Water-loving alder can grow as happily in woodland as it does in damper, cool soil. The wood of this tough tree doesn’t rot when waterlogged, instead turning stronger and harder.
Alder is the only British native deciduous tree to develop cones. It provides food for the caterpillars of several moths, its catkins provide an early source of nectar and pollen for bees, and the seeds are eaten by birds including goldfinch. When growing in wetter conditions, alder roots make the perfect nest sites for otters. The roots have nitrogen-fixing nodules, conditioning the soil and improving soil fertility on former industrial wasteland and brownfield sites. Alders are also used in flood mitigation.
The green dye from alder flowers was used to colour and camouflage the clothes of outlaws like Robin Hood, and was thought to also colour the clothes of fairies. Alder wood’s ability to withstand rotting in water mean that historically, it has been used in the construction of boats and water pipes. Alder used to be the preferred wood to make clogs, and it was said that a few alder leaves placed in the shoes before a long journey would cool the feet and prevent swelling.