34 MODERN FOREST ECONOMY. 



of silver to repay extraction by the improved modern 

 methods. Professor Hendreich relates, according to 

 L 1 'Union Medicale, that under these scoriae, for at least 

 1,500 years, has slept the seed of a poppy of the species 

 Glaucium. After the refuse had been removed to the 

 furnaces, from the whote space which they had covered 

 have sprung up and flowered the pretty yellow corollas of 

 this flower, which was unknown to modern science, but is 

 described by Pliny and L)ioscorides. This flower had dis- 

 appeared for fifteen to twenty centuries, and its reproduc- 

 tion at this interval is a fact parallel to the fertility of the 

 famous " mummy wheat." ' 



Many like cases are mentioned by Marsh* in regard to 

 the unexpected appearance not only of herbaceous, but 

 also of ligneous vegetables. In Northern Europe I have 

 had details given to me in regard to numerous cases of 

 coniferous woods having been destroyed and birches 

 springing up in their place. The remains of trees found 

 at different depths in peat-bogs in Denmark testify to a 

 continuous succession of forests of different kinds of trees 

 having appeared in the same locality. The laws regu- 

 lating the succession have to some extent been evolved, 

 and attention has been given to sources whence the seeds 

 have proceeded ; but it is the fact alone with which we are 

 at present concerned. In a volume entitled Reboisement in 

 France (pp. 45-47) I have cited cases of extinct torrents 

 which have been extinguished by the natural extension of 

 forests over ground which had been previously denuded 

 of these ; and in the American State of Ohio there exist 

 remarkable mounds and earthworks, constructed by man's 

 device, overgrown with 'a dense clothing of forest not dis- 

 tinguishable, or scarcely distinguishable, in dimensions or 

 character of growth from the neighbouring forests, the soil 

 of which had probably never been disturbed. Such has 

 been the recuperative power of the forest, and such is it 

 still ; but in the unequal struggle with man forests have 



* The Earth as Modified by Human Action, 



