Black alder

LEPANGES-SUR-VOLOGNE ALDER

Diameter: 57 and 60 cm
Height: 25 m
Estimated age: 80 years

We form a group of two trees located in a very humid basin, a favorite place for trees of our species. In common parlance, we are called alder, verne or elk. We are very widespread, from the hilly level to the mountain level (1200 meters). Of all the alder species, we are the ones that best tolerate stagnant water and heavy soils. Unfortunately, we suffer very quickly from drought. Our favorite places are the riparian forests* where the soils are constantly humid.
Trees of our species tend to be pioneers*, so we do not tolerate competition well and tend to disappear when other species take hold.
Overall, our species is threatened in European natural ecosystems, due to two factors:
- alder groves have declined sharply, in favor of poplar cultivation (poplar growing) or the drainage of wetlands for cultivation, pasture or urbanization:
- in riparian forests*, the water temperature and the weak current promote the deposition of inoculum of a fungus called Phytophthora at the foot of the trees. The quality of the water does not seem to be the cause, but the type of soil and the presence of artificial structures (dams, bridges) can increase the risk of infection by aggravating the frequency of floods and water stagnation. The death of alders contributes to reducing the shade of the rivers and therefore their warming, which - in a perspective of global warming - could further promote the multiplication of the fungus.

*Vegetable cordon made up of trees, shrubs and other smaller plants bordering a watercourse.
The means of control are difficult to implement. Coppicing* allows - in the affected areas - to produce healthy strands.
As a preventive measure, it is necessary to promote the diversity of riparian forests, made up of native species, adapted to the environment and with an irregular structure*.