58 



BULLETIN 272, U. S. DEPARTMENT OF AGRICULTURE. 



because of the high expense in handling and the low grade of the 

 product. The percentage of increase in volume is relatively much 

 greater in trees from 10 to 18 inches in diameter than in larger trees. 



COST OF PROTECTION, THINNING, ETC. 



The holding of a small portion of the virgin stand for a second cut 

 entails no essential additional outlay. Fire menace is at a minimum, 

 and no other form of damage requires attention, including- timber 

 trespass and grazing. In case planting is done to fill in blank spaces, 

 an additional expense of between $4 and $10 per acre must be 

 reckoned. A detailed account is given on pages 67 to 69. 



VALUE OP CROP PRODUCED. 



Cypress trees from 15 to 18 inches in diameter left on cut-over 

 land in southern Louisiana, 1 measured in 1908, 1910, and 1913, were 

 found to be increasing in breast-high diameter at the rate of an inch 

 in a little over two years. Trees of the younger classes on cut-over 

 lands will be stimulated in growth by the admission of additional 

 light. Table 16 shows the average volume in board feet for cypresses 

 of various diameters, also the corresponding increase in volume for 

 each increase of 1 inch in breast-high diameter. For example, a 

 15-inch cypress contains 23 board feet more than a 14-inch tree. 

 If the rate of growth is an inch in diameter in 3 years, the volume of 

 the tree is increasing 8 board feet a year. Growing at the same rate, 

 an 18-inch tree adds about 10 board feet, and a 24-inch tree 20 feet 

 annually. A slower growth of 1 inch in 4 years will give slightly 

 decreased figures. It is known that the rate of diameter growth 

 remains about constant in cypress for the sizes shown in the table. 



Table 16. — Rate of increase in volume for second-growth cypress trees, 10 to 24 inches 

 in diameter {Southern United States) . 



Diameter 



Volume 







Annual rate of increase in volume. 



Increase in volume 









breast- 



of tree 



from preceding di- 



Rapid 



Moderate 



Slow 



high. 



(Doyle 



ameter class. 



growth ■ 



growth 



growth 





rule). 





(1 inch in- 



(1 inch in- 



(1 inch in- 









crease in 3 



crease in 4 



crease in 6 









years). 



years). 



years). 



Inches. 



Boardfect. 



Boardfect. 



Per cent. 



Per cent. 



Per cent. 



Per cent. 



10 

 11 



20 

 37 













17 



S5 



28.3 



21.2 



14.2 



12 



54 



17 



46 



15.3 



11.5 



7.7 



13 



72 



IS 



33 



11.0 



8.2 



5.5 



14 



92 



20 



28 



9.3 



7.0 



4.7 



15 



115 



23 



25 



8.3 



6.2 



4.2 



16 



141 



26 



23 



7.7 



5.8 



3.8 



17 



169 



28 



20 



6.7 



5.0 



3.3 



18 



200 



31 



18 



6.0 



4.5 



3.0 



19 



234 



34 



17 



5.7 



4.2 



2.8 



20 



271 



37 



16 



5.3 



4.0 



2.7 



21 



312 



41 



15 



5.0 



3.8 



2.5 



22 



359 



47 



15 



5.0 



3.8 



2.5 



23 



413 



54 



15 



5.0 



3.8 



2.5 



24 



473 



60 



15 



5.0 



3.8 



2.5 



i Belle River, Grand River Basin, St. Martins Parish, La. 



