How does checking in poles affect their strength?
“The question of ‘How does checking in poles affect their strength?’ is raised frequently, probably because most poles exhibit checking to some degree. It is more prevalent in CCA treated poles than in creosote treated poles because the CCA makes the timber more responsive to atmospheric moisture. Most pole specifications allow checks to penetrate to the centre of the pole. In very dry locations checking to this degree can occur and is a natural consequence of the difference in shrinkage in wood between the radial and tangential directions. Briefly, checks have practically no effect on strength. To explain, the effect on bending strength is negligible because the checks do not cut across the wood fibres but they follow the grain. Thus there is no interruption to the ”flow” of stresses along the grain. In fact, the existence of checks indicates the wood has dried out and the pole will therefore, be stiffer and stronger than one which has not dried out.”