THE GROWING STOCK. '265 



An absolutely accurate determination of the age is only 

 necessary when the data are required for the preparation of 

 yield tables or other scientific purposes. Fairly approximate 

 data suffice for the purpose of working plans. 



In the case of even-aged or nearly even-aged woods, one or 

 more sample trees are examined. 



If considerable differences of age exist in a wood, the limits 

 should be given, and the wood placed into that age class to 

 which it belongs according to its economic character. If some 

 older or younger groups exist, which are not of sufficient extent 

 to be classed as separate woods, this should be mentioned. 

 The same holds good for a limited number of standards which 

 are to be held over for a second rotation, or for young growth 

 which has sprung up in an old wood. 



A minute calculation of the mean age is rarely called for. 



In the case of woods which have been kept back in their 

 development, the economic and not the actual age must be 

 given. For instance, a young wood, which has stood under 

 heavy shelter and is now 80 years old, but of a development 

 which is ordinarily reached in 10 years, must be entered as 

 10 years and not as 30 years old. 



In the regeneration class the age of the overwood and 

 underwood must be given separate!} 7 . 



In selection forests it suffices to give the limits of the age 

 gradations, which are frequently determined by the number of 

 years during which cuttings go once round the forest. 



In coppice with standards the ages of the overwood and 

 underwood are given separately ; for the former the limits of 

 the existing gradations are given. 



The age of coppice can generally be easily ascertained from 

 the time when the last cutting occurred. 



e. Origin and Past Treatment. 



Whenever the necessary data can be ascertained, a short 

 history of each wood should be prepared, giving the method 

 of formation, whether by natural or artificial means, planting 



