4. ‘‘Cultural old-growth’’ forests
In severaldefinitions, old-growthforests havebeencharacterised
by a long-term absence of intensive disturbance. However, in some
old-growth forests, regular minor disturbances are required to
maintain old-growthness or to stabilise forest structure (Kaufmann
et al., 2007). Well-known examples of this type of forest include the
ponderosa pine forests in western North America (see Kaufmann
et al., 2007 for more examples).While stand-replacing fires are rare,
theseforestsweresubject to frequent (3–38years) lowintensityfires
in the pre-European era. Native Americans likely had a major
influence on this fire regime to encourage development and fruiting
of plants, to increase the abundance of selected species while
discouraging others, and to facilitate hunting (Hessburg and Agee,
2003). Other opinions suggest that Native American burns only
supplemented or substituted for natural lightning fires in these fireprone
environments (Baker, 2002). However, the fire-regimes
changed substantially in many places with the landscape changes
subsequent to the arrival of European settlers