So I’m having a Week, and all I really want right now is to flee the lab and run away to the forest. But I can’t so, I’m looking at pictures I took a couple months ago and plotting art projects, and so here’s an assortment of trees:
My favorite time to wander in the forest is after the rain. When the ground is still soggy and everything is vividly green and alive, the sun is bright but not yet returned everything to the stasis of summer and drought. When all you can hear is the sound of ephemeral streams trickling down hillsides and the last drops of rain falling on leaves.
You’ll notice that while yes, these trees are mostly redwoods, they’re not the giants you see in some parks. This area was clear cut relatively recently in tree years, so these trees are all babies. Redwoods grow up first, and then out, so they are mostly spindly things, but still too tall to really convey in pictures.
Sometimes they creak and sway in the wind, which is mildly alarming when you are underneath them. Another favorite thing: the difference of the sound of the wind in different sorts of trees, and the way you can track the wind’s course by listening to it move through different patches of forest.
I also like poking around in the undergrowth and looking for interesting little plants tucked around the trees. Lots of poison oak, but also lots of tiny flowers and interesting ferns.
Recently I went and visited my family in Washington and noted that there was a lot of moss around all the trees there. I don’t have a lot of moss in the forest where I live. I figured it had to do with the amount of rain, as we generally have a warmer, drier climate.
But then I went out to my forest between the rain this week, and was struck by the sight of an enormous tree completely coated in moss. The entire trunk was green.
But none of the trees around it had any moss. Poking around a bit more, I realized that all the trees with moss were Douglas firs, and the trees without (but often with a lichen?), were redwoods. This remained true wherever I went, suggesting it wasn’t some something to do with that particular tree’s environment. Being very much not a plant scientist (or a moss scientist), I didn’t know much about what was going on, and wondered if the species-specific moss growth had to do with something structural (is redwood bark too smooth for moss to grab on to? do douglas firs move water/nutrients in a way that moss can better appreciate?), or chemical (do redwoods deter moss growth?). I decided the chemical deterrent hypothesis made more sense, because I found moss on old redwood stumps that had lost most of their outer bark.
Having wasted a great deal of time eating lunch and staring at trees, I went back to the lab and did some reading:
Other people have observed this phenomenon (link to paper on JSTOR) through studies of epiphytes in redwood forest. The authors of this paper suggest moss are deterred by anti-fungals produced by redwoods. Also fascinating, they describe their tree-climbing equipment/process in their methods section! Also more complex tree structure/surface area = more species growing on it.