Lichen and Air Quality

Nw3gNGNbWhen I visited California, I spent a great deal of time with people learning about natural dyes. One of the most interesting and challenging types of dyeing involved the use of fungus or lichens to dye fabric. Lichen is a delicate symbiosis of fungus and algae, which requires moisture, sunlight, and good air to grow. When I mentioned that I didn’t really think we had much lichen in my town, the response I got was, “What kind of a place do you live in?!?”

I didn’t think much about it at first. I know the air quality in southern Ontario, Canada, isn’t great, but I brushed it off. I figured we didn’t have as much lichen because our forests are somewhat dry, despite the high humidity in our air. But lichens can give beautiful colours ranging from browns and yellows to blues, purples, pinks, and reds, and I eventually decided I wanted to take the plunge. Once that happened, I realized the full impact of that statement about, “what kind of place I live.” I was mostly right. We don’t have much in the way of lichen in our town. But now I understand why.

_MG_8432Lichen is a bioaccumulator, collecting nutrients, and chemicals, from the air and storing them. In places where pollution is high, most lichens can’t survive. A few who thrive on the elements ubiquitous in smog and industrial exhaust do well, but the rest are hardly found in areas of poor air quality. In fact, lichen is such a good indicator of air quality that in the city of Hamilton, Ontario, they’re using it as an indicator plant for air quality studies.

In order to have the best chance of finding lichens, I used those air quality surveys to find a park which was in a lower-pollution area. Even then, the lichens I found were surprisingly sparse and of only about three to four types. Back home, I think I’ve found all of two types of lichen. One is impossible to scrape off of fallen branches, and the other gives brown dye.

Why do I care about air quality? Ask all those people who walk around cities wearing hospital masks. With my chemical allergies, lower pollutant levels in the air are probably a good thing. When I visit cities like Vancouver where the pollution is hemmed in by mountains, or otherwise high, my sinuses become stuffed, and I’m sure it doesn’t do much better for my skin reactivity.

100_4239When I move next, I’m going to look at the trees. I want it to be to an area where lichen is plentiful. That will give me the best chance of lowering my allergic reactivity and sinus congestion.

Do you live in a place where lichen is nonexistent, or plentiful? How do you think air pollution affects your allergies? Comment below.

Important Note:

Lichen grows very slowly, and an entire population can be decimated by irresponsible collection. I collect lichen only from fallen tree branches, where the inevitable decay of the wood and biodegradation of the lichen means it’s already doomed.

Leave a Reply