798 DIGGING AND PREPARATION OF PEAT. 



is an intention of utilizing the peat and then converting the 

 bog into a forest or meadows, so much of it will be dug each 

 year in accordance with the purpose in view, to which the 

 utilization of the peat is merely subsidiary. If, however, it is 

 intended to have a permanent supply of peat, only so much 

 should be dug yearly as the bog produces in a year. 



Fresh peat is produced regularly in all bogs where the 

 conditions remain unaltered. Thus some bogs produce annu- 

 ally layers of peat 6 or 8 inches thick, or even thicker ; others 

 a mere film of new peat, and others none at all.* 



The first condition for a renewal of the peat is a drainage 

 system by means of which the parts of the bog from which 

 the peat has been dug can be irrigated properly. If these 

 portions can be kept submerged continually, but not too 

 deeply (about 2 to 4 inches), whilst here and there ridges and 

 mounds remain above water-level, the water containing humus 

 and the base of the bog not being completely freed from peat 

 a continual production of peat may be anticipated. In order 

 to secure these conditions, the useless upper layers of peat and 

 other refuse are thrown on the cleared areas and trenches, 

 care being taken to keep these latter inundated. 



The mode of reproduction of a bog cannot be explained in a 

 general manner, but only observed on individual bogs, whilst 

 any change in the drainage of the surrounding land may 

 greatly affect matters in this respect. As, therefore, a long 

 period is required for such observations, during which changes 

 in the water-supply may occur and the rate of production of 

 peat vary in different parts of the bog, it is rare that working 

 plans for a bog take into consideration its reproduction. It 

 is, therefore, considered sufficient to prepare a plan for from 

 50 to 100 years, accor(}ing to the extent of the bog, the demand 

 for the peat, and amount of labour available ; a fixed quantity 

 of peat is thus supplied annually, whilst the cutting proceeds 

 in a proper direction. In the latter respect, it is customary to 

 commence operations at the highest part of the bog, if it is 

 intended that the peat shall be reproduced, and thence to 

 proceed gradually to its lower parts. 



* For the rate of growth in various moors, see Sendtner, oji. rif., p. l!l(>. 



