Exotic tree seedlings grow next to native
species in the southeastern German village of Laufen, at a site where
researchers are experimenting with ways to restore forests lost to the
effects of climate change.
The forest of the future - made
up of the Bulgarian fir (Abies borisii-regis), oriental beech (Fagus
orientalis), silver linden (Tilia tomentosa), Lebanon cedar (Cedrus
libani) and Canadian hemlock (Tsuga canadensis) - maintains some
characteristics of the old native German firs, beeches and oaks, but is
more resistant to climate change.
"Here, we are planting the future," Randolf Schirmer, director
of the experimental botanical bureau of the Forest Service in the
southeastern state of Bavaria, in charge of the Laufen site, told
Tierramérica.
In the last 40 years, climate change and related phenomena
have decimated Germany's native trees, especially the spruce (Picea
abies), Schirmer said. This species has shallow roots, so it needs
regular rainfall and is not very resistant to storms.
The especially dry and hot summers of the past decade in
Europe, and the increased frequency and intensity of storms in Central
Europe have taken a toll on the spruce.
According to the German government's 2009 forestry report,
more than 60 percent of the country's spruce trees suffered as a result
of drought and storms since 1984. The greatest damage - evident in the
trees' dryness and lack of growth of the tree crowns - occurred in
1992, 2002, 2003 and 2004.
The weakening that climate change causes in the spruce also makes it more vulnerable to disease and parasites.
Many German forest experts estimate that by 2100 at least half of the existing spruce forest will have disappeared.
The government report also confirms similar damage to beeches,
pines, firs and oaks. As a result, the authorities are working to
create a new type of forest, one that can better adapt to new climate
conditions.
Furthermore, say experts, the forest of the future should
protect biodiversity, ensure the continuity of the water cycle, prevent
erosion and provide - in a sustainable way - the economic resources
that society needs.
The search for new trees for the German forest, begun in 2008, has followed the trail being left by climate change.
The trees to be imported should already grow in regions where
the climate change conditions predicted for the second half of the 21st
century in Germany already exist: temperatures that average two degrees
Celsius higher than they are now in Central Europe, and 25 percent less
rain in the summer season.
The regions being explored in search of appropriate species
include the "altiplano" or high plains of the Bolivian Andes,
mountainous areas of Canada, China, the western United States,
southeast Europe (especially the Balkans), and the eastern shores of
the Mediterranean: Turkey, Syria and Lebanon.
Seeds of some exotic trees were planted in Laufen in the
spring of 2009. But some, like the princess tree (Paulownia tomentosa),
did not survive the change in habitat.
Native to China, this tree grew normally during its first
German summer, reaching a height of almost one metre. But when autumn
hit, followed by the frigid temperatures of the current winter season,
all of the princess trees planted in Laufen died.
The initial rapid growth of the species had been one of the
reasons behind importing it as a substitute for the fir, explained
Schirmer.
In contrast, trees like the black pine (Pinus nigra) and downy
oak (Quercus humilis), originally from Turkey, as well as the ponderosa
pine (Pinus ponderosa), from the western U.S., seem to have adapted to
the Laufen climate.
Over the next several years, the species that demonstrate
resistance to the region's climate will be transplanted to other areas
in Central Europe with similar conditions to those of Laufen, whether
in Germany, Austria or Switzerland, in order to monitor their ability
to adapt to the new habitat, he said.
However, the introduction of exotic species could create new ecological problems.
The new species could destroy the equilibrium of the new
habitat or introduce parasites and diseases previously unknown in the
region.
There are problems, for example, with the Douglas fir
(Pseudotsuga menziesii), which was initially seen as an ideal
replacement for the German fir because of its wood. But the Douglas
grows very quickly, ultimately reaching 60 metres, and would easily
displace shorter local species.
"In the regions where the long-term climate predictions are
very uncertain, the authorities should adopt low-risk strategies" when
it comes to importing exotic trees, Andreas Bolte, of Germany's
Institute of Forest Research, told Tierramérica.
The slow growth of forests in general means it will be 40 or
50 years before scientists can be sure that their current attempts at
forest restoration were on the right path in terms of mitigating the
effects of climate change.
Inter Press Service