88 Practical Forestry 



Abatement Society that Westminster Abbey had suffered 

 from more rapid decay in the last hundred years than 

 in all the previous centuries of its existence. The chief 

 cause of the destruction of the stonework has been shown 

 to be the presence in the air of sulphur acids : the stone is 

 converted into sulphate of lime ; in the process of its forma- 

 tion this disintegrates the stone by expansion. The con- 

 nexion between smoke and stone decay appears to lie in the 

 action of invisible gases emitted from the smoke particles. 



If stonework suffers so at the hands of smoke and sul- 

 phuric and other acids, what, it may be asked, must the 

 effect be on the foliage of trees and shrubs particularly such 

 as are planted in the most smoke-infested parts of our great 

 towns and cities ? When compared with Continental 

 cities Paris, Brussels or Berlin where tree culture is 

 carried out most successfully, the atmosphere of British 

 towns is impregnated to a far greater extent with noxious 

 fumes. Dry low-lying and confined areas, particularly 

 where excessive heat and atmospheric impurities are 

 present, are decidedly the worst, while open and high- 

 lying districts, though in the centre of a town, offer 

 fewer difficulties. 



That certain trees and shrubs succeed best in particular 

 towns is a well known fact, and the smoke-proof London 

 Plane is by no means the best tree for some of the colliery 

 districts ; in Sheffield, for instance, its place is largely taken 

 by the Canadian Poplar. In Manchester, the Lime would 

 appear to thrive best, after which the Elder, Thorn and 

 Plane succeed in the order named. The variegated-leaved 

 Sycamore and the horse chestnut are favourites where the 

 smoke from collieries is most offensive. But many such 

 cases could be pointed out, and even in the case of bedding 

 plants certain species succeed best in particular localities. 

 In the gardens about the Royal Mint, where they are 

 exposed to the deleterious fumes from gold-refining works, 

 Fuchsias do remarkably well ; indeed, the dwarf edging 

 variety, Golden Treasure, thrives so well that advantage 

 has been taken of the fact to propagate some of the stock 

 that is annually required for one of the London parks 



