PLATE II 
In these specimens from a virgin or first-year operation at Columbia, Miss., 1916, the bark appears at 
the top of the figure in all except figure 4. The 1916 ring or its incipient formation is shown next the bark. 
All the other rings shown were formed by the trees before turpentining began. 
AR, annual ring; SP, spring wood; SM, summer wood; T, tracheids or wood fibers; R, rays; and 
GP, groups of parenchyma cells or resin passages. 
Fig. 1.— An example of the condition of the tree on April 13, 1916. No wood or resiniferous tissue had 
fully differentiated, but cambial activity (preliminary stages of wood formation) is apparent (at C) 
next the bark. 
Fig. 2.— By June 13, 1916, at least 5 or 6 tracheids are apparent, and resiniferous tissue appears to be 
about to differentiate. In the first year several rows of wood cells usually formed before resin passages 
were produced. 
Fig. 3.— Specimen cut July 5, 1916. Numerous resin passages present developed early in the annual 
ring. Compare size of passages in the 1916 ring with size of those in the other rings. 
Fig. 4.— Tangential section through 1916 ring, showing longitudinal view of vertical resin passages (GP), 
formed in a turpentined tree. Also T, tracheids; R, ray parenchyma; FR, ray with horizontal resin 
passage; and X, a crossing of the vertical and horizontal resiniferous systems. 
Fig. 5.— Specimen cut July 5, 1916. In the 1916 ring, forming next the bark, are tangential series including 
several resin passages. This very abundant formation of resin passages accompanies the wounding or 
turpentining. The exudation from these is shown in Plate III, figure 2. 
