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1 July 2016 Variation In Old-Growth Coast Redwood (Sequoia sempervirens) Reference Sites In Mendocino County, California
Kristin K. Michels, Will Russell
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Restoration and management of old-growth conditions in coast redwood (Sequoia sempervirens [D. Don] Endl.) forests are traditionally based on an idealized set of characteristics that occur in productive stands. We compared three old-growth sites to quantify variability among remaining reference stands of the central coast redwood range in Mendocino County, California. Two of the sites are protected from coastal influence, have rich alluvial soils, and relatively high visitor usage. The third site is in close proximity to the coast with variable soil conditions and little visitor access. We randomly sampled twenty, 20-meter circular diameter plots in each site to evaluate basal area, tree density, species richness, canopy cover, shrub cover, and herbaceous species cover. We conducted multivariate analyses including nonmetric multidimensional scaling (NMDS), perMANOVA, and indicator species analysis (ISA) to examine the structural clustering and compositional metrics among the sites. Results indicated a strong separation among old-growth reference sites in the NMDS ordination and significant differences in sites using perMANOVA. The inland sites had high tree density, basal area, herbaceous understory cover, and cover of Oxalis oregana Nutt., Adenocaulon bicolor Hook., and Viola glabella Nutt. The coastal site had a high abundance of Trillium ovatum Pursh (an old-growth associated species), high shrub cover in canopy gaps, diverse species assemblages, and relatively high abundance of woodland-adapted perennial species. ISA provided a distinct suite of understory species for each site. The unique characteristics and high variability among these sites may offer a new, and potentially more accurate, standard for restoration and management.

Kristin K. Michels and Will Russell "Variation In Old-Growth Coast Redwood (Sequoia sempervirens) Reference Sites In Mendocino County, California," Madroño 63(3), 258-267, (1 July 2016).
Published: 1 July 2016

Coast redwood
indicator species
understory diversity
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