THE LONGEVITY OF TREES. 117 



kind grow very slowly ; but there are no accounts on record, 

 so far as we can learn, respecting their rate of growth. Our 

 own observations, though not so extended as could be wished, 

 incline us to adopt the standard which De Candolle assumed 

 for the Yew ; namely, the twelfth of an inch for the annual 

 increase of old Cypresses in diameter, when growing in their 

 native forests. But we would only apply this rule to trunks 

 of large size, and with all the precautions that have already 

 been mentioned ; for the Cypress grows, or at least may grow, 

 quite rapidly for the first century or two ; but when old, it 

 appears to increase quite as slowly as the Yew. We have 

 counted sixty layers of the wood in the space of an inch. A 

 fine section of a Cypress-trunk, which grew near Wilmington, 

 in North Carolina, now lies before us, which, on an average 

 radius of twenty-seven inches, or diameter of fifty-four inches, 

 exhibits six hundred and seventy annual layers. It has, 

 therefore, grown throughout at the average rate of less than 

 the twenty-fourth of an inch a year, measured on the radius, 

 or the twelfth of an inch on the diameter. The trunk was 

 thirteen inches in diameter at the expiration of its first cen- 

 tury, and twenty-seven inches about the close of the second ; 

 it added seven inches to its diameter during the third century, 

 and a nearly equal amount during the fourth ; and for the 

 remaining three hundred and seventy years, it grew at a still 

 slower, but, on the whole, nearly equable rate. 



Now it is deemed a safe mode, as we have already shown, 

 to employ the rate of growth deduced from comparatively 

 young trees for the determination of the age of larger and 

 older trunks of the same species. Not only is our estimate, 

 in all such cases, likely to fall below the truth, but the larger 

 the trunk in question the less the danger of exaggeration. 

 Let us apply to the Mexican Cypresses the data furnished 

 by our Wilmington tree. If the Cypress of Montezuma has 

 grown, on the average, even a little more rapidly than the 

 trunk before us, — has increased in diameter at the mean rate 

 of an inch in twelve years, — it must now be fully two thou- 

 sand years old. But if we suppose it to have grown at twelve 

 times this rate (which is the maximum for young Cypresses 



