Polyporus Hispidus and a Canker of Oaks

Polyporus hispidus has been recognized as a serious heartwood-rotting fungus for many years. Evidence is submitted that an important canker or oaks also is caused by this fungus. A study of an area in Connecticut showed that 2 per cent o! the white oak, 8 per cent of the chestnut oak, and 13 per cent of the black oak had cankers. The average total loss resulting from the cankers amounted to 2 per cent of the cordwood volume and 3 per cent of the boardfoot volume. In a selected one-tenth acre plot the loss amounted to 29 per cent of the cordwood volume and 33 per cent of the boardfoot volume. Felling and, where possible, utilizing infected trees is the best method of control.