Report - ICP Forests

4. National Survey Reports in 2009 115
Discolouration was not detected on 90.6% of the conifers and slight discolouration on 9.4%. The
degree of discolouration calculated for all broad-leaved species was as follows: no
discolouration 95.9%, slight 3.0%, moderate 0.6%, severe discolouration 0.5% trees and dead
0.0% trees.
No visible damage symptoms were observed on 84.3% of the conifers, 8.5% showed slight
damage, 6.0% conifers were moderately and 1.2% were severely damaged. As for broad-leaved
tree species, the proportions of trees with visible damage symptoms were as follows: no damage
on 88.7%, 8.2% with slight damage, 2.0% moderately damaged trees, 0.6% trees with severe
damage and 0.5% trees were dead.
4.23 Slovak Republic
The 2009 national crown condition survey was carried out on 108 Level I plots on the
16 x 16 km grid net. The assessment covered 4 944 trees, 4 049 of which being assessed as
dominant or co-dominant trees. Of the 4 049 assessed trees, 32.1% were damaged (defoliation
classes 2-4). The respective figures were 42.7% for conifers and 24.5% for broadleaved trees.
Compared to 2008, the share of trees defoliated more than 25% increased by 2.9 percent points.
Mean defoliation for all tree species together was 24.6%, with 28.0% for conifers and 22.2% for
broadleaves. Results show that crown condition in Slovak Republic is worse when compared to
the European average. This is mainly due to the condition of coniferous species.
Compared to the 2008 survey, worsening of average defoliation was observed in Fagus
sylvatica, Quercus spp., Picea excelsa and Abies alba. Improvements were observed in
Carpinus betulus.
Since 1987, the lowest damage was observed for Fagus sylvatica and Carpinus betulus, with
exception of fructification years. The most severely damaged species were Abies alba, Picea
abies and Robinia pseudoacacia.
From the beginning of the forest condition monitoring in 1987 until 1996 results show
a significant decrease in defoliation and in visible forest damage. Since 1996, the share of
damaged trees (25-32%) and average defoliation (22-25%) has been relatively stable. The
recorded fluctuation of defoliation depends mostly on meteorological conditions.
As a part of the crown condition survey, damage types were assessed. 31.9% of all sample trees
(4 944) had some kind of damage symptoms. The most frequent damage was caused by insects
(14.0%) and fungi (12.7%) at tree stems. Additional damage causes were logging activities
(11.1%), and abiotic agents (3.7%). Epiphytes had the most important influence on defoliation.
63% of trees damaged by epiphytes revealed defoliation above 25%. In addition, abiotic agents
had a direct influence on defoliation.
4.24 Slovenia
In 2009 the Slovenian national forest health inventory was carried out on 44 systematically
arranged sample plots (16 x 16 km net). The assessment encompassed 1 056 trees, 407