68 FIRST BOOK OF FORESTRY 



In our northern states, where the oak is more sensitive 

 to shade, it will need to be given a little advantage in order 

 to keep elm, maple, etc., from crowding it. Other sensitive 

 trees, like hickory, chestnut, and walnut, need watching 

 and should be planted before the other kinds get started. 



The age at which the trees should be cut — the rotation — 

 naturally varies for different places; it is longer for cold 

 districts and slow-growing trees than for warm localities 

 and rapid growers, and of course it depends also on the 

 size of trees to be raised. In our temperate region and on 

 better soils most of our hardwoods make good-sized timber 

 in an eighty- or one-hundred-year rotation; on poorer 

 lands — mountain districts such as the Adirondacks and 

 Alleghenies — one hundred and fift}^ to two hundred years 

 are needed. The white pine makes salable material at 

 sixty years, good lumber at one hundred ; the red fir, white 

 cedar, and redwoods of the Pacific will do the same, while 

 spruce and balsam for pulp purposes may l)e managed on 

 a still shorter rotation. 



In carrpng out the method of starting the 3'oung growth 

 under seed trees several things should be kept in mind. 

 The pieces of forest which are taken in hand at au}^ one 

 time should not be too large. Thus, if a man had a forest 

 of a thousand acres, worked on a hundred-year rotation, 

 and wished to have it in such order that a fifth of all his 

 woods were between eighty and a hundred years old, a 

 fifth between sixty and eighty years, etc., then he might 



