What is glowing green on my tree, in Chicago?
January 9, 2018 8:54 PM   Subscribe

Tree in my backyard, don't know what kind, pretty tall -- definitely too tall for me to get up where the glowing is -- has maybe two dozen spots, spread throughout the canopy, that glow green after dark. They're BRIGHT! There are also a handful of spots on the nearby phone/power lines, fairly evenly spaced. If you go around the south side of the tree, there are also two red glowing spots. I'm in the Chicago suburbs. What in the heck am I seeing?

My husband swears it's some kind of fungus; to me it looks positively man-made (like paint maybe?); but it's utterly invisible from the ground during the daytime so we are no closer to a guess, and neither of us has been able to capture a good photo or a good glimpse of the cause with binoculars or zoom lens, day or night.

We'd love to know what it is, but if you have questions that can help us narrow it down, we'll investigate that too! (Like, I keep bugging him to look first thing in the morning when it's still dark, to see if they're still glowing, because that would suggest whether it's a charge-and-glow-for-a-while reaction or an all-night thing, but he keeps forgetting.)
posted by Eyebrows McGee to Science & Nature (23 answers total) 7 users marked this as a favorite
It's not light beams shining on the tree, is it? The two colors are odd.
posted by Johnny Wallflower at 8:59 PM on January 9, 2018

Could it be glowworms? Or glow in the dark paintballs?
posted by the webmistress at 9:03 PM on January 9, 2018

One of those Christmas projector lights from a neighbour's yard? I have a projector light that's a grid of green dots with a few red ones throughout.
posted by GuyZero at 9:09 PM on January 9, 2018 [7 favorites]

Response by poster: Definitely not light beams or a Christmas projector -- the light source is definitely ON the tree and on the wires, glowing, not projected from elsewhere.

I first noticed the green in the tree in early December so it's been there at least a month (I assume longer).
posted by Eyebrows McGee at 9:14 PM on January 9, 2018

I agree with GuyZero that one of your neighbors has a Star Shower Laser projector.
posted by Hatashran at 9:26 PM on January 9, 2018 [4 favorites]

Probably glow in the dark paint. How it got there? I would guess paintball or slingshot.
posted by fshgrl at 9:53 PM on January 9, 2018

posted by poffin boffin at 10:08 PM on January 9, 2018 [16 favorites]

Solar powered decorative lights?
posted by jamjam at 10:09 PM on January 9, 2018

Borrow a pole saw, hack off an affected limb, examine the remains. Only way to be sure.

...or, easier, wait for a stiff breeze and observe. If the lights move in sync with the limbs, then the light is attached to the limbs. If not, then not. Pay particular attention to stippling while in motion (this helps you identify relative motion on multiple planes).

But, realistically, it's a light projector. Like the kind I bought this winter. Shoots a remarkable distance if you're not paying attention.
posted by aramaic at 12:11 AM on January 10, 2018 [7 favorites]

The Star Shower lasers are pretty weak compared to some of the better (and much more expensive) laser projectors. They'll make noticeable spots in your trees, but only if they're right there with the trees. I picked up a bunch of them this year for that very purpose, and it makes for an unusual yard decoration. Once you get beyond around 30-40 feet, the Star Shower dots start to get hard to see, depending on ambient light levels.

Whether you are using a Star Shower or a more powerful unit, the normal way these are deployed revolves around providing a pleasing coverage of a house or other object. This provides a lot of opportunity for some spillover.

Aiming one of our "more powerful" units down the street, I have no problems putting noticeable dots on a dark house almost a block away. I can also get some reflections off of a window.

Given that you noticed this starting in December, and it's green and red dots, it's really very likely that it is some laser projector on someone else's stuff that's hitting your trees and the phone wire. It could be several houses away, on the other side of the block, etc.
posted by jgreco at 3:46 AM on January 10, 2018 [5 favorites]

Response by poster: Guys, it's not a projector. It's on all 360 degrees of the tree -- not just one side -- and it clearly moves with the branches.

I started noticing it in December because that's when I got a new telescope mount and was in the backyard after dark looking intently at things.
posted by Eyebrows McGee at 4:46 AM on January 10, 2018

Pretty sure there’s no arboreal bioluminescent fungi in the region, fwiw.
posted by SaltySalticid at 4:50 AM on January 10, 2018 [4 favorites]

Well, if you have a telescope, you can aim the telescope at the spots when you see them, and leave it pointed at them for your husband in the early morning, or for you in the daytime. Then you can see what they look like in other times, while knowing you are still looking in the right place.
posted by Huffy Puffy at 5:18 AM on January 10, 2018 [1 favorite]

Is this a new phenomenon you just noticed, or a longstanding one? What happens to the spots when you shine a powerful light on them?

The utility lines seem like an important clue to me. Maybe ComEd painted them to indicate where work was being done, or where the tree was to be trimmed to prevent its branches from damaging the power lines. If the tree branches used to touch or rest on the power lines, that would explain why they’re both marked.

I’m in Chicago and I’ve never noticed glowing trees before, FWIW!
posted by lieber hair at 5:20 AM on January 10, 2018

Response by poster: Okay I went out with binoculars, and I could see something that plausibly looks like it could be paint in small splotches on the tree. I couldn't see anything on the power lines, though. I'll try going out in the late afternoon and early evening to see if I can definitively spot a glowing patch before it's too dark to tell what it is; otherwise I'll make careful note of where they are when they start glowing so I can binocular again in the morning. I THINK my husband has a high-powered light we could shine up there so I'll try that too.

