AND HORTICULTURIST. 



371 



Natural History and Science. 



COMMUNICATIONS. 



LONGEVITY OF TREES. 

 BY THOMAS MEEHAN. 



At the meeting of the Botanical Section of the 

 Academy of Natural Sciences, of Philadelphia, 

 Mr. Thomas Meehan remarked that there was 

 nothing phenomenal in the great age of the mam- 

 moth Sequoias, as other trees on the Pacific Coast 

 exhibited great age. In order to ascertain wheth- 

 er more than one annual circle of wood is formed 

 in each year, he tested the matter in various ways. 

 For instance, a pine or spruce would be found 

 to make an average growth of a foot a year up to 

 fifteen years old ; from that to about thirty years, 

 nine inches ; from that on, six inches ; after that a 

 stage was reached where the erect growth ceased 

 to any considerable extent, and the growth force 

 seemed turned towards the lateral branches. In 

 the pine forests of the Pacific Coast there was no 

 danger of error in fixing the age of the average 

 tree of sixty feet high at about fifty years. When- 

 ever such a tree was cut down, and an opportunity 

 afforded to count the circles, they would be found 

 to correspond so nearly with the calculated age, 

 as to prove that it was quite safe to assume a 

 single circle for a single year. Then there was a 

 remarkable degree of uniformity in the diameter 

 of these annual growths in most trees, so that 

 when once we had the number of circular lines 

 to an inch, and the diameter of the tree, we could 

 tell its age near enough for general purposes. In 

 some pine trees growing on very rich soil, he had 

 found as few as about four circles to an inch. 

 For instance, a section of a Pinus Lambertiana in 

 Mariposa, four feet across, had but 189 circles ; 

 but here the increased size of the trees corresponds 

 with the larger annual circles. Trees of this 

 species of pine here measuring thirty, and a few 

 thirty-three feet round were not uncommon. No 

 matter, however, how vigorous may be the growth 

 of trees under fifty or over one hundred years, 

 they decrease with age, and we may safely allow 

 six rings to an inch in these older sugar pines, 

 which would make the thirty-three feet tree 396 



years old. The outer growths of sequoia were 

 very narrow. He counted as many as eighteen 

 to the inch, while the rings in the interior of cross- 

 sections would show about six to the inch. Allow- 

 ing twelve as the average per annum, a tree of 

 thirty-three fe^t diameter would give 2,376 years 

 old, which is about the same as given by an actual 

 count of the rings. 



At Harrisburg, or Juneau, in latitude 58-, a 

 Sitka spruce (Abies Sitkensis) cut down gave 149 

 rings from center to circumference— 298 lines in 

 a trunk three feet across. This gave an average 

 of about eight to an inch in this 149-year-old, 

 three-foot tree. At Wrangel, latitude 56° 30', a 

 tree of the Western Hemlock (Abies Mertensiana) 

 which had been blown down and afterwards divi- 

 ded by a cross-cut saw at four feet from its base, 

 gave eighteen lines to an inch, and the annual 

 growths seemed very regular almost to the centre 

 of the tree. It was six feet in diameter, and must 

 have been a grand old tree in its day. It had evi- 

 dently been broken off years before it was blown 

 j down, but the length of the trunk up to where it 

 had been broken was 132 feet, and four feet in 

 diameter at that height. But allowing as much as 

 twelve to an inch, it would give for the point cut 

 across, six feet, an age of 432 years. At Kaigan 

 Harbor, latitude 55°, the Sitka spruces were very 

 large, and of great height. He measured two of the 

 largest, which were twenty-one feet in circum- 

 ference each. Allowing eight to the inch, as in the 

 tree of the same species at Harrisburg, it gives 336 

 years as the age of the tree. So far as appearances 

 went, these trees were in the height of vigor, and 

 there seemed no reason, judging from experience 

 in other cases, why these trees might not flourish 

 for a hundred years yet. Mr. Meehan had no 

 doubt that these trees in these latitudes in Alaska 

 would easily have a life of 500 years. 



Turning now to the Atlantic States, we find 200 

 years as the full average term of life for its forest 

 trees, with the exception, perhaps, of the plane 

 (Platanus occidentalis), which is the longest lived 

 of all. Trees famous for longevity in Europe are 

 comparatively short lived here. In the old Bar- 

 tram Garden near Philadelphia, and where the 



