Forest Condition in Europe - ICP Forests

78 Forest Condition in Europe 2013
The total share of not defoliated trees, 49,4, was by 1,4 % lower as in 2011. Percentage of
trees in classes 2 to 4, moderately to dead, was 7,8. Thereby percentage of conifers in classes
2 to 4, moderately to dead, was in 2012 6,7 %.
In Estonia the most defoliated conifer tree species has traditionally been Scots pine (Pinus
sylvestris), but a little improvement in crown conditions as compared to 2011 happened.
Some decrease of defoliation of Norway spruce (Picea abies) occurred, the share of not defoliated
trees (defoliation class 0) was 54,3 %.
Percentage of broadleaves in classes 2 to 4, moderately to dead, was in 2012 15,0, but in 2011
only 3,0 %. Thus the serious changes in crown conditions as compared to 2011 happened. The
share of not defoliated birches was in 2011 74 and in 2012 59%.
Numerous factors determine the condition of forests. Climatic factors, disease and insect
damage as well as other natural factors have an impact on tree vitality.
In 2012 8.2 % of the trees had some kind of insect damages, 28,3 % identificable symptoms
of disease and 4,8 % identifiable abiotic damages. Pine shoot blight was the most significant
reasons of biotic damage of pine and winter moth was the main reason of increased birch defoliation.
5.9. Finland
The large-scale crown condition survey (Level I) has been carried out in Finland on a systematic
network of permanent sample plots for 26 years, since 1986. Before 2009, a subsample of
the permanent plots established during 1985–1986 in connection with the 8th National Forest
Inventory (NFI).
The integration between ICP Level 1 and NFI was accomplished in 2009 in Finland. The
sampling design of the current NFI is a systematic cluster sampling. The distance between
clusters, the shape of a cluster, the number of field plots in a cluster and the distance between
plots within a cluster vary in different parts of the country according to spatial variation of
forests and density of road network. Principally, every fourth cluster is marked as a permanent
cluster. Annually, a new set of permanent plots, established during the 9 th NFI in 1996-2003,
is assessed in the forest condition survey. The trees are sampled by the relascope. Tallied
dominant and co-dominant Norway spruce, Scots pine and birch trees from six pre-selected
permanent plots from each cluster are assessed. The same permanent plots will be assessed in
five- year intervals. In 2009-2010 all trees were assessed, but since 2011, a maximum of six
trees per appropriate species were included in the sample, resulting in a reduced number of
assessed trees, owing to limited resources.
Please note that because the plots assessed during 2009 -2012 are completely different samples
each year, the results are not directly comparable with each other or with the results from
the previous years. Also please note that the number of assessed trees was greatly reduced in
2011 and 2012, as compared to 2009 and 2010.
The results of the 2012 forest condition survey are reported from pre-selected 785 permanent
sample plots. The number of observation trees was 4676. Of the 4637 trees assessed for defoliation,
61,9 % of the conifers and 45,7 % of the broadleaves were not defoliated (leaf or needle
loss 0-10 %). The proportion of slightly defoliated (11- 25 %) conifers was 37,3 %, and
that of at least moderately defoliated (over 26 %) 14,6 %. For broadleaves the corresponding
proportions were 32,9 % and 12,8 %, respectively. The proportion of moderately defoliated
trees, especially broadleaves, was somewhat higher than in 2011.