Alder (Alnus) root nodules!?

[Aiki_Joker]

Anyone ever seen prolific nodules on Alnus spp.? Just removing these for the old folks and loads of nodules. Hopefully innocous? The soil is quite poor, dry in summer, wet in autumn/winter, gley constituent. Roots were covered in these, maybe due to low nitrogen content and drainage/drying issues of the clay based soil? The saplings look to be healthy and have shot up over the past few years.

Thoughts?

 

[Bonsai Nut]

Root nodules are most common on legumes, but Alnus (alder) is one of the tree genera where they can occur. They are caused by symbiotic nitrogen-fixing bacteria. They are beneficial to the tree and provide nitrogen in nutrient-poor soils.

 

[Aiki_Joker]

Most appreciated Bonsai Nut! All birches have this predisposition?

 

[Bonsai Nut]

Most appreciated Bonsai Nut! All birches have this predisposition?

No it is not universal. You can check out the list here.

 

[Bonsai Nut]

They are beneficial to the tree - but they are a sign the tree isn't getting enough nitrogen. If you are concerned about aesthetics, fertilizing the tree with a standard nitrogen fertilizer will reduce/suppress their development.

 

[Aiki_Joker]

No it is not universal. You can check out the list here.

Many thanks!! :0)