Nature News: Harvesting oyster mushrooms in the wild

By Susan Pike

Oyster mushrooms growing up a live poplar Sue Pike photo

I am thinking that with the predicted relatively mild (for this time of year), wet weather this week we could still see some mushrooms popping up in the woods. I hope so. I’ve found a tree that seems to be hosting some oyster mushrooms. I’ll be visiting it again this week in the hopes of one last harvest.

I am very hesitant to forage for mushrooms in the wild. I won’t eat anything I have found growing from a stump, a dying tree or the forest floor unless it has absolutely no poisonous look-alikes and I have quadruple-checked its identity. Keeping that in mind, while out in the woods a few weeks ago, I happened upon a tree bearing what I knew must be oyster mushrooms. I checked them with iNature as well as some Googling, then cut some from the tree (but left some for others, people or animals) and walked out with my handful of mushrooms and plans for dinner.

Dinner! Sue Pike photo

Know the substrate!

Being a teacher comes in handy sometimes. It is amazing how many current and previous students I often meet while out on the trail. This time, a previous student, now in college, was out hiking with his roommates. He is a marine bio major, one roommate was an environmental engineer, the other was a forestry major. This was great. The forestry major could help with the ID! One of the things to look for when identifying fungi is the substrate from which they are growing. Mushrooms are usually substrate-specific. Chanterelles grow from the soil, usually under oak and beech trees, but sometimes under conifers. Turkey tails usually grow on deciduous trees. The currently trendy, medicinal reishi mushrooms are only found on conifers, primarily hemlocks.

Oyster mushrooms are most likely to grow on deciduous trees so I wanted to make sure that was the kind of tree “my” oyster mushrooms had been harvested from. Luckily, the young forestry major was able to identify the tree as a poplar, which checked off one more box in the positive identification of these mushrooms.

Double check your ID with field guides-the more different ones the better.

I have at least 10 different mushroom field guides. So, when I got home I checked them all, looking for other characteristics of oyster mushrooms: they can smell of anise (mine did), the stems have no ring (mine didn’t), and it was the right time of year. Finally, I sent photos to some mycologist friends just to be absolutely sure and they concurred with my identification. So, I cooked some up for my dinner to make sure that they sat well with me. They did, and the next night fed my family. Is it worth it going through all this to eat a mushroom that I can buy at a local farmers market or grocery?  I don’t know about everyone, but the satisfaction of eating something found in the wild can’t be beat.

Most trees can be identified by bark alone…I’m not great at that….but am fairly certain this was a poplar

Is mushroom picking sustainable?

However, I worry about the sustainability of foraging. It is a luxury that I can go out and forage, it’s a hobby. I don’t need to do it.  And I worry, if I take mushrooms from the forest, what about the deer, rabbits, squirrels and mice, not to mention, the numerous insects that also feast upon fungi? They can’t pick up some wild mushrooms at the grocery. So, I don’t always pick mushrooms, and when I do, I leave some for everyone else.  

What about the mushrooms themselves? Overharvesting should always be avoided. If you are picking mushrooms whose gills are open, there is a good chance they have already released their spores. They’ve done their job, so that is a good time to harvest.  The point of a mushroom is reproduction. The mushrooms we eat are the fruiting bodies (reproductive parts) of fungi. They contain the spores which they disperse for reproduction.

What exactly are you eating? A fruiting body?

When you eat a mushroom, you are eating something organized in a bizarrely different way from our plant and animal neighbors. When nature gives the cue that it is a good time to reproduce, mushrooms are formed from hyphae, thin threads that make up the “body” of most fungi. The hyphae are always there, they extend throughout whatever substrate the mushroom emerges from – a rotting log, the forest floor, the soil, sometimes forming vast networks (called mycelia). These are the white threads you find if you dig through some leaf litter or turn over a rotting log. That mushroom you are eating for dinner (the fruiting body) is composed of these long tubular hyphae, molded into fantastic shapes, their only goal – to release spores and reproduce. That’s what my oyster mushrooms were doing, releasing spores to the wind.

I’m looking forward to a few more mild, rainy, mushroom-friendly days. Oyster mushroom season lasts through November in the Northeast. However, most of the time I will enjoy just looking and only occasionally bring some home for dinner.

Susan Pike, a researcher and an environmental sciences and biology teacher at Dover High School, welcomes your ideas for future column topics. She may be reached at spike3116@gmail.com. Read more of her Nature News columns on paper (the Portsmouth Herald, Foster’s Daily, the York Weekly etc) or online at Seacoastonline.com, here at pikes-hikes.com, and follow her on Instagram @pikeshikes.

Nature News: Sparking Curiosity About What Doe-Eyed Creatures See

published on seacoastonline.com and in The Portsmouth Herald, the York Weekly, Fosters Daily Democrat etc.

White-tailed doe gazing at a drone in Addison ME photo by Everett Grant

My classes have been remote this fall. This is a hard thing for a science teacher-I like my classes to be messy, to get outside and explore, to get to know my students face to face, not through the lens of a computer’s camera.  I try to bridge the electronic gap by sharing stories about things I have recently seen, hoping to make some kind of connection, spark some curiosity.  

Last week I was telling my biology class about some people out walking in Kennebunk Plains who were wearing blaze orange vests that had a black camo pattern.  I said I thought this was weird–if you’re wearing bright orange, why the need to camouflage?  I had a few hunters in the class who explained about it being deer season and the necessity of wearing blaze, which led us off path and down the rabbit hole following the question, what exactly do deer see?  Can they see that bright orange vest?  If so, then the camo pattern is pointless.  But, if they can’t see bright orange, then the camo makes sense.  This didn’t fit in with my daily curriculum plan, but it is biology, so we did some research.

