The rows of trees intersect each other at right angles, and cultivation may be carried on conveniently either crosswise or lengthwise of the orchard. The planter has the choice of placing the trees the same distance apart both ways, or of planting them closer together in the rows than the distance between the rows. [Illustration: FIG. 30. Rectangular Planting System.] It has been argued that space is not equally divided among the trees, and while this is apparently true, yet, on the other hand, the roots of pecan trees, in most cases, penetrate and permeate all the space allowed in ordinary distances. The roots will certainly secure all the food and moisture in the top two or three feet of soil. When trees are to be planted by this system, the stakes must be set so as to be exactly in line, whether viewed from the end or from the side of the field. _Hexagonal, Septuple or Equilateral Triangle System._ By this system, six trees are set equidistant from a seventh placed in the center. The basis of the system is not the square, but the circle, since the radius of the circle is approximately equal to one-sixth of the circumference of the circle. The name septuple, sometimes applied to this system, refers to the fact that the number of trees in each group-unit is seven. Equilateral triangle system refers to the planting of the trees in equilateral triangles, but is identical with the hexagonal or septuple. [Illustration: FIG. 31. Hexagonal Planting System.] It is the only system whereby each tree is placed equally distant from each of its adjoining neighbors, and the only system which equally divides the space among the trees. By this method about fifteen per cent. more trees can be set per acre than by the rectangular. For permanent plantings, at regular distances, this system and the rectangular should be recommended before other systems. LAYING OUT BEFORE PLANTING. Level and smooth the ground, harrow and pulverize thoroughly, then proceed to stake the ground off, placing a stake for every tree. _Laying Out Squares or Rectangles with the Plow._ If a good plowman can be secured, very satisfactory work can be done with the plow. In some cases a man can be found who needs nothing in the way of a guide, except two or three stakes. But with a sufficient number of stakes and a marker attached to the plow, good results can be secured by almost any plowman. Furrows should be run both lengthwise and crosswise of the field, their intersections marking the place where the trees are to stand. At each one set a stake. It is essential that a true, square corner should be secured. This may be done by sighting with an ordinary carpenter's square set upon three posts.