TITLE:
Herbaceous Understory Indicators of Post-Harvest Recovery in Coast Redwood (Sequoia sempervirens) Forests
AUTHORS:
Will Russell
KEYWORDS:
Indicator Species, Coast Redwood, Timber Harvest, Old-Growth, Trillium ovatum
JOURNAL NAME:
Open Journal of Forestry,
Vol.10 No.2,
March
9,
2020
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.