42 BULLETIN 2>72, U. S. DEPARTMENT OF AGRICULTURE. 



The slower initial but more sustained rate of growth in cypress as 

 compared with the faster initial growth but earlier decline in rate in 

 loblolly pine is clearly seen in Table 9. It is quite notable that 

 between the ages of 90 and 100 years the two species are growing in 

 height at about the same rate, and afterwards cypress leads until 

 about 150 years. In the second century, loblolly pine averages 20 

 feet and cypress 24 feet of growth in height. The region of greatest 

 height for cypress is apparently in South Carolina and Georgia, 

 where also probably occurs the largest average diameter. Stands 

 frequently average 125 feet in height, and individual trees 140 feet 

 high are scattered through the forest. 



GROWTH IN DIAMETER. 



Cypress is popularly considered a tree of very slow growth. This 

 belief is due to the slow rate of growth of virgin timber, and is justi- 

 fied by measurements shown in Table 12. In regard to second- 

 growth or open-grown cypress the case is very different. The diam- 

 eter growth of the latter, shown in Table 11, compares well with that 

 of the more important southern hardwoods and some of the pines. 



Annual increase in diameter is markedly irregular in individuals 

 from year to year, or in successive periods of years. Cypress is 

 extremely persistent in diameter growth. Old hollow trees grow 

 steadily at about the same annual rate for several centuries. 1 In this 

 character, cypress closely resembles the redwoods of the western 

 United States, in contrast with the southern pines, which at a very 

 much earlier age fall off in the rate of their diameter increment. 

 Table 10 shows that there is little variation during the first 200 years 

 in rate of growth at breastheight of virgin cypress in Louisiana. 

 Second-growth in Maryland, between 60 and 100 years, is very 

 uniform at a rate of 1 inch in every 5 years. 



Measurements on trees up to 800 and 900 years old show the 

 beginning of a marked decline in diameter growth at points varying 

 from 350 to 500 years, and occasionally not until the tree reaches the 

 age of 600 years. 



1 Annual rings of growth on the swell-butted stump of cypress axe very faintly marked lines often 

 difficult to distinguish. False rings consisting of well-marked brown bands or stains are numerous, 

 especially in early life, and easily mistaken for true rings unless close attention is given. 



