702 JOURNAL OF FORESTRY 



windfall and a tree having a sound trunk resists windbreak, and that a 

 tree having infected roots and trunk will be more susceptible to the 

 action of the wind. 



Graves,^ Fiirst,^ Nisbet,^*^ Reuss/^ Bernhardt,'' Fisher/'^ Matthes,^' 

 Weigle and Frothingham,-^ and Weir^^ are some of the investigators 

 in forestry subjects who record the direct relation between defective 

 roots caused by fungi and resultant windfall. Reuss finds a large 

 amount of root rot present on a 48-year-old spruce plantation which 

 had suffered considerable snow-throw and windfall. This rot he 

 ascribed as a cause for the windfall, tracing the entrance of the fungus 

 to a too-deep planting of the roots. Matthes" states that in trees with 

 shallow roots the wind action causes the breakage of many of these 

 roots, even though the tree itself is not thrown. To this wounding of 

 the roots he attributes the majority of the root rot. The attack of the 

 roots by insects is also given as a cause for fungous entry. In respect 

 to root injury as a means of fungous infections, it is well to mention 

 here the part played by fire scars. In a report on the forest reserves, 

 published in 1898, Graves^ states that fire scars at the base of trees allow 

 decay to creep in, thus weakening the trees, causing windfall and also 

 windbreak at the base. Fire scars are among the most important fac- 

 tors in western white pine (Pinus monticola Dougl.) to which fungous 

 entrance is traced. Most of these scars occur as "cat faces" at the base 

 of trees, the fire often exposing and injuring the roots, and in this 

 manner root and butt rots enter the tree. 



Weir-^ gives an account of observations on windfall trees of Douglas 

 fir, western yellow pine, and western larch {Larix occidentalis Nutt.) 

 found upon an area in the Whitman National Forest of Oregon. Root 

 rot was found directly responsible for the weakening of the brace roots 

 and subsequent windthrow. The honey mushroom, Armillaria mellea 

 (Vahl.) Quel., was found to be one of the root fungi attacking the 

 trees. 



The principal fungi concerned in the problem of the relation of fungi 

 to windfall are those which attack the roots either as heart or sap rots. 

 Frequently a typical heart rot of the trunk advances deep into the butt 

 of the tree and invades the heartwood of the roots. The butt rots nor- 

 mally extend to a greater or lesser extent into the roots, advancing a 

 considerable distance into such roots as are large and contain much 

 heartwood. Of the fungi considered above, Fomes annosus Fr. and 

 Armillaria mellea are the most important sap-rotting species. Poly- 

 porus schzveinitzii Fr., Trametes pini (Brot.) Fr., Bchinodontium tine- 



