Tree of The Week: Alder

The Alder tree is a member of the Birch family and not to be confused with the Elder Tree 😉. It is a pioneer species, meaning that they are often the first trees to colonise sites disturbed or damaged by landslides, fires, floods etc, as well as being very adaptable to many conditions. This could be due to its rare symbiotic relationship with nitrogen-fixing bacteria that live in the trees roots. In exchange for sugars, these bacteria create fertiliser for the tree, enabling it to invade, and flourish in waterlogged or infertile ground.

Alder is native to almost the whole of continental Europe, United Kingdom and Ireland. Its natural habitat is moist ground near rivers, ponds and lakes and it thrives in damp, cool areas such as marshes, wet woodland and streams where its roots help to prevent soil erosion 🙌. Worldwide, there are 30 species and it’s fairly easy to spot an Alder tree as they have small brown cones, which are the female catkins that stay on the tree all year round. What’s a catkin I hear you ask: A catkin is a slim, cylindrical flower cluster, usually with no petals that uses the wind to pollinate. Their catkins provide nectar and pollen for bees, and the seeds are eaten by some small birds. The bark is a bit like Birch tree, generally smooth until the tree gets bigger when the bark gets rougher, it’s dark and often covered in lichen. The leaves are dark green and round/oval shaped with serrated edges not to be confused with Hazel leaves, which are softly hairy compared to the larger shiny ones of Alder.

We love the Alder tree because it is great for reforestation projects as it is fast growing (about 1m/3ft per year) and regenerates the soil. They improve the fertility of the soil wherever they grow through their nitrogen rich bacteria, even improving soil fertility on former industrial wasteland and brownfield sites. Better soil helps the other plants around them and that follow after the tree has died - they have short life spans of about 60 years, it’s almost as if they are here to do a job of preparing the soil for those who follow ♥️.

The wood of this tough tree doesn’t rot when waterlogged, instead turning stronger and harder, as long as it remains completely immersed, Alder wood will keep its strength for hundreds of years. This is why it was used as much of the foundations for building one of our favourite cities, Venice.

As we see climates changing and more and more flooding in the UK and elsewhere, Alders can be used for flood migration - another one of Mother Earth’s technologies at play, stabilising banks and preventing erosion and flood damage to the landscape.


Alder cones have special anti bacterial and anti fungal properties - but NOT for human consumption. If you go out foraging and collect the seed cones once they are empty, then add them to warm water, leave for 15 mins to create a great water to sterilise equipment, use on wounds if your caught out in the woods or most commonly used for lower the PH and soften water for keeping some types of fish. The Red Alder species, mostly found in North America, was used by Native Americans to treat skin irritations, the bark contains salicin, the precursor to aspirin. Natures medicine box.

You can also use the flowers to created a green dye, it is said that the clothes of outlaws like Robin Hood where camouflage with Alder dye.

Well that’s a lot of amazing goodness from one tree, next time you see one may be stop and say thank you.