122 ECONOMICS OF FORESTRY. 



crop, provided the litter is left, and, moreover, that 

 he can grow his crop on soils which are not fit 

 for agriculture. 



This fact, which also refers to soils and situa- 

 tions that are topographically unfit for ploughing, 

 is one of greatest importance to the political econo- 

 mist. For with the increased need of food supplies, 

 the necessity of using the soils to their utmost 

 arises, and the possibility of relegating the non- 

 agricultural soils to forestry use is a welcome aid 

 in the solution of this problem. This relegation 

 of soils to their best use is now actively and con- 

 sciously going on in the densely populated Ger- 

 man states, the economic policy being to exchange 

 worn-out, poor agricultural soil for forest use, and 

 to turn agricultural soil under forest to farm use.^ 



Hence, also, the mountain slopes, the very places 

 where, for the sake of favorable water conditions, 

 a forest cover is needed, are par excellence forest 

 lands; for a slope of 15° makes them unfit for 

 plough land, and one of 20° to 30° excludes them 

 from use as pastures, while forest growth will still 

 maintain itself satisfactorily on slopes of 40° or 

 more. 



We come here to the recognition of a natural 

 subdivision of our soils into absolute forest soils, 

 those which are only fit for forest crops, and rela- 

 tive forest soils, which may come into competition 



^ Prussia has for some years appropriated large sums ($250,000 

 annually) for the purchase and reforestation of poor, worn-out lands. 



