Tom Kimmerer, PhD
@tomkimmerer.bsky.social
I am a forest scientist, botanist, tree physiologist writing about relationships between trees and humans including climate change. A Fulbright Scholar, Author of Venerable Trees and books in progress. Read about trees here: https://ourtrees.substack.com.
We probably don't often plan to snack on tree bark, but we certainly do. Cinnamon is tree bark. There are five species of cinnamon from different geographical locations with distinctly different flavor profiles. This one is Cinnamomum verum, Sri Lankan cinnamon. Eat some bark today!
December 31, 2025 at 4:29 PM
We probably don't often plan to snack on tree bark, but we certainly do. Cinnamon is tree bark. There are five species of cinnamon from different geographical locations with distinctly different flavor profiles. This one is Cinnamomum verum, Sri Lankan cinnamon. Eat some bark today!
Why are these fir trees floating in a lake? These are Christmas trees pursuing their second career creating fish habitat. Fish and wildlife managers are improving fish management using trees. This is a great use of our trees after their retirement. Read about it at Our Trees, ourtrees.substack.com
December 29, 2025 at 4:22 PM
Why are these fir trees floating in a lake? These are Christmas trees pursuing their second career creating fish habitat. Fish and wildlife managers are improving fish management using trees. This is a great use of our trees after their retirement. Read about it at Our Trees, ourtrees.substack.com
Where do our Christmas trees go after the holidays? If we live in the right place, they may have a new career as fish habitat.
Christmas Trees for the Fishes
How our holiday trees can continue to do good.
substack.com
December 28, 2025 at 6:25 PM
Where do our Christmas trees go after the holidays? If we live in the right place, they may have a new career as fish habitat.
This sycamore fruit would make a fine holiday tree decoration, but it is only available in May. Sycamore, Platanus occidentalis.
December 28, 2025 at 4:28 PM
This sycamore fruit would make a fine holiday tree decoration, but it is only available in May. Sycamore, Platanus occidentalis.
Here is the fruit of one of the most spectacular trees in our flora, kingnut, Carya laciniosa. With the largest fruit of any hickory, it was called kingnut long before somebody slapped onthe name shellbark hickory. We should restore the original, appropriate name of this tree: kingnut
December 24, 2025 at 4:17 PM
Here is the fruit of one of the most spectacular trees in our flora, kingnut, Carya laciniosa. With the largest fruit of any hickory, it was called kingnut long before somebody slapped onthe name shellbark hickory. We should restore the original, appropriate name of this tree: kingnut
Another tree that decorates itself for the holidays is oak, not just one tree but over 500 species mostly in the north temperate zone. Acorns were an important food source for people before we invented agriculture, and there were large acorn-processing factories all over the world.
December 22, 2025 at 3:59 PM
Another tree that decorates itself for the holidays is oak, not just one tree but over 500 species mostly in the north temperate zone. Acorns were an important food source for people before we invented agriculture, and there were large acorn-processing factories all over the world.
@acidlich.bsky.social A little joy of nature that might brighten your day. Ponderosa pine forest with Humphreys Peak in the background. Coconino National Forest.
December 21, 2025 at 6:27 PM
@acidlich.bsky.social A little joy of nature that might brighten your day. Ponderosa pine forest with Humphreys Peak in the background. Coconino National Forest.
Another tree decorated for the holidays is honeylocust, Gleditsia triacanthos. It's not only decorative, but settlers combined it with persimmon fruit to make beer. The gum inside the legumes is sweet and a good thickener. 1/3
December 21, 2025 at 6:15 PM
Another tree decorated for the holidays is honeylocust, Gleditsia triacanthos. It's not only decorative, but settlers combined it with persimmon fruit to make beer. The gum inside the legumes is sweet and a good thickener. 1/3
Many trees are wearing their holiday decorations, like this pond cypress, Taxodium ascendens. Happy Holidays!
December 20, 2025 at 9:06 PM
Many trees are wearing their holiday decorations, like this pond cypress, Taxodium ascendens. Happy Holidays!
One of the world’s most enthralling places.
Happy 238th #birthday to the great State of #NewJersey, home of the 1.1-million-acre Pinelands National Reserve (our country’s first National Reserve and an International Biosphere Region). 🎂 … We’re from Jersey, baby. 🌎
📷: Paul Leakan, NJPC
#wildlife #Conservation #trees
📷: Paul Leakan, NJPC
#wildlife #Conservation #trees
December 18, 2025 at 11:20 PM
One of the world’s most enthralling places.
