Oct 08 2011

Glow in the Dark

Published by at 8:47 am under Plants


October is a good time of year to see wood glow in the dark.

The phenomenon is called foxfire and is most often caused by the honey mushroom (Armillaria mellea), native to eastern North America.

Armillaria mellea feeds primarily on hardwood and is most often noticed when it produces fruit –> honey mushrooms.  The mushrooms are like the apples on a tree.  There’s a big plant structure that produces the fruit, but in the case of Armillaria you can’t see the “plant” until it glows.

The glowing comes from its rhizomorphs that look like long, black bootlaces and grow under the bark of dead trees, downed logs, old roots and stumps.  They also grow on living trees which they eventually kill.

The faster they grow, the more they glow because their feeding process produces light.  Their bioluminescence is a chemical reaction that’s the opposite of photosynthesis.  The tree they’re consuming used CO2 + light to produce organic (carbon-based) material + oxygen.  The fungi use luciferin molecules to combine organic material + oxygen to produce CO2 + light.  Pretty ingenious, eh?

Finding foxfire is problematic, especially for city folks like me.  The light produced is a faint green or blue glow that’s easily swamped by man-made light.

The habitat and weather must cooperate too.  The infected wood has to be damp — not too wet, never dry — and the best temperature is 77oF though anything above freezing is acceptable.  Summer heat (86oF+) shuts down bioluminescence which makes autumn, with its early sunsets and cooler temperatures, an optimal time to see it.

I’ve never seen foxfire but that’s no surprise.  I’d have to drive to a very dark place (how far?) and wander in the woods at night looking for a faint glow, hoping I don’t encounter a mammal I don’t want to meet.  Spooky!

Have you seen foxfire?  Where?

(photo of foxfire in Allegany State Park, New York by highlatitude on Flikr, Creative Commons license.  Click on the photo to see the original)

76 responses so far

76 Responses to “Glow in the Dark”

  1. Jessicaon 03 Dec 2015 at 12:46 pm

    Omg,I was googling just now what this was and was lead here as well. My fiancè was taking our puppy to podi last night and 3 trees in the front/side of our yard were glowing in several (ALOT) on the branches. Nost were neon green glows but we spotted some that were glowing red as well…. We were a little creeped out as we werent sure what this was. I will b happy to inform him today I have fig’d out what this is and what causes it. But most say it happens in warm weather and it is by far warm here in Knob Noster, MO…. It was high 30°’s here and was 9:00pm at night…. Was the craziest but coolest thing we have ever seen as well 😉

  2. Jasonon 03 Dec 2015 at 9:55 pm

    Just lost a quadcopter in my pine tree trying to figure out what the stang green and red dots were. Should have checked this out first but having never seen nor hear of such phenomenon I decided to investigate… now to get my quadcopter back from ~50ft.

  3. Amyon 03 Dec 2015 at 10:19 pm

    Just saw this for the first time in south-central Montana. My husband was taking the trash out and thought the stars were shining really brightly between the bare tree branches of the neighbor’s giant elm tree across the alley. As he got closer, he realized there were little blue lights – and a few red lights – at the very tips of some branches. Then he noticed it on two other trees in two other back yards. They look a little like tiny Christmas lights but are just at the very top of the trees and way out on the tips. Shining a flashlight on them washes them out. We found this website when we searched for a possible cause. We had never heard of this before. Thanks to everyone for sharing!

  4. Deniseon 03 Dec 2015 at 10:38 pm

    Tonight was the second time that I noticed patches of glowing green in some tall old trees in my backyard. The larger patch looked like it fluttered. I’m in northern Illinois and it is 34 degrees with 76% humidity. The glowing spots were in different trees than tonight. I’m sure glad that there is a reasonable explanation.

  5. Peggyon 04 Dec 2015 at 4:14 am

    A tree in my yard glows with foxfire. It is beautiful!

  6. Pamelaon 05 Dec 2015 at 9:48 pm

    Yep! It’s a real thing…just saw it this evening on one of our trees. Glowing was red and green..kinda cool, but a drag to know that our tree may not survive. Thanks for the information!

