SMOKE AND TREES. 87 



this class of plants, good specimens of which are scarcely to be 

 found in this neighbourhood. I have already said that coniferous 

 plants, and particularly Scots Firs, are the worst sufferers of all. 

 But, before adding a little about their appearance, I would remark 

 that, at no very remote time, the residents in this city who like to 

 see a good Scots Fir tree will have to travel some distance to 

 gratify their desire. Those near at hand, old and young alike, are 

 without exception more or less seriously affected, their state of 

 health being far from satisfactory. Their leaves fall off a year 

 or more too soon, it being quite common to see them, at the 

 beginning of the growing season, with nothing but the previous 

 year's leaves adorning them, instead of two years complete and the 

 greater portion of a third, thus detracting very much from their 

 appearance, giving them a thin, tufted, stunted and unhealthy look. 



On approaching the city from any side, particularly from the 

 east or north-east, the general effect of smoke is in evidence, I 

 think I may say, on all trees, some certainly being affected more 

 than others, and any one of an observant nature, who travels to 

 and from the city for a number of years, cannot fail to recognise 

 the fact that the effect of smoke is of a cumulative nature as 

 regards the health of the trees. If once a tree is noticed to be 

 decidedly suffering from that cause it is doomed, its death being 

 only a matter of time, it may be long or short, according to the 

 species or variety and its suitability to the soil on which it is 

 growing. The first sign is the early fall of the leaves, then the 

 crown gets thinner, and the annual growth less, until it is 

 practically at a standstill, and gradually the tree dies a premature 

 death. Such symptoms are no doubt mainly due to the first- 

 named cause, viz., the presence of acid in the atmosphere — the 

 other causes Lending their assistance, but certainly to a less degree. 

 On going further afield, the injurious influences gradually become 

 less discernible, and it takes a much longer time before there is 

 any serious results, unless with very susceptible trees. 



From what has been said, I am sure anyone will assume that 

 the annual growth of trees is greatly reduced in smoky atmospheres, 

 particularly those in the immediate vicinity of the city, but it is 

 also quite noticeable a considerable way out, where the traces of 

 injury through acid are scarcely to be found. On Pollok Estate 

 I have watched this deficiency in growth, with no little interest, 



