84 THE AGE OF TREES. 



VIII. The Age of Trees. 



It was the opinion of De Candolle, and other eminent botanists, 

 that trees cannot really be said to die of old age, since their 

 tissues ai*e renewed from year to year, but that we must attribute 

 their decay chiefly to accidental causes. The baobab, which Adan- 

 son proved by ingenious and plausible calculations to be 5150 

 years old, the Taxodium, which analogous reasoning would make 

 still older, and other examples, seem to confirm the idea that 

 thei*e may be at present some trees in the world of immense an- 

 tiquity, witnesses perhaps of its later physical revolutions. " We 

 can easily conceive," says De Candolle, " that errors may happen 

 in calculations of this kind, and that they cannot be considered as 

 the expressions of exact truth, until examples of this vegetable 

 longevity are multiplied to such an extent as to support one an- 

 other." The means of ascertaining the longevity of trees would 

 be greatly increased were observations such as we are about to 

 record more frequently made on the subject. 



Mr Twining was engaged in the year 1827 in measuring and 

 inspecting hemlock timber, cut from the north-eastern slope of the 

 East Rock, New Haven, America, destined for the foundation of 

 a wharf. While thus employed, he took particular notice of the 

 successive layers, each of which constitutes a year's growth of the 

 tree, and which in that wood are very distinct. These layers were 

 of various breadths, and plainly showed that in some seasons the 

 trees made a greater advance than in others, some layers being 

 five or six times broader than others. Every tree had thus pre- 

 served a record of the seasons for the period of its growth, whether 

 thirty years or two hundred ; and every tree told the same story. 

 Thus by beginning at the outer layer of two trees, the one young, 

 the other old, and counting back twenty years, if the young tree 

 indicated by a full layer a growing season for that kind of timber, 

 the older tree indicated the same. " I had then before me," says 

 this intelligent writer, " two or three hundred meteorological 

 tables, all of them as unerring as Nature ; and by selecting one 

 tree from the oldest, and sawing out a thin section from its trunk, 

 I might have preserved one of the number to be referred to after- 

 wards. It might have been smoothed on the one side by the 

 plane, so as to exhibit its record to the eye with all the neatness 

 and distinctness of a drawing. On the opposite side might have 