  7. Kealaon 06 Dec 2015 at 1:04 am

    Everyone, thank you for sharing your experiences! We are looking at foxfire tonight, in Wake Forest, NC. We had no idea how the hundreds of green (and a few red) lights made their way into a naturally forested area behind a neighbor’s house…some of the lights glowed from the tops of 50-plus feet trees, as well as all points in-between and on the ground. We managed to get some pictures by leaving the shutter open for several seconds at a time. The lights do not flicker or change intensity, and have remained unchanged for almost an hour. I went online to see if any info was available and found this website. Thank you for helping us figure out that what we are seeing is foxfire!

  8. Kealaon 06 Dec 2015 at 6:30 am

    Follow-up note: over 6 hours later and the foxfire lights are still visible. It’s beginning to get light (dawn), so some of the lights near the treetops are fading from view.

  9. Kealaon 07 Dec 2015 at 8:09 pm

    Final follow-up note:
    False alarm everyone…our neighbor has a new lighting product that projects many small green lights into buildings, trees, forests, etc. He has several of these, thus the widespread swath of lights that we observed. So, we did NOT see foxfire – we saw new technology holiday lighting. Pretty, and disappointing, at the same time.

  10. Callion 09 Dec 2015 at 9:51 am

    I live in a suburban neighborhood in Montgomery, Alabama. I woke up at 4am this morning and went out in my backyard to look at the stars. It was a beautiful, clear night, lots of stars. Then I noticed some of the “stars” I was seeing were high up in a pine tree. I got my binoculars and saw that they were oddly shaped and glowing green. I had seen “glow worms” before, and foxfire on the ground. But this is December, with temps in the 30s, and these were high up in a tree. I guess my pine tree might be in trouble, but it is a fascinating sight to behold on a cold winter Thanks for solving the mystery.

  11. Heidion 10 Dec 2015 at 11:18 am

    I live in MN and saw it high up in two trees on an dark early morning walk with my dog. My experience was the same as thinking I was looking at stars. Since it is Christmas time, I was trying to figure out if they could have been some subtle Christmas decoration but then couldn’t fathom how they would have gotten it up there and spread out (foam gun? spray gun, droplet spray….). And then I though maybe it was some weird thing that a bird had eaten and pooped out. However it had happened, it was really magical. I am glad I found this website and now know it is foxfire. I no longer have to figure the logistics if they had been Christmas decorations. :-)

  12. M. Kellyon 14 Dec 2015 at 8:49 pm

    I’m so glad that other people are seeing this too! We have been watching this stuff now for 3 nights. It’s warm and humid here in Virginia for December. I guess that’s what is bringing it out. It is on several trees, oaks and pines. All are at least 30 feet up and mostly on the tips of branches. One big patch is on the trunk of a pine tree.
    The big patch when watched through binoculars does turn itself on and off. And the glow can be very bright like a glow stick. It is beautiful but darned freaky looking. I wish we could get a video of it or at least a few pictures, but it won’t show up on our cameras.
    Strange that we are all seeing it at about the same time in December isn’t it?

  13. Jasonon 17 Dec 2015 at 8:12 pm

    I live in Falmouth ma. My branches and trunks are glowing in spots right now. My wife said the other night there was a bowling bowl sized red spot glowing. I heard its a fungus nicknamed foxfire. I have been here for 8 years and have never seen this!

  14. Jasonon 17 Dec 2015 at 8:17 pm

    More importantly is there a treatment for foxfire or will all my trees eventually succumb to this and if so how long will it take?

  15. Kate St. Johnon 17 Dec 2015 at 10:36 pm

    Jason, foxfire appears after the fungus has already grown inside the tree. Check with an arborist to find out if it can be saved.

