Alder Trees

Alder trees can be found throughout the UK, growing alongside rivers, lakes, and wetlands. The root systems can be important in preventing erosion in river banks and are even used as nesting sites by otters, and it is also an important source of early nectar in these habitats.

In the winter months it can be easily identified by the woody female catkins, which look a little like tiny pine cones. The male flowers take the form of long thin yellow catkins, which look a little similar to those found on hazel trees. Alder trees are monoecious, meaning that both male and female flowers can be found on a single tree.

In addition to its value as a food source for invertebrates and birds, alder also has a fascinating relationship with the nitrogen fixing bacteria Frankia alni. This enables alder to grow in nutrient poor soils, allowing it to colonise new areas of habitat, improving the soil quality for other species of plant.

Mixed alder and willow woodlands are frequently very damp, and the bark is often covered in mosses and lichen. These conditions can be ideal for the small pearl bordered fritillary and chequered skipper butterflies.

By Chris Eyles, Senior Warden for Exmoor

Leave a Reply

Your email address will not be published. Required fields are marked *