46 TRANSACTIONS OF ROYAL SCOTTISH ARBOKICULTURAL SOCIETY. 



down the chalk will hold moisture well (and this is the 

 cause of the success here of the alder) ; it is the compactness 

 of chalky soils which is the difficulty. Where the top soil 

 is thin the rapid drying of the surface is of course an 

 important hostile factor, but, in view of what M. Fliche says, it 

 should not be utterly impracticable to afforest a chalk down with 

 a thin soil, if the surface soil were scraped together in mounds 

 running in contour lines round the hillside and planted with a 

 mixture of beech and Austrian pine. 



VIII. In these Notes last year there was mention of 

 Robif/ia, and now I find that a M. Vadas, a Hungarian, has 

 written about it in his own country. It has been planted there 

 with success since 1807. The author is evidently enthusiastic 

 about it, and lays stress on its rapid growth, excellent wood, 

 moderate demands in regard to soil, its extraordinary power 

 of spreading by suckers and the extension of its roots, which 

 make it so useful in fixing shifting sands ; finally, the great 

 number of uses to which it can be put. His ideal treatment 

 appears to be as a high-forest with only a 50-year rotation, 

 Robi)iia taking the upper stage, with plenty of room for the 

 individual stems, and a shade-bearer as underwood. Although 

 said to be unexacting as to soil, its growth is immensely better 

 on a free soil with a warm climate, such as those required by 

 vineyards and the Spanish chestnut. He gives some figures of 

 growth of woods 32 years old, which are enlightening : — 



Good soil. Medium soil. Poor soil. 



Number of stems . . .616 



Volume in cubic metres . . 242 



Mean height, metres . . 23-3 



Mean diam. at chest height, metres -229 



IX. Weymouth pine is used to afforest marshy places in the 

 Vosges. We find a description of a wood of 8|- acres, said 

 to be by no means the best in the neighbourhood, but just 

 taken as an example. It is 46 years old, rather open, but 

 contains 1276 trees, ranging from 7'8 inches to 23-6 inches 

 diameter, of a volume of over 4000 cubic feet per acre. The 

 value, including about ;£iZ per acre as the estimated present 

 value of the land, is now about ^^96 per acre. Before planting 

 this marshy land was worth about ;^3, 5s. od. per acre, and 

 produced practically nothing. Spruce appears to have beer> 



