SUCCESSION OF FOREST TREES. 11 



SUCCESSION OF FOREST TREES. 



From an Address before the Middlesex Agricultural Society. 



RY JIKNUY D. THOREAU. 



I have often been asked, as many of you have been, if I could 

 tell how it happened, that when a pine wood was cut down, an 

 oak one commonly sprang up, and vice versa. To which I have 

 answered, and now answer, that I can tell — that it is no mys- 

 tery to me. As I am not aware that this has been clearly shown 

 by any one, I shall lay the more stress on this point. Let me 

 lead you back into your wood-Io*^s again. 



When, hereabouts, a single forest tree or a forest springs up 

 naturally where none of its kind grew before, I do not hesitate 

 to say, thougii in some quarters still it may sound paradoxical, 

 that it came from a seed. Of the various ways by which trees 

 are knoivn to be propagated — by transplanting, cuttings, and the 

 like — this is the only supposable one under these circumstances. 

 No such tree has ever been known to spring from any thing else. 

 If any one asserts that it sprang from something else, or from 

 nothing, the burden of proof lies with him. 



It remains, then, only to show how the seed is transported 

 from where it grows to where it is planted. This is done chiefly 

 by the agency of the wind, water and animals. The lighter 

 seeds, as those of pines and maples, are transported chiefly by 

 wind and water ; the heavier, as acorns and nuts, by animals. 



In all the pines, a very thin membrane, in appearance much 

 like an insect's wing, grows over and around the seed, and in- 

 dependent of it, while the latter is being developed within its 

 base. Indeed this is often perfectly developed, though the seed 

 is abortive, nature being, you would say, more sure to provide 

 the means of transporting the seed, than to provide the seed to 

 be transported. In other words, a beautiful thin sack is woven 

 around the seed, with a handle to it such as the wind can take 



