22O 



make the better trees grow tall and 

 straight. 



When to thin is important. Usually 

 thinning is needed : 



(a) In young, fully stocked stands 

 when about 15 to 20 years old; 



(b) in the young stands that have 

 stopped growing or become stagnated ; 



(c) when the crowns of young trees 

 are crowded and many dead branches 

 occur; 



(d) when an interval of 5 to 1 

 years has passed between thinnings and 

 the trees again crowd each other. 



How to thin is sometimes more diffi- 

 cult than knowing when to thin. 



A single thinning should not remove 

 more than one-quarter of the volume 

 in a stand. 



Yellow-poplar, cottonwood, sweet- 

 gum, loblolly pine, slash pine, and any 

 fast-growing trees can be thinned more 

 heavily than trees such as white oak, 

 basswood, and ash. 



For southern pines and hardwoods 

 the rule of thumb called D+6 is often 

 used. For example, the diameter at 

 breast height of one healthy tree is 10 

 inches and the diameter of the other 

 healthy tree is 6 inches. Added together 

 and divided by 2, the average diameter 

 of the two crop trees is 8 inches; 8 

 inches considered as 8 feet, plus 6, 

 equals 14 feet, the proper spacing be- 

 tween crop trees of this size. 



In the West, the rule D + 4 can be 

 used for spacing crop trees of pon- 

 derosa pine. Other species may require 

 different spacing and local advice may 

 be needed in such cases. 



Good sense is needed in thinning 

 the small forest. Following a rule may 

 result in thinning a clump of 6 to 10 

 good trees to only 2 or 3, when actually 

 it might be better to cut only 2 or 3 

 trees, which will give the clump plenty 

 of room to grow. 



When a fast-growing young tree is 

 directly under a mature tree that is 

 soon to be cut, the young tree should 

 be left for a future cutting. 



Consider each tree individually and 

 determine its chances of growing into 

 good timber. 



Yearbook, of Agriculture 1949 



3. Liberation and salvage cuttings 

 are part of the care. Wolf trees large, 

 branchy individuals with spreading 

 crowns often keep down the more 

 desirable little trees that should be 

 growing for the future. Forked, knotty, 

 crooked, and other poorly formed trees 

 also take up space needed by better 

 seedlings and saplings. Diseased, rot- 

 ting, as well as insect-infested trees will 

 probably die before they can be cut 

 into fuel wood or fence posts; they 

 should be removed by poisoning or by 

 girdling with an ax. 



The undesirable hardwood trees and 

 sprouts can be poisoned successfully 

 with Animate ( the trade name for am- 

 monium sulfamate) . This poison can 

 be applied close to the base of the tree. 

 Chip out small cups in the tree trunk 

 with an ax at 6-inch intervals around 

 the tree. Place 2 level tablespoonfuls of 

 Ammate crystals in each cup for trees 

 4 inches in diameter and over. For 

 trees under 4 inches in diameter, 1 

 tablespoonful a cut is enough. Leave 

 the trees to die; they should not be 

 girdled or cut down because sprouting 

 might occur. After a year, it is gen- 

 erally safe to cut the tree down if you 

 want to. Use the poison in late sum- 

 mer or early fall. A 32.5-percent water 

 solution of Ammate sprayed on green 

 leaves will kill small trees and sprouts 

 of undesirable species, such as black- 

 jack oak. 



Other poisons, obtainable from seed 

 houses, are used for killing undesirable 

 trees and shrubs like the persimmon, 

 blackgum, and sweetgum. 



Vines growing on trees kill them by 

 shading or bending. Protect the crop 

 trees by cutting the vines off at the 

 ground. 



Usually it is best to make a libera- 

 tion cutting in early summer; sprouts 

 from fresh stumps are less likely to ap- 

 pear then ; and, it is easier to see which 

 trees to cut. 



Salvage cutting means removing the 

 overripe trees that are growing too 

 slowly to be profitable. Overripe trees 

 are usually recognized by their light- 

 colored bark, flattened crowns, and 



