2 28 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



fully with such requirements may not perhaps be found numer- 

 ous enough in Great Britain to yield sufficiently reliable results, 

 the collection of the necessary statistics may be somewhat 

 delayed. Nevertheless, the opportunity afforded by the carrying 

 out of the survey recommended in the Memorandum submitted 

 by the Royal Scottish Arboricultural Society to the members 

 of the Development Commission, might well be taken advantage 

 of in order to collect such " Yield Table " statistics as may be 

 possible. We would also invite the attention of our readers 

 to an article on the Coombe Plantation, Keswick, which appeared 

 in a recent number of the Journal of the Board of Agriculture^ 

 as an example of what can be done in this direction. 



The importance of Yield Tables, and their practical utility in 

 the determination of the financial results of forestry, are well 

 exemplified in Part II. of Sir William Schlich's manual, dealing 

 with " Forest Valuation," and perhaps we cannot do better than 

 quote a couple of examples showing the practical application of 

 the various mathematical formulae worked out in the body of the 

 book. On pages 124 and 125 the author shows, by the use 

 of Yield Tables, how it is possible to calculate what sum of 

 money a proprietor may be justified in paying for a given piece 

 of land, according to the species he may intend to plant, 

 provided he is satisfied with a given per cent, at compound 

 interest on his investment. Thus the author shows (the problem 

 being worked out in detail, step by step) how, in a given locality, 

 it would be profitable to pay ;^2o, 4s. an acre for land to be 

 cultivated with Scots pine, to be worked on a rotation of eighty 

 years ; whilst, all other conditions remaining the same, he would 

 not be justified in paying more than ^18, 6s. for the same 

 area of land if it were to be planted with beech. Again, on 

 page 161, the author shows how the following useful problem 

 may be satisfactorily worked out : — " Is it more profitable to use 

 a given acre of land for agriculture or forestry under a given 

 set of conditions ? " This latter problem belongs to that all 

 important branch of scientific forestry, " Forest Statics," which 

 weighs and considers the comparative merits of the different 

 methods of treatment to which forests may be subjected : so that 

 when several methods of treatment lead to the realisation of the 

 desired object, it is left to the owner to base his decision on 



^ The fournal of the Board of Agriculture, vol. xvii., No. 4: "Coombe 

 Plantation, Keswick," by R. L. Robinson, B.A., B.Sc. 



