30 BULLETIN 604, U. S. DEPARTMENT OF AGRICULTURE. 



control is the first step in eliminating the disease. Where possible, 

 also, trees with large wounds, whether from fire or otherwise, should 

 be marked for cutting in preference to sound ones, and no trees with 

 a fruiting body of Polyporus amarus or with the cup-shaped depres- 

 sions described above should be left standing. 



FIRE. 



Repeated ground fires are responsible for considerable damage 

 throughout the range of incense cedar, and few mature trees are 

 to be found that do not show some evidence of this in burned butts 

 and cat faces. In some regions fire damage has been extreme, prac- 

 tically every tree being hollowed out at the base or felled by repeated 

 fires. The thick bark of this species and its rather fire-resistant 

 foliage offer considerable protection to mature trees; but severe 

 fires, especially where there is an accumulation of debris, do a 

 great deal of damage, since the somewhat resinous bark burns like 

 punk, and a fire once started in it often burns for a long time. Re- 

 peated fires eat into the tree, each successive fire enlarging the 

 wound already made and increasing the danger of infection from 

 disease. Incense cedar is, however, persistent, seldom succumbing 

 to fire alone unless completely girdled or so burned out at the base 

 that it falls through lack of mechanical support. Burning stimu- 

 lates the natural tendency of the tree to buttress, extraordinary 

 growth frequently being made in this way in an attempt to overcome 

 the damage done. 



In stands of young cedar damage from fire is usually more severe, 

 owing to the thinner bark and the greater exposure of the crown to 

 the heat of the flames. Although somewhat more fire resistant than 

 the more resinous pines, its power of recovery is less, and it ranks 

 after yellow and sugar pine, owing apparently to a lower fire resist- 

 ance of the terminal buds. As a consequence, an incense cedar when 

 scorched is usually as severely damaged as appears at first, while 

 pines frequently recover entirely in a year or two, though at first the 

 entire crown apparently has been killed. 



The greatest damage by ground fires is to reproduction. No 

 matter how light the fire, the smaller seedlings, growing half buried 

 in the litter, are destroyed, and no future stand can be expected 

 where the practice of light burning is followed or adequate fire 

 protection is not given. 



INSECTS. 



Incense cedar rarely is killed by insect infestation, except in the 

 seedling and sapling stage. Like the sequoias, mature trees are prac- 

 ticallv immune from attacks causing death in one season. Mature 



