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dinous chimneys of our larger centres of industry is, no doubt,, 

 bad enough ; but when we have to contend with an atmos- 

 phere largely impregnated with the outcome from chemical,, 

 gas, or iron works, the difficulties to be encountered are great 

 indeed. 



Preparation of the Ground and Planting. — In 

 order that success may crown the effort, it may truly be said 

 that no work of the horticulturist requires more skill and 

 good management than the proper planting of trees alongside 

 streets and avenues. 



The material with which roads are usually made up are 

 ill-fitted for sustaining a healthy condition in trees, at least 

 for any great length of time, and this is well known to those 

 who have taken an interest in the matter — broken stones, 

 clinkers and gravel, affording but small support for vegetation, 

 be it of whatever kind, but particularly large-growing trees 

 and shrubs. Many failures in street-planting from this very 

 cause might be pointed out, and in not a few cases the future 

 result will certainly be discreditable to all concerned, simply 

 because the work has not been properly done. 



In crowded streets and squares, where the air is vitiated 

 with impurities, and the soil hard and often surcharged with 

 gaseous matter, tree-planting is often a different matter to 

 what it is along the side of a field. In the latter case it may 

 be sufficient to open a small pit, insert the tree and stake it, 

 but in our large towns the case is totally different, for the 

 soil, hard as iron, and composed mainly of clinkers and 

 shingle, affords but little nourishment to a rapid-growing 

 tree, and one that, moreover, has to do battle above ground 

 with the deleterious effects of an impure atmosphere. 

 Another fruitful cause of failure in street-planting is placing 

 the pavement above the roots, and in too close proximity to 

 the stems. The roots should always be allowed plenty of 

 breathing room, and to effect this a good-sized space should 

 be railed off around each tree, and no pavement laid within 

 it. In so doing a double benefit is conferred, by allowing 

 free access of rain to the roots, and avoiding the accumulation 

 of noxious gases in the ground (as has been proved to be the 

 case when closed pavement has been used) which are 

 inimical to the welfare of the trees. 



In proof of what is said, we may refer to the trees at the 

 Chelsea end of the Thames Enbankment, which have been 