  16. lisaPon 21 Dec 2015 at 10:30 am

    Hi I live in Clinton Mississippi, a small town outside of Jackson. I moved here for work about year and half ago. About 3 weeks ago I went outside on my back patio to BBQ some chicken one night. I looked up and there was green like glow sticks up high in this large old tree. Like 2 to 3 stories up there. I thought I was crazy or seeing things.
    I had no inclination of what this could be. I have never heard of this phenomenon or anyone I have asked heard or saw anything like this. I assumed maybe a squirrel found a kids glow stick and thought it was cool took up the tree? It has never been there before and none of the other trees around it has it. I have watched it every night. The green glowing spots move around, some nights in places the next night different places will glow. Sometimes they do seem to flicker at least some of them. The largest seems about like grapefruit in size from the ground, maybe a little larger. Other spots seem more like lines or smaller areas, some even being tips of end tiny branches. Its hard to tell from the ground. Some will glow really bright others medium to faint. At first it spooked me but after finding out what this is I feel like its now my special tree. I tell everyone and they look at me like I’m nuts. How common is this? No one Iver told has heard of this or seen it. I feel quite lucky we get to see such a thing. BTW we think it is some kind of old oak tree. Being from AZ I don’t know many trees here. Besides how common is this another question would be how long will it last? What kills it or makes it go away? Will it spread over the whole tree eventually?

  17. lisaPon 21 Dec 2015 at 10:33 am

    Another comment, Yes I cannot seem to get it on pictures like the others said. I have tried every camera I have and it doesn’t show up. Wish I could!

  18. amandaon 21 Dec 2015 at 11:15 pm

    In Colorado – 12/21/2015 …. warm day, super cold night….. super green, started fading, took my kids and went back and reddish pink started to appear in one spot – a few hours later after my bf got off of work I tried to show him, but it had disappeared as colder, below freezing weather set in

  19. Carolon 28 Dec 2015 at 3:48 pm

    We seen red, and green glowing areas all over our neighbors, and our trees, in MICHIGAN. Weird.

  20. Christopheron 29 Dec 2015 at 9:16 am

    We saw what we assume is this, but it was high up on the small branches of a living tree. Is that the same stuff?

  21. Kate St. Johnon 29 Dec 2015 at 9:33 am

    Christopher, it might be. The glow is from fungi and a variety of them can grow at any level.

  22. Pamelaon 29 Dec 2015 at 11:29 pm

    A few days ago I noticed this strange phenomenon in both of my pear trees! At first I thought some critters had crawled up the tree and we’re looking at me with their eyes glowing green! Kind of creeped me out! I walked with flashlight and my iPhone to see what was in the trees. It glowed from within the tree with no light shining on it! The green glow was scattered about both trees! The temp has been extremely warm, hovering around 70 to 80 and very wet for a few weeks. I took pictures with my iPhone and it really shows in the photos! Glad to know what I am seeing, but not happy that I could loose my two pear trees!

  23. Christopheron 30 Dec 2015 at 1:01 pm

    Than you, Kate St. John and Pamela, for sharing your knowledge and similar experiences. I guess it is pretty safe to assume that this is some sort of bioluminescent fungus rather than some X-Files-like phenomenon :-)

  24. Margaritaon 12 Jan 2016 at 7:20 pm

    I was so pleased to have found this site. I am in Australia, 80 kms SW of Sydney CBD in a rural area. We have a long stand of old pine trees along our front boundary.
    My husband returned from work 2 nights ago at around 11pm and noticed numerous green glowing patches over the bark of one of the trees.
    He showed me the following night. Some had disappeared but there were many more dotted throughout the whole stand. They were not isolated to just our pine trees. As we gazed across our lane, we noticed many in a neighbour’s deciduous liquid ambers.
    Such a beautiful and mysterious sight which we now know the cause of. Thank you!

  25. Debbieon 01 Feb 2016 at 8:54 am

    We got up this morning to our firewood in front of our stove glowing. My guy was very excited. He saw this when he was 11. He is 74 now. He woke our 11 year old to show him. We live in Packwood WA. Amazing phenomenon!

  26. Debbieon 01 Feb 2016 at 8:57 am

    I also went to the woodpile on the porch and it to was aglow! Thank you for the explanation!

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