Report - ICP Forests

116 4. National Survey Reports in 2009
coniferous and 649 broad-leaved trees. The sampling scheme and the assessment method was
the same as in the previous years.
The mean defoliation of all tree species was estimated to 26.5%. In comparison to the results of
2008 when the mean defoliation was 25.7%, the change is 0.4%. The mean defoliation for
coniferous trees was 26.4% and for broadleaves 25.9% in 2009.
In 2009 the share of trees with more than 25% of unexplained defoliation (damaged trees)
reached 35.4%. In comparison to the results of 2008, when the share of trees with more than
25% of unexplained defoliation was 36.9%, the value decreased by 1.5 percent points. Also
obvious is the decrease in defoliation for broadleaves where the share of damaged trees dropped
from 34.6% in 2008 to 33.3% in 2009.
Like in the previous years conifers are still more damaged than broadleaves. While their mean
defoliation and the share of damaged trees were assessed to 26.4% and 39.1% respectively (in
2008 26.0% and 40.7%) the values of the both indicators for broadleaves were assessed to
25.9% and 32.8% (in 2008 25.4% and 34.6%). However, the health condition of coniferous
sample trees was better than in 2008.
4.25 Spain
Results obtained in the 2009 inventory show a certain decline process when compared to
previous years. 82.3% of the surveyed trees were healthy (compared to 84.4% in the previous
year). 15.7% of the trees were included in defoliation classes 2 and 3, indicating defoliation
levels higher than 25%, with a clear deterioration, whereas in 2008 this percentage was 14.2%.
The number of damaged trees increased slightly and the number of dead ones increased to a
larger extent. This general worsening was slightly less noticeable in conifers, with a percentage
of 85.1% healthy trees (87.1% in the previous year), than in broadleaves (79.3% in 2009 and
81.6% in 2008).
The mortality of trees (2.0% dead trees of the total sample, compared to 1.4% in 2008) was due
to decline processes related to drought and felling operations (frequently sanitary cuts). Apart
from water shortages, the causal agents most frequently quoted were spring defoliators on
broadleaves, the continuous increase in the occurrence of the pine processionary caterpillar,
followed by bark beetles (Escolitidae), broadleaves borers, insects present in Eucalyptus stands
(Gonypterus, Ophelimus, Glycapsis…), as well as defoliating fungi infestations in Eucalyptus
stands; moreover, there were decline processes in Pinus radiata stands near the Cantabrian
coasts and the general presence of chestnut blight and chestnut ink disease in chestnut stands.
Mistletoe infestations are continuously relevant in certain areas affecting pines and juniper trees,
as well as a new decline process of a still unknown origin that seems to affect alder forest stands
near the Cantabrian coasts. Last but not least a punctual decline process can be observed in fir
stands in the Pyrenees. There is not a noticeable increment in damage due to drought symptoms
in Holm and cork oak stands.
The importance of atmospheric pollution in the evolution of forest condition is a factor which
can not be quantified directly, as it is frequently disguised by other kind of processes which are