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Restoration Ecology Courtesy of Michael R. W
Restoration Ecology
A New Forest Management Paradigm,
or Another Merit Badge for Foresters?
hat ecological restoration is a growing field is illustrated
Tby the startup of a professional association (the Society for
Ecological Restoration, created in 1987), the development of
two new journals (Restoration Ecology and Ecological Restoration,
the latter having been Restoration and Management Notes), and
the publication of 50 or more papers each year. In the
22 October 2000
Forest Restoration Multiple-Use Management
Southwest alone, several large forest tails negotiating the best possible out- Focusing on the Southwest but raising ques-
restoration projects are under way. come for a specific site based on eco-
The notion of “restoring” ecosys- logical knowledge and the diverse per- tions that are more broadly applicable,we
tems seems laudable enough. For some, spectives of interested stakeholders.” compare ecological restoration with conven-
however, ecological restoration assumes Certainly, restoration generally as- tional management regimes—multiple-use
a moral imperative for a “bold new ori- sumes a holistic perspective and a need management,ecosystem management,and
entation toward nature” (Higgs 1991). for active intervention, but that hardly managing for specific resource objectives.
We evaluate ecological restoration in distinguishes it from ecosystem man- That restoration assumes a holistic perspec-
the larger context of other land man- agement or other approaches for tive and active intervention does not distin-
agement philosophies like multiple-use achieving ecosystem health (sustain- guish it from other approaches to achieving
management, ecosystem management, ability, integrity, etc.). Is ecological ecosystem health.We find that foresters and
and managing for specific resource ob- restoration the only way to achieve eco- restorationists both use ecology,but restora-
jectives (e.g., wildlife, commodity pro- system health? If a management activ-
duction). We ask, is ecological restora- ity improves forest health, is it then tionists use a reference condition as a substi-
tion sufficiently conceptually devel- ecological restoration? tute for specific objectives.We believe that
oped, experimentally tested, and neces- What distinguishes restoration from restorationists who advocate substituting a
sary to warrant its adoption as a new other land management activities is reference condition for meeting a priori ob-
forest management paradigm? that recovering the ecological integrity jectives must demonstrate the advantage of
of a site requires using the techniques this approach.We identify the conceptual lim-
Ecological Restoration, Defined of reestablishing the composition, itations to ecological restoration and ques-
The techniques, objectives, and de- structure, and disturbance regime of a tion the uses of restoration.
finitions of ecological restoration have historical or indigenous reference eco-
evolved over the past decade as practi- system (Cairns 1993; Meffe and Car-
tioners and scientists sought to define a roll 1994; Bradshaw 1996). By Michael R.Wagner,
new, applied discipline. Between 1991
and 1997 the Society of Ecological Choice of Reference William M.Block,Brian W.Geils,
Restoration modified its definition of A reference or standard is essential and Karl F. Wenger
ecological restoration five times for planning and monitoring any pro-
(Palmer et al. 1997). Restoration was ject that promises to produce certain
first used to describe landscaping and results within given specifications. De-
replanting to reclaim stripmines and sired conditions and performance stan-
toxic dumps. Later, restoration de- dards may be determined by a collabo-
scribed agricultural lands that were re- rative decision process that assesses the
vegetated to resemble native prairies, likely outcome of alternative manage-
and new wetlands that were created to ment policies. A restorationist’s ap-
replace those lost to other uses. More proach is to define desired conditions
recently, and especially in southwestern and standards as those exemplified by a
forests, the term forest restoration has specific historical or indigenous ecosys-
been used to describe activities in- tem. For the Southwest, a preferred ref-
tended to recreate the forest structure erence is the ponderosa pine forest that
and fire regime that prevailed just prior existed just prior to European settle-
to Euro-American settlement (Coving- ment, produced under a disturbance
ton and Moore 1994; Covington et al. regime of frequent ground fires result-
1997; Stone et al. 1999). ing in open stands with groups of large
The purpose of restoration has been ponderosa pine trees and a sparse
variously described as repairing dam- woody understory but dense grassy
age, renewing ecosystem health, recov- cover (Covington et al. 1997). Opposite:A stand of ponderosa pine
ering ecological integrity, and regener- Although some dendrochronology as captured in this historical photo-
ating harmony between humans and data support the contention that fire graph (circa 1890s) from the Coconino
nature (SER 1994; Higgs 1997; Palmer occurred at a regular but variable fre- National Forest, Arizona. Clumps of
et al. 1997). Health and integrity refer quency prior to Euro-American settle- large-diameter ponderosa pine and
to desired biological diversity and sus- ment, there is also some relatively new open savannah between clumps are the
tained ecosystem functioning. In terms information based on extensive re- common reference condition used in
familiar to foresters, a recent Society of search in other ponderosa pine stands the Southwest. Note in the background
Ecological Restoration workshop defi- suggesting that the severity, frequency, somewhat more dense pockets of
nition read, “ecological restoration en- and spatial occurrence of fire was even young trees.
