34 BULLETIN 2*72^, U. S. DEPARTMENT OF AGRICULTURE. 



cypress about 265 years old (PL VII). Outside of these successive 

 age classes in the form of concentric rings, the main stand was mostly 

 300 to 400 years with a considerable mixture of bays and gum. In 

 logging, only a few of the larger trees in the 140-year-old class and 

 practically all of the surrounding older stand were taken. 



The subsidence theory. — The theory that the Atlantic and Gulf 

 coasts are gradually sinking is held by some to account for the irregu- 

 lar and unsatisfactory reproduction of cypress. This theory of a 

 general subsidence is one upon which authorities hold quite opposite 

 views. Those who believe in subsidence indicate a rate of about 

 one-tenth of a foot in a decade. Cypress seed, however, usually 

 germinates the first year, and the seedling makes an average growth 

 of from 10 to 18 feet in height during the first decade. The prevail- 

 ingly better reproduction of cypress on low wet situations than on 

 better drained or upbuilding soils, except near salt water, is an 

 evidence against the adverse effect of any subsidence that may be 

 in progress by either checking the incoming of reproduction or sub- 

 sequently retarding its growth. The effects, if any, from subsidence at 

 so slow a rate would be more apt to appear in the tree during periods 

 measured in centuries than during the few years of the reproduction 

 stage. On upbuilding lands cypress is clearly receding before the 

 hardwoods, and similarly, the best reproduction of cypress is found 

 in very wet situations, where it is equally the dominating and the 

 advancing species over all associated swamp hardwoods. 



DEMANDS UPON CLIMATE AND SOIL. 



Cypress grows in a wide range of temperature. Its natural range 

 extends from below the frost line in southern Florida northward to 

 New Jersey. Its extended potential range takes it northward to a 

 line connecting Massachusetts and Michigan, where it experiences 

 minimum temperatures of about —20° F. More than 90 per cent of 

 the total cypress stand is found at an elevation of less than 100 feet 

 above sea level. In the Middle Atlantic coastal States the 100-foot 

 contour marks the upper line of elevation, while over the central 

 Mississippi Basin the species prevailingly stops at an elevation of 

 about 500 .feet. Hundreds of miles west of the great coastal swamps 

 cypress reaches large size around the edges of deep hollows on the 

 Edwards Plateau of Texas at elevations ranging from 1,000 to 1,750 

 feet. It appears that atmospheric moisture and rainfall both play 

 an unimportant part in the distribution of cypress, as compared with 

 soil moisture. 



SOIL. 



Cypress thrives in a wide variety of soils, including muck, clays, 

 and the finer sands. It has been commonly reported that sandy 



