80 Forestry Quarterly. 



An article by Kathriner discusses at length procedure in Alpine 

 bogs. The first requirement is a survey, and map on a scale of 

 not less than i :5ooo; but this does not obviate a close personal 

 inspection of drainage conditions, and especially ascertainment of 

 the cause of swampiness, as this may suggest the proper remedy. 

 If, for instance, the surface and ground waters from a slope 

 are subject to stowage by a change of angle to flat surface, and 

 thus give rise to swampy condition, a simple ditch along the line 

 of change of slope will remedy the trouble. 



In most cases impenetrable subsoil and large precipitation are 

 the cause, when a system of ditches becomes necessary. The 

 density of this network is dependent on degree of wetness and 

 character of soil ; the distance of effective drains varying from 

 12 to 25 times the depth of the ditch. Hence, in very wet com- 

 pact soil with a depth of ditch of 30 inches, the ditches would 

 have to be 8 yards apart, while in a loose soil 18 yards might 

 suffice. In order to avoid mis judgment due to accidental weather 

 conditions, the flora should be used as an indicator of general 

 moisture conditions. It is essential not to crowd the ditches. 

 The depth of ditches may vary according to soil and circum- 

 stances from 2 to 3 feet with a width at base of 10 to 14 inches, 

 wider in loose, narrower in compact soil, the slope of the sides 

 being in loose soil made one foot per foot depth, steeper in stiffer 

 soils, but it does not pay to save in this respect as maintenance 

 becomes more expensive with steeper slopes. 



The most difficult question is to what extent it is necessary to 

 reduce the maximum water stage. In Alpine situations, where 

 excessive rainfall is the main cause of swamps, there is little 

 danger of drying out too much, and in most cases, even though 

 species adapted to weather situations may be used, except in real 

 peat bogs or high moors, the danger of over drainage is not great. 



In peat bogs (which are the "swamps" to which we have re- 

 ferred above) there is danger of over drainage, because here, not 

 so much as the author points out, is there a relative poverty of 

 mineral constituents, but the physical conditions for water con- 

 duction and perhaps chemical conditions as yet unexplained are 

 unfavorable. 



It must, therefore, not be supposed that mere drainage of these 

 bogs will improve them. The experience so far had points to 



