LIMITS TO USE OF LITTER. 783 



glades, roads, ditches, etc. ; it should be removed from areas 

 used for tree-growth, but which are covered deeply with dead 

 leaves, depressions, or freshly-sown compartments. All weed- 

 litter may and should be removed, wherever it is a hindrance 

 to natural regeneration, or to the development of forest plants ; 

 also litter containing numerous larvaB or pupae of destructive 

 insects. Woods growing in localities, where the climate is 

 cool and moist, and where the rainfall is heavy are chosen in 

 preference to dry localities for the removal of litter. 



2. Soil. 



Soil that is mineralogically rich can withstand the removal 

 of litter better than poor silicious soil ; on poor soils the effect 

 of this removal is felt soonest and most severely. 



Schwappach states that in spruce woods of the best quality, 

 the annual removal of litter even for long periods has no bad 

 effects. Laspeyres found that the use of litter on good soils 

 is indifferent ; that in years of drought litter may be taken 

 from inferior soils. Bleuel* showed that annual removal of 

 litter during periods of 23 to 30 years caused a falling off of 

 increment in old beech woods, on inferior soil, of 32, 39, 42 

 and even 56 per cent., while on good basalt soil (Khone) the 

 loss was only 8 per cent. Under similar conditions, the loss 

 of increment in Scots pine woods of good quality was 7*5, 9*3 

 and 10'9. Kemoval of litter every three years in the Spessart 

 from beech woods caused a loss of increment of 13 per cent., 

 every six years, of 10 per cent. These observations showed 

 further, that the loss of increment increased steadily from 

 period to period. 



The condition of the subsoil is also important ; if it is of 

 boulders, gravel, or of rock full of cracks, and also the ground is 

 sloping, the water descends to such a depth, as to be useless 

 for the forest. The ill effects of the removal of litter from 

 soils full of springs or from deep soils are felt less ; its bad 

 effects are nowhere greater than on shallow soil, with a subsoil 

 of gravel, etc. 



* Bleuel, " tiber den Einfluss der Streunutzungauf die Massenproduction des 

 Holzee." 



