Book II. THINNING YOUNG PLANTATIONS. 653 



certain modifications, by taking out every other tree, and so on ; but even if the obtaining of such 

 equal distance were practicable, experience would show that another way should be preferred, of which 

 the eye must be the judge, by taking out such trees as are least thriving, stand nearest another good 

 tree, &c. &c. ; at the same time keeping in view the rule prescribed. By measuring a chain square, or 

 any quantity of land, and counting the trees thereon ; then trying the height of two or three trees in that 

 quarter, and taking one fifth of such for the distance, it would be readily seen how many trees should 

 be contained in the piece measured : or the practice may more simply be regulated by taking the distance 

 of eight or ten trees added together, the average of which should be equal to a fifth of the height of the 

 trees." [Smith's Mechanics, vol. ii. p. 358.) 



4011. In thinning mixed plantations, the removing of the nurses is the first ohject 

 ■which generally claims attention. This, however, should be cautiously performed ; other- 

 wise the intention of nursing might, after all, be thwarted. If the situation be much 

 exposed, it will be prudent to retain more nurses, although the plantation itself be rather 

 crowded, than where the situation is sheltered. In no cases, however, should the nurses 

 be suffered to overtop or whip the plants intended for a timber crop ; and for this reason, 

 in bleak situations, and when perhaps particular nurse plants can hardly be spared, 

 it may be sometimes necessary to prune off the branches from one side entirely. At 

 subsequent thinnings, such pruned or disfigured plants are first to be removed ; and then 

 those which, from their situation, may best be dispensed with. 



4012. At ivhat period of the age of the plantation the nurses are to be removed, cannot easily be deter- 

 mined ; and, indeed, if the nurses chiefly consist of larches, it may with propriety be said, that they 

 should never be totally removed, while any of the other kinds remain. For, besides that this plant is 

 admirably calculated to compose part of a beautiful mixture, it is excelled by few kinds, perhaps by 

 none, as a timber tree. But when the nurses consist of inferior kinds, such as the mountain ash or Scots 

 pine, they should generally be all moved by the time the plantation arrives at the height of fifteen or 

 twenty feet, in order that the timber trees may not, by their means, be drawn up too weak and slender. 



4013. Before this time it may probably be necessary to thin out a part of the other kinds. The least 

 valuable, and the least thriving plants, should first be condemned, provided their removal occasion no 

 blank or chasm ; but where this would happen, they should be allowed to stand till the next or other 

 subsequent revision. 



4()14. At what distance of time this revision should take place cannot easily be determined ; as the mat- 

 ter must very much depend on the circumstances of soil, shelter, and the state of health the plants may 

 be in. In general the third season after will be soon enough ; and if the plantation be from thirty to 

 forty years old, and in a thriving state, it will require to be revised again, in most cases within seven 

 veafs. But one invariable rule ought to prevail in all cases, and in all situations, to allow no plant to 

 overtop or whip another. Respect should be had to the distance of the tops, not to the distance of the 

 roots, of the trees : for some kinds require more head room than others ; and all trees do not rise per. 

 pendicular to their roots, even on the most level or sheltered ground. 



4015. With respect to the final distance to which trees, standing in a mixed plantation, should be 

 thinned, it is hardly possible to prescribe fixed rules ; circumstances of health, vigour, the spreading 

 nature of the tree, and the like, must determine. Whether the trees are to be suffered to stand till 

 full grown, which of the kinds the soil seems best fitted for; whether the ground be flat or elevated ; 

 and whether the situation is exposed or sheltered, are all circumstances which must influence the 

 determination of the ultimate distance at which the trees are to stand. It may, however, be said, in 

 general, that if trees be allowed a certain distance, of from twenty-five to thirty feet, according to their 

 kinds and manner of growth, they will have room to become larger timber. 



4016. Pontey shows, that fortv feet distances are necessary (or only about twenty-seven to the acre) to 

 the unassisted growth of large oak trees, owing to the flat, spreading, and close form of their heads ; but 

 that the properly trained, open, high, and conical heads of such trees will admit of their standing at 

 twenty-five feet distances, or about seventy trees on the acre, and of the most profitable kind. What 

 an inducement to pruning and management ! (Farcy's Derbyshire, vol i. p. 28;>.) 



4017. Plantations of Scots pine, if the plants have been put in at three, or three and 

 a half, feet apart, will require little care until the trees be ten or twelve feet high. It is 

 necessary to keep such plantations thick in the early part of their growth, in order that the 

 trees may tower the faster, and push fewer and weaker side branches. Indeed, a pine and 

 a soft wood plantation should be kept thicker at any period of its growth, than plantations 

 consisting of hard wood and nurses already mentioned ; and it may sometimes be proper to 

 prune up certain nurse plants, as hinted at above (4011.), for nurses in a mixed plantation. 

 Those pruned-up trees are of course to be reckoned temporary plants, and are afterwards 

 to be the first thinned out; next to these, all plants which have lost their leaders by acci- 

 dent, should be condemned ; because such will never regain them so far as afterwards to 

 become stately timber; provided that the removal of these mutilated trees cause no ma- 

 terial blank in the plantation. Care should be taken to prevent whipping ; nor should 

 the plantation be thinned too much at one time, lest havock be made by prevailing 

 winds ; an evil which many, through inadvertency, have thus incurred. This precaution 

 seems the more necessary, inasmuch as Scots pines, intended for useful large timber, are 

 presumed never to be planted except in exposed situations and thin soils. At forty 

 years of age, a good medium distance for the trees may be about fifteen feet every way. 

 It may be worthy of remark, that after a certain period, perhaps by the time that the 

 plantation arrives at the age of fifty or sixty years, it will be proper to thin more 

 freely, in order to harden the timber ; and that then this may done with less risk of 

 danger, from the strength the trees will have acquired, than at an earlier period ; but still 

 it should be done gradually. 



4018. Plantations of spruce and silver firs, intended for large useful timber, should 

 be kept much in the manner above stated, both in their infancy and middle age. As 

 already remarked, planting and keeping them as thick as is consistent with their health 

 are the best means of producing tall, straight, clean stems, and valuable timber. When 

 planted for screens or for ornament, they require a different treatment. " To larch 