Lots of lichen in the areas where I saw the glowing, but none on the power lines, and apparently no bioluminescent fungi in Chicago (thanks Salty Salticid!).

It doesn't look like utility markings (and why would they use glow in the dark paint?), but the paintball theory could be plausible. When I first saw it (which, thinking back, was probably in October, but I forgot about it until I was out a lot in December), I thought it was some kind of solar powered fairy lights thing from the last residents, I suppose it's possible someone decorated their tree with glow in the dark paint, and hit the power lines a few times accidentally! Although then I want to investigate whether there's any on the fence or house or neighbor's garage, it'd be a little weird to miss your tree target and ONLY hit the power lines when you missed, instead of the large structures nearby.

Anyway, based on your suggestions, I will seek more data tonight and return with a report! I am pretty positive it's not a projector but I'll see what I can do to rule that out definitively.

"Is this a new phenomenon you just noticed, or a longstanding one?"

We just moved here so I don't know!

Whatever it is, it's pretty, and I'm having fun trying to figure it out.
posted by Eyebrows McGee at 7:15 AM on January 10, 2018 [4 favorites]

It could be a fungus/bioluminescent lichen called Foxfire! A friend had this on her ponderosa pines and it took a group of about 50 to figure it out, but her descriptions sounded just like yours. More info and pics here.
posted by stellaluna at 8:58 AM on January 10, 2018 [4 favorites]

And here’s a link to her tree. Red and green lights!
posted by stellaluna at 10:13 AM on January 10, 2018 [6 favorites]

Wow stellaluna, I never heard of red lights from a fungus!

And it may clear up a mystery I've been puzzling over for a long time: the Japanese term for the fungal glow we call Foxfire also translates literally as 'fox fire', and I had what I thought of as an Aha! moment when it occurred to me that it might not be just a supremely unlikely coincidence if the reflected glow from a fox's eyes were to be the same green as the Foxfire fungus, and I was quite crestfallen to read that the glow from a fox's eyes is ruby red!
posted by jamjam at 10:44 AM on January 10, 2018

And it makes a person think about possible origins of Christmas tree lights a little bit differently.
posted by jamjam at 10:50 AM on January 10, 2018 [2 favorites]

>Wow stellaluna, I never heard of red lights from a fungus!
I haven't either. And when I read about bioluminescent fungi, I see only descriptions of green to blue-green. Red is not mentioned in the wikipedia article for foxfire, only blue/green. Luciferase/Luciferin can produce reddish tones in animals, but I can't find any fungal examples at present.

Honestly, I am not sure that the photo showing a red light linked above is not either a photographic artefact, or some other light.

On both the color and foxfire in general: while I am happy to be corrected, that name refers to many species, including many strictly tropical and strictly Asian species.

The only species that I can find so far that can light up at night and live in CHI is the Honey Mushroom (i.e. an Amarilla spp.) . Amarilla mellea can apparently grow in CHI at the western edge of its range, but it only glows blue/green, and favors dead wood, and hardwood species.

Eyebrows: If you have good reason to track down the fungal angle based on visual evidence, we'll need the kind of tree, at least broadly.

Keep us posted!
posted by SaltySalticid at 3:41 PM on January 10, 2018 [1 favorite]

Response by poster: It's been raining non-stop the last couple days, which impedes my ability to get a really good look, but I can report it continues glowing even in the rain, and we took a family detective drive around the neighborhood seeking projectors and did not spot any in a two-block radius in all directions. (Although it's possible someone has one in a backyard we didn't spot, although that would be kind-of weird.) As best we can tell, by checking every few hours, it's brightest at sundown and fades towards dawn, which makes me think paint is probably the culprit. What I really need is a tall enough ladder to get up to the glowing spots! But I am pretty content with the paint explanation, although one of course wonders WHY. We'll do more looking when it's sunny/the night after a good sunny day, and keeping looking over the next couple months to see if it disappears (in case it is a secret projector!).
posted by Eyebrows McGee at 7:27 PM on January 11, 2018 [5 favorites]

Home Depot rents ladders/scaffolding, and I am going to go goddamn insane if we don’t get a solid answer here!

(Cue sound of me winding up for a freak out)
posted by aramaic at 7:38 PM on January 11, 2018 [4 favorites]

Response by poster: Update: WE SOLVED IT, and you'll see why it took so long! Come summer we climbed up and we DID see some splotches of what appeared to be glow-in-the-dark paint, although not nearly enough to explain the winter phenomenon, so we remained puzzled. Then come Thanksgiving this year, one of our neighbors put up a projector YES IN HIS BACKYARD (which is weird) and aimed at a very strange angle, and the overflow is in my tree, almost exactly the same color as the glow-in-the-dark paint splotches.

So it was BOTH paint AND projector, which is why neither explanation alone explained what we were seeing!

The glowing red dots on the "back" of the tree did not reappear this year; we guess it was a different neighbor's projector that only a couple of spots escaped from, that they're either not using this year, or repositioned.

(The sole remaining question is, why did someone put glow in the dark dots of paint all over our tree and up on the telephone wires? But at least we know what it is now!)

We also remain unclear on why the one neighbor has a Christmas projector pointed mostly at his back fence, and leaves it up until April? But to each their own!
posted by Eyebrows McGee at 6:23 PM on December 24, 2018 [3 favorites]

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