Some useful information about Redwood Forest Ecology and Management

[Vince Taylor]

Dear Colleagues,

I came across a paper by Dr. Will Russell that was presented at a conference of redwood restoration that the Campaign to Restore Jackson Forest held in 2000. I was surprised to see how much of what he said bore on issues that are before the JAG now. I think you will find all of it useful, but especially the sections on the benefits of older stands for biodiversity, natural regeneration in redwood forests, and the section dealing with Jackson Forest as a case study. I have attached the paper. Below are some excerpts that struck me as particularly pertinent to our conversations. 

Dr. Russell concludes his paper with a recommendation for Jackson Management:

Conclusions: A New Management Proposal
The concept of maximum-sustained-yield
indicates that in order to reap the greatest commercial
benefit from growing timber, trees should
be harvested after they reach their maximum
growth rate and they begin to reach maturity.
Coast redwood, one of the longest lived trees, is
known to grow vigorously for centuries, reaching
maturity at about 500-600 years, indicating that
harvesting of redwood should occur at approximately
this point. In contrast, the harvest rotation
for this species has generally been applied at 80 to
100 years or less. The consequences of this prescription
have been a decline in productivity on
redwood lands, a decline in the quality of wood
products, and a decline in the natural processes
necessary to sustain the forest. In addition, the
misconceived idea that coast redwood is a “moderately
shade intolerant species” (California
Department of Forestry and Fire Protection 2000)
has led to even-aged management on nearly all
redwood lands.

The proposed “uneven-aged”
management scenarios mentioned above are inappropriately
named, as virtually all trees within
JDSF would be in an immature state (0-100 years)
under this plan. The concept of uneven-age management
is intended to include representatives
from all age classes: for coast redwood that would
include ages up to 1000-1500 years or more. It is
clear that coast redwood has not been managed to
its greatest potential and that a shift in the managerial
paradigm will be necessary if the coast redwood
forest is to endure. In order to begin to
restore the coast redwood forest the following
management prescription should be adopted.

1. Timber harvesting should be conducted on
single-tree or cluster prescription only in
order to mimic the natural regeneration of
redwood. The overall harvest rotation for
any stand of redwood should be approximately
500 years.

2. Unentered old-growth should remain
unentered and serve as a model of the ecological
processes necessary for a healthy
forest.

3. Unentered second growth stands of 80-100
years or greater should be preserved, or
managed to promote late seral attributes.

4. The patchwork of multiple entry stands
should be employed as an opportunity to
apply cutting edge sustainable forestry
techniques with a goal of restoration of the
structure, diversity, and processes inherent
in the original primeval stands.

5. The depletion of soil resources should be
slowed by eliminating old road beds. This
process has already been initiated by CDF
in Jackson State Forest and should be
expanded.

These principles of management more closely
mimic the natural disturbance regime of a coast
redwood forest. Their application will eventually
return the forest to a late seral successional state.
The inherent qualities of a restored forest include
high biotic diversity, habitat and structural complexity,
and natural regenerative processes, which
have great value ecologically, scientifically, and
economically (Peterken 1996).

Here are a few other pertinent excerpts from Dr. Russell's paper:

... Further problems were caused by miscalculations
resulting from scientific misconceptions. Early
measurements of regeneration within coast redwood
stands indicated that seedling germination was
exceedingly low under closed canopy conditions,
suggesting that redwood was intolerant of shade
(Fritz 1957). These findings led researchers to promote
even-age management as a silvicultural prescription
in redwood stands in order to increase
regeneration and growth. Since that time this prescription
has been used almost exclusively and has
resulted in practices such as massive herbicide
application to newly regenerating stands in order to
discourage truly shade intolerant species such as tan
oak. These miscalculations were made as a result of
a poor understanding of the basic life cycle of coast
redwood and because of an inability to conceptualize
regeneration over large time scales.

The first error was in not recognizing that most regeneration
of coast redwood occurs from asexual clonal expansion.
When a coast redwood is blown over or dies in
place, abundant sprouting occurs as a stress
response from cambial tissue present at the base of
the tree and in the roots. These sprouts compete as a
cohort group, eventually leading to a few survivors
that can develop into mature trees.

The second error was in not considering the life span of the dominant
trees. Where one might be rightly concerned to find
only one or two seedlings per acre in a stand of short
-lived trees such as bishop pine (Pinus muricata), for
trees that have life spans of upwards of a thousand
years the concern is unwarranted. The regeneration
rate is relatively low because the rate of canopy
recruitment is exceedingly low. Regeneration at any
greater level would be an inefficient use of resources
that could be better used for growth.

Natural Regeneration in Coast Redwood
Natural processes created the forests, fisheries,
and recreational opportunities that we are
currently enjoying. Therefore, mimicking natural
processes in our management of these resources
allows us the best opportunity for their continued
use. An understanding of the natural life cycle of
the coast redwood as a species, and the dynamics
of redwood stands as a whole, are important in
developing management strategies that are sustainable
from both an ecological and economic perspective.

Stand replacement has historically been
used as the standard model for forest regeneration
by both foresters and ecologists in virtually all forest
types. This model is appropriate for forests that
regularly experience catastrophic disturbance such
as crown-fire, but does not work well for communities
where stand replacement is rare such as the
coast redwood forest.

In undisturbed coast redwood forests most
regeneration and succession is tied to a process
known as gap phase disturbance (Pickett and
White 1985). Regeneration occurs in small
canopy openings created by tree fall or “chablis”
(Halle et al. 1978) resulting in forest stands with
complex spatial structures and high species diversity
(Sugihara 1992). In contrast, regeneration
through stand replacement results in even-aged,
low-diversity stands.

Natural regeneration conditions occur in a
high moisture, relatively high shade environment.
Individual trees that expand to fill canopy gaps
were often recruited many years before and have
persisted as suppressed sub-canopy trees. In stand
replacement events, such as large fires and clearcutting
treatments, individual trees must be recruited
following the disturbance in a low shade, low moisture
environment which is not optimal for the
growth of redwoods. Survival of seedlings, naturally
recruited or planted, following these events is
low, indicating that conditions are not favorable. In
addition, the conditions created by complete canopy
removal often induce long periods of shrub domination,
which is removed at great expense with herbicides
or through mechanical means.

Mimicking natural processes through timber
harvest with coast redwood suggests the use of single-
tree or small-group selection with high canopy
retention.