TIMBER; FORESTRY 121 
trees and bushes. Contour plowing (that is, plowing around 
the hill instead of up and down it), terracing, ditching at 
right angles to the lines of slope, and underdraining, all help 
to prevent erosion. 
113. Rules for forest management. For a detailed account 
of the mode of keeping up the productiveness of woodlands 
and of handling timber one must go to special treatises on 
forestry.1 In this place there is room to name only a very 
few of the things to which the forester, or manager of timber- 
lands, must attend. 
1. A timber forest, or woodland, consisting in considerable 
part of full-grown trees, should be cut over on a selective 
plan; that is to say, only those trees should be felled which 
are nearly or quite full-grown, or which are too much crowded 
or in some way imperfect or diseased. This kind of selection 
may not be possible in case the location of the forest is rather 
inaccessible, and therefore large gangs of men must be taken 
into the woods and the cutting all done within a limited season. 
As far as possible the felling must be so managed that prom- 
ising young trees are not barked or otherwise injured by the 
falling trunks of the trees which are cut. 
2. In managing coppice woods the trees must be cut as soon 
as they reach a merchantable size — usually in from twenty to 
forty years. 
8. During the period of most active growth all woodlands 
should be kept covered with a reasonably close stand, so as 
to secure self-pruning and to discourage the growth of much- 
branched trees, like those shown in figures 99 and 219, which, 
when cut into lumber. will be very full of knots. 
+. Forest fires must be prevented, especially in woods of 
coniferous trees. No fires for any purpose should ever be 
kindled during dry weather in the heart of such woodlands, 
except in moderately large clearings that are free from brush. 
Cutting up large tracts of forest into smaller portions by 
1 For elementary principles, see Roth, First Book of Forestry. Ginn and 
Company, Boston. 
