Fusiform rust disease was also favored by the shift to the more 

 susceptible loblolly and slash pines and the increase in area of 

 susceptible host type (Dinus 1974). Spread of the rust was accel- 

 erated by nursery and reforestation practices and by fire control, 

 which increased the growth of oaks, the alternate host for this 

 rust fungus. Before widespread planting of pines in the 1930's, 

 fusiform rust was a relatively unimportant part of loblolly and 

 slash pine ecosystems. Today, it is the most costly disease in 

 southern forests. Removal of rust-infected trees during thinning 

 and planting operations has had some limited benefit in reduc- 

 ing losses, and screening for rust resistance has shown promise. 



Impacts of southern pine beetle may continue to increase due to 

 the abundance of host type, increasing stand age, and high stock- 

 ing levels. Impacts of fusiform rust will probably continue to be 

 serious for the foreseeable future. 



UPLAND OAKS AND OAK-PINE TYPES 



Successful fire control, chestnut blight, land use patterns, and 

 past harvesting practices have greatly altered the composition 

 and structure of the upland oak and oak-pine forest types. In ad- 

 dition, drought and pest epidemics have resulted in widespread 

 and sometimes severe decline of oaks. Much of the problem is 

 occurring in stands where harvest or regeneration cuts are not 

 planned for some time, or where recreation and wildlife objec- 

 tives predominate. Concern about the future status of these 

 stands is widespread among both forest managers and the public. 



Introduced Pests 



Introduced pests are a serious concern. Unlike native pests, intro- 

 duced pests usually have few natural regulating factors in North 

 American forest ecosystems. Some introduced pests have caused 

 permanent, irreversible changes in forest ecosystems and contin- 

 ue to spread and cause damage in new areas. Introduced pests 

 have proven to be difficult and expensive to manage. As global 

 trade and travel increase, the potential for new introductions of 

 forest pests also increases. Preventing additional introductions of 

 exotic pests to North America is a continuing concern for the 

 governments of Canada, the United States, and Mexico. The 

 strategies for dealing with introduced pests have to be very differ- 

 ent from the strategies for native pests. 



Healthy Forests for America 's Future — A Strategic Plan 1 5 



