﻿MOORE— SUCCESSION 



63 



In this case, at least, the conclusion appears unavoidable that the 

 occurrence of pine and oak is attributable largely, if not primarily, 

 to the occurrence of distinctly different soils. This does not mean 

 that the factors tending to bring about a succession from pine to 

 oak are absent, but merely that these factors appear in this case 

 to be distinctly subordinate to the character of the soil. Only the 

 most thorough quantitative investigation can begin to unravel 

 all the factors involved, and final conclusions cannot be expected 

 until further progress has been made in the sciences on which the 

 investigation must be based, particularly in plant physiology and in 

 physics, chemistry, and bacteriology of soils, all of which deal with 

 the phenomena which go to make up the vegetative cover as we 

 find it. 



There is in this same locality another kind of succession, different 

 from the physiographic one 3 above referred to; this is a succession 

 started by the interference of man. 4 



At the edge of the oak forest above described was found a patch 

 of young pitch pine about 20 years old. The soil proved to be 

 more gravelly than under the oaks, but with still a considerable 

 proportion of clay or fine silty material. It might appear offhand 

 from this that the clays do not necessarily support oaks; but 

 the true explanation fails to corroborate this idea, and is very simple. 

 Further examination revealed old, almost obliterated furrow marks, 

 showing that this land had formerly been cleared and cultivated. 

 That it originally supported oak was indicated by a strip of oak 

 standing between the pines and a field still used for growing hay, 

 and still further by a sharp line of demarcation between an old 

 forest of oak and the young pine. There is but little scrub oak 

 among the pines, and the better oaks, scarlet oak, black oak, and 

 white oak, are coming in on the edges. It is obvious, therefore, 

 that the pine is merely a temporary cover which has taken posses- 

 sion of the land after the oaks had been completely cleared off (not 

 merely clear-cut), and the land later abandoned. If further evi- 

 dence that pine is a forerunner of the forest on cleared and 



3 Cowles, H. C, A textbook of botany. Vol. II. Ecology, p. 940. New York. 



