230 TRANSACTIONS OF ROYAL SCOTTISH ARBORICULTURAL SOCIETY. 



management, but the chapters which will perhaps be read with 

 the greatest interest by the practical scientific forester, are those 

 dealing with the determination of the rotation, with the size and 

 distribution of the age-classes, and with the area to be cut over 

 annually, under the different methods of treatment. 



Having thus obtained a clear picture of the constitution of the 

 ideal or normal forest, the reader is at once led on to undertake 

 the preparation of the working-plan proper, or the scheme which 

 lays down the execution of the various measures which are 

 necessary, so that the management of the forest to be dealt with 

 may be carried out in an orderly manner. A working-plan (such as 

 the author contemplates) has for its object "to lay down, according 

 to time and locality, the entire management of the forest, so that 

 the objects for which the forest is maintained may be as fully as 

 possible realised. And this must be done in an economic 

 manner, for extravagance has no place in forestry.'" Moreover, 

 " the forest working-plan must be based on the principles of 

 silviculture ; it must not contravene them." Bearing these 

 remarks in mind, the preparation of a working-plan may be 

 said to consist of two main operations: the preliminary 

 work, which gives the forester a picture of the existing condition 

 of the forest, enabling him to compare this with the ideal or 

 normal forest, and the preparation of the working scheme which 

 prescribes the works required to bring the forest, as nearly as 

 possible, to the normal state. The preliminary works include 

 the reconnaissance of the area, the choice of the method of 

 treatment, the formation of working circles, the analysis and 

 description of the crop, the calculation of the volume of material, 

 and the determination of the exploitable age ; all of these lead 

 up to the drawing up of the working scheme and the determina- 

 tion and regulation of the yield under the method of treatment 

 selected. The author very correctly confines himself to describing 

 the most important only of the numerous methods which have 

 been devised for the calculation of the " Possibility," by which 

 is meant the quantity of material which may be felled in a forest 

 annually or periodically for the time being, without encroaching 

 on the normal forest capital or growing stock. We are glad to 

 find that adequate space is provided for the description of the 

 procedure to be followed in calculating the Possibility in the 

 particular cases which would probably be of most frequent 

 occurrence at the present moment in the British Isles, in the 