I had always thought that deer were color blind, and so thought I knew the answer to the question I had posed-what do deer see?  Turns out I only knew part of the story.  

If you have ever looked at the face of a white-tailed deer you have noticed its prominent  brown eyes.  Doe-eyed means (according to the Oxford Dictionary) “having large, gentle, dark eyes.” Deer have large eyes because, as a prey species, they need to be able to see as much of their environment as possible so that they can flee at the slightest hint of danger.  Their eyes are placed to the sides of their heads allowing them to see in a wide arc without moving their heads – a helpful adaptation for survival.  Deer have the eye placement of prey, humans, with our forward-facing, binocular vision that allows for better depth perception have the eyes of a predator.  Deer can both graze and watch for predators at the same time, we humans would need to post a guard.

But, what can deer see? Can they see that blaze orange vest? 

Like many nocturnal and crepuscular (active at dawn and dusk) animals, deer have a much higher density of rods in their retinas compared with cones.  Rods are light receptors (more than 1000 times more sensitive to light than cones).  Because deer are most active at dawn and dusk they need to be as sensitive to light as possible, packing lots of rods into their retinas helps them see very well in the dark.  Cones, on the other hand, are active at higher light levels, they detect color and are responsible for high resolution vision.  According to Penn State’s Jeannine Fleegle,“Even though deer have less than half the number of cones in the eye as humans, deer can still distinguish among different colors. During low-light conditions, deer are likely more sensitive to the blue to blue-green portion of the spectrum (due to the high rod density). Studies indicate that deer are less sensitive to light of long wavelengths (orange and red) and rely upon their perception of only 2 colors – yellow and blue.” (from “The Eyes Have It” published in the Deer-Forest Blog  2015). 

This means that red, orange and green all look the same to a deer-meaning that blaze orange vest might very well blend into the surrounding greenery.  But to truly blend in you have to be careful what material your vest is made out of and what you wash it with.  Deer lack a UV filter in their eye-they can see further into the UV spectrum than we can (we have a UV filter in our lens, presumably to help protect our eyes from damaging UV radiation-an issue when you are most active in daylight).  Shiny materials and cloth washed with various detergents and brightening agents all emit more radiation in the bluer/UV part of the spectrum and will stand out to a deer in the same way that blaze orange vest stands out to us. 

Sparking curiosity?

What we learned in class is just the tip of the iceberg in the study of deer vision. Other aspects of deer eyes come into play-their horizontal pupils for one.  Why do some animals have horizontal pupils? Great question! Sadly the quarter is over and I won’t get to pursue this in class, but I’m hoping that, having been introduced to the interesting differences between human and deer vision, my students might want to investigate this question all on their own.

Nature News: The albedo effect affects the warming of Earth’s atmosphere

published November 9, 2020

Lonesome Lake with ice cover. photo by Sue Pike

I was up in the mountains this weekend hiking up to North Kinsman Mountain via Lonesome Lake. It was so warm for November. Even though we had packs full of winter gear, even though we started early, a warm breeze had begun to blow and we were down to T-shirts and shorts within the first mile.

This is a beautiful little lake nestled in among the mountains at around 3,000 feet. When we got there, it was still mostly covered with ice. There was even ice and old snow along the shaded parts of the trail. I was struck by how warm it was in the surrounding woods and rocky outcroppings, yet cold by the water.

I am about to teach a big climate unit in my freshman Integrated Earth Science class.   Earth’s energy budget is a big part of this, so the sun and its interaction with the Earth have been on my mind. Walking through this dramatic change in air temperature made me realize that I was experiencing the albedo effect. 

Albedo is the fraction of incoming solar radiation reflected back (instead of being absorbed) by an object. The term “albedo” comes from the Latin for whiteness. The albedo effect is a measure of how much of the sun’s energy is reflected back into space. This is one of many factors that affect the warming of the atmosphere. Solar radiation passes through our atmosphere, strikes the ground and is either reflected back into space or absorbed and re-radiated as heat. So a surface with high albedo that reflects a lot of the solar radiation warms the atmosphere less (if at all) than a surface with low albedo that absorbs solar radiation and transforms it into heat.

Lonesome lake near Mt Kinsmen in the White Mountains. The ice kept this area cooler-albedo! -Sue Pike

When I realized what I was feeling, I got so excited. It was like I was walking through one of my science class experiments. I really wished my students were there with me so we could experience albedo together. Walking through the forest, or further up the mountain, the incoming solar radiation (short wavelength energy) was being absorbed by the dark green forest and granite and changed into longer wavelength energy (heat).  The atmosphere was heating up and we felt warmer. By the lake, that incoming solar radiation was reflecting off the ice, bouncing off at the same wavelength, there was no conversion to heat and so the immediate area was cooler. I can talk about this phenomenon in class, but imagine how cool it would be (pun intended) to be standing next to a big ice-covered lake mirror and make this connection.

Why care about albedo? It is a huge regulator of Earth’s climate. Understanding albedo helps us understand why we are experiencing accelerated warming of the poles. As temperatures warm and ice melts, the open ocean with its low albedo replaces ice cover that has a high albedo, increasing the amount of solar radiation transformed into heat, increasing the temperature. This is a positive feedback loop that only ends when the ice disappears. We are, in effect, rapidly losing a giant northern mirror that reflects solar radiation back into space before it can be turned to heat.

Examples of climate feedbacks, like albedo, are all around us. I guess this is obvious, but it hasn’t always been so to me. Until I learned what albedo was I wouldn’t have recognized what I was experiencing on that hike. I wouldn’t have gotten so excited. This, for me, is one of my biggest motivators as a teacher and a learner. The more we understand the science that underlies the world around us, the better we can appreciate it, which might just motivate us to protect it.