Report - ICP Forests

40 2. Large Scale Crown Condition Surveys
2.2.2.7 Quercus ilex and Q. rotundifolia
Quercus ilex and Quercus rotundifolia trees
mostly occur in evergreen broadleaved
forests in the western Mediterranean region.
Most of the plots are located in Spain. There
is a remarkable deterioration in defoliation
at the beginning of the observation period.
In 1991 4.4% of the trees were rated as
damaged whereas 29.6% of the trees were
in the respective defoliation class in 1995.
After a period with fluctuating defoliation,
the share of damaged trees nearly reached
the 30% mark in 2005 and 2006 again.
Since then, there is some recuperation
recorded which might be attributed to
favorable weather conditions reported from
Spain. From 2007 to 2009 crown condition
remained stable (Figure 2.2.2.7-1).
The map clearly shows the importance of
Spain with respect to the evergreen oak
species, since there are no data from
Portugal reported. In the north-east of Spain
and in southern France there are hardly any
plots with improvements in mean
defoliation (Figure 2.2.2.7-2).
N trees 0-10% >10-25% >25%
1991 2942 58.7 36.9 4.4
1992 2961 46.6 45.3 8.1
1993 2961 41.0 51.9 7.1
1994 2954 31.7 53.6 14.8
1995 2999 20.0 50.4 29.6
1996 2976 17.3 54.6 28.2
1997 2974 22.2 58.0 19.7
1998 2933 28.5 56.3 15.2
1999 3776 21.6 56.7 21.6
2000 3829 19.6 59.4 21.0
2001 3845 19.8 63.3 16.9
2002 3831 16.6 62.6 20.8
2003 3763 14.6 62.0 23.4
2004 3808 18.4 62.8 18.8
2005 3770 10.0 62.0 28.1
2006 3778 8.8 63.7 27.5
2007 3831 9.6 67.8 22.6
2008 3870 11.8 67.2 21.0
2009 3854 11.2 67.3 21.5
N trees 0-10% >10-25% >25%
1998 2957 28.3 56.4 15.3
1999 3800 21.6 56.9 21.5
2000 3853 19.5 59.2 21.3
2001 3869 19.8 63.4 16.8
2002 3855 16.5 62.8 20.7
2003 3787 14.5 62.2 23.3
2004 3856 18.2 63.1 18.6
2005 3818 10.0 62.0 28.1
2006 3826 8.8 63.6 27.6
2007 3879 9.9 67.6 22.5
2008 3894 12.1 67.0 20.9
2009 3878 11.6 67.0 21.4
100
80
60
40
20
0
1991
1992
1993
1994
1995
1996
1997
1998
1999
Percent of trees
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
0-10% (91-09)
>25% (91-09)
0-10% (98-09)
>25% (98-09)
Year
Figure 2.2.2.7-1: Shares of trees of defoliation 0-
10% and >25% in two periods (1991-2009 and 1998-
2009).