TREES AND SHRUBS FOR LARGE TOWNS. 



78 



and replaced by good loam, with which sand or road-scrapings 

 may be incorporated in quantity proportionate to the density of 

 the loam. A small quantity of leaf-mould may also be added, 

 but, as a rule, the most experienced planters deprecate the 

 employment of manure, at least in the first instance. Discon- 

 nected pits or holes are commonly the only possible means, but 

 in laying out new streets it would be far better, wherever 

 possible, to form a continuous trench, removing the bad soil and 

 supplying its place with good. 



The distance to be secured between tree and tree is dependent 

 upon the size the tree is likely to attain. Generally from^thirty 

 to forty feet is allowed in street planting. The necessity of taking 

 precautions that the roots are not injured by gas leakage is obvious. 

 This may be effected by interposing slabs of slate between the tree 

 and the pipes. The fact that trees will grow if they have a chance 

 is too often overlooked, and we find, as on the Thames Embank- 

 ment, forest trees of large dimensions planted much too closely, 

 as if the ultimate object were to obtain scaffold-poles or ships' 

 masts. There are various ways of obviating or overcoming the 

 evils of overcrowding (which, by the way, is even more frequent 

 in shrubberies), as, for instance, by the Hibernian method of 

 avoiding them altogether, by the selection of low-growing trees 

 and shrubs that if planted sufficiently far apart will never 

 encroach upon and weaken each other ; by timely thinning — a 

 process usually quite neglected in towns ; and lastly, and least 

 scientifically, by periodically pruning and reducing the dimen- 

 sions of the tree. This last is -the plan followed on the Thames 

 Embankment, with the result that the trees are made to re- 

 semble those toy-trees with which we were familiar in our 

 childhood, but which can scarcely be held up as models for 

 imitation except by those who prefer conventional to natural 

 forms. 



In planting in tow T ns the same precautions are required as in 

 ordinary cases elsewhere. The trees should have been previously 

 transplanted in the nursery, so as to secure the formation of a 

 good " ball " of fibrous roots, which will not only facilitate trans- 

 plantation, but also increase the feeding capacity of the tree, and 

 if the soil be good there will be no temptation for the roots to 

 wander in search of food. 



Some practitioners recommend that the trees should be 



