Ninety-two years of change in a second-growth coast redwood forest

Ben Iberle

Dept of Forestry and Wildland Resources,

Humboldt State University

Stephen C. Sillett, Robert Van Pelt, and Mark Andre

Coast Redwood Science Symposium

Eureka, CA

September 13, 2016

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Research on “mature” second-growth:

Fritz’s Wonder Plot (Allen et al. 1996, Gerhart 2006) Observed from 70 to 150 yrs stand age

Existing data on second-growth spans a brief slice of stand development

16050

From Van Pelt et al. 2016

A unique opportunity

Two one-acre plots established in

1923 by Woodbridge Metcalf in the

Arcata Community Forest

History of the Metcalf Plots

1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020

Protected watershed

for Arcata

1955 - Purchased

by the city

Used as

pasture

Metcalf surveys

1990 - Becking survey

Rediscovered!

Burned after

logging

Logged within

1875-1885

1923 - Plots

established

History of the Metcalf Plots

1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 2020

Metcalf surveys

1990 - Becking survey

Rediscovered!

Burned after

logging

Logged within

1875-1885

1923 - Plots

established

Total stand age ~135 years

Eight surveys from ~43 to 135 years

Metcalf Plots in the region

Metcalf Plots in ACF

Lower plot

Upper plot

Surveys 1923-1963

No plot maps found

All trees >3” DBH: Some trees:

Painted number Height

DBH

Species

Crown class

Survey 1990

Mapped tree locations with sketches

All trees >3” DBH: Some trees:

DBH Height

Species ID tags

Crown class

16’ logs

Survey 2013-2015

Lower plot in fall 2013 w/ HSU class

Upper plot in spring/summer 2015

All trees/stumps/snags >5cm DBH:

Aluminum tag at diameter measurement

Functional diameter (fDBH) at 1.37m

Diameter at top of buttress (DTB)

Species

Total height and height to crown base

- Laser from climbed trees

- Or from LiDAR dataset

Four crown radii in cardinal directions

Tree and log locations mapped

with laser and compass

Intensively measured trees

Two redwoods (53 and 57m)

Two spruces (63 and 65m)

Crown mapping:

Trunk diameter every ~10m

Branches:

- Basal diameter

- Length

- Length >4cm in diameter

Dendrochronology:

Increment cores taken every ~15m

Bark depth at core hole

Cross-dated cores → annual ring widths

Building new allometric equations

Based on hierarchical sampling of branches, detailed trunk measurements,

and increment cores (see Sillett et al. 2015 and Van Pelt et al. 2016)

Stepwise power functions with predictors fDBH, DTB, height, or crown volume

Tree-level

quantities

2nd-G Redwood

(n=34 trees)

Sitka spruce

(n=24 trees)

Douglas fir

(n=27 trees)

Total aboveground

biomass

fDBH, height fDBH, DTB fDBH, DTB

Total volume fDBH, height fDBH fDBH, DTB

Heartwood/sapwood

volume

fDBH, height fDBH fDBH, DTB

Cambium area fDBH, crown vol fDBH, crown vol fDBH, crown vol

Leaf mass fDBH, crown vol fDBH, crown vol fDBH, crown vol

Leaf area fDBH, crown vol fDBH, crown vol fDBH, crown vol

Grand fir Biomass, stem volume, and leaf mass equations with DBH and

height predictors from Canadian Forestry Service report (Standish et al 1985)

Lower plot

Upper plot

The Wonder Plot was winning until mortality evened the score

Wonder Plot data from Gerhart 2006

Metcalf Plots already approach old-growth in leaf mass

Metcalf

plots

Old-growth

plots

Metcalf

plots

Old-growth

plots

Old-growth data from Van Pelt et al. 2016

Final observations

- Redwood canopy dominance approaching…

- Strong growth despite heavy human impacts

- Potential for accelerating development

- Future of the plotsAll historical photos from Fritz-Metcalf

Photograph Collection, UC Berkeley

Thank you!

- Dr. Stephen Sillett

- Dr. Bob Van Pelt

- Dr. Jeff Kane

- Mark Andre and the City of Arcata

- Allyson Carroll

- Ethan Coonen

- Bill Kruse

- HSU FOR 210 students, Fall 2013

- Al Stangenberger

- Fisher Chair for Redwood Forest Ecology

- Save-the-Redwoods League