The Canadian hemlock, one of the tree species planted in an experimental forest in Germany.
Credit: Scott Detwiler
Planting the Future Forest
By Julio Godoy
The urgent need to reforest its national territory has led German officials to search around the world - including the Bolivian Andes - for tree species that are resistant to climate change.
BERLIN, Feb 1 (Tierramérica).- 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 renovate the forests lost to the effects of global warming.
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 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 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 2009 forestry report of the German government, more than 60 percent of the country's spruce trees suffered as a result of drought and storms since 1984. The greatest damage - manifest 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, 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, 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 an average of two degrees Celsius warmer than they are now in Central Europe, with 25 percent less rain in the summer season.
The regions being explored in search of appropriate species include the high plains (Altiplano) 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 meter. But when autumn hit, and then 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, or Austria or Switzerland, in order to monitor their adaptation to the new habitat, he said.
However, the importation of exotic species could create a new ecological problem.
The new species could destroy the equilibrium of the new habitat or introduce parasites and diseases previously unknown in the region.
That is the case of 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 meters. It 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 from now before scientists can know if their current attempts at forest renovation were correct for mitigating the effects of climate change.
* IPS correspondent.