1G4 TREE GROWTH. [July 



"At Harrisbiirg, or Juneau, in latitude 58°, a Sitka spruce (Ahics 

 SitJcensis) cut down gave 149 rings from centre to circumference — 

 298 lines in a trunk 3 feet across. This gave an average of about 

 8 to an inch in this 149-year old 3 -foot tree. At Wrangel, in lati- 

 tude dd"^ 30', a tree of the western hemlock (Abies Mcrtcnsiana) 

 which had been blown down, and afterwards divided by a cross-cut 

 saw at 4 feet from its base, gave 1 8 lines to an inch, and the annual 

 growths seemed very regular, almost to the centre of the tree. It 

 was 6 feet in diameter, and must have been a grand old tree in its 

 day. It had evidently been broken off years before it was blown 

 down, but the length of the trunk up to Avhere it had been broken 

 was 132 feet, and 4 feet in diameter at that height. But, allowing 

 as much as 12 to an inch, it would give for the point cut across, 

 6 feet, an age of 432 years. At Kaigan Harbour, latitude 55°, the 

 Sitka spruces were very large and of great height. We measured 

 two of the largest, which were 21 feet in circumference each. 

 Allowing 8 to the inch, as in the tree of the same species at Harris- 

 burg, it gives 336 years as the age of the tree. So far as appear- 

 ances w^ent, these trees were in the height of vigour, and there 

 seemed no reason, judging from experience in other cases, why they 

 might not flourish for 100 years yet." Mr. Meehan had no doubt 

 that these trees in these latitudes in Alaska would easily have a life 

 of 500 years. 



In contrast to this, trees famous for longevity in Europe are 

 comparatively short-lived in the Atlantic States of the American 

 Union, where 200 years is the average lifetime of a forest tree. 

 Thus the English oak (Quercus robur), said to live 1000 years in its 

 native clime, has grown to full size and died away in the old 

 Bartram Garden near Philadelphia when little more than 150 years 

 old. So silver firs (Ahics pectinata) planted in the same vicinity in 

 1800 are decaying. This is the general experience. And the 

 difference appears caused by the relative humidity of the atmo- 

 sphere in the two countries. Evergreens, like Cerasus, Lauro-cerasus, 

 LaiLTus nohilis, and Vihurnum Units, will endure a temperature of 

 25° below freezing-point in Great Britain, but are killed at 10° in 

 Philadelphia. On the contrary, the climate of Alaska has the same 

 favouring influences which influence that of Great Britain. The 

 presence of the Warm Sea of Japan on its south-eastern border, 

 where the great trees grow, a moist atmosphere, and almost no 

 severe weather, winters where no ice is seen, all favour the 

 longevity of trees. 



