Too Little of A Good Thing? Early Seral in the Pacific Northwest
Bob Zybach is bringing this draft review article to our attention.
The article is by Mark Swanson, a professor at Washington State University.
Here is the abstract
Early seral forest is attracting increasing attention from scientists and managers. This literature review, produced under contract to the United States Forest Service, addresses basic questions about this important seral stage in the forests of the Pacific Northwest (west and east of the Cascades Range). Generative processes, historic landscape abundance, ecological value, associated species (and their ecological adaptations and conservation status), landscape-scale considerations (including patch size), and issues relatied to forest management are central topics. In general, naturally structured early seral forest in the Pacific Northwest is important for many ecosystem services and species (including obligates and near-obligates), but has declined from historic landscape proportions.
And the Conclusions:
While the public is not necessarily predisposed against early seral forest (and in some cases may favor certain types), there is still greater public concern over late-successional types (Enck and Odato 2008), likely due to widespread policy and media emphasis on old-growth forests and their relationship to management. However, specific values associated with early seral habitats, from big game production to huckleberry harvesting, are attracting increasing attention from the public. Managers concerned about maintaining rare species are increasingly acknowledging the value of early seral habitats for a substantial portion of the biodiversity of the Pacific Northwest. Potential management responses may include:
Deferring salvage and dense replanting across all or parts of major disturbed areas (Lindenmayer and Noss 2006, Lindemayer et al. 2008))
When salvaging, practice variable retention to retain significant structural elements such as large-diameter live trees, snags, and down woody debris (Franklin et al. 1997, Eklund et al. 2009).
Avoiding reseeding with exotic plant species such as perennial ryegrass (Lolium perenne) following fire or volcanic eruption (see Dale et al. 2005b).
Attempt to incorporate elements of natural disturbance regimes into landcape-scale management (Lindenmayer and Franklin 2002)
Deliberate creation of large, early seral areas via silviculture (Swanson 2010).
Researchers have an important role to play in facilitating changing attitudes. Much of the excellent research done on seral dynamics in Northwestern forests (e.g., Ruggiero et al. 1991) was focused on biota associated with young, dense forests, mature forests, and late-seral forests. The pre-canopy closure stage component of succession was either not measured (as in Ruggiero et al.), or clumped together with stem exclusion (sensu Oliver and Larson) stands in analysis. While there is an increasing amount of research on true early seral forest, and management responses to these advances (King et al. 2011), much remains to be done in most temperate forest regions both in terms of research and management (Swanson et al. 2011b). It is hoped that the diversity and value of early seral conditions, from clearcuts to structurally and compositionally complex early seral habitat, will come to be recognized and widely incorporated into contemporary land management.