It is greatest in straight-grained specimens with thick-walled fibres.

Cross grain of any kind materially reduces the tensile strength of wood, since the tensile strength at right angles to the grain is only a small fraction of that parallel to the grain.
|--------------------------------------------------------------| | TABLE II | |--------------------------------------------------------------| | RATIO OF STRENGTH OF WOOD IN TENSION AND IN COMPRESSION | | (Bul.

10, U.S.Div.of Forestry, p.

44) | |--------------------------------------------------------------| | | Ratio: | A stick 1 square inch in | | | | cross section.

| | | Tensile | | | KIND OF WOOD | strength | Weight required to-- | | | R = -- --------- +----------------------------| | | compressive | Pull apart | Crush endwise | | | strength | | | |---------------+-----------------+------------+---------------| | Hickory | 3.7 | 32,000 | 8,500 | | Elm | 3.8 | 29,000 | 7,500 | | Larch | 2.3 | 19,400 | 8,600 | | Longleaf Pine | 2.2 | 17,300 | 7,400 | |--------------------------------------------------------------| | NOTE .-- Moisture condition not given.