Forest monitoring: ARNEWS and
NAMP
Among the activities of the Canadian Forest
Service are two initiatives set up to detect damage to forests caused
by biotic factors (e.g., insects) and by abiotic factors (e.g.,
acid rain).
Distribution of ARNEWS sites in Quebec based
on date when they were established.
Map: J.-P. Bérubé / J. Thibault
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From 1984 to 1999, the Acid Rain National
Early Warning System1 (ARNEWS) aimed at detecting
the first signs of damage to Canada’s forests and monitoring
changes in vegetation and forest soils. As for the North
American Maple Decline Project2 (NAMP), it aimed at monitoring
the condition of sugar maple throughout northeastern North America
and it operated from 1988 to 1999.
ARNEWS had 150 study sites in Canada, including 32
in Quebec. NAMP had 233 sites across Canada (24 in Quebec) and the
United States in stands that were not managed or that were used
for maple syrup production.
This dual network enabled tree condition to be rigorously examined,
in particular by annual inspection of tree crowns (quality of foliage,
defoliation). In addition, by recording any changes in the chemical
characteristics of soils and foliage, ARNEWS made it possible to
identify the
long-term impacts of acid deposition and other pollutants on ecosystems.
The natural forest mortality rate varies from 1 to
3% and is caused by known disturbances (insects, diseases, natural
thinning). Thanks to the monitoring done under ARNEWS and NAMP,
researchers were able to isolate the effects of pollutants and extreme
climatic conditions on forest health and suggest possible causes
for year-to-year variations (see boxes).
These two monitoring networks have been replaced
by three case studies focusing on particular stress factors in forests.
Two of these studies cover eastern Canada: the Forest Indicators
of Global Change Project (FIGC), which looks at many of the same
sites as NAMP and ARNEWS, and the case study on the impact of the
1998 ice storm and the subsequent recovery, which ends this year
(2003).
Distribution of NAMP sites across Canada.
Map: R. Simpson (AFC) / J. Thibault (LFC)
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To ensure the sustainability of Canada’s forests,
it is essential to maintain a research network that is able to detect
damage to forests caused by atmospheric changes (global warming,
ground-level ozone, ultraviolet radiation, etc.) and to establish
the requisite causal links.
Effect of freezing
rain on NAMP maple stands
The 1998 ice storm affected 38 NAMP sites. The
risk of moderate or serious damage to the crown was 1000 times
higher in the area that received more than 60 mm of freezing
rain. Similarly, the risk of damage was 1000 times higher
in natural stands than in maple stands managed for sap collection.
The damage also increased with site altitude and was more
severe in areas where nitrate deposition caused by acid rain
was higher. Finally, red maple ran a risk of damage five times
higher than sugar maple.
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Observations from ARNEWS
surveys
Critical load calculations show that rain
acidity exceeds the capacity of forest ecosystems in most
study sites in Quebec. It is difficult, however, to establish
a link between decline and the fact that the critical acid
load is being exceeded. Other causes of decline were also
noted: insect infestations, Armillaria root rot, drought,
the age of trees, and competition within the stand. In areas
affected by the 1998 ice storm, its effect on tree crowns
was still visible in 1999.
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Forest Conditions, Monitoring and Reporting
www.nrcan-rncan.gc.ca/cfs-scf/science/resrch/conditions_e.html
For further information, please
contact:
Pierre DesRochers
Natural Resources Canada, Canadian Forest Service
Laurentian Forestry Centre
1055 du P.E.P.S., P.O. Box 3800, Sainte-Foy, Quebec G1V 4C7
Phone: (418) 648-3922 • Fax: (418) 648-5849
E-mail:
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1 In French: Dispositif national d’alerte rapide
pour les pluies acides (DNARPA).
2 In French: Projet canado-américain d'étude du dépérissement
de l'érable.
© Her Majesty the Queen in Right of Canada 2003
Catalogue Number Fo29-54/7-2003E
ISBN 0-662-34024-8
ISSN 1705-5784
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