138 Forestry Quarterly. 



creased light together with protection from the remaining stands 

 on the side, resulting in increased rapidity of growth, while oflFer- 

 ing a much simpler method of getting the amount to be cut each 

 year than the technically difficult method of repeated cuttings in 

 the shelterwood systems, blinded the advocates of clear cutting to 

 the resulting disadvantages of insect damage, deterioration of the 

 soil and of the stand to drouth, frost and wind dangers, and 

 finally, to the important fact that during the period of regenera- 

 tion, the clear cut area was not only unproductive, but usually 

 deteriorating, whereas under shelterwood cuttings the produc- 

 tivity of the old stand was maintained until the new stand became 

 fully established. 



The very wide clear cut strips led to immense destruction of 

 the young stands by the May beetle. In some parts of Prussia, 

 foresters despaired of ever successfully re-establishing pine on the 

 cut-over areas. At this juncture, Danckelmann evolved the 

 scheme of narrowing the strips to not over twice the tree height 

 and alternating them so that the age classes would not be in succes- 

 sive steps but spaced irregularly. In this way, he hoped to com- 

 bat the May beetle which flies diagonally from the tops of stand- 

 ing trees and thus, at the short width of two tree-heights, would 

 fly over the regenerated strip and into the next mature strip 

 where it would be comparatively harmless. This scheme proved 

 successful only in so far as the May beetle danger which is still 

 a very real one has been kept at bay. 



But Danckelmann's narrow strips — as Borggreve points out — 

 had many real disadvantages. The last strips were always most 

 difficult to regenerate, even by planting of sturdy stock, owing to 

 the rapid deterioration of the soil and the choking cover of weeds 

 and other herbaceous growth — notably Vaccinium and Erica. 



Therefore, the tendency of the best practice in Prussia to-day 

 is towards encouraging all hardwoods which occur naturally in 

 mixture — and especially beech, oak, birch, blue beech (Carpinus), 

 aspen, and locust. All of these trees (with the possible exception 

 of birch) have the property of improving the soil aside from the 

 well known silvicultural advantages of mixed stands. Thus pine 

 needles or beech leaves alone do not decompose as readily or as 

 advantageously as do pine needles and beech leaf litter mixed. 



It is true that, temporarily, pure stands of pine are still officially 

 countenanced in Prussia, but this is largely from an economic 



