Tree Rings and Fingerprints

tree finger prints

The similarity between a fingerprint and the rings of a tree is really interesting. Are there any other connections between the human prints and the rings and whorls of a tree?

A fingerprint is an impression left by the friction ridges of a human finger. They are probably best known for their use in crime scene forensic science. Dactyloscopy is the science of fingerprint identification. It relies on the analysis and classification of patterns observed in individual prints.

Human fingerprints are detailed, nearly (but not absolutely) unique, difficult to alter. They are quite durable but do break down somewhat in old age. All of that makes them suitable as long-term markers of human identity.

They are used by the police but in the 21st century, they have been used for identification on iPhones and other devices. These biometrics are not foolproof and though your fingerprints may be unique and durable, they can be reproduced and faked.

Chemicals and residues on your hands can be transferred in a print and used to know things about you such as that you are a smoker (of cigarettes or marijuana) or have handled certain drugs or chemicals.

But they are not like the lines on your palms. Palmistry (AKA palm reading, chiromancy, or chirology) is the practice of fortune-telling through the study of the lines on your palm. The practice is found all over the world, with numerous cultural variations. Those who practice chiromancy are generally called palmists, hand readers, hand analysts, or chirologists. Unlike the study of fingerprints, palm readers lack consistency in their interpretations so palmistry is generally viewed as pseudoscience by academics.

tree rings

Dendrochronology is the study of data derived from tree ring growth. That data is used in archaeology for dating materials and artifacts made from wood. Chemists use tree rings for radiocarbon dating. In climate science, particularly in paleoclimatology, it allows scientists to learn about the environmental conditions of the past, locally or globally. Dendrologists are tree scientists and examine all aspects of trees but tree rings can tell about the present local climate

Dendrochronology is tree-ring dating which is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed.

Scientists doing dendroclimatology study of climate and atmospheric conditions during different periods in history. That can be done on very old tree trunks but also for much younger trees and it gives us data about local events such as wet periods, droughts, fires, sunlight competition, and diseases.

Studying changes in the environment and climate is very important to all of us, but analyzing the wood found in archaeology or works of art and architecture, such as old panel paintings is also a way to date things.

New growth in trees occurs in the outer layer of cells near the bark. Each ring marks a complete cycle of seasons, or one year, in the tree’s life.

I read that we have securely dated tree-ring data for the northern hemisphere going back 13,910 years. We can even measure variations in oxygen isotopes in each ring.

And I haven’t even gotten into the rings in our teeth. Yes, mammalian tooth enamel grows in waves. Under high magnification, they look like tree rings. These waves are known as the “Striae of Retzius.” They grow in a regular pulse, between one day and eight days, depending on the size of the mammal and as with tree rings, a line marking a new layer of growth can be seen after each pulse.

I have answered my own question about how the rings in trees, fingers or teeth might be related, but doesn’t it seem like somehow they must be connected?

Will 2021 Be A Mast Year?

Image by klimkin from Pixabay

Acorns have been bombing my home’s roof and deck and pinging the roof of the metal shed in the backyard heavily since late summer. The quantity of acorns seems to vary from year to year. This year might be what is known as a “mast year.”

I had to look up what a mast year means.  The fruits, nuts, berries, and buds produced by trees and bushes are called “mast.” Things like walnuts, pecans, hickory nuts, hard seeds, and acorns are called hard masts, and berries and fruits, and buds are soft mast. A mast year is a year when the amount of that mast is unusually high in number,

Since my first association with the word “mast” is with a sailing ship, I had to check the etymology of this botanical usage. It comes from Middle English and earlier Old English mete similar to mæst in Old High German where it meant food. If you think of an acorn as food (many animals and some humans do) then inside that shell is the meat.

Can we predict these cycles of acorn plenty? Do we know why they occur? There are theories but it is still mostly a mystery.

