Natural History of Nova Scotia, 647 



dora canadensis Z,.], wliich are, after the lapse of a few years, 

 in their turn overtopped by the alder, which is always soon 

 followed by a growth of firs. A number of plants whose 

 seeds never vegetate during the fertile period now appear; 

 among which we notice the mayflower, the trailing evergreens 

 (lycopodiums), snakeroot [^ristolochia Serpentaria £.], mit- 

 chella [Mitchella repens W.\ linnea [Linna2 N « borealis Gron.i 

 the American form of this species is different from the Euro- 

 pean one], pigeon berry, mountain tea [Gaultherza procum- 

 bens £.], maidenhair [^diantum pedatum £.], several kinds 

 of aster, and golden rods [Solidago]. The mosses follow, 

 and the thicket, in the course of thirty or forty years, resumes 

 nearly its former appearance, except that the trees are smaller, 

 and that the balsam fir forms a larger proportion of the 

 wood. This tree of rapid growth, by its shelter, covers the 

 more valuable spruce from winds, and prevents it from form- 

 ing strong lateral branches, which would deteriorate the 

 timber, till, having reached the height of 30 ft. or 40 ft., it is 

 overtopped and suffocated by it. When a very old growth 

 of hemlock [^4 N bies canadensis Mx.~\ and spruce has been de- 

 stroyed by fire, it sometimes happens that a growth of beech 

 [.Fagus sylvatica L. and ferruginea L. are wild in North Ame- 

 rica], birch, and maple takes its place. It also sometimes happens 

 that when an old grove of pine is destroyed, it is replaced by 

 white [J5etula ^opulifolia H. K.~] and yellow birch [Z?etula ex- 

 celsa H. K. : see the Penny Cyclopaedia^}, and oak. But these 

 changes are less frequent than is imagined. Most hemlock 

 woods, when killed by fires, are at first overgrown with birch 

 hooppoles, mixed with firs ; but, when the birch has reached 

 the height of 20 ft. or 30 ft., it turns mossy, and continues 

 nearly stationary for perhaps twenty years, during which a 

 young growth of hemlock again springs up, and most of the 

 birches perish. In a similar way, the pine woods, when killed, 

 are first covered with alder, followed by white birch [ZJetula 

 jpopulifolia H. K.~], poplars, and a little oak ; but these trees 

 rarely reach any considerable size before they are overtopped 

 by spruce and hacmetac, which is, finally, again mixed with 

 pine. Whenever a growth of hardwood, on a poor soil, is 

 cut down, the land burnt over, and exposed for several years 

 to the pasturage of cattle, it will, if left undisturbed, grow up 

 with a mixture of fir and spruce. 



Wherever the soil is so poor that turf is formed on the 

 upland, peat earth is formed in the swamps and bogs. It is 

 most abundant on vitriolic soils, and, generally, in situations 

 that have formerly been ponds or shallow lakes : most of the 

 trees that grow on their banks fall, finally, into them. Every 



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