My friend Barry Blumberg received the Nobel Prize for his discovery of Hepatitis B and development of its vaccine. He saved millions of lives, but the monstrous fools of the Trump public health agencies are now trying to unravel his work. They will cause millions of deaths, but we can stop them.
Tom Kimmerer (@tomkimmerer)
Barry Blumberg, my friend and hiking partner, was a renowned physician and scientist. Through his research, he saved millions of lives. We need to step up and do the same.
Baruch Samuel Blumberg, MD,...
substack.com
December 15, 2025 at 4:29 PM
My friend Barry Blumberg received the Nobel Prize for his discovery of Hepatitis B and development of its vaccine. He saved millions of lives, but the monstrous fools of the Trump public health agencies are now trying to unravel his work. They will cause millions of deaths, but we can stop them.
Are you an undergrad interested in plants? Here is a terrific summer research opportunity.
Our plant-focused REU program, led by Prof Nagel, is open for applications, please forward to undergrads and reskeet etap.nsf.gov/award/7573/o... 🌱 🧪
NSF Education & Training Application | ETAP
etap.nsf.gov
December 12, 2025 at 3:30 PM
Are you an undergrad interested in plants? Here is a terrific summer research opportunity.
On a snowy day, trees created the stage for a scene, but there was no play. Suddenly, a boy walked right into the scene, making a story.
Tom Kimmerer (@tomkimmerer)
I was standing in this snowy field seeing how the tree stems and branches framed a scene as if it was s stage. I was trying to figure out how to make a photo out of this as the snow came down. As the ...
substack.com
December 11, 2025 at 7:54 PM
On a snowy day, trees created the stage for a scene, but there was no play. Suddenly, a boy walked right into the scene, making a story.
Very interesting. This is the famous lacquer tree, Toxicodendron vernicifluum, related to poison ivy. The lacquer is comprised of urushiol, which is the same chemical that causes poison ivy rashes. Urushiol causes severe skin reactions until the lacquer polymerizes and becomes safe.
When urushi trees that have finished being tapped are cut down and stacked up, the logs are called "kakigara".
When I see a whole pile of kakigara logs, I can’t help wanting to say, “Thank you for all your hard work.”
When I see a whole pile of kakigara logs, I can’t help wanting to say, “Thank you for all your hard work.”
December 11, 2025 at 3:07 PM
Very interesting. This is the famous lacquer tree, Toxicodendron vernicifluum, related to poison ivy. The lacquer is comprised of urushiol, which is the same chemical that causes poison ivy rashes. Urushiol causes severe skin reactions until the lacquer polymerizes and becomes safe.
Snow caught in loblolly pine (Pinus taeda) cones.
December 10, 2025 at 3:39 PM
Snow caught in loblolly pine (Pinus taeda) cones.
Ursula Davidson was a courageous young botanist. In 1950, she completed the first survey of ancient trees in The Bluegrass. She did this in spite of being disabled, unable to walk because of polio. Read about her at Our Trees.
Tom Kimmerer (@tomkimmerer)
A Courageous Woman
Ursula Davidson was a young botanist pursuing her master’s degree at the University of Kentucky. In 1950, she undertook a difficult task, a survey of all the ancient bur oaks in Fa...
substack.com
December 8, 2025 at 3:49 PM
Ursula Davidson was a courageous young botanist. In 1950, she completed the first survey of ancient trees in The Bluegrass. She did this in spite of being disabled, unable to walk because of polio. Read about her at Our Trees.
Coffee and Chocolate
This is the next in our holiday trees series at Our Trees. I hope you will read the story, and your comments are welcome.
This is the next in our holiday trees series at Our Trees. I hope you will read the story, and your comments are welcome.
Coffee and Chocolate
Making good choices for the future.
open.substack.com
November 23, 2025 at 9:44 PM
Coffee and Chocolate
This is the next in our holiday trees series at Our Trees. I hope you will read the story, and your comments are welcome.
This is the next in our holiday trees series at Our Trees. I hope you will read the story, and your comments are welcome.
Asher Elbein, a fine science journalist, has had a prolific year of good writing. Here are his favorite storie. They are worth your time to dive into.
Recently finished up my last freelance work of the year before moving on to a mad sprint of book writing, so —rather earlier than usual — it's time for my year in review! Here, in no particular order, are the features I'm proudest of.
November 21, 2025 at 1:30 PM
Asher Elbein, a fine science journalist, has had a prolific year of good writing. Here are his favorite storie. They are worth your time to dive into.
