FOREST PROTECTION 



209 



80 percent of which was spent by the Federal 

 Governm.ent (table 129). Ninety-seven percent 

 of this Federal expenditure went to the blister 

 rust program. Of the States' share, 80 percent 

 went to blister rust, 13 percent to oak wilt, and 

 the remainder to other diseases. The Nation's 

 effort in forest disease control cannot be appraised 

 fairly by the expenditures listed in table 129, 

 since these were only the direct costs and were 

 made largely for the control of one disease. 



Table 129. — Expenditures for direct control of 

 forest diseases in continental United States, 1.952 



Disease 



White pine blister rust 



Oak wilt 



Brown spot of longleaf pine 



Dwarf mistletoe 



Fusiform rust of southern 



pines 



Larch sanker 



Miscellaneous diseases 



Total 



State 



and 



private 



Dollars 



608, 700 



101, 700 



17, 000 







8, 900 



200 



23, 800 



760, 300 



Federal 



Dollars 



2, 995, 000 



25, 900 



34, 800 



19, 000 



600 



6, 200 



15, 500 



3, 097, 000 



Total 



Dollars 



3, 603, 700 



127, 600 



51,800 



19,000 



9, 500 



6, 400 



39, 300 



3, 857, 300 



Control Through Silviculture Gaining 

 Ground 



As has been mentioned, most control efforts 

 are predicated on adjustments in forest manage- 

 ment practices. The impacts of many of the 

 diseases listed in table 128 can be materially 

 lessened through corrective silvicultural measures. 



Heart rots are major factors in determining 

 the best rotation age for many species, particularly 

 when they become critical at early ages, as in 

 aspen and balsam fir. The changed cull status 

 between the old unmanaged southern pine timber 

 and the younger second-growth forests of today 

 indicates the relation between overage and heart 

 rot, since cull in the old timber usually made up 

 over 20 percent of the volume, while the mean 

 southern pine rot cull in 1952 was estimated at 

 only 3 percent. 



Butt rot losses are being curtailed through fire 

 protection and greater care in logging. Trunk 

 rots are being checked by reducing logging damage, 

 removing high rot-risk trees in partial cuts, making 

 salvage cuts in badly damaged stands, pruning 

 in the case of ponderosa pine, and, with some 

 highly rot-susceptible species, adjusting rotation 

 ages to minimize decay loss. Much of the 

 merchantable volume lost to heart rots and sap 

 rots can be reduced only through judicious 

 scheduling of salvage operations. 



Dwarfmistletoe dam.age can be checked by 



removing the parasite from the overstory in the 

 course of harvesting, and taking out small infected 

 trees in stand-improvement operations. Such 

 operations can also reduce losses from many other 

 diseases, including fusiform rust and the hardwood 

 cankei-s. Although there has been a gradual 

 increase in stand-improvement measures for dis- 

 ease control; they are not yet in wide use. 



A beginning has been made toward replacing 

 shortleaf pine with other species on the soils 

 where the littleleaf disease prevails. In deciding 

 OTi the proper spacing in slash and loblolly pine 

 plantations, the high incidence of fusiform rust in 

 the wider spacings is an important consideration. 

 Maintaining high-stand density reduces Hypoxy- 

 lon canker losses in aspen. Even with blister rust, 

 forest-management practices have a direct bear- 

 ing on control and offer great promise for the 

 future. 



Some diseases have killed such large concentra- 

 tions of timber that it has been profitable to con- 

 duct salvage operations. About 32 percent of the 

 chestnut killed by the blight over a dozen States 

 has been salvaged, and dead chestnut is still being 

 utilized. Most of the ponderosa pine recently 

 killed by Elytroderma on the Ochoco National 

 Forest was salvaged. Many cankered eastern 

 hardwoods are used annually for mine props and 

 other uses. Heavily mistletoe-damaged ponderosa 

 pine is often salvaged in the Southwest. On 

 many of the larger forest properties in the Pied- 

 mont of the Southeast and in the northern half 

 of Alabama, most of the timber cutting consists of 

 salvaging littleleaf-diseased trees before they die. 



There are many major gaps in our knowledge of 

 disease behavior and control in connection with 

 most of our more important diseases. New 

 weapons in the fight against tree diseases com- 

 parable to the antibiotics in medicine, and DDT 

 and other comparable insecticides in entomology, 

 are not available against forest diseases. Only 

 research can lead to such new developments. 



STATUS OF PROTECTION 

 FROM INSECTS 



Insects are among nature's most active killers 

 of forest trees. To the extent that they sometimes 

 thin overdense young stands or kill decadent and 

 suppressed trees, they may be considered bene- 

 ficial. But beyond this they injure useful trees 

 and sometimes develop devastating epidemics. 

 How to prevent or control insects and utilize 

 much of the vast amount of timber they kill 

 every year are major forestry problems as yet 

 largely unsolved. 



Outright killing by insects may ba endemic or 

 epidemic in character. Endemic mortality is 

 normal to a forest and is unlikely to be materially 

 reduced except by forest management that changes 

 the composition, age, or character of the stands. 