These mast years seem to occur in irregular cycles of two to five years. An abundance of acorns is often said to be a nature sign of a bad winter. The folk belief is that squirrels, chipmunks, mice and other animals somehow know that they need to stock up for a bad winter and that nature somehow knows to increase the supply chain of acorns. But there’s no real science behind that folk wisdom and weather lore. that they need to stock up. The Farmers’ Almanac – which has lots of folklore around weather – seems to indicate that if acorn numbers mean a bad winter then almost every year is a bad winter.

But I continue and observe and write about signs of the seasons in nature and keep a nature calendar.

Squirrels, mice, chipmunks and deer feed on the acorns in my neighborhood.  When the trees produce smaller crops for a few consecutive years, they are in effect keeping the populations of these animals in check. But during a mast year, the trees produce more food than the animals can possibly eat.

This abundance causes a boom in the populations of smaller mammals. It also guarantees that some acorns will survive and grow into new trees. Producing nuts slightly stunts the tree’s growth, but as it happens in cycles the tree gets a chance for growth in the non-mast years. Living things generally live to reproduce.

Chipmunks hibernate in cold weather and so in Paradelle, they spend most of the winter sleeping in their dens. I read that one chipmunk can gather up to 165 acorns in a day.  But those cute little Disneyesque critters don’t just eat acorns. Along with seeds and fungi, they will eat grain, fruit, nuts, insects, and worms. I was surprised to find that though they don’t hunt for bird eggs and even nestling birds and baby mice, they will eat them when they find them. They also love to dig in my outdoor potted plants, so cute as Chip and dale might be, they are also pests around here.

In 2020, the chipmunk population locally was insanely large. This year I barely saw any – until the acorns started to fall in late August and now they are all over my backyard and deck. Where were they all spring and summer?


In reading the novel The Overstory by Richard Powers and some other research as a follow-up. I learned a lot about trees. For example, most people probably believe that trees compete with each other for sunlight, water, and nutrients. That isn’t true. In fact, in most settings, they communicate and cooperate.

With acorns, temperature and moisture are probably factors in these cycles, and now it is theorized that oaks might be sending chemical signals to coordinate their production. In my part of the country (Northeast) last winter and spring were generally mild winter and so white and red oak trees are able to produce more of them when they start creating seeds in the spring. A harsh winter or cold spring or freeze can mean little acorn production, or sometimes none at all.

There are still mysteries in all this. How trees communicate with each other is still being explored. We can’t predict when any one species will have a mast year.

but we do better understand what causes it. The weather certainly has a part to play. To produce a healthy crop, the trees need the right combination of temperature and rainfall in the spring.

Phenology is the study of the timing of natural events in relation to the weather. This is the scientific version of weather lore and the studies continue.

SIDEBAR: Can humans safely eat acorns? Yes, they can be used in a variety of ways. They can be eaten whole, ground up into acorn meal or flour, or made into mush to have their oil extracted. Once you’ve safely leached the tannins from your raw acorns, you can roast them for 15 to 20 minutes and sprinkle them with salt for a snack. I haven’t tried eating yet, but maybe this is a good year for it.

The Overstory: A Novel
The Hidden Life of Trees: What They Feel, How They Communicate
The Heartbeat of Trees: Embracing Our Ancient Bond with Forests and Nature


Celtic Tree Divination

apple tree card
Some years ago, I was given a gift of a book and card set about the Celtic tree oracle and the ancient beliefs about certain trees which could be used to see into the future.

In the Celtic Ogham, also known as the tree alphabet, each letter embodies the spirit of a tree or plant.

I don’t profess any consistent ability to do divination (the practice of seeking knowledge of the future or the unknown by supernatural means), but I have been known to use runes or cards. I have found that their “answers” offer an opportunity to consider possibilities – often ones that I would not have considered on my own.

Ogham (in Modern Irish or in Old Irish: ogam) is an Early Medieval alphabet used primarily to write the early Irish language dating back to the 4th to 6th centuries AD) and later into Old Irish language. Ogam alphabet is the Celtic equivalent of the runes and seen as a way to teach, rather than tell, us about our future. You do a cast of the cards/runes and their order and position tells a story.

