Lichens can be found growing on rocks, rotting wood, soil, trees, as well as other substrates. Lichens are present on every continent, including both the Arctic and Antarctic. Lichens are extremely resilient to drought. They can quickly absorb 3 to 35 times their weight in water. They can also absorb moisture from dew, fog, and humid air. Thanks to the fungal structure, they dry out slowly. This allows the algal components to continue producing food for as long as possible. There are even lichen varieties in the desert. This sturdy specimen can survive at all altitudes, and in all climates. Lichens are also present in literature. In The Writings of Henry David Thoreau, Volume 9, Thoreau discusses studying Lichens. For such a resilient and ubiquitous life form, we spend little time discussing or appreciating it. Let’s start at the top. What is a lichen exactly? Is it a fungi…yes? Is it an algae….yes? Huh? Lichens are actually two life forms living in a symbiotic relationship. They consist of fungi and algae providing for the needs of one another.
Maybe this story will make clear what lichens are, and how the fungi and algae relationship works. Imagine a fungi. Give it whatever cartoonish character look that you choose. Now this Fungi is a fantasic carpenter. Fungi can build a structure (like a house) in no time flat, and will keep building on that structure as the family grows. Well, this carpenter, Fungi, is out hiking through the forest one day, when he comes upon Alga. Alga is the finest cook in the whole forest. You see, Alga has chlorophyll, which allows her to use sunlight, carbon dioxide, and water to cook up the most delicious and nutritious food. Her secret cooking method is called photosynthesis. Alga shares this nutritious and delicious food with Fungi, and he falls in love immediately. This is the finest cooking he has ever tasted in his whole life. Fungi says to Alga, “If only I could provide something so wonderful for you, we could live happily ever after”. Alga explains that, while she needs sunlight for cooking, she is delicate, and too much sun will dry her out. Of course, Fungi steps up and says, “I will build a structure to protect you, and together we will grow a family”. So the story goes…and they live happily ever after.
One often asked question is, “Will that ‘stuff’ hurt my tree”. The answer is absolutely NO. There are extremely rare exceptions, with a few pest fungi that may have a negative effect on some plants. However, Lichens are a good thing to see in the landscape. Their presence indicates a lack of air pollution. Yep, they are bioindicators. We discussed bioindicators in our article, Garden Detective 202. Certain Lichen varieties are sensitive to certain pollutants. Scientists study the types of lichen and their population size as an inexpensive and effective method of monitoring air pollution.
Lichen are beneficial in many other ways. They are an important winter food source for Caribou and their European cousins, reindeer. In some cases, lichen may provide 90% of the winter food source for Caribou. Deer eat it. Some frogs eat it. Hummingbirds, some songbirds, and squirrells use it for nesting material. It also provides homes for insects which are a food source for larger animals. Lichens have been used in human cuisine as well. Before you run out and grab a mouthful though, realize that lichen are extremely difficult to digest. In addition to that, some varieties are actually toxic. Take the old mushroom adage to heart…”There are old mushroom hunters, and there are bold mushroom hunters. There are no bold, old mushroom hunters”. Don’t eat anything unless you are completely sure that it is safe.
After natural disasters and cataclysmic events, lichen are often the first life forms to move into the area. After the Glaciers descended across the landscape, leaving nothing but exposed rocks in their wake, lichens played a key roll in creating new soil and an environment hospitable to plants. They can break down rock. It is an extremely slow process, but with its resilience, time is on lichens’ side. This process is caused by lichen wedging itself into cracks in the rock and breaking it into small pieces. Some secondary chemicals produced by lichen also breaks down rock, releasing minerals.
The benefits of lichens are still being studied throughout the world. They have been used in products like deodorants, laxatives, expectorants, tonics, and healing pastes over the years. Research on these organisms is suggesting they might hold promise in the fight against certain cancers and viral infections, including HIV. If we look at them with some understanding, their most valuable quality may be aesthetic. There are thousands of species on this planet, each with it’s own beauty. Next time you’re out in the garden, try to find and identify some of your lichens. Here are some resources for lichen identification:
We would love for you to take a photo and send it to us with the identification. If you haven’t signed up for our newsletter yet, click here. With spring just around the corner, we will be discussing important and timely material.Share Tweet