Understory Recovery in Coast Redwood Communities: A Case Study Comparing a Naturally Recovering and an Actively Managed Forest

Nowadays, there remain only approximately 5% of the original coast redwood forests. The rest is composed of post-harvest second growth forests, including both actively managed stands and preserves where natural processes have been allowed to reassert themselves. With so little of the original old-growth remaining, there is growing interest in restoring characteristics associated with old-growth to these maturing second growth stands. Natural recovery is an effective method restoring many late seral features, and does not require the additional disturbance of active management.

In this paper, in order to better understand management impacts on redwood understory abundance and composition, data were collected in naturally recovering stands and in stands that were actively managed with the explicit intent of promoting old-growth characteristics. Ten 10 m diameter plots with three 2 m diameter nested sub-plots were randomly sampled in two sites within each management type. General stand characteristics were recorded at plot center for each tree plot including: elevation, aspect (using an azimuth compass), slope (using a clinometer), and canopy cover (using a spherical densitometer). Within each tree plot, species richness, abundance, and diameter breast height (DBH) were recorded for all tree species over 1 m in height with a DBH > 10 cm. All data analyses were conducted using IBM SPSS statistical software. Descriptive analyses were used to explore the potential differences between the two management styles for all sample variables.

Results indicate that tree canopy cover, native species cover and richness, richness of coast redwood associated species, and the cover of Trillium ovatum (western wake robin) were significantly higher in naturally recovering versus actively managed stands. In addition, several coast redwood associated understory species were exclusively recorded in the naturally recovering stands including: Asuram caudatum (wild ginger), Prosartes hookeri (hooker’s fairybells), Maianthemum racemosum (false solomon seal), Scoliopus bigelovii (fetid adder’s tongue), Viola sempervirens (redwood violet); while only one such species was recorded exclusively in the actively managed stands: Trientalis latifolia (pacific star flower).

In conclusion, natural recovery appeared to support understory recovery more effectively than active forest management in this case.

Article by Alyssa Hanover and Will Russell, from San Jose State University, San Jose, USA.

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