Growing Up With Trees - Stage Two

Last year the native tree seeds were collected and stored for the winter. In spring it is time to remove them from the mixture of sand and compost, sort the seeds out and re-plant them to leave outside. They need protecting from mice by covering the pots with chicken wire. They should be left in a non-drafty place out of direct sunlight, such as against a north facing wall.

alder in spring

Alder catkins are less well known than the hazel, however they are just as attractive

As with hazel, the catkins produce the pollen, which is carried by spring breezes to the flowers, shown here. It's too early in the year for the tree to rely upon insects to act as pollinators

This alder is still carrying a few cones from last year. Successfully polinated flowers develop into these seed bearing cones during the summer, and the small and light seeds are distributed by wind and water during the late autumn.

nitrogen nodules on alder roots

Here's a section of alder root, showing the nodules formed by the nitrogen fixing actinobacterium Frankia. This ability to "fix" nitrogen helps alder to grow in wet and nutrient poor soils where other trees would struggle to survive.