Est-ce que les plantations épargneront
nos forêts naturelles?
mythes enveloppent encore les enjeux concernant la foresterie intensive et
les plantations. Par exemple,
il y en a encore qui prétendent que les plantations n’ont aucun effet négatif
sur la biodiversité parce qu’elles sont biologiquement la même chose
que des forêts naturelles, et même que ces plantations réduisent les
pressions sur les forêts naturelles.
mythes, toutefois, ne tiennent pas compte pleinement de la complexité des
écosystèmes forestiers, ni de l’évidente réalité de la consommation
accélérée de notre société alimentée par son avidité et par la
croissance sans limites de sa population.
croyons qu’il existe des différences importantes entre une plantation
d’arbres et une forêt naturelle, et plus spécialement dans notre forêt
Acadienne diversifiée. Nous
croyons que la promotion sans réserves des plantations forestières est
irresponsable sur le plan écologique, et ne sert qu’à détourner
l’attention du mouvement vers une foresterie durable.
Our Natural Forests?
Peter Salonius & Judy Loo, Canadian Forest Service
view that plantations, with their faster growth of wood fiber, are
necessary given our wood-hungry world and an ever-shrinking land base
seems to die hard. Ample evidence of this is the Forest Products
Association's demand on behalf of the forest industry to double the
province's softwood harvest, and promote intensive softwood forest
management on 60% of our Crown land forests.
Myths still abound that cloud the issues surrounding intensive
forestry and plantations. These myths suggest that plantations have no
adverse effect on biodiversity because they are biologically the same
as natural forests. Or that plantations reduce pressure on natural
forests. The more plantations, the more land for parks, old growth,
bird and animal habitat, and watershed protection. However, these
myths do not fully recognize the complexity of our forest ecosystems,
nor the reality of our society's accelerating resource consumption,
driven by greed and open-ended population growth.
We believe that there are important biological differences between
a plantation and a natural forest, especially in our diverse Acadian
Forest. Take a walk in a maintained plantation and you see only one or
maybe two tree species. Compare this to the many tree species you will
see in most forests of this province - ranging from, say, four to
eight. Add to these the animal and other plant species that depend on
the missing tree species.
Plantations usually result in a drastic change in age and
size-class structure. The natural mix of sizes and age classes is
replaced with a single age class of uniformly sized trees. Plantations
also lack large standing and fallen dead trees. Gone or reduced are
the many species dependent on deadwood, from various fungi and insects
to Pileated Woodpeckers and American Marten. Gone too, are the
services provided by deadwood - water retention, nutrient storage, and
Think also of the genetics of plantations. In a natural stand,
intense selection pressure due to competition for soil moisture and
light results in only a tiny fraction of available seed surviving and
becoming part of the next generation. Dynamics differ among stands
resulting from different natural disturbance regimes and various
genotypes have adapted to the different dynamics. A plantation, on the
other hand, has a single simplified stand dynamic. Selection pressures
are largely by-passed by nursery conditions, site preparation,
herbicide use, and thinning, all of which reduce competition.
Further, the argument is often made that a plantation of
genetically improved trees has a greater genetic diversity than the
natural stand it replaces. But this is diversity of the planted
species and ignores the genetic diversity among and within the species
that are displaced. Also, it is wrong to think of the one plantation
in isolation. A seed orchard consists of perhaps forty parents. Given
that there are only forty parents populating many plantations across
the landscape, genetic diversity is reduced when considered at the
landscape level among different populations.
Another myth, that plantations reduce pressures on natural forests,
makes sense in theory - if we can produce more wood per unit of land
then we won't have to harvest from as much land. However, this
argument fails to consider four facts. First, to date, softwood
plantations have satisfied only a limited market - low quality
softwood lumber and pulp fiber. Though rotation length is being
increased in some instances, thereby increasing potential for higher
quality lumber, markets for hardwood and high quality softwood lumber
will likely continue to rely on natural forests.
Secondly, the myth assumes that plantations will produce high
volumes of wood indefinitely. Studies in Europe, however, have found
that successive plantations lead to soil acidification and nutrient
leaching, thereby reducing the productivity of the site.
Thirdly, the myth assumes that increased productivity on one unit
of land will necessarily alleviate pressure on another unit of land.
However, for this to be true, the demand for wood would have to be
static, which, of course, is not the case. Our society is addicted to
a consumption and growth paradigm that creates an open-ended and
constant increase in demand. That is, of course, until the resource
collapses. Cod, anyone?
Finally, the myth fails to consider the use of the "allowable
cut effect" in determining annual allowable cut. Increased
harvesting of natural forests is justified on the forecasted fiber
increases that silviculture will generate. Thus, contrary to
proponents of this theory, increasing plantations can actually result
in a direct increase in natural forest harvesting.
At best, plantations are a partial solution to the root problem of
over-consumption by an increasing population, and, in all likelihood,
will only exacerbate the degradation of our forests. They represent
the long-term, continually increasing appropriation of nature in that
they replace complex, stable, self-renewing ecosystems with simple,
unstable wood-producing farms that require large non-renewable fossil
fuel inputs - a boon to banks and big business, a blow to
All this said, we do not believe that all tree planting is
inappropriate from an ecological perspective. Tree planting can be
used to help restore the natural diversity of our forest by planting
an appropriate diversity of species on abandoned agricultural land and
in impoverished forests. Tree planting may also be appropriate in
forests that naturally have few tree species, such as sites that are
naturally black spruce or jack pine. In this way, tree planting is a
part of ecosystem-based forestry, in which woodlot owners and
foresters work with the forest. However, we believe that the
uncritical promotion of plantation forestry is ecologically
irresponsible, and serves only to sidetrack the movement toward