Les mutations
du climatL’effet
de serre est produit en grande partie par l’émission de dioxyde de carbone.
L’émission de dioxyde de carbone dans l’atmosphère est due à deux causes. La
première provient des combustibles fossiles brûlés afin de produire de l’énergie
(pétrole, charbon, gaz naturel).
La deuxième découle de la déforestation.
Moins il y a d’arbres, moins
il y a de photosynthèse
(un phénomène biologique
où une plante absorbe
du dioxyde de carbone).
D’autre part, après que les arbres
ont été coupés, du dioxide de carbone se forme à partir du carbone qui est dans le
sol.
(Pour en savoir davantage sur la rétention du carbone,
clicker ici.)
Ce processus diminue la fertilité du
sol.
Au Canada, les rejets de gaz à effet de serre se chiffrent à 21 tonnes par personne
par année. Dans les pays non industrialisés, 1,85 tonnes de gaz à effet de serre sont
rejetés, en moyenne, par personne par année.
Le Centre de Falls Brook, situé dans le comté de Carleton, est devenu le coordonateur
du « Analog Forestry Network », une association travaillant à la restauration
des forêts.
Le « Arbofilia » au Costa Rica, « The NeoSynthesis Research
Centre » au Sri Lanka, le « Rainforest Rescue » en Équateur et le
« COICAP » au Pérou comptent parmi les groupes importants qui mènent des
projets de reboisement.
Le type de sylviculture pratiqué par
cette association vise à créer un écosystème
forestier en fonction du maximum que pouvait soutenir,
à l’origine, la région reboisée.
Other CIDA funded articles:
The Kyoto Protocol
Pedal Power in El Salvador
A Return To Diversity
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Climate
Change:
Different Realities North and South
Jean Arnold,
Falls Brook Centre
September 1998
 hese days,
global warming and climate change is a hot issue. The main greenhouse gas produced as a
result of human activity is carbon dioxide (CO2). Carbon dioxide is emitted when we burn
fossil fuels (i.e., coal, oil and natural gas) to produce energy to power our industry, to
heat and light our homes and businesses, and to fuel our vehicles. Carbon dioxide is also
released to the atmosphere through deforestation.
Canadians use more energy per person than any other industrialized nation. Exhaust
emissions from burning fossil fuels total about 21 tonnes of greenhouse gas per year per
Canadian. By comparison, people living in non-industrialized countries emit about 1.85
tonnes of carbon dioxide per person per year.
Clearly, we in the industrialized world must address climate change. We can do this by:
reducing our over-dependence on fossil fuels as an energy source; supporting energy
conservation, renewable energies such as solar and wind; and the reduction of energy use.
Restoring Forests
Falls Brook Centre, a sustainable development demonstration and training centre in
Carleton County, New Brunswick, has been engaged in restoration projects for the past 10
years. On-site there are tree nurseries, forest trails, heritage seed gardens, a
herbarium, forest gardens and a new Acadian Forest restoration nursery. Falls Brook is the
Secretariat for the Maritime Region Forest Stewardship Council.
Analog Forestry Network -
a new approach
At the international level, Falls Brook has been coordinating the Analog Forestry
Network, an association of organizations working on forest restoration. Arbofilia in Costa
Rica, The NeoSynthesis Research Centre in Sri Lanka, Rainforest Rescue in Ecuador and
COICAP in Peru, along with other smaller community- based organizations, are part of a
coalition of groups rebuilding the degraded forest lands in their area. This ecological
forestry restoration program has been active for the past five years and incorporates a
seed exchange between the members that offers protection from multi-national patenting
efforts.
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(photo: Falls Brook Centre)
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Canadian host -
J. Arnold,
Falls Brook Centre
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Southern Realities
In the non-industrialized world, tropical deforestation is being driven by several
factors: greed, poverty and industrialization. Alongside fossil fuel reduction,
reforestation can counter-balance some atmospheric emissions by fixation of carbon
dioxide. As long as terrestrial plants are growing, their rate of uptake of CO2 through
photosynthesis is greater than their release of that gas, and the net effect is a
reduction of CO2 in the atmosphere.
How Forests Regulate Carbon
Forests and wetlands are natural reservoirs for storing the earth's supply of carbon.