Journal of Forestry 23
may never be repeated, so why should
we assume that a past forest structure is
better suited to the much different cli-
mate that exists today? Add uncertain
global climate change and Pacific
decadal oscillations, and recreating for-
est structure to reflect a unique histori-
cal climate seems of dubious value.
From a forest management perspec-
tive, a climatic pattern that has per-
sisted for 200 years is more than ample
time to produce one or two rotations
of multiple products. It seems most
agner sensible to manage existing forests in
the existing climate to meet current ob-
jectives rather than managing to recre-
Michael R. W ate the past. Aronson et al. (1995) in-
An abundance of the exotic mullein (Verbascum thapsus), which was largely absent sist that a reference ecosystem, even if
in the untreated control,is apparent in the understory vegetation five years after a arbitrary and imperfect, is necessary for
full restoration treatment in ponderosa pine at Fort Valley Experimental Forest, the design and evaluation of restora-
Arizona.Details of the treatments are in Stone et al.(1999). tion projects. The question, however, is
whether any single ecosystem condi-
more variable than previously thought nessee had “vast quantities of maize.” In tion is a sufficient reference if it was the
(Shinneman and Baker 1997; Brown et the Coosa Valley of present-day Al- product of a unique combination of
al. 1999). Brown et al. also clearly abama they found “large and numerous climate and human interaction that
demonstrate the existence of stand-re- settlements and the fields were continu- may never be repeated.
placing fires, which had rarely been ous” (DeVivo 1992).
considered a component of the south- The European immigrants of the Obstacles to Restoration
western reference condition. early 17th century found perhaps only The evolving science and theory of
small, scattered villages, still rather ex- ecosystems. Ecosystems are always re-
The Presettlement Condition tensive open fields, but also “dense sec- sponding to previous disturbances: tree
Human influence on forest condi- ond-growth forests characterized by fall, firestorm, volcanic eruption, ice
tions prior to European settlement is fifty to 100 year old trees, unhindered ages, and meteor strikes. Ecosystem de-
underappreciated. The latest estimate of by human impact.” This offered the il- velopment after disturbance is greatly
the native population of North America lusion of “virgin forest” (DeVivo influenced by chance; what remains
at the time of discovery is 50 million. 1991). Similarly, in the Southwest and what is nearby influence ecosystem
According to DeVivo (1991), the pre- there were periods of occupation and trajectory. Ecosystems endure with
contact New World population peaked abandonment by native peoples. Thus, change. Species evolve and are re-
between 90.04 million and 112.55 mil- the activities of native peoples were the placed, structures are built and decay,
lion indigenous people, equally split be- major agents determining the vegeta- process rates vary but life goes on. The
tween North and South America. But tive conditions over much of the significance of these characteristics is
Europeans introduced diseases for United States until the time of the Rev- that every ecosystem is unique to the
which the natives had no resistance. As olutionary War. Should the reference place and time in which it exists.
the inhabitants tried to flee the diseases, condition include or exclude the Ecological restoration relies on
they apparently spread them through- human impact of indigenous people? many ecological concepts, some of
out eastern North America. DeVivo which are not clearly understood; oth-
concludes, “No doubt, the aboriginal Transient Climate ers are still being defined and tested.
inhabitants of mainland North America Dendrochronology studies in the One of the basic concepts of succession
suffered dramatic population decline Southwest suggest that from roughly was once viewed as a single, determin-
before face-to-face contact with Euro- 1800 to the present, the climate was istic pathway to a climatic climax type.
peans” from the diseases introduced by substantially wetter than from 1400 to This basic concept has been replaced by
the Europeans. The population decline 1800 (Grissino-Mayer et al. 1997) (fig. a nonlinear model of exploitation-con-
apparently had not yet run its course 1). The common reference period in servation-release-reorganization (Holl-
during the 1539–42 DeSoto expedition the Southwest is the pre–European set- ing 1995). For example, restorationists
through what is now the eastern United tlement period of roughly 1860 to the often cite a need for diversity to en-
States. In the Blue Ridge Mountains 1880s, or 60 to 80 years after a 400- sure ecosystem stability. The ecologi-
they marched for “one day through cul- year dry period. The climate that cre- cal debate on that issue has progressed
tivated fields.” Towns in eastern Ten- ated this popular reference condition from discussions on stability to re-
24 October 2000
silience, to a recent suggestion that
overconnectedness leads to brittleness 3
(Holling 1995). Likewise, it is equivo-
cal whether diversity creates stability 2
or structure ensures function in
ecosystems.
