32 TREES OF MASSACHUSETTS. 
The effect will then be less and less,—rapidly diminishing as 
you recede from the sea. On the capes and headlands pro- 
jecting into the Atlantic, along the coast of Massachusetts and 
Maine, and exposed to the terrible northeast winds, the undis- 
turbed original forests, when half a mile wide, have in the 
middle as large trees as are due to their depth of soil. 
It is often very difficult to make trees begin to grow near the 
sea; sometimes it is impossible, without protection. But alow 
wall of loose stones, seaward, is sufficient to protect young trees 
near it until they get a little higher than the wall. The suc- 
cessive rows inland will be better and better protected, and will 
rise each higher than the preceding; until, at the distance of a 
few rods, they may rise to a tolerable height. When a belt of 
trees is once established, in such a situation, it should be kept 
undisturbed as long as it will serve the purpose of protecting 
the trees within, though it may be of no other value. 
A course altogether similar should be taken in planting a 
much exposed hill. By beginning at the bottom and gradually 
planting upwards, the top may at last be clothed; as every belt 
of trees of a few feet in height, will protect a younger one a 
little higher on the hill. | 
‘Wherever trees are planted for use in the arts, it is important 
to give them the most rapid growth possible. Of wood growing 
on the same soil, that which grows most rapidly is strongest. 
That of which the circles of growth are narrowest is also weak- 
est.* This fact is familiarly known to ship-builders, makers 
of lasts and of trenails, and of all those articles which require 
great strength. ‘Ihe reason is obvious. The circles of annual 
growth are separated by zones of loose, porous structure and 
inferior strength. 
The strength of wood is proportioned to its weight. And as 
* Buffon, II., 307. A circle of wood is annually formed on the trunk of a tree, 
between the outer previous circles and the inner bark. The space intervening 
between the annual circles or layers, is loose and porous, and contains very little 
solid substance or strength. The more frequently, therefore, these weak spaces 
succeed each other in a given thickness of wood the less must be the solidity and 
strength of the wood. 
