CHAPTER VTI 



HEART-HOT CLAUSED ?>V OTHER FUNGI 



Poh/ponts Schirn'm'tzii, Pmia rnpnrdrid, Pdliipnrii-'^ xiilphtircii.'^. Trnmetes 

 Pini. 



lloart-roi eauspcl hy Polyporus Scliwcinitzii, Fr. Next to 

 Fames annosvs tliis fungus is the most frequent cause of 

 lieart-rot. Tliougli in many respects resembling the two 

 following diseases, this rot may easily be distinguished from 

 that caused by the Fowc.^ by the rotted wood being very- 

 dry, light, and frial)le, and not spongy or fibrous. It has 

 marked cleavage surfaces whicli are at right angles to each 

 other, so that the wood l)reaks up qasily into more or less 

 cubical blocks, and, owing to shrinkage, the cracks often 

 open before the tree is felled and tlie interstices become 

 filled with white mycelium wiiieh frequently becomes 

 embedded in resin and assumes a chalky consistency. When 

 the rot is fai- advanced the wood is usually light or dark 

 brown and reeks strongly of turpentine. 



The fungus enters by the roots and grows up the stem, 

 and is in the vast majority of cases confined to the heart- 

 wood. But dead trees are occasionally found in \\lii(h all 

 the wood u]) to 20 ft. or more from the giouiid is rotted. 



The disease is reported as faii'ly common on llie Ton- 

 tinent, especially on Scots ])ine, Weymouth pine, and 

 larch. There are frequent notices of it in the TnitcMl States 

 of America on Weymouth ])ine, balsam fir, white and red 

 spruce, and arhoi- vitae, and in New England it is con- 

 sidered one of the most (h'structive diseases (Schrenk, 1000). 

 In Scotland, Muii'ay (191(5) reports it as occuning on 

 Douglas, spruce, and Scots pine. My own observations 

 have been made in the south of b]ngland, where I have 

 found i1 on Scots pine, cluster pine, and laicli. chiefly in 

 Sussex, Suirev. Beikshire. .iiid l)c\ (insiiire. ImiI I li;i\-e no 