New ecosystem components. Another precipitation1
major obstacle in restoration is dealing
with the components of the ecosystem 0
that are present now that didn’t exist
previously or organisms that exist in –1
greater numbers than before. Specifi-
cally, we are referring to exotic organ-
isms. The open vegetation structure –2
and reintroduction of fire as a distur- Below-average Above-average precipitation
bance agent that characterize forest –3
restoration in the Southwest are also 200 BC 1 200 400 600 800 1000 1200 1400 1600 1800 2000
conditions that are highly suitable for Year
invasive species. With the exception of
Allen (1995) and Montalvo et al. Figure 1.A 2,129-year reconstruction of precipitation based on 10-year averages
(1997), few authors have discussed the for northwestern New Mexico.Unprecedented above-average precipitation charac-
relationship between ecological restora- terizes the most recent 200-year period,which was preceded by significant
tion and increased invasion by exotic droughts.Which climatic period should be used as the reference condition?
species. Some authors have suggested Source: Grissno-Mayer et al.1997
that exotic invasions can be beneficial
(Hobbs and Mooney 1993). Recent trees that provide a diversity of habitats rently under forest management—we
data on understory vegetation response (multiple use); harvest and regenera- want to use the example of ecological
(Griffis et al., in press) suggest that ex- tion activities that protect soil and restoration and wildlife.
otic species respond dramatically to the water (sustained yield); and fire, insect, Numerous goals underlie traditional
reintroduction of fire as part of surro- and disease within acceptable limits management of wildlife, including
gate restoration treatments (fig. 2, from a long-term perspective (forest maintaining viable populations of all
p. 26). This response is also visually health). Silvics, silviculture, mensura- native and desired nonnative vertebrates
dramatic in full restoration treatments. tion, and forest protection indicate that (prescribed by the National Forest Man-
Consequently, in forests where exotic these are realistic objectives, achievable agement Act of 1976), recovering
species become established, ecological using tools like timber harvest. threatened and endangered species
restoration treatments may create a for- Foresters and restorationists use the (mandated by the Endangered Species
est health problem that is as undesir- same ecology, but restoration ecologists Act of 1973), and providing consump-
able as the pretreatment condition. use a reference condition as a substitute tive (hunting, fishing, trapping) and
Societal needs. What often distin- for specific objectives. Creating a refer- nonconsumptive (birdwatching, pho-
guishes foresters from ecologists is that ence ecosystem condition has its greatest tography) recreational opportunities. To
foresters are asked to manage forests to utility as a research tool to better under- achieve these goals, management is
achieve specific societal objectives stand how ecosystems function (Ehren- often directed at maintaining or en-
within ecological constraints. Forestry feld and Toth 1997; Michener 1997). hancing conditions for focal species. In
as an applied science has developed We certainly recognize understanding contrast, ecological restoration is guided
alongside ecology. These sciences ma- ecosystems as a laudable goal of ecologi- by broader goals that emphasize ecosys-
tured together and benefited from in- cal restoration. Fixing badly degraded tem composition, structure, and func-
teraction. A science can be defined by ecosystems—landscapes that have been tion rather than specific ecosystem ele-
the questions it asks. Forestry asks how deforested or contaminated with envi- ments. Implicit in restoration is the as-
trees grow, respond to competition and ronmental toxins—also is an important sumption that successful restoration will
release, and reproduce. Foresters are ecological restoration objective (Dobson provide favorable conditions for native
also interested in maintaining soil, et al. 1997). Again we concur this is a species of wildlife. Thus, effects of
water, and species other than trees. laudable use of restoration. restoration on wildlife are more appro-
Tending a stand of trees is seen as a Compatibility with achieving other priately considered an outcome rather
long-term commitment, but econom- values. To answer the question we pose than a specific goal of management.
ics dictates a minimum of interven- in our title—whether restoration Given that traditional approaches to
tion. A forester could be satisfied with should be viewed as an alternative land wildlife management are mandated by
an age-diverse landscape (regulated for- management paradigm for the bulk of law or deeply imbedded in many soci-
est) of stocked stands of well-growing forest lands in the United States cur- eties (Leopold 1933, 1949), it is un-
Journal of Forestry 25
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