School is closed for at least part of next week, so you may be able to recruit a few good mathematicians for your quantitative work like, for example, dendrochronology. Just be sure to pay them well.
Tom Kimmerer (@tomkimmerer)
School is closed for at least part of next week, so you may be able to recruit a few good mathematicians for your quantitative work like, for example, dendrochronology. Just be sure to pay them well. ...
substack.com
November 20, 2025 at 11:33 PM
School is closed for at least part of next week, so you may be able to recruit a few good mathematicians for your quantitative work like, for example, dendrochronology. Just be sure to pay them well.
You are probably aware of the global loss of biodiversity. It is happening right in front of us, and many of us don't notice. Here is a magnificent white ash that is now gone. There are things we can do to stop the invasion of foreign insects and diseases that kill our trees. More at Our Trees.
Tom Kimmerer (@tomkimmerer)
You have probably heard about threats to biodiversity — to the number and diversity of organisms in our ecosystems — but how aware are you that it is happening right in front of us? Ash trees (Fraxinu...
substack.com
November 20, 2025 at 4:35 PM
You are probably aware of the global loss of biodiversity. It is happening right in front of us, and many of us don't notice. Here is a magnificent white ash that is now gone. There are things we can do to stop the invasion of foreign insects and diseases that kill our trees. More at Our Trees.
Join us at Our Trees as we begin an exploration of the trees we use during these holidays, including some that may be threatened or endangered. Until December 15, we offer you a 30% discount on monthly or annual subscriptions to everything that Our Trees has to offer.
Tom Kimmerer (@tomkimmerer)
Come join us as we begin our exploration of the trees we use during these holidays, including some that may be threatened or endangered. This series will continuue until December 15. And during this p...
substack.com
November 17, 2025 at 12:31 AM
Join us at Our Trees as we begin an exploration of the trees we use during these holidays, including some that may be threatened or endangered. Until December 15, we offer you a 30% discount on monthly or annual subscriptions to everything that Our Trees has to offer.
This famous cartoon by my friend Joel Pett tells us what we need to know while the current climate conference, COPE 30, is dominated by fossil fuel lobbyists. We have it in our power to defeat the fossil fuel oligarchs and their pet politicians. By doing so, we can create a much better world.
Tom Kimmerer (@tomkimmerer)
The climate conference known as COPE30 is under way in Brazil. The conference is dominated by oil industry lobbyists whose goal is to continue to stall progress. This cartoon by my friend Joel Pett is...
substack.com
November 15, 2025 at 4:27 PM
This famous cartoon by my friend Joel Pett tells us what we need to know while the current climate conference, COPE 30, is dominated by fossil fuel lobbyists. We have it in our power to defeat the fossil fuel oligarchs and their pet politicians. By doing so, we can create a much better world.
Farewell pennies. I have fond memories of pennies in threes. At my elementary school, lunch was free but a 1/2 pint of milk was 3¢. And is it really lunch without milk? My classmates and I carried a few extra pennies in our pockets so that kids who lacked pennies could get their milk too.
November 14, 2025 at 4:38 PM
Farewell pennies. I have fond memories of pennies in threes. At my elementary school, lunch was free but a 1/2 pint of milk was 3¢. And is it really lunch without milk? My classmates and I carried a few extra pennies in our pockets so that kids who lacked pennies could get their milk too.
Among the large variety of trees we use during the holidays, for decoration and for food, many are threatened or endangered. At Our Trees, we are beginning a series on using these trees. Come join us.
Tom Kimmerer (@tomkimmerer)
We have been discussing the many tree products we use during the holidays, from Christmas trees to spices. Surprisingly, many of these trees are endangered or at risk of extinction, including those sh...
substack.com
November 13, 2025 at 7:47 PM
Among the large variety of trees we use during the holidays, for decoration and for food, many are threatened or endangered. At Our Trees, we are beginning a series on using these trees. Come join us.
What is your favorite Christmas tree? I have loved fir, various Abies species, since I was a kid. Fraser fir is a very popular tree in the east and is actually an endangered species. Favorite trees often reflect on our childhood experience. Please, tell us yours.
Tom Kimmerer (@tomkimmerer)
What is your favorite Christmas tree? For many of us, it is the tree we were familiar with as kids. For me, that means fir, various species of Abies. In the eastern US, Fraser fir is a common Christma...
substack.com
November 12, 2025 at 2:57 PM
What is your favorite Christmas tree? I have loved fir, various Abies species, since I was a kid. Fraser fir is a very popular tree in the east and is actually an endangered species. Favorite trees often reflect on our childhood experience. Please, tell us yours.