COLLECTION AND CALCULATION OF STATISTICAL DATA. 



57 



Volume tables have from time to time been prepared by 

 various compilers for the following species of economic importance 

 in the United Provinces : 



Sal ' 2S , chir *>, oak a , deodar -*, spruce ^ and silver fir * : Data 

 are also being collected for the following additional species sain, 

 sissoo, bakli, haldu, kanju, khair, simal, jaman. 



It will simplify the discussion to divide the uses of the tables 

 in practical forest management 



(a) in the preparation of working plans, i.e., by the working 



plans branch. 



(b) in the preparation of outturn of coupes and marked trees 



for sale, i.e., by the executive staff. 



Under (a) the tables will be useful for the following : 



(1) In calculating the rotation. 



(2) In calculating the yield and increment. 



(3) In the calculation of reduced areas according to 



quality class. 



(4) In the calculation of the value of the estate. 



The following discussion of che subject is taken from Smythies' 

 and Howard's Distribution and Types of Sal Forest in the United 

 Provinces as an illustration, as, although it refers primarily to 

 sal forests, yet the principles involved are universal to all species 

 and all forests, and reliable yield tables for other species are not 

 as yet available. 



(1) The calculation of the rotation. 



A reliable yield table is extremely useful in helping to deter- 

 mine the rotation. A yield table for sal has recently been 



Volumt Tahiti for Sal. HOWARD. 

 M Silviculture of Indian Trees. TROUP. 

 17 Kulu Working Plan. TREVOR. 



' Rawalpindi Working Plan. JERRAM. 

 " Raniknet Cantonment Working Plan. CANNING. 

 M Kulu Working 



The 

 of volume 

 and yield 

 tables in 

 forest 

 manage- 

 ment. 



