SUGAR PINE. ; 5 
Since extremely low temperatures do not occur very often in the 
sugar pine belt, frost injuries are infrequent. Sapling and pole 
stands are occasionally injured by the wet snows of early winter, 
but sugar pine suffers less than yellow pine. 
Breakage caused by lightning, winds, or wet snow is serious, not so 
much in itself, as because it opens the way to attack by insects. Not 
infrequently such damage gives rise to epidemic insect infestations. 
STOCK, RODENTS, AND BIRDS. 
Under regulated grazing the damage to young trees by cattle and 
horses is almost negligible. Sheep and goats, particularly goats, how- 
ever, do appreciable damage by tramping down and nipping the 
leaders of young seedlings and saplings. Such stock should not be 
close-herded on areas of promising young forest, and should be 
moved frequently. They should be excluded from cut-over areas 
until reproduction is well started. 
Each year the red or Douglas squirrel and the gray squirrel cut 
large quantities of cones, often while still unripe, and consume or 
store the edible seed. Other smaller rodents, as well as quail and 
jays, relish it also. The gray squirrel is so destructive to the seed 
of this species as to cast doubt upon the wisdom of according him. 
-the protection of the game laws in heavily forested counties. Wood 
rats and rabbits are destructive in young sugar pine plantations, 
sometimes cutting back every tree to the surface of the ground. 
DISEASES. 1! 
Sugar pine is without doubt one of the healthiest of our coniferous 
trees: Even the younger parts, such as the twigs and needles, are 
rarely attacked by the ordinary enemies of associated tree species, 
such as mistletoe (Razovmofskya cryptopoda), which frequently causes 
the formation of heavy witches’ brooms and gnarls the branches of the 
yellow, Jeffrey, and lodgepole pine. A small bluish witches’ broom, 
caused either by a parasitic fungus, cr more probably, a mite, and 
resembling a spiny ball from 1 inch to 20inchesin diameter, is fairly com- 
mon throughout the Sierra Nevadas. An unidentified species of Perider- 
muum, probably P. harknessi, is also occasionally found on sugar pine. 
The foun caused by these diseases is, however, insignificant. The 
wood-destroying fungi cause more fern ee. but the loss is rarely more 
than 3 per cent of the gross board measure content of the stand. The 
_ fungi almostinvariably attack the heartwood of the older and more valu- 
able trees; therefore, though the number of trees killed is small, the 
monetary loss through their work is appreciable. Trametes pini and 
Fomes larvcis are by far the most destructive of the wood-destroying 
fungi which attack sugar pine. Sporophores of Fomes pinicola have 
1 Inquiries regarding diseases of forest trees should be HECEESSES to the Bureau of Plant Industry, U. S. 
Department of Agriculture. 
