296 



Yearbook of Agriculture 1949 



length of this period should depend on 

 the time at which the stand will need 

 thinning. If no thinning will be re- 

 quired for 10 or 20 years, then two or 

 even three faces can be worked one 

 after another on each marked tree. On 

 the other hand, if the stand is over- 

 crowded and needs thinning soon, the 

 trees can be turpentined heavily with 

 the use of acid on one wide or two 

 standard faces for 1 to 3 years before 

 they are removed. The number of well- 

 stocked natural and planted stands is 

 increasing rapidly, and these new tech- 

 niques for rapid turpentining in ad- 

 vance of thinning in crowded stands 

 should become increasingly applicable. 



The best guide to the need for thin- 

 ning in a southern pine stand is the 

 proportion of the total height of the 

 tree that is occupied by live crown. 

 The stand should be so managed as 

 to keep this proportion between 30 and 

 40 percent for wood production and 

 perhaps somewhat nearer 50 percent 

 for maximum gum production. 



The optimum density to be main- 

 tained under management in naval 

 stores stands of different ages and on 

 different soils has not yet been deter- 

 mined. A rule of thumb for selecting 

 trees for cupping 3 to 5 years in ad- 

 vance of thinning is to leave between 

 the reserved trees a space equal in feet 

 to twice the average tree diameter in 

 inches. Thus the space between an 8- 

 and a 12-inch tree would be about 20 

 feet (10X2), which is also equal to 

 the sum of the two diameters in inches. 



Where selective cupping results in 

 tapping a smaller number of trees per 

 acre, it results in some increase in cur- 

 rent production costs. However, a 

 stand that is dense enough for a thin- 

 ning will ordinarily provide an accept- 

 able number of trees for turpentining, 

 just as it would for selective cutting. 

 If a loss of efficiency is occasioned by 

 wider spacing in a given selective cup- 

 ping, it should be repaid with interest 

 in the second cupping cycle, when the 

 next trees to be tapped will be con- 

 siderably larger in diameter. A 12-inch 

 tree yields 50 percent more gum than 



a 9-inch tree, although the increased 

 cost of turpentining per tree is negli- 

 gible. On the Osceola National Forest 

 northeastern Florida, the plan of 



n 



management calls for three successive 

 cycles of turpentining before the stand 

 is removed. In each cycle, those trees 

 are turpentined which a forester has 

 marked to come out in the next thin- 

 ning or other cutting. 



In understocked stands, where thin- 

 ning is not needed, the owner has a 

 choice of deferring any turpentining 

 until the trees are larger and denser, or 

 cutting off the stand and replanting it, 

 or marking it for a seed-tree cutting to 

 get reproduction. The important pre- 

 caution is that he should not simply cup 

 every tree over 9 inches without know- 

 ing what his next step in stand manage- 

 ment is to be. 



The regeneration of the even-aged 

 stands of slash pine is no problem as 

 long as there is sufficient seed source. 

 In longleaf pine, regeneration by natu- 

 ral means is a good deal less certain. In 

 Florida the preference is toward leav- 

 ing longleaf seed trees in groups. Long- 

 leaf pine seedlings need sizable open- 

 ings wherein to become established. 



Repeated and untimely fires are the 

 worst enemy of reproduction, and 

 many areas with a seed source restock 

 rapidly as soon as they are brought 

 under protection. Other areas may 

 have so much vegetative growth that 

 reproduction is facilitated by using 

 carefully controlled fire to burn off the 

 accumulated "rough" in advance of 

 seedfall. 



Improvements in planting machines 

 and the shift to more intensive forestry 

 will probably result in a great increase 

 in forest planting in the naval stores 

 belt. In the future the problem of 

 "nonrestocking lands" ought to vanish. 



BURNING THE WOODS to improve the 

 forage is common practice in the naval 

 stores area. In the open-range sections, 

 where the law allows unrestricted graz- 

 ing of unfenced land, the landowner 

 either has to burn his land or expect 

 others to burn it for him. If the land 



