CONTINENTAL NOTES GERMANY. 235 



for the time being by broad-leaved species. In addition to broad- 

 leaved species, the silver fir has so far proved to be free from 

 infection, but on heather lands this tree has not maintained its 

 character as a soil improver. It entirely changes its original 

 root-system in these localities, and instead of the deep-growing 

 roots which it developes in its natural habitat, and which so 

 materially aid the circulation of air by loosening the soil, it only 

 grows far-stretching surface roots. The Douglas fir also is 

 believed to be unaffected by the root-rot, for as yet no trace of 

 the disease has been found where the tree has been cultivated 

 on waste lands ; however, the tree is not as yet very plentiful 

 in the heather tracts, and the oldest specimens, though they look 

 strong and healthy and show a magnificent development, even 

 on inferior soils, are only lorty-five years old. The Douglas 

 was planted in considerable numbers thirty years ago by the late 

 Mr John Booth (a gentleman who acquired a reputation as a 

 practical forester in Germany) in the midst of a pest-stricken 

 pine forest. Till now none of these shows any signs of the disease, 

 and they are finely-grown trees. Some foresters hail this 

 tree as the possible saviour of the situation, at least in the 

 Lueneburger Heide, where the precipitation is much greater 

 than farther inland. The Douglas has proved to be a decided 

 soil improver. Its well-developed root-system not only loosens 

 the soil, thereby facilitating air circulation, but seems also to 

 have a pronounced exciting influence on the activity of useful 

 bacteria in the soil. Comparative experiments with soils, in 

 regard to nitrifying bacteria, proved negative in the case of pine 

 soils, but showed nitric acid in the Douglas soils within forty 

 days. The latter soil also produced, under equal conditions, 

 double the quantity of ammonia with a solution of peptone. 

 However, I notice in the discussions on Dr Nisbet's paper on 

 Afforestation in these Islands, read at the last meeting of the Royal 

 Society of Arts, that in Scotland the Douglas fir had, in a good 

 many instances, been attacked by a rather serious fungus disease. 

 A matter of such importance must, under existing circum- 

 stances, be of the greatest interest to our fellow foresters in 

 Germany, and I would be grateful for any information which 

 any of your readers may be able to impart regarding the 

 character of the disease, and especially whether it has occurred on 

 waste-land soils only, or whether it has been observed also on 

 trees growing on true forest soils. 



