408 PRACTICAL BOTANY 



of thousands in some of what were once the most fertile parts 

 of southern Europe have been ruined in this way. Such de- 

 struction may be prevented by retaining hillsides in a wooded 

 condition, or at least leaving belts of trees at intervals, run- 

 ning at right angles to the lines of slope. The early stages of 

 erosion may be cheeked by damming the principal gullies with 

 logs, stones, and brushwood, and then replanting with suit- 

 able trees and bushes. Contour plowing, — that is, plowing 

 around the hill instead of up and down it, — • terracing, ditch- 

 ing at right angles to the lines of slope, and underdraining 

 all help to prevent erosion. 



376. 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.! In this place there is room only to name 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, so that large gangs of men must be taken into 

 the woods and the cutting all done within a limited season. 

 As far as possible tlie felling must be so managed that promis- 

 ing 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 m from twenty 

 to forty years. 



(3) During the period of most active growth all wood- 

 lands should be kept covered with a reasonably close stand, 

 so as to secure self-pruning and not encourage the growth of 



' For elementary principles, see Roth, First Book of Forestry. Ginn 

 and Company, Boston. 



