Table 3. Examples of agents of change and their effects in frequent-fire, old-growth conifer forests of the western United States
|
|
Agent |
Examples of potential effects |
Reference |
|
Fire-regime disruption |
|
|
Fire exclusion |
Increase tree density |
Stephenson 1999 |
Increase fire severity |
Eradicate old trees |
Savage and Mast 2005 |
Ranching |
|
|
Livestock grazing |
Reduce palatable plants |
Clary 1975 |
Fragmentation |
Restrict wildlife movements |
Milchunas 2006 |
Watershed disruption |
Damage/eradicate springs |
Belsky and Blumenthal 1997 |
Wood harvesting |
|
|
Large-tree removal |
Reduce some wildlife habitat |
Tecle and Covington 1991 |
Road building |
Spread exotic plants |
Fornwalt et al. 2003 |
Fuelwood harvest |
Affect oak structure |
Fulé et al. 1997 |
Other |
|
|
Predator control |
Regional species extinctions |
Dahms and Geils 1997 |
Exotic plants |
Reduce some native plants |
Keeley 2006 |
Urban development |
Fragmentation |
Dale 2006 |
Climate change |
Increase tree mortality |
Breshears et al. 2005 |
|
|
|