FOREST PROTECTION 



215 



and may take 70 to 75 percent of the seed crop 

 in some areas. They also bite off cones, some- 

 times before the seed matures. 



White-footed mice, because of their fondness 

 for tree seed, their wide distribution, and their 

 fecundity, are sometimes the most important 

 single factor limiting successful forest regenera- 

 tion, particularly in the Pacific Northwest. 

 Favorable habitat conditions for these mice are 

 created as a result of fire and slash burning. The 

 new vegetation appearing on such areas provides 

 abundant food and results in a buildup of the 

 mouse populations. The increased animal pres- 

 sure often leaves little opportunity for successful 

 natural or artificial seeding. 



Animal Damage Can Be Controlled 



The only feasible means of reducing and con- 

 trolling forest damage by livestock and big game 

 is through good range practices and game manage- 

 ment. These animals are not incompatible with 

 timber production if they are managed on the 

 basis of proper utilization of key forage plants. 



Control of forest damage requires the establish- 

 ment of specific carrying capacities in a multiple- 

 use forest. Thus where game animals are damag- 

 ing their habitat, hunting seasons should be 

 liberalized and the harvest of surplus animals by 

 sport shooting encouraged in order to maintain 

 desirable numbers. Proper multiple-use forest 

 management also often requires that silvicultural 

 practices be modified to maintain desirable game 

 habitats. In most areas where game problems 

 have developed, progress is being made toward 

 obtaining proper livestock and big-game herd 

 management. 



Fencing can be used to exclude larger animals 

 from small areas, but its cost is so high that it can 

 seldom be justified as a means of controlling big 

 game on large areas. Where high-value tree 

 crops are at stake, however, it is sometimes prac- 

 tical to control domestic livestock by fencing. 



Control of small rodents is extremely difficult, 

 largely because populations recover rapidly. Poi- 

 sons have been effective on small areas, but the 

 costs are high, and trapping on large areas is not 

 practical. Moreover, recent studies indicate that 

 certain seed-eating rodents, particularly deer 

 mice, consume large numbers of certain insect 

 enemies of forest trees. Seed to be sown directly 

 in the field may be coated with substances that 

 repel rodents and perhaps birds also. Several 

 such preparations hold promise but have not yet 

 been fully evaluated. 



The porcupine's conspicuousness, slow gait, and 

 dependence on quills for protection makes control 

 by clubbing or shooting easy, and systematic 

 hunting is justified where porcupine concentra- 

 tions are heavy or especially valuable stands are 



being damaged. Trapping, baiting, and fencing 

 may also be effective. 



Reducing snowshoe hare populations is not 

 often practical except in small areas. Nursery 

 seedlings to be planted in hare habitats can be 

 treated with repellents, but will be protected only 

 until new growth develops. 



Beaver can be controlled by trapping. Most 

 States rigidly control beaver trapping, so that 

 beavers doing damage must be removed by State 

 employees or licensed trappers. 



The obvious method for control of deer, bear, 

 and other big-game animal populations that have 

 grown to a point where they are causing damage 

 to their food supply is through liberalized hunting 

 seasons. 



Records indicate that less than $100,000 was 

 spent in 1952 to control animal damage to forest 

 stands. This was mostly for controlling hogs in 

 the South and rodents and bears in the West. 



WEATHER EFFECTS DESTRUCTIVE 

 TO TIMBER 



Weather damage in 1952 resulted in a growth 

 impact of 957 million cubic feet of growing stock, 

 including 3,869 million board-feet of sawtimber. 

 This was 9 percent of the total national growth 

 impact from all sources (table 113). The loss, like 

 that from fire, varies considerably from year to 

 year, especially in certain regions. In 1952, 88 

 percent was outright mortality (fig. 72). 



Growth impact in the West resulting from 

 adverse weather in 1952 was primarily from storms 

 and far exceeded the weather losses in the North 

 and South combined (table 114). In the Pacific 

 Northwest, where some of the great historical 

 blowdowns have occurred, mortality from storms 

 exceeded that from any other cause, making up 

 40 percent of the regional mortality. In this 

 region alone, 1,613 million board-feet of timber 

 was lost, largely from wind. In the Northern 

 Rocky Mountain Region, wind caused mortality 

 that was exceeded only by insects. Wind is 

 periodically important in all of the western regions. 

 It prostrates trees over great acreages, blows down 

 root-rotted trees especially, and sets the stage for 

 insect attacks and fire. 



Hurricanes are frequent in much of the South, 

 and in recent years have occasionally been damag- 

 ing throughout aU of the States bordering the 

 Atlantic Ocean and the Gulf of Mexico. Tornadoes 

 are an annual occurrence in the South, but, unlike 

 hurricanes, they usually cause damage in only a 

 very narrow path. Ice, frost, hail, and snow cause 

 periodic losses in the West, in the entire North, 

 and southward through the Appalachian Moun- 

 tains. An important damaging aftereffect of ice 

 storms is the heart rot that develops from limb 

 and top breakage. 



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