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Retain biological legacies

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Approach

EASTERN:
Biological legacies are organisms, structures, or patterns inherited from a previous ecosystem and often include mature trees, snags, and down logs remaining after natural disturbance or harvesting (Society of American Foresters 2008). Biological legacies can enhance species and structural diversity, serve as a seed source, or provide nurse logs for seed germination (Gunn et al. 2009). Mature trees can often survive through periods of unfavorable climate, even while conditions become unsuitable for seedling establishment (Brubaker 1986). In a changing climate, biological legacies may play a critical role in a species’ persistence or colonization of new habitat (Gunn et al. 2009). (1)

WESTERN:
Biological legacies are organisms, structures, or patterns inherited from a previous ecosystem and often include mature trees, snags, and down logs remaining after natural disturbance or harvesting (Society of American Foresters 2008). In California, a few notable examples of biological legacies include giant sequoia, coastal redwood (Sequoia sempervirens) and the bristlecone pine (Pinus longaeva) forests, stands and groves. Biological legacies are often critical components of habitat for many species of wildlife, such as large trees with structures suitable for nesting, denning, roosting, or resting sites. Consequently, biological legacies can enhance species and structural diversity, serve as a seed source, or provide nurse logs for seed germination (Gunn et al. 2009, Hessburg et al. 2016). Additionally, mature trees can often survive through periods of unfavorable climate, even while conditions become unsuitable for seedling establishment (Brubaker 1986). In a changing climate, biological legacies may play a critical role in a species’ persistence or colonization of new habitat (Gunn et al. 2009). These unique ecological legacies also have important historical and cultural significance. (2)

Tactics

  • Retaining the oldest and largest trees with good vigor during forest management activities (1, 2).
  • Retaining survivors of pest or disease outbreaks, droughts, windthrow events, or other disturbances during salvage or sanitation operations (1, 2).
  • Retaining individual trees of a variety of uncommon species to maintain their presence on the landscape (1, 2).
  • Retaining wildlife trees and logs for habitat purposes, including living trees with decay or broken tops, trees with brooms, hollow trees (cavities) and standing dead (snags) (2).

Strategy Text

Land managers already work to increase structural and species diversity in many cases, and as an adaptation strategy this general goal receives added effort and focus (Mooney et al. 2009). Structural and species diversity may buffer a community against the susceptibility of its individual components to climate change (Peterson et al. 1998). In other words, a community may still experience stress as individual components fare poorly, but the redundancy of particular roles and variability among all species’ responses contribute to the resilience of the community (Elmqvist et al. 2003). Although a forest is often defined by its dominant or most abundant species, even rare species can act as keystone species or contribute to the suppression of invasive exotic plants (Mooney et al.2009).

Citation

1. Swanston, C.W.; Janowiak, M.K.; Brandt, L.A.; Butler, P.R.; Handler, S.D.; Shannon, P.D.; Derby Lewis, A.; Hall, K.; Fahey, R.T.; Scott, L.; Kerber, A.; Miesbauer, J.W.; Darling, L. (2016). Forest Adaptation Resources: Climate Change Tools and Approaches for Land Managers, 2nd Edition. Gen. Tech. Rep. NRS-87-2. U.S. Department of Agriculture, Forest Service, Northern Research Station p. http://www.nrs.fs.fed.us/pubs/52760,
2. Swanston, C.W.; Brandt, L.A.; Butler-Leopold, P.R.; Hall, K.R.; Handler, S.D.; Janowiak, M.K.; Merriam, K.; Meyer,
M.; Molinari, N.; Schmitt, K.M.; Shannon, P.D.; Smith, J.B.; Wuenschel, A.; Ostoja, S.M 2020. Adaptation Strategies
and Approaches for California Forest Ecosystems. USDA California Climate Hub Technical Report CACH-2020-1.
Davis, CA: U.S. Department of Agriculture, Climate Hubs. 65 p.