68 FOEESTS, WOODS, AND TEEES 



of these being 18 to 24 feet high in 1912. Oak, ash, 

 beech, sycamore, and elm also did fairly well. This is 

 remarkable, considering the character of the mound, of 

 which only the surface has disintegrated, the material be- 

 neath being caked into hard masses containing considerable 

 quantities of pyrites. In spite of this, the trees have made 

 nearly as good growth on the mound as trees of the same 

 species in ordinary soil in the neighbourhood, according to 

 measurements made by Mr. P. Murray Thomson (5). 



In the colliery districts of Scotland a few attempts have 

 been made to plant the spoil heaps, which are locally known 

 as pit bings (6). When these consist of a mixture of shale 

 and stones, trees grow readily, the best species being prob- 

 ably alder. Successful results have been obtained by Mr. 

 Whitelaw at Gartshore, near Kirkintilloch. Mr. J. Milne 

 Home sends me some notes about recent plantations on pit 

 banks near Dalkeith. On the upper bing on Wester Cowden 

 Incline, which was an old colliery pit bank that had been 

 left untouched for many years, an acre was planted in 1913 

 with 1200 sycamore, 450 birch, 2000 grey alder, and 

 1200 European larch. At present grey alder shows the 

 best growth, while larch has done fairly well, but sycamore 

 has been a failure. In 1 9 1 4 about 2^ acres on the neighbour- 

 ing lower bing were planted with 2300 sycamore, 500 birch, 

 and 4200 grey alder. It will be interesting to watch the 

 further growth of these two plantations. Before the war 

 grey alder was procurable at a cheap rate from French 

 nurseries as one-year and two-year seedlings. It grows 

 with great vigour on most soils, and succeeds in wind- 

 swept localities and in situations liable to late and early 

 frosts. Its wood is equal in value to that of the common 

 alder. 



Mr. H. M. Cadell (7) tells me that about ten years ago 

 he planted up some old colliery bings at Grange, Linlithgow, 

 with Japanese larch, Scots pine, etc. The Japanese larch 

 are now about 15 feet high, but a good many have died. 

 These pit heaps, though forty years old, were not suffi- 

 ciently disintegrated, and the dry undecomposed material 



