Forest Condition in Europe - ICP Forests

Forest Condition in Europe 2013 77
verse ratio of temperature to precipitation amount was highest in March when precipitation
reached only 38% of the normal amount and average temperature was higher by 2.7° C than
the long-term average. Higher temperatures particularly at lower altitudes above sea level
have a negative influence on the health status of spruce stands.
No pronounced change has been recorded in the emissions of main pollutants (particulate
matter, SO 2 , NO x , CO, VOC, NH 3 ) in the last ten years; total emissions of the majority of
these compounds have moderately decreased in the long run in spite of some fluctuations and
the emissions of particulate matter and NH 3 have been at a constant level.
5.8. Denmark
The Danish forest condition monitoring in 2012 was carried out in the National Forest Inventory
(NFI) and on the remaining Level I and II plots. Monitoring showed that most tree species
had satisfactory health status. As in previous years an exception is Fraxinus excelsior
where the problem with extensive dieback continued. Average defoliation was 29% for all
monitored ash trees, and 42 % of the trees had more than 30% defoliation. In some ways,
even these data do not completely reflect the situation, because many diseased ash stands are
clear cut. This is reflected in timber statistics, where the amount of ash harvested rose significantly
in 2010 and 2011.
Picea abies stayed at a low average defoliation of 6%, and the health situation for P. abies in
Denmark is still very good based on monitored stands. However, it should be recalled that the
main calamities of Norway spruce in Denmark are wind throw and bark beetle (Ips typographus)
attack. These problems are rarely reflected in defoliation scores, as such stands are removed
by forest management. Other conifers such as Picea sitchensis and Pinus sp. had a
slightly higher defoliation at 9,5% and 11% respectively, but the health of conifers in general
can be considered satisfactory. The average defoliation score of Fagus sylvatica decreased to
9%, and the health of beech is clearly influenced by average precipitation in the growth season,
which has increased in the past decade. Average defoliation of Quercus (robur and petraea)
increased to 18% due to widespread attacks by defoliators such as Operophtera brumata,
and the frequency of damaged trees rose from 15% to 22%, reflecting the importance of
spring defoliation by caterpillars for the health of oak.
Based on defoliation assessments on NFI plots and Level I & II, the results of the crown condition
survey in 2012 showed that 77% of all coniferous trees and 68% of all deciduous trees
were undamaged. 18% of all conifers and 21% of all deciduous trees showed warning signs of
damage. The mean defoliation of all conifers was 7% in 2012, and the share of damaged trees
was less than 5%. Mean defoliation of all broadleaves was 12%, and 11% of the trees were
damaged, which is similar to 2011. The main damage causes were ash dieback and defoliation
of oak.
6.9 Estonia
Forest condition in Estonia has been systematically monitored since 1988.
In 2012 altogether 2348 trees, thereby 1465 pines Pinus sylvestris, 582 spruces Picea
abies and 227 birches Betula pendula,were examined on 97 permanent Level I sample
plots from July to October.