FORESTRY COMMISSION. 55 



Dioval of such inferior trees before they have seriously injured their better 

 neighbors is, of conrse, always desirable. 



Kccoiid. Control of the qiuility of the timber produced. 



If often hax^pens that many of the dominant trees of the stand are more 

 or less defective in form or in soundness. The stand will, of course, be 

 improved by their removal before they have seriously injured better trees 

 in their immediate neighborhood, whicli, on their removal, may be able to 

 utilize the space to better advantage. 



Third. The maturity of the crop may be hastened. 



If we assume hat a pine tree of thirty inches in diameter is mature, it is 

 safe to say tliat the maturity of the pine stand may be hastened by at 

 least twenty years by judicious thinning. This is accomplished by the 

 opening up of the canopy or crown cover from time to time to enable the 

 trees which are to constitute the final stand to enlarge their crowns and 

 thereby make possible a more rapid increase in diameter. 



Fourth. "N'aluable wood may be saved. 



Just how valuable this wood may be depends entirely on the location 

 of the woodlot and the character of the stand. Where the stand thins 

 itself without the aid of man, all trees which are killed by this process 

 are lost by the ravages of insects and decay. On most farms this material 

 jnight be utilized to advantage for fuel, posts, vine crops, rails and other 

 purposes. 



The time at which a first thinning should be carried out in a dense young 

 stand will be very largely determined by the local market conditions. As 

 a rule, no thinning should be undertaken until the material to be removed 

 will have acquired sufficient size to be of value for fuel or for some other 

 purpose. On most wood lots in Southern Michigan this time will usually 

 come when the stand is between iifteen and twenty-five years old. It is 

 true that in leaving the stand so long untouched many good trees may be 

 seriously injured by being overtopped by inferior neighbors, which have 

 chanced to have gotten the upper hand in the struggle for light, but as a 

 rule there will still remain many more good trees unharmed than are re- 

 quired for the future stand. In the case of some very rapid growing trees, 

 especially where the quality of the wood makes the product merchantable 

 at an early da>', as in the case of Catalpa and Black Locust, the first 

 thinning may be carried out to ad\-antage as early as the sixth or seventh 

 year. 



The amount of ma,terial to be removed in a. thinning of this kind Avill 

 depend on the site, the species, and the purpose for which the timber is 

 grown. In general, it may be said that trees occupying, situations very 

 favorable for tree growth may be thinned more severel}^ than when the 

 location is less favorable. The more rapid growing species, and those 

 capable of enduring greater shade, may also be more heavily thinned than 

 such as grow more slowly or are incapable of enduring gi'eat shade. As 

 a rule, no opening shuld be made in the crown cover which cannot reason- 

 ably be expected to close again in the course of five to seven years. 



It should be added in this connection that the margins of woodlot should 

 not be as heavily thinned in any case as the interior, unless they are 

 thoroughly protected by a windbreak mantle. This is particularly true 

 of western borders. 



The overcutting of the mature timber in woodlots is not of infrequent 

 occurrence. A number of woodlots were noted where the owners, think- 



