of the whole. 
