Sect. V, 1922 [45] Trans. R.S.C. 



\^III. The Bog-Forests of Lake Memphremagog: Their Destruction and 

 Consequent Successions in Relation to Water Levels 



By F. E. Lloyd, M.A., F.R.S.C, and G. W. Scarth, M.A. 



(Read May Meeting, 1922) 



The very extensive destruction of bog forest which is to be seen 

 fringing the lakes in the Eastern Townships region of Quebec province, 

 is naturally ascribed to the erection of dams at the outlets. But a 

 study of the conditions at Lake Memphremagog in particular shows 

 that this is not the only factor, nor, in this case at least, the most 

 important one. 



Descriptive. — The two chief localities — viz,, the mouth of Cherry 

 river at the north end of the lake and the mouth of Barton and other 

 rivers entering the south end — include many hundreds of acres of 

 dead and moribund trees. The bare or scantily foliaged trunks that 

 still stand amid a new vegetation of lower growth and totally different 

 character are but a small remnant of a former dense growth, as is 

 proved by the greater number of uprooted and fallen trees. Evidently 

 there existed at one time a climax bog forest, the dominant species 

 being tamarack (Larix laricinaY and cedar {Thuja occidentalis) with 

 frequent spruce {Picea mariana) and a few large pines {Pinus strohus). 

 Besides the destruction of the trees, however, a great change must 

 have taken place in the forest floor; for instead of the typical con- 

 tinuous, gently undulating surface, the ground is broken and uneven. 

 Durable structures, such as roots and logs, retain around them 

 portions of the old forest fîoor, but even these are generally more or 

 less undermined, while the intervening spaces have sunk to a much 

 lower level. The soil in the depressions is no longer the fibrous 

 "raw humus" of a forest fîoor but a fine black "muck." 



The new vegetation which flourishes amid the ruins of the old is 

 naturally varied on so uneven a substratum. It varies both locally 

 and over whole areas with relation to the summer level of the water- 

 table, ranging from aquatic almost to mesophytic. 



The lower levels of a drainage system are occupied by extensive 

 beds of Typha. Here the destruction of trees and forest floor has 

 been very great, only stumps remaining as a rule to testify to their 

 former existence. The same applies to areas occupied by bog shrubs 

 {Chamaedaphne, Myrica, Spiraea, Cephalanthus) . 



^Nomenclature according to Gray: New Manual etc., 7th ed. 