It possible that the Irish scholars or druids who created the alphabet might have done so a way to pass on political, military or religious communications secretly. At the time we believe it was created, the Roman Empire ruled over southern Britain, and was a threat to Ireland.

Druidic mythology contains this 1,500-year-old oracle which uses the symbolism of the “tree letters” and their “magical” properties, characteristics and folklore.

As a boy, I felt a connection to a big apple tree that was in our backyard. I climbed it, sat in its shade to read, and ate the apples that came from it. It didn’t surprise me that the apple tree has many associations in different belief systems. I wrote about that earlier.

The apple represents the light half of the year, from May 2 until the end of October. My birthday is in late October.

Drawing the Quert (apple) card signals a choice that you need to make and commit to following. The Major Arcana card in tarot, The Lovers, correlates with Quert in divination and it is also about struggling with choices. Our immediate association with The Lovers is romantic and the choice might be romantic but not necessarily so.


When I used the tree cards recently, the holly card caught my attention. There is a large holly right outside my window. Holly is considered the male counterpart to the female Ivy. The evergreen holly tree, or “holy tree,” has thorny, prickly leaves and red berries that represent suffering, but taken with the other cards I cast, the holly can predict a fresh start, or time of renewal. A reunion also lies ahead. This almost post-pandemic time suggests a number of reunions and I also have a big high school one ahead of me.

I remember that when we planted it, it came with a little booklet that said that as a protective herb, it was believed to guard against lightning, poison, and evil spirits.

This “Tree of Sacrifice,” called Ilex as the eighth month of the Celtic Tree calendar (July 8 – August 4) is the eighth consonant of the Ogham alphabet (Tinne).

Three of the beliefs associated with holly relate to dreams – another topic I pay a lot of attention to. Dreaming of holly means you should be mindful of what is troubling you, and picking holly in your dreams means you will have a long life. If you want your dreams to come true (which can be a dangerous wish), you are supposed to silently collect nine holly leaves after midnight, on a Friday, and wrap them in a white cloth using nine knots to tie the ends together. Place this beneath your pillow and your dreams will come true.

If you want to learn more and try some divination yourself, a second book on my shelf is Ogam: The Celtic Oracle of the Trees: Understanding, Casting, and Interpreting the Ancient Druidic Alphabet which is a practical (not scholarly) guide to the ancient oracle.

A Story of Trees

I heard an interview with writer Richard Powers. I haven’t read his books and from that interview about his newest book, The Overstory, I thought the book was non-fiction. It’s not.

His books are often described as: compelling, cerebral, dramatic, emotionally involving stories. His 2006 novel The Echo Maker is about neurology. It won a National Book Award.

The new novel is The Overstory is about our endangered biome and it revolves around trees. The overstory is that part of a forest that is above the canopy. The canopy is the “ceiling” of the forest. There is also is the understory that sits below the canopy but above the ground, and the shrub layer below that and, finally, the forest floor where we walk.

Of course, overstory and understory also suggest the story of writers.

This is Powers’ twelfth novel. It’s a novel of activism and resistance . It’s a love song to the natural world.

This is a long book and I am not finished with it, but I am enjoying it. The first part of the novel consists of 8 separate short stories (ranging from 9 to 33 pages) telling us about what seem to be unconnected characters.

There is an Air Force soldier in the Vietnam War is shot while flying, falls, but is saved by falling into a banyan tree. An artist inherits many photographs of one doomed American chestnut. A college student is brought back to life by nature. A scientist discovers trees are communicating with one another.

I’m not a fan of this kind of novel structure and I know that the four of them and some others will eventually come together. Networks of roots. Concentric tree rings.

The main character, so far, is a young botanist named Patty Westerford who is the one that discovers that “trees are social creatures” In the interview I heard that Patty is based on some real scientists and a book called The Hidden Life of Trees.

