Biodiversity-based Productivity: Foundation of Ecologically Sustainable Forestry

Joseph Zorzin redoak at
Sat Oct 7 08:20:21 EST 2000

posted in alt.forestry

The following article was in the latest issue of "Ecoforestry"
journal published by the Ecoforestry Insitute of Canada. Their
web site is I have permission from the
author to post it here.

Biodiversity-based Productivity: Foundation of Ecologically
Sustainable Forestry

Ray Travers

"One of the most fateful errors of our age is the belief that
'the problem of production' has been solved."
E.F. Schumacher (1974)

Recent experimental studies on whole ecosystems support what
many ecologists and observant lay people have long suspected:
the more species which live in a biologically diverse ecosystem,
the higher its productivity, and the greater its resiliency and
capacity to withstand insects, disease, drought and other forms
of environmental stress. Since we depend on ecologically
sustainable ecosystems to clean our water, enrich our soil,
produce our food, fibre and the very air we breathe,
biodiversity is clearly something that we ought not to
systematically degrade through ill-conceived forest practices.

These new studies have enormous policy and practical
implications. Their findings are dismembering the rationale for
plantation forest management, even as they promote building the
institutional capacity to move quickly to ecoforestry. There is
now little scientific, ecological, economic or social
justification for perpetuating these outdated practices, because
this new knowledge is removing the very underpinnings and
justification behind zoning for intensive forest management,
widespread use of clear-cutting and setting the allowable annual
cut above the long-run, sustained yield.

In plantation forestry, the destruction of biological diversity
is seen as a necessary and unavoidable tradeoff to "enhance"
productivity. A managed forest, in this outdated view, is
defined as "normal," where the objective is to maximize
production of marketable timber. For example, the Ministry of
Forests Act, Section (a) declares its mandate is to "encourage
maximum productivity of the forest and range resources of the

Since species richness and diversity (including the presence of
numerous non-marketable, non-industrial species) characterize
natural forests, this interpretation, in effect, brands natural
forests as "abnormal." It also defines the natural forest, in
its diversity, as "chaos" and the plantation forest, in its
uniformity, as "order." According to this plantation paradigm,
biological diversity works against productivity.  These new
studies now reveal the contradiction that plant "improvement"
requires the destruction of the biological diversity to supply
its raw material.

In brief, the strategy of basing productivity on the destruction
of biological diversity is dangerous, counter productive and
unnecessary. Also, it is misleading for economic calculations of
forest productivity to include only the yield of a particular
commercial tree species, while overlooking other land uses and
the yield of  "non commercial" species. This distorted measure
typically also ignores the benefits of internal inputs from
natural processes, and the financial and ecological costs of
intensive forest management, such as fertilizers and herbicides.

If the gross primary productivity of all species is included and
the biomass of all species is measured, the biodiversity-based
productivity of a complex ecosystem is usually greater than a

There are two contrasting ways society might choose to become
sustainable. The most familiar, the plantation paradigm, can be
called "technological sustainability."  The second, promoted by
ecoforesters, is called "ecological sustainability."

The primary assumption in the technological paradigm is that
society can become sustainable through efficient application of
better technologies and more accurate prices. The second view is
that sustainability is best achieved by working within the
limits of natural systems and using nature as a model to design
our forest practices, economy and society.

Advocates of technological sustainability tend to believe that
every problem has either a technological answer or a market
solution. Advocates of ecological sustainability agree with Wes
Jackson who said that "the patterns and processes discernible in
natural system ecosystems still remain the most appropriate
standard available to sustainable agriculture. . .what is needed
are countless elegant solutions keyed to particular places."

Not until biological diversity is made an inherent part of the
logic of production will it be adequately conserved. Determining
the relationship between species richness and productivity is
vital, both in the context of diversity loss in natural
ecosystems and intensive forest management. In nearly all
human-managed ecosystems, from agricultural field crops to
plantation forests, people have reduced the number of plant
species far more drastically than any glacier ever did.

In both managed and natural ecosystems, accumulating evidence is
demonstrating the real payoff of biological diversity comes with
the stabilization of productivity over the long term, allowing
the ecosystem to capture and use available resources
efficiently, and to resist and recover from climatic and other
impacts. Therefore, managing for a healthy ecosystem should not
focus on achieving maximum productivity in a single year but
more on accomplishing sustainable productivity over time.

An important recent addition to our knowledge of the impact of
reduced species richness on productivity is now available from
the BIODEPTH project in Europe ( See pages 4 to 6 in this
issue.) Started in 1997, this study is being conducted on eight
grassland sites from Greece to the high latitudes in Sweden.
Early results confirm that a loss of 50 percent of species
results in a decline of 10 to 20 percent productivity; and a
monoculture means a 60 percent reduction in productivity.

When the reduced capacity to withstand impacts and stress, the
rapid conversion of natural forests into plantations through
over cutting, clear-cutting and intensive management are
considered, the pursuit of so-called technological
sustainability is folly. The time for biodiversity-based
productivity, the foundation for ecological sustainability, has

Ray Travers, RPF, is board chair of the Ecoforestry Institute
Society, based in Victoria, B.C. He is a forestry consultant.
E-mail will reach him at rtravers at

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