366 FUTAIE, OR FULL-GEOWTH SYSTEM. 



der of the original forest is felled, and tlie wood now consists 

 wholly of young and vigorous trees. This result is obtained 

 after about twenty years. At convenient periods, the unhealthy 

 stocks and those injured by wind or other accidents are removed, 

 and in some instances the growth of the remainder is promoted 

 by irrigation or by fertilizing applications.* When the forest 



* The grounds wliich it is most important to clothe with wood as a conser- 

 vative influence, and which also can best be spared from agricultural use, 

 are steep hillsides. But the performance of all the offices of the forester to 

 the tree — seeding, planting, thinning, trimming, and finally felling and remov- 

 ing for consumption — is more laborious upon a rapid declivity than on a level 

 soil, and at the same time it is difficult to apply irrigation or manures to trees 

 so situated. Experience has shown that there is great advantage in terracing 

 the face of a hill before planting it, both as preventing the wash of the earth 

 by checking the flow of water down its slope, and as presenting a surface 

 favorable for irrigation, as well as for manuring and cultivating the trees. 

 But even without so expensive a process, very important results have been 

 obtained by simply ditching declivities. "In order to hasten the growth of 

 wood on the flanks of a mountain, Mr. Eugene Chevandier divided the slope 

 into zones forty or fifty feet wide, by horizontal ditches closed at both ends, 

 and thereby obtained, from firs of different ages, shoots double the dimensions 

 of those which grew on a dry soil of the same character, where the water was 

 allowed to run off without obstruction." — Dumont, Des Travaux Publics, etc., 

 pp. 94^96. 



The ditches were about two feet and a half deep, and three feet and a half 

 wide, and they cost about forty francs the hectare, or three dollars the acre. 

 This extraordinary growth was produced wholly by the retention of the rain- 

 water in the ditches, whence it filtered through the whole soil and supplied 

 moisture to the roots of the trees. It may be doubted whether in a climate 

 cold enough to freeze the entire contents of the ditches in winter, it would not 

 be expedient to draw off the water in the autumn, as the presence of so large 

 a quantity of ice in the soil might prove injurious to trees too young and 

 small to shelter the ground effectually against frost. 



Chevandier computes that, if the annual growth of the pine in the marshy 

 and too humid soil of the Vosges be represented by one, it vdll equal two in 

 ordinary dry ground, four or five on slopes so ditched or graded as to retain 

 the water flowing upon them from roads or steep declivities, and six where 

 the earth is kept sufficiently moist by infiltration from running brooks. — 

 Comptes Bendus d I' Academic des Sciences, t. xix., Juillet, Dec, 1844, p. 167. 



The effect of accidental irrigation is well shown in the growth of the trees 

 planted along the canals of irrigation which traverse the fields in many parte 

 of Italy. They flourish most luxuriantly, in spite of continual lopping, and 

 yield a very important contribution to the stock of fuel for domestic use ; 

 while trees, situated so far from canals as to be out of the reach of infiltration 

 from them, are of much slower growth, under circumstances otherwise equally 

 favorable. 



In other experiments of Chevandier, under better conditions, the yield ol 



