46 BULLETIN 272, U. S. DEPARTMENT OF AGRICULTURE. 



to various other species when growing in an excess of water. Tem- 

 porary effects must always be distinguished from permanent injury or 

 benefit, and further detailed observations before and at successive 

 periods following the drainage will be necessary in the case of cypress 

 before the effects can be completely stated. 



CYPRESS STANDS. 



Cypress occurs both in pure stands and in mixture with various 

 hardwoods. It may be said to be a tree of even-aged groups within 

 all-aged stands. This is due to the very intimate relation between 

 water level and successful seed germination mentioned in the discus- 

 sion of reproduction and the transitory character of swamps as com- 

 pared with dry-land farms. In considering trees in the aggregate, or 

 stands, it is essential to know (1) the composition of the stand, and (2) 

 the amount of timber produced per acre under different conditions, 

 or the yield. 



PURE STANDS. 



Cypress forms practically pure stands in the back swamps, ox- 

 bows, or cut-offs, and the deep swampy portions of alluvial river 

 flood plains. These places a,re commonly known as " sloughs" and 

 the bodies of pure cypress as "cypress brakes." In the large inland 

 swamps of the Atlantic Coastal Plain pure stands of cypress occur in 

 the form of concentric rings of progressive-age classes around the 

 bodies of open water. The home of the pure or nearly pure cypress 

 forests of large extent is in Louisiana and Florida, in deep swamps 

 overflowed for a portion of the year. Pure stands of cypress, although 

 widely distributed, are local rather than regional in their occurrence. 

 Cypress is characteristically the dominant tree wherever it occurs. 

 The number of trees per acre and the amount of timber in pure stands 

 is discussed on page 48, under the subject of " Yields." 



MIXED STANDS. 



The home of the mixed cypress and hardwood forest is on the 

 undulating portions of swamps, known as glades. These occupy an 

 intermediate position between the ridge on one side and the slough 

 or back swamp on the other (see figs. 2 and 3, p. 22). In wet or 

 swampy situations in the Southern States slight differences in the lay 

 of the land, with accompanying differences in moisture content, cause 

 a wide diversity in the character of the forest stand. The glade for- 

 mation is the prevailing type over much of the southern swamp lands. 

 During periods of high water the glades are overflowed for several weeks 

 at a time, but become partially drained after the floods disappear. 

 The average water table is usually from 1 to 2 feet below the surface. 

 Over the glades cypress is supreme in all the depressions and water 

 holes, and occurs both in groups and in pure stands. 



