412 THE CANADIAN NATURALIST. [Dec. 



3rd. The process of restoration may be interrupted by succes- 

 sive fires. These are most likely to occur soon after the first 

 burning, but may happen at any subsequent stage. The re- 

 sources of nature are not, however, easily exhausted. When 

 fires pass through young woods, some trees always escape ; and 

 so long as any vegetable soil remains, young plants continue to 

 spring up, though not so plentifully as at first. Repeated fires, 

 however, greatly impoverish the soil, since the most valuable part 

 of the ashes is readily removed by rains, and the vegetable mould 

 is entirely consumed. In this case, if the ground be not of great 

 natural fertility, it becomes incapable of supporting a vigorous 

 crop of young trees. It is then permanently occupied by shrubs 

 and herbaceous plants ; at least these remain in exclusive posses- 

 sion of the soil for a long period. In this state the burned 

 ground is usually considered a permanent 'barren,' — a name which 

 does not, however, well express its character ; for though it may 

 appear bleak and desolate when viewed from a distance, it is a 

 perfect garden of flowering and fruit-bearing plants, and of 

 beautiful mosses and lichens. There are few persons born in the 

 American colonies who cannot recall the memory of happy youth- 

 ful days spent in gathering flowers and berries in the burnt 

 barrens. Most of the plants already referred to, as appearing 

 soon after fires, continue to grow in these more permanent 

 barrens. In addition to these, however, a great variety of other 

 plants gradually appear, especially the Kalmia angustifoUa, or 

 sheep laurel, which often becomes the predominant plant over 

 large tracts. Cattle straying into the barrens deposit the seeds 

 of cultivated plants, as the grasses and clovers, as well as of many 

 exotic weeds, which often grow as luxuriantly as any of the 

 native plants. 



4th. When the ground is permanently occupied for agricultural 

 purposes, the reproduction of the forest is of course entirely pre- 

 vented. In this case, the greater number of the smaller plants 

 found in the barrens disappear. Some species, as the Solidagos 

 and Asters, and the Canada thistle, as well as a few smaller 

 plants, remain in the fields, and sometimes become troublesome 

 weeds. The most injurious weeds found in the cultivated ground 

 are not, however, native plants, but foreign species, which have 

 been introduced with the cultivated grains and grasses; the 

 ox-eye daisy or white-weed, and the crowfoot or buttercup, are 

 two of the most abundant of these. 



