While walking through Totem Park recently, I noticed something red that seemed to be growing on or at the base of red alders (Alnus rubra) near the estuary. In places, it was unclear whether they were coming out of the ground, but I did find a couple where it was clear that they were growing out of the alder tree itself. There was some branching, but many were unbranched, and the surface was very smooth to the point of being slippery (though I don’t think it was slimy).
As best I could tell, they are roots, though I don’t know why they would be sending roots out into the air (and why they would be so red). At this point my best guess is the moss growing on the tree trunk blocks enough light and holds enough moisture that the tree responds as if it were buried at that point, and so sends out roots. It doesn’t take long for the roots to get outside the moss covering, so I’m not sure why they would keep growing, but I think they do die off over the winter.
Questions:
- Does anyone have other ideas for what’s prompting these growths?
- Why are they red?
- What mechanisms drive root development (that is, how does a tree ‘know’ where to grow roots)?
I have seen something similar with alder roots doing the same growing into flowing water from a stream.
I have seen the same root-like red objects on moss covered base of Alnus glutinosa also. But its was short, less then 2 cm. Firstly I supposed that it is roots, than consider that is tubers of Frankia alni bacteria colony. I’m still not sure what it really is.
Thanks for your comment Mikhail – I have seen the nodules that I understand are the home for the bacteria, but they looked quite a bit different. I have a picture of the nodules in this photojournal post.
Yes, you are right. Frankia nodules is quite different.
I’m afraid I’ve already misled hundreds of people in our mushroom community with these roots.