ROOT DISEASE IN SCOTS PINE ON FARM LANDS. I45 



existing farm lands, on afforested fields under pine crops of , 

 various ages, and on the adjoining forest lands. The physical 

 analyses were always made on the spot, which naturally is the 

 only way of obtaining reliable results. The chemical analyses 

 of the various soils showed in no instance sufficiently pronounced 

 differences to account for any marked changes in the growth of 

 the crop, for although a gradual decrease was observed in the 

 percentage of humus and nitrogen in the surface-soil of farm 

 lands, which had been for some time under Scots pine, this was 

 nowhere considerable enough to produce any marked decrease 

 in the rate of growth, and certainly could not cause its entire 

 cessation. A remarkable and constant diff'erence was, how- 

 ever, found to exist between the physical condition of forest 

 soils and of farm-land soils. The porosity of the latter was 

 invariably much less than that of the soils in adjacent forest 

 tracts, and this diff'erence increased in most cases down to 

 a depth of 12 to 18 inches and more. In many instances 

 the porosity of farm lands fell below 40 per cent. Dr 

 Albert's researches proved that no improvement had taken 

 place in these conditions, or at least the very slightest only, 

 on areas under a pure Scots pine crop, but that, where 

 Acacia had been planted in destroyed portions of the original 

 pine afforestation, the forest soil conditions were produced in an 

 incredibly short space of time. It was found that the same 

 physical conditions had established themselves on farm-land 

 areas which had been afforested 65 years ago with a mixture of 

 Scots pine, beech, and birch. No root disease ever took place 

 in these crops, though they were surrounded by especially 

 severely attacked afforestations of pure Scots pine. Even an 

 inter-mixture with equi-aged oak was found to have protected 

 the pine from root disease, and to have restored the forest soil 

 condition to a considerable extent. 



As soon as Dr Albert had established the existence of a constant 

 difference between farm-land soil and forest soil, he assumed 

 that if the disease was due to this fact, then all trees growing on 

 farm lands should show at least primary symptoms of the disease. 

 This proved to be the case. As Dr Albert began his detailed 

 studies of roots only after he had finally established the existence 

 of an unvarying difference in the physical condition of the soils, his 

 observations in this respect are not spread over as many localities, 

 but they are nevertheless very instructive and convincing. 