I think it is the ideas presented in that book that most intrigued me to read Powers’ book. Tree families are like human families – or maybe we are like trees. Tree parents live together with their children. They communicate with them. They support them as they grow. They share their food with them. They protect them from diseases, and the climate extremes and changes.

Autumn Color

Autumn on Reservoir Road

Not all leaves turn vivid colors in autumn. And not all places get to experience fall foliage. But most parts of North America have some level of autumn foliage change.

Most of the attention goes to the most northern states, especially New England, as places to see spectacular colors in a wide area. I can see a great road or hillside and even just a few backyard trees on fire with autumn here in Paradelle.

If you are one of those “leaf peepers” who seeks out the foliage, you might know the answer to the why of autumn color. It is a combination of the right climate and light conditions and an abundance of the right tree varieties.

Typically, Columbus Day weekend is the color peak in New England. Up in Maine, it can start in mid- to late September and then it starts to move south. It varies year to year based on conditions but peaks in Connecticut in late October and is still strong in New Jersey at the end of October.

So, you start with the deciduous trees (those that lose their leaves) that have the best color, which are the maples, aspens, oaks, and gum trees.

Next, you need to start losing daylight. The amount of daylight we get is tied into the autumnal equinox and, as days grow shorter, the reduced light triggers chemical changes in the trees (and other deciduous plants).

A cork-like “wall” called the abscission layer forms between the twig and the leaf stalk. Eventually, this blockage will cause the leaf to fall because it blocks off the vessels that both supply nutrients and water and allows anything to exit. The simple sugars in the leaves are trapped. Without, light, nutrients and water, there is no production of the green pigment, chlorophyll, in leaves.

But, two other pigments will take over and react with the sugars: carotene (yellow) and anthocyanin (red). They are actually in the leaves all summer but they are masked by the chlorophyll. Tannin, a chemical that exists in many leaves (especially oaks), is what creates the browning of the leaves.

You will get the most brilliant color after a few bright fall days. Cloudy and rainy days produce more pastel shades, so, a dry fall produces the biggest explosion of really vibrant colors.

Speaking for the Trees

The Lorax is a “children’s book” written by Dr. Seuss that was first published in 1971.

It’s a fable that chronicles the plight of the environment. The Lorax character speaks for the trees and for the environment and battles the greedy Once-ler. (Seuss chose to never show the Once-ler’s face in any of the illustrations.)

A boy comes to town to visit the Once-ler and learn about the Lorax. He discovers that when the Once-ler first arrived there had been a forest of Truffula Trees. They were beautifully colorful woolly trees that were spread throughout the area. They were also the habitat of a number of fantastical creatures.

I took the book down this weekend from the shelf of books I read to my sons when I was writing something for my environmental blog about the wildlife in a leaf pile.

It probably wouldn’t surprise you that this gentle “children’s”  book about our stewardship of the planet has often been seen as controversial. It’s probably Seuss’ most controversial book.

The most common claim against the book is that it is unfair to the logging industry.  A book in answer to it was published called The Truax which took a a logging-friendly perspective. Tree-hugger that I am, I do recognize that there can be responsible harvesting of planned forests through re-seeding etc. And we do need lumber. The Truax was written by a member of a family-owned hardwood flooring factory and published by the National Wood Flooring Manufacturers’ Association. No one was pretending that it wasn’t biased in its intent.

I would still recommend making yourself and young people you know aware of the Lorax’s story. It can be a good conversation starter. The teacher in me also thinks that taking a look at the Truax’s story is a good thing. (It’s actually available free online as a pdf document, so there’s no reason for not checking it out.)

Side note: I also see online that a 3-D film based on The Lorax is targeted for a March 2, 2012 release, which falls on the birthday of Dr. Seuss, who died in 1991. The cast includes Danny DeVito as the Lorax, Zac Efron as Ted, Ed Helms as the Once-ler and Betty White as Ted’s grandmother.

The Lorax (Classic Seuss)