Establish or encourage new mixes of native species

EASTERN:
Repeated periods of warming and cooling over the last 15,000 years have resulted in large shifts in species composition (Davis 1983, Jacobson et al. 1987, Shuman et al. 2002). Novel combinations of climatic and site conditions are expected to continue to affect individual species in different ways. Although some species may not occur in a forest or community type as currently defined, they may have been together previously. Novel mixing of native species may lead to the dissolution of traditional community relationships and result in conversion to a newly defined or redefined forest or community type (Davis et al. 2005, Root et al. 2003). (1)

WESTERN:
Repeated periods of warming and cooling over the last 15,000 years have resulted in large shifts in species composition (Davis 1983, Jacobson et al. 1987, Shuman et al. 2002, Crausbay et al. 2017). Novel combinations of climatic and site conditions are expected to continue to affect individual species in different ways. Although some species may not occur in a forest or other community type as currently defined, they may have been together previously. Novel mixing of native species may lead to the dissolution of traditional community relationships and result in conversion to a newly defined or redefined forest or other community type (Root et al. 2003, Davis et al. 2005, Williams and Jackson 2007, Comer et al. 2019). (2)

Species composition in many forest ecosystems is expected to change as species adapt to a new climate and transition into new communities (Iverson et al. 2004b). This strategy seeks to maintain overall ecosystem function and health by gradually enabling and assisting adaptive transitions of species and communities in suitable locations. This may result in slightly different species assemblages than those present in the current community, or an altogether different community in future decades. This strategy includes aggressive actions to promote ecosystem change rather than an unchanging community or species mix. Many of the approaches in this strategy attempt to mimic natural processes, but may currently be considered unconventional management responses. In particular, some approaches incorporate assisted migration, which remains a challenging and contentious issue (McLachlan et al. 2007, Ricciardi and Simberloff 2009). It is not suggested that managers attempt to introduce new species without thoroughly investigating potential consequences to the native ecosystem (Ricciardi and Simberloff 2009). This approach is best implemented with great caution, incorporating due consideration of the uncertainties inherent in climate change, the sparse record of previous examples, and continued uncertainties of forest response. Outcomes from early efforts to transition communities can be evaluated to provide both information on future opportunities and specific information related to methods and timing.