NOTES AND QUERIES. 8 1 



is to make the crop pure, but in South Germany, beech and 

 silver fir may occur in mixture with it. The continental forester 

 rightly values beech as a constituent of his forests. It was 

 something of a shock, therefore, when Wiirtemberg experiments 

 showed that in a 22-year-old wood of spruce (83 %) and 

 beech (17 %), the volume production was reduced considerably 

 below that of the pure crop. 



There is an interesting note on clear cutting and the removal 

 of litter. In this, stress is laid on the results of the Swiss 

 Experimental Station which showed that the air capacity of a forest 

 soil is reduced by two-thirds on clear-cut areas. The air spaces 

 and porosity of a forest soil are of extreme importance. When 

 it is changed none of the ordinary methods of cultivation will 

 improve it again. It is to the destruction of the porosity that 

 the writer seems to refer the almost universal root-rot of spruce 

 on old ploughed land. 



The writer also comments on the evil influence of forest 

 finance on forest practice. Conifers replaced hardwoods on 

 account of their earlier sale value. As the writer says, " It was 

 such fun to figure, in the mathematical formulae, on the 

 recurrence of thinnings and of final yields at fixed intervals." 

 But after all, the whole thing is based on false premises — 

 Normal Yield Tables as applied to a single area. Although 

 the classification may be correct at the moment, time will 

 change it and make it either lower or higher. The cry is now 

 " Back to Nature," and the German forester is learning from 

 his failures to avoid clear cutting, to mix species, to adopt 

 long rotations, and not to attempt to raise a species much 

 outside its natural habitat. 



Certain experiments made at Tharandt will interest foresters 

 in this country, where various ideas are held as to the im- 

 portance of clearing away the debris of cleanings and thinnings. 

 This material is liable to favour the spread of fires, and it also 

 acts as a good place of shelter for rabbits. It is, however, a very 

 valuable mulch, preventing the rapid loss of water and the 

 undue heating of the soil in summer. It also provides a certain 

 amount of humus. At Tharandt, in the comparison of two 

 pine plots, one with and the other without litter, the former 

 showed in the second year an increase of height-growth of 

 3 inches as compared with the latter. In addition the needles 

 were longer and of a much more healthy colour. 



