Canadian Forestry Journal, August, ipi6 



675 



The wind belt of a plantation 

 which is usually from 20 to 30 yards 

 deep should not be thinned as it 

 protects the inner trees which may 

 then be more severely thinned. 

 Gaps in the plantation must be 

 avoided. AYhen the trees are much 

 crowded, the thinning must not be 

 too severe at one time. In thinning 

 a wood which has been too long 

 neglected, the outer margin should 

 not be too severely thinned; and 

 trees isolated by thinning are apt to 

 be thrown by wind. In mixed woods 

 with several species the more valu- 

 able trees require more protection 

 than the. rest. 



Autumn and early Winter are the 

 periods usually chosen for thinning 

 plantations. But it should be re- 

 membered that at the latter time the 

 lowest percentage of moisture (47 

 per cent according to Webster) is 

 present and the timber therefore is 

 then most valuable for construction 

 purposes. Larch is ready for thin- 

 ning at. from 12 to 15 years, Scots 

 Pine at about 25, Oak at 20 to 25, 

 Beech at 25 to 30, Spruce and Sil- 

 ver at 30 to 35 years. Trees which 

 naturally open out such as the Pine 

 do not respond as surely to thinning 

 as Beech and Silver, for if the Pine 

 does not get suflFicient light and 

 space in time, it is suppressed for 

 good. Therefore special care must 

 be taken to thin Pine plantations 

 and those similar at the time when 

 they will respond. It is well to 

 commence thinning the plantation at 

 the centre or most sheltered spot, 

 so that the outer intact boundary 

 continues to form a shield against 

 wind which might prove harmful to 

 the trees which had previously stood 

 in close formation. 



Classes of Trees. 



In a plantation we find the follow- 

 ing classes of trees : 



1. Predominating trees which 

 have outgrown the others : 



(a) Trees whose stems and 

 general formation are 

 good. 



(b) Trees whose stems are 

 bent and gnarled and al- 

 together badly developed. 



2. Dominating. 



3. Dominated stems. 



4. Suppressed. 



5. Diseased and cankered. 



In thinning it is well to retain as 

 many of class 1 as possible in equal 

 distribution all over, more particu- 

 larly those of sub-division (a). If 

 trees of class 2 interfere with the 

 stems of class 1 (a) they should be 

 removed, but care must be taken 

 that this removal does not break the 

 canopy which would result in wind- 

 fall. Trees belonging to class 1 (b) 

 should, if possible, be replaced by 

 those of class 2 and this should be 

 done early in the thinning process. 

 In classes 3 and 4 pretty severe 

 thinning among light demanders 

 should be done. Shade bearers 

 stand more crowding than light de- 

 manders — they can do with 30 to 50 

 per cent less space, therefore thin- 

 ning need not be nearly so severe 

 among them. Trees of classes 2 

 and 3, dominating and dominated, 

 are those which require most light. 

 As a rule dominated trees should 

 only be removed when they are poor 

 struggling specimens or of a species 

 not wanted in the particular planta- 

 tion being thinned. 



I have in this paper only touched 

 the fringe, as it were, of the interest- 

 ing study of thinning and have not 

 attempted to discuss the various 

 methods practised in the forests of 

 Germany. France and America. My 

 aim has been to assist, if possible, 

 practical beginners in this particu- 

 lar branch of the absorbing and 

 fascinating subject of forestry. 

 The Monarch oak, the Patriarch of 



the trees. 

 Shoots, rises up, and spreads by 



slow degrees; 

 Three centuries he grows, and 



three he stays. 

 Supreme in state, and in three more 

 decays. — Dryden. 



