Report - ICP Forests

106 4. National Survey Reports in 2009
4.11 France
The assessment of crown condition in France in 2009 was based on 9 949 trees on 500 plots of
the transnational grid (16 x 16 km). This survey included 66% broad-leaved and 33% coniferous
tree species. Compared to the previous year, the overall health condition remained stable.
Pinus pinaster represented 21% of all coniferous trees. Pinus sylvestris, Abies alba, Picea abies
and Pseudoplatanus menziesii constituted together almost 60% of the conifers assessed. The
broad-leaved forests were in majority represented by Quercus petraea (19% of observations).
Quercus robur, Fagus sylvatica, Quercus pubescens, Castanea sativa and Quercus ilex
represented 60% of the assessed broadleaves. The diversity of species included 42 different
broad-leaved species and 15 coniferous species.
The mean defoliation of all species was 23%, the same defoliation as in 2008 (19% for
coniferous and 26% for broadleaves). In general, the repartition within the defoliation classes
was the same as in the two previous years.
Compared to 2008, the defoliation class repartition slightly moved to higher defoliation (class 3
and 4), but this trend is not significant. The trees were mainly classified in the three first classes
(29%, 38% and 30%, respectively) which show a general good forest health. Almost 10% of the
trees had no defoliation (26% for coniferous and 3% for broadleaves). Broadleaves stayed at a
higher defoliation level than conifers.
In spite of the increasing populations of defoliating insects, the crown condition of Quercus
species has continued to improve thanks to the good climate conditions during the previous
years (the classes 0 and 1 are the most represented).
The highest mean defoliation was recorded for Quercus ilex and Quercus pubescens. The
attacks of Tortrix viridana were really important in 2009 for the latter one. Castanea sativa
remains very sensitive to Cryphonectria parasitica: the infections are still often mentioned (43%
of known causes). This species recorded the most important broadleaf dead rate but the main
health condition is relatively steady.
The storm which broke out in January and the growing bark beetle populations highly affected
Pinus pinaster. There was severe mechanical damage in the South-East. A total volume of
37 millions m 3 timber was damaged by storm. In the South-East, the particular dried climate
conditions during two years increased the discoloration and the defoliation levels. Pinus pinaster
recorded the most important death rate (3.2%). The defoliation recorded for Picea abies and
Abies alba were very low (more than 80% in class 0). Most of the Pinus sylvestris are severely
damaged (4.3% in class 3). This effect is particularly due to high snow damage.
The dry and warm summer had consequences to Fagus sylvatica: the classes 2 and 3 of
discolouration increased. Moreover, Orchestes fagi was responsible for a loss in the defoliation
class 0 on this species.
In 2009, the most frequently identified damage types were microphylla (54% of mentions), then
Viscum album (12%), fructifications (5%), and storm damage (3.9%). After windbreak, snow
was the most important abiotic damaging factor which appeared very early in 2009, especially in
the mountains.