CONTENTS. 
Xl 
Page 
The food of plants is extracted from the soil. But if 
the plants are returned to the soil, no impoverish¬ 
ment takes place - - - - - 158 
Roots do not excrete - - - - -161 
Sociability of plants a fancy - - - - 165 
Sociability of holly and beech owing to holly bearing 
shade better than other plants - - - 175 
The soil of woods does not become poorer, but richer - 179 
Is there any other cause for this besides protection by 
the roots from aqueous denudation ? - - 179 
Aqueous denudation is universal, and is not confined 
only to the lines of torrents and rivers - - 181 
No necessity for rotation in Nature’s cropping - 207 
PART IV. 
Pruning and thinning - - - - 210 
For beauty we should have every variety of growth - 210 
Trees cannot attain their maximum height by nature, 
— that is, without pruning and thinning - - 210 
The works of God can be improved by man - - 211 
To grow valuable timber, maximum head on maximum 
height of branchless stem - - - - 212 
Rules for pruning for height - - - - 212 
Plantations are, and should be , planted too thick to grow, 
and should be thinned every year - - - 214 
No turnips without hoeing; no trees without thinning - 215 
Never too late to thin - - - - 215 
Cut the worst plants worst placed ; leave the best 
plants best placed - - - - -215 
Pruning does not increase the aggregate quantity of 
wood made by a tree, but, by improving its location , 
increases the measurable timber - - - 217 
Example ------ 218 
That a branchless stem is a natural attribute of a tree 
is a mistake of De Candolle’s - - - 221 