At times, these reservoirs act as "sinks", absorbing more carbon than they
release; at other times they become "sources", releasing more carbon than they
absorb. On average, natural cycling processes are believed to have removed as much carbon
as they have added, thus keeping greenhouse heating in check.
The concern among scientists is that human activities have raised the concentration of
greenhouse gases in the atmosphere, thereby trapping additional heat. Deforestation has a
double effect: shifting carbon contained in trees to the atmosphere, while also reducing
the number of trees that remove carbon dioxide from the air. Due to the cutting of
forests, the opening of the earth for agriculture and the burning of fossil fuels, we are
adding more carbon into the atmosphere than ever before.
As the temperature rises, the climate changes. Hurricanes and storms become more
intense than before. Normal long-term events come more often and last for longer periods
of time (for example, El Nino). Rains come at different times, so farmers find it harder
and more difficult to rely on regular rainfall. Now that it is affecting farming in the
North, people are beginning to pay attention.
Foster biodiversity and support human needs
Analog Forestry is a system of silviculture that seeks to establish a tree-dominated
ecosystem similar in function to the original climax forest and vegetation of a region.
The tree and plant species act in an analogous fashion to the original natural structure
and function of the forest while also being useful to humans as crop plants. It seeks to
empower rural communities, both socially and economically, through the use of species that
provide marketable products. It provides specialized products of high value and products
that can be processed at the community level, as well as providing the highest carbon
sequestering value of any silviculture crop.
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Analog Forest
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(photo: Falls Brook Centre)
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Analog forestry addresses biodiversity, sustainability, traditional uses, medicine,
soil conservation, watershed management, and the ecological functions of tree species.
Because Analog Forestry has a high potential for carbon sequestration, it enables rural
communities to engage in the current discussions around climate change. (Analog forestry as a tool in joint implementation by Ranil
Senanayake)
Northern Problems
Move South
Currently being discussed at the global level is Joint Implementation (JI) This means
that one country can approach another country and pay them to plant trees to offset the
first country's polluting emissions. At this point in time the tree planting efforts are
monocultural, i.e. planting only one tree species, mostly pine and eucalyptus. Pine and
eucalyptus are short term tree crops with a 25-30 rotation that do not fix much carbon in
the soil.
In short-term plantations, carbon gets fixed for 30 years, is released and lost to the
atmosphere in about 60 years. Then it is fixed again in the next rotation. This rotational
pattern is valid only if land remains productive. If we had 90 year rotations - carbon
would be fixed for 90 years and would be less labourious. Analog Forestry designs its
landscape for a long term rotation of 90-100 years. (On the setting
of value for carbon sequestering by Ranil Senanayake)
Carbon Improves
Soil Fertility
Another key aspect is soil. When trees are removed from a landscape, the carbon
component oxidizes and turns into carbon dioxide, and the soil gets thinner and thinner.
When carbon is oxidized, acidity forms. The carbon - nitrogen ratio means the more carbon
there is, the more nitrogen that can be held. Carbon holds on to nitrogen (compost,
manure) When nitrogen enters the soil, carbon fixes the nitrogen and holds on to it for a
long time. If there is a lack of carbon content, the soil will use up the nitrogen very
quickly. All farmers need nitrogen and maintaining carbon is important.
The soils' carbon pool is stored in three stages. Long-term forests are the most
efficient storage. In natural forests, carbon is stored in the soil horizon by decantation
and microbial action to form long-age molecules. When we cut a native forest and change to
an agricultural or plantation system, the relationship is reversed. With agricultural land
or short-term crop rotation, carbon is held for a short time only.
Thus to gain maximum advantage of the soil, carbon pool plantations should be similar
or analogous to the natural system as natural forests sequester carbon for the longest
time. In Analog Forestry, which mimics the structure and species of the natural forest,
long-term pools are created as the soil matures.
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(photo: Falls Brook Centre)
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Bandaraela Valley -
UVA region Neo-Synthsis Research Centre
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Currently, world thinking is still dominated by the monocultural phase. However we must
ensure that these scientific facts are included in global planning because it allows small
farmers to count their analog forest area as a component of carbon sequestering. The Falls
Brook Centre works with the Analog Forestry Network members to help prepare them for the
global credit trading that will undoubtedly occur. This trading will only be a poor
substitute for requiring Northern polluting companies to "Clean Up Their Act."
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