408 THE THREE GREAT SYSTEMS OF REGENERATIOST COMPARED. 



Artijieial Segeneration. Natural Begeneration by Regeneration by Coppice. 



Seed. 



suppression 

 difficult. 



of 



weeds which clear fellings ara 

 made. 



19, The warm, open, 

 loosened soil and the con- 

 centration in one place of 

 an enormous quantity of 

 food in the shape of plants 

 of more or less the same spe- 

 cies and condition of growth, 

 favour the multiplication 

 of destructive insects. 



The multiplication of des- 

 tructive insects kept down 

 by the very opposite con- 

 ditions to those which 

 exist in an artificially-raised 

 crop. 



In respect of ravages by 

 insects stands midway be- 

 tween the two seed sys- 

 tems — a loosened soil is 

 wanting except when the 

 trees are cut inside the 

 ground, and the leaf-canopy 

 is rapidly reformed. 



20. Can be undertaken, Can do with still less Impossible unless a con- 

 as sowings or year-old plant- illumination than ai-tificial siderable amount of direct 

 ing, under more or less regeneration, since the re- sunlight reaches the 

 complete cover. quirements of the slow- ground, 



growing selfsown seedlings 



are obviously comparatively 



insignificant. 



21. Owing to its rapid 

 development, the forest 

 reaches eariy a, stage of 

 growth at which the equa- 

 fity of height of the trees 

 prevents the removal of 

 certain from among them 

 for the expansion of the 

 rest, without opening out 

 the leaf-canopy too much 

 and' leading to the dete- 

 rioration of the soil. At 

 this stage, the crop, not 

 being fit to be thinned, al- 

 though unable to grow 

 without being thinned out, 

 must be felled.. Hence com- 

 paratively short rotations. 



22. The plants being all 

 of one and the same age 

 and, therefore, of nearly 

 the same stature and 

 vigour, and necessarily 

 standing apart from one 

 another, the individual 

 trees are unable to draw 

 one another up to the full 

 heights attainable by their 

 respective species, and the 

 boles remain short and 

 become knotty from 

 epicorms, and often also 

 misshapen. In addition to 

 this, the shortness of the 

 rotations prevents the at- 

 tainment of any consider- 

 able girth. Thus artificial 

 regeneration gives timber of 

 only moderate dimensions 

 and quality, and a larger 

 proportion of fuel than na- 

 tural regeneration by seed. 



The unequal growth of 

 the individual trees per- 

 mits of the maintenance of 

 a much larger number of 

 stems than m an artificial- 

 ly-raised crop of the same 

 age, so that the forward 

 trees can be constantly 

 given more growing room 

 until they have nearly at- 

 tained their largest dimen- 

 sions while still remaining 

 sound, and this without 

 over opening out the leaf- 

 canopy to any dangerous 

 extent. Hence possibility 

 of very long rotations. 



Requires by very much 

 the shortest rotation of the 

 three systems, owing, to 

 the limited age up to which 

 trees can generally coppice, 

 to theimmediate appearance 

 of a new generation, to the 

 great early rapidity of 

 growth, and to the usually 

 increasing unsoundness of 

 the stems. 



The plants come up 

 close together and grow up 

 some faster than others, 

 thereby constantly pushing 

 one another up, until the 

 more forward ones have 

 reached the maximum 

 height attainable by their 

 species. They thus furnish 

 long, straight, clean-fibred, 

 more or less cylindrical 

 timber, which the long 

 rotations permit to acquire 

 the largest girth possible 

 under the prevailing con- 

 ditions of soil and cUmate. 

 Hence if we wish to obtain 

 the most considerable quan- 

 tity of the best and largest 

 timber, we will adopt 

 natural regeneration by 

 seed. And in respect of 

 an classes of wood general- 

 ly, the very long rotations 



The vei7, short rotations 

 necessearily prevent the 

 production of more than a 

 very moderate quantity of 

 timber. This timber is 

 furnished by the stores, 

 which, towering above the 

 undergJ:owth^ enjoy an 

 isolated, existence from 

 the close of the very 

 first rotation, and it is 

 therefore tougher, harder, 

 stronger, and more durable 

 than timber otherwise 

 gi-own. But as stores 

 generally begin to decay 

 early at the base, they are 

 usually felled before they 

 can attain the largest 

 dimensions attainable by 

 their species. Moreover, 

 the isolation in which they 

 develop, dwai-fs them and 

 renders their boles even 



