International Archives of the Photog
even in past centuries, especially after big windthrows. Broken
trees build natural origins of a new beetle generation that is able
to reproduce two times a year and therefore is able to spread
rapidly in its beloved spruce tree paradise.
Therefore people differ on the idea of a german jungle,
especially if they are owner of private forests adjacent to
national park borders. Thus the main focus is on analyzing how
the national park's vegetation will develop in the near futurc
resp. how long it will probably take to get back to a green forest
which matches better with human inherent expectations of what
a national forest should normaly look like.
Figure 1. Deadwood in Bavarian Forest National Park
Trying to find answers on that question boils down to
understand the spreading behaviour resp. the impact of
influencing factors as well as to monitor the development of
natural rejuvenation. This is the only way and therefore
represents the hope to put oil on troubled waters and to get back
to a green, more beetle-resistant forest in future, at least for our
next generation.
zi : ET dimi au À
Figure 2. Time series of deadwood spreading
after bark bectle outbreak
[n the meantime almost 4000 ha of spruce stands are died off
which makes up roughly one third of the core park area, where
no protection measures are tolerated. The bark beetle’s
behaviour is not yet entirely explored and still under research.
Though it is no longer a question when and how far bark beetles
fly and that main influencing factors of the beetle’s activity can
be found in climate, forest structure including tree species and
age, soil type resp. watcr situation, yet dead wood spreading
seems to be rather arbitrary. lt is hard to find regular patterns
that match fine with the site-related-factors mentioned above. In
addition all real world natural phenomena are particularly tough
to see through and to predict because nobody knows what kind
of e.g. spring temperatures we'll face in near future. Currently a
further completely different approach is followed that lights up
the spreading from another point of view by capturing and
analyzing the air's pheromon accumulation to get to an entire
A
Do
xgrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B4. Istanbul 2004
understanding about the beetles' communication and dispersion
behaviour.
1.2 Natural forest rejuvenation carries hopes
Monitoring the very young forest is time consuming as it cannot
(yet) be automated by using new techniques like laserscanning
or radar. Considering the shielding of older trees there's no way
to obtain complete and reliable information about the number
and condition of upcoming plantlets or natural competition
among the vegetation. This leads to get down on the floor, setup
long-term sample areas, survey every single sapling, mark them
out using unique identifiers and reexplore them at least several
consecutive years!
x E y E IBEX
Figure 3. Natural rejuvenation raises hopes for forest recovering
[n Bavarian Forest National Park a bunch of long-term
monitoring areas were selected in a manner to represent
different area types with varying impact characters, to allow
distinctions between planar and exposed monitoring areas,
certain degrees of matured forest dying oft as well as different
National Park regions that differ in accepting man-made
reforestation or not. Figure 4 documents one of the 40 x 40 m
monitoring squares that comprises border area, core zone, plant
sociological surveying areas, sample circles and soil samples
extraction points.
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gure 4. Sketch of a monitoring area to analyze
forest rejuvenation development
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