THE SUCCESSION OF FOREST TREES. 39 



The shade of a dense pine wood is more unfavor 

 able to the springing up of pines of the same species 

 than of oaks within it, though the former may come 

 up abundantly when the pines are cut, if there chance 

 to be sound seed in the ground. 



But when you cut off a lot of hard wood, very often 

 the little pines mixed with it have a similar start, for 

 the squirrels have carried off the nuts to the pines, 

 and not to the more open wood, and they commonly 

 make pretty clean work of it ; and moreover, if the 

 wood was old, the sprouts will be feeble or entirely 

 fail ; to say nothing about the soil being, in a measure, 

 exhausted for this kind of crop. 



If a pine wood is surrounded by a white-oak one 

 chiefly, white-oaks may be expected to succeed when 

 the pines are cut. If it is surrounded instead by an 

 edging of shrub-oaks, then you will probably have a 

 dense shrub-oak thicket. 



I have no time to go into details, but will say, in a 

 word, that while the wind is conveying the seeds of 

 pines into hard woods and open lands, the squirrels 

 and other animals are conveying the seeds of oaks and 

 walnuts into the pine woods, and thus a rotation of 

 crops is kept up. 



I affirmed this confidently many years ago, and 

 an occasional examination of dense pine woods con 

 firmed me in my opinion. It has long been known 

 to observers that squirrels bury nuts in the ground, 

 but I am not aware that any one has thus accounted 

 for the regular succession of forests. 



On the 24th of September, in 1857, as 1 was pad 

 dling down the Assabet, in this town, I saw a red 

 squirrel run along the bank under some herbage, with 

 something large in its mouth. It stopped near the 



