OF YIELD TABLES GENERALLY. 97 



By a yield table is understood a tabular statement 

 which gives the course of the development of a wood from 

 early youth up to a fixed age, either from year to year, or for 

 intervals of a certain number of years. 



2. Object and Contents of Yield Tables. 

 Yield tables are used for a great variety of purposes, as : 



(a) Determination of the volume of woods. 

 (&) increment of woods. 



(c) ,, ,, ,, quality of localities or of woods. 



(d) ,, ,, ,, most profitable species, method of 



treatment and rotation. 



(e) ,, value of the soil, growing stock, or 



both. 

 (/) ,, ,, ,, yield of forests. 



In order to meet all these requirements, yield tables should 

 show, per unit of area (acre) : 



(1) The progressive volume which may be found in a fully- 



stocked wood. 



(2) The number of trees. 



(3) The basal area of trees. 



(4) The height of the wood. 



(5) The form factors. 



(6) The current annual and mean annual increment. 



Separate yield tables must be prepared for 



(a) Each species. 



(b) Each method of treatment, as high forest, coppice wood, 



and combination forest. 



(c) Each quality of locality. 



The volume is given divided into the different classes of 

 wood, as timber, firewood, fagots, etc. The volume of thinnings 

 is entered separately from that of final yields. 



Yield tables are only prepared for " normal " woods, that is 

 to say for woods which are fully stocked, taking into considera- 



VOL. III. H 



