PLATE V

In each case the specimens came from the Columbia, Miss., tract and were cut midway between the shoulder and the peak at the streak. The bark is shown at the top of each figure. The two annual rings next the bark (top) were formed during turpentining in 1916 and 1917, respectively. The other rings (below) were formed by the unturpentined timber. In all figures the greatest number of resin passages is present in the rings formed after turpentining.

SPECIMENS FROM THE DOUBLE-CHIPPED AREA CUT NOVEMBER, 1917

FIG. 1.-Marked reduction in ring width and amount of summer wood accompanying turpentining. This was generally greatest in trees with vigorous wood formation.

FIG. 2.-Tendency to increased ring width in 1916 but reduced summer wood formation. Both ring width and summer wood were reduced in 1917. At this height resin passages are present earlier in the 1917 spring wood than in that of 1916, where probably short resin passages, formed in 1916, have been cut away by chipping.

SPECIMENS FROM THE NARROW-CHIPPED AREA

FIG. 3.-Specimen cut November, 1917. The 1916 and 1917 rings are both wider than the rings formed during the three years previous by the unturpentined timber. The 1917 ring is somewhat wider than the 1916 ring, showing the sustained vitality of the tree in spite of turpentining, and of a poorer season

in 1917.

FIG. 4.-Specimen cut July 24, 1917. Here also sustained vigor associated with this rather conservative method is apparent. Note the closed condition of the resin passages.

FIG. 1.-Cross section, cut April 24, 1916, from the peak, about 6 feet above the ground, of one of the trees shown in figure 4. The effects of 2 years of heavy chipping are manifested, even in this vigorous timber, by reduction in width of ring and in amount and density of summer wood in the 1914 and 1915 rings. More resin passages than usual are present. The effect of the wound is apparent in the wood formed 6 feet above it in the 1914 ring. No wood formation for 1916 had occurred. Material from near Bogalusa, La.

FIG. 2.-A boxed tree heavily chipped for five years. Wood structure shown in figure 3. Tree near Florida National Forest.

FIG. 3.-Specimen cut from the peak of the tree shown in figure 2, about 8 feet above the ground. The response to turpentining is apparent in reduced wood formation in the five annual rings next the bark (top). The effects in the ring formed when turpentining was first begun were produced about 8 feet above the wound. The specimen was cut in May, 1916. No wood formation for that year was yet apparent.

FIG. 4.-Timber of which the specimen shown in figure 1 is an example.

FIG. 5.-Very heavy chipping was used on this small tree for 3 years. The wood formation was markedly reduced. The specimen was cut May 6, 1916. No wood formation for that year had occurred. FIG. 6.-Specimen from a conservatively chipped small tree. (Second year of turpentining by the French method.) This tree is from the same locality as the specimens shown in figures 3 and 5. Here, however, 5 or 6 rows of wood cells and one series of resin passages were already formed by May 6, 1916 (top next bark). In 1915, the first year of turpentining, summer wood formation was not reduced in this specimen.