Herbaceous Understory Indicators of Post-Harvest Recovery in Coast Redwood (<i>Sequoia sempervirens</i>) Forests

Abstract

Assessment of forest recovery following disturbance is enhanced by the use of biological indicators. One such indicator, the abundance of understory species, was examined in coast redwood (Sequoia sempervirens) forests using non-metric multiple dimensional scaling (NMDS) and indicator species analysis (ISA). Randomly distributed 10 m diameter circular plots were employed to record the abundance of all understory species across three treatments: actively managed (0 -45 years since harvest); mature second-growth (~80 -120 years since harvest); and unharvested old-growth stands. NMDS with perMANOVA analysis signified separation between treatments with the shade tolerant herbaceous species Trillium ovatum, Viola sempervirens, and Oxalis oregana positively correlated with mature second-growth and old-growth treatments. ISA supported the inclusion of T. ovatum, with the addition of Prosartes hookerii, as indicators of mature second-growth and old-growth. Both NMDS and ISA specified associations for Ceanothus thyrsiflorus and Stachys bullata with actively-managed stands. Occurrence of non-natives was low across treatments, though significantly higher on actively managed stands, with the shade intolerant invasive plants, Cortaderia sp. and Myosotis latifolia, occurring exclusively in actively-managed sites.

Initial Floristic Response to High Severity Wildfire in an Old-Growth Coast Redwood (Sequoia sempervirens (D. Don) Endl.) Forest

“…The post-fire recovery of understory cover, at approximately 4%, was quite low [35]. Though cover and richness were reduced due to conditions created by the fire, it was encouraging that many of the species commonly associated with coast redwood forests, such as Oxalis oregana, T. ovatum, Viola sempervirens, and Prosartes hookeri were present [36]. The most abundant understory species observed was V. ovatum, which was able to regenerate vigorously from basal sprouts and underground rhizomes.…”

Anthropogenic Edges and Effective Preserve Size in the Coast Redwood (<i>Sequoia sempervirens</i> (D.Don) Endl.) Forest

“…Vegetation in the southern range of the coast redwood forest, where this study Open Journal of Forestry (Russell, 2020). Gap phase succession resulting from windthrow dominates the natural regenerative processes in the coast redwoods (Lorimer et al, 2009), and while fire and flood are common occurrences, they rarely lead to standing replacement (Jacobs et al, 1985).…”

Effects of forest management on native bee biodiversity under the tallest trees in the world

“…Climax flowering plants of the mature old‐growth coast redwood forest understory include the shrub Rhododendron macrophyllum and several shade‐adapted understory flowering plants (Figure A1 : Appendix ). Of these flowering plant species, some are known to be sensitive to timber harvest, including Oxalis oregana (redwood sorrel), Trillium ovatum (Pacific trillium), Lysimachia latifolia (Pacific starflower), and Viola sempervirens (redwood violet; Russell, 2009 , 2020 ; Russell & Michels, 2011 ). Little detailed data on native bees is available from coast redwood forest ecosystems.…”

“…Gujral et al ( 2022 ) documented native bees visiting Dudley's Lousewort ( Pedicularis dudleyi ), a rare and endangered redwood plant. Mature secondary growth redwood forests (101–130 years since clear‐cutting) are characterized by a lower age and size diversity of trees and higher tree density than in old growth forests, smaller large woody debris (LWD), and a lower diversity and coverage of native understory herbs and shrubs (Russell, 2020 ; Russell & Michels, 2011 ). Large woody debris from fallen mature trees or branches and deadwood can provide nesting substrate for cavity‐nesting bees in forests (Rappa et al, 2023 ).…”

“…Active management of secondary growth redwood forests through retention forestry can cause some harvest effects on forest structure, such as increased soil compaction and the introduction of non‐native plant species (Russell, 2020 ). A study by Hanover and Russell ( 2018 ) found that tree canopy cover and native understory flowering plant species cover and richness were significantly higher in naturally regenerating as compared to actively managed redwood stands.…”