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 OF CROP PRODUCED. 
Cypress trees from 15 to 18 inches in diameter left on cut-over 
land in southern Louisiana,’ 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). 
Annual rate of increase in yolume. 
Diameter) Volume | Increase in volume 
breast- | oftree | from preceding di- Rapid Moderate Slow 
high. (Doyle ameter class. growth growth growth 
Tule). (1 inch in- } (1 inch in- | (1 inch in- 
crease in 3 | crease in 4 | crease in 6 
years). years). years). | 
Inches. |Board feet.| Board feet | Per cent.| Percent. | Percent. | Percent. 
20 
TU igs PRMD Fast] Ra eM ae | NE | Cage Aree Gee ae ee phe Rt as Se 
11 37 17 85 28.3 21.2 14.2 
12 54 17 46 15.3 11.5 nor 
13 72 18 33 11.0 8.2 5.5 
14 92 20 28 9.3 720 4.7 
15 115 23 25 8.3 6.2 | 4.2 
16 141 26 23 Wad 5.8 3.8 
17 169 28 20 6.7 5.0 328 
18 200 31 18 6.0 4.5 3.0 
19 934 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 
93 413 54 15 5.0 3.8 2.5 
24 473 60 15 5.0 3.8 2.5 
1 Belle River, Grand River Basin, St. Martins Parish, La. 
