of Kensington Gardens. 151 



allowed to remain, having no longer the shelter of those taken 

 away, will require to have their tops lightened by severe pruning. 

 13. The thinning of these masses will also be required, in order 

 to make room for the pits to contain the new trees which it is 

 intended to introduce to a certain extent in the masses, no less 

 than where the old trees have been felled or blown down. 



li. In order to encourage the growth of the trees in the 

 masses, and also the growth of all the other trees in the garden, 

 the surface of the ground ought to be top-dressed with a rich 

 compost; beginning at those places where the soil is poorest, 

 and where the trees have most need of assistance. Next to ad- 

 mitting light and air to the existing trees, there are no means 

 whatever that will so effectually add to their strength and beauty 

 as enriching the surface soil : it will add greatly to the strength 

 of the fibrous and slender roots vvhich run along the surface, and, 

 in a few years, will change them into ramose roots, which will 

 have sufficient strength to enable the trees to resist storms, even 

 though the hearts of the trunks, and all the larger roots that are 

 deep in the soil, should be completely rotten. A new coating 

 of wood will be deposited on the outer surface of the trunk, 

 however rotten it may be in the inside, provided the bark be 

 uninjured ; by which means the tree will not only be strengthened 

 and enlarged, but its period of duration greatly prolonged. The 

 vigour thus infused into the trees will enable them, in a great 

 measure, to resist the attacks of insects. The grand causes of the 

 diseases and the death of trees in artificial plantations are, the 

 want of organic nourishment, and the want of water, light, and 

 air. Were these duly supplied for ever, it is difficult to conceive, 

 from the physiology of a tree, how it could die otherwise than 

 by accident. Nourishment is supplied by top-dressing, and light 

 and air by thinning. Water is not so easily supplied; and, for 

 want of this, many trees, after they have attained a certain size 

 above ground, and filled the soil in which they grow with their 

 roots, die, in consequence of the evaporation by the leaves being 

 greater than the absorption of moisture by the roots. It is not 

 easy to supply water to a wood or grove of full-grown trees, 

 otherwise than by intersecting the ground with very deep and 

 wide drains, filling these half full of loose stones, and then 

 connecting the ends of the di'ains with a supply of water. This 

 mode may be considered too expensive for general practice, 

 except in scenes of limited extent; and, therefore, the principal 

 thing is to prepare the soil to the depth of 6 ft. or 8 ft., or even 

 10 ft., before planting the trees ; for, as prepared soil acts like a 

 sponge in retaining the water, so this would add greatly to the 

 size of that sponge, and thus prevent a greater portion of what fell 

 from the atmosphere from sinking into the subsoil, or running- 

 off along the surface ; and, in either case, being lost. 



L 4 



