The selection of the proper shrubs for a park and their distribution is a matter that requires the advice of an expert gardener. The following list of ordinary shrubs that will thrive well almost anywhere in this country may however be of use for reference: Aucubas. Azaleas. Box. Berberises. Euonymus. Hollies. Ivies. Laurels. Lilacs. Mahorrias. Pampas grass. Privet. Rhododendrons. Thorns. Yuccas. With regard to the selection of trees, this also requires skilled advice, but a list is given further on in this chapter, of trees suitable for street planting, which may be also some guide in this respect. In high gales of wind the surveyor may be expected to endeavour to save valuable trees in a public park from being blown down. This may sometimes be effected by a judicious application of chains or ropes, but the better plan is to keep all trees well pruned and as free as possible from “top hamper” and undue leverage from overhanging limbs. On the pruning of trees and the removal of large limbs I must refer my readers to a most admirable little book recently published in America, being a translation from the celebrated ‘Treatise on Pruning Forest and Ornamental Trees, by A. des Cars,’ which enters most fully into the subject, and being of great practical value, should be studied by anyone who has anything to do with the care of forest or other trees.[219] With regard to the planting of trees along the sides of streets, our French neighbours are much in advance of us.[220] It is true that in this country, owing to the much larger consumption of coal as a domestic fuel, there is more soot in the air, but it is erroneous to suppose that trees will not thrive well in England. No doubt the moisture of our climate causes the soot or “blacks” to adhere to the leaves and limbs of the trees, but for that reason deciduous and not evergreen trees should be selected for planting in towns, and these, if well chosen and carefully planted, will most undoubtedly fully repay their first cost and maintenance by the additional beauty to the street, the agreeable shade they cast, and their generally healthful action on the population. In selecting trees to plant along the sides of the streets or roads in any towns, it is well to bear in mind that the following qualities are necessary:-- The tree must be hardy; it must not be affected by a long-continued drought; heat must not wither it nor make it look rusty; it must be able to withstand dust, smoke, soot, foul air, and the insidious attacks of insects, and be able to recover from any malicious or accidental injury it may receive. The tree must be of rapid growth, and develope a straight, clean stem with shady foliage. It must be graceful either in full leaf or when bare as in winter; its roots must not require too much room, and they must be able to withstand the effects of pollution or rough treatment.