This Thursday is Groundhog Day which is one of the worst examples of phenology.
Phenology is nature’s calendar. It is the recording and analysis of what happens in nature – first leaves and blooms, the appearance of certain insects, birds, or animals. If you read earlier posts about silly Groundhog Day, you find that at one time the careful observation of animals emerging from hibernation naturally (not for TV cameras) was a way of tracking the natural calendar and even making some predictions about things like planting.
Many birds time their nesting so that eggs hatch when insects are available to feed nestlings, and insect emergence is often synchronized with leaf out in host plants. Things are connected.
I’ve been tracking my little corner of the world. You can do it too. Climate change gets lots of attention and rightly so, but phenology may be altered by changes in things like precipitation. And on a very local level – like my garden in Paradelle – it can be affected by a tree being taken down, a neighbor putting up a fence or the growth of trees. Changes in phenological events like flowering and animal migration are among the most sensitive biological responses to climate change. Across the world, many spring events are occurring earlier—and fall events are happening later—than they did in the past.
The USA National Phenology Network was established in 2007 to collect, store, and share phenology data and information. I looked this weekend at the “status of spring” across the country on their website. Based on observations, as of January 23, 2023: “Spring leaf out conditions have arrived in southern states. Spring is up to three weeks earlier than average (the period of 1991-2020) in parts of Texas, Arkansas, Louisiana, Mississippi, Alabama, Georgia, and South Carolina. Austin, TX is 9 days early, Jackson, MS is 12 days early, and Charleston, SC is 10 days early.”
So far in my Paradelle, no signs of spring, even though January has been mild and snowless. But February is typically the most wintery month here.
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.
My earlier posts here about weather lore and how we sometimes forecast the weather for the upcoming months have been getting more hits lately. A glance at the sidebar list of popular posts will probably show that this month. People are worrying about what winter has in store for them.
You can define the end of a season in several ways. I wrote earlier about seasons that you can use the astronomical calendar of equinoxes and solstices to officially chnage the seasons. You can use the meteorological calendar which makes the four seasons into neat three-month chunks of time.
But I like to examine a third way of defining seasons which is more fluid. It is phenology – the study of periodic plant and animal life cycle events. The start of a season using this method is not based on set dates or a single event like an equinox or solstice. We look to the natural world.
You use this method, even if you never heard of phenology. You probably have watched the tree foliage changing color, the pumpkins ripening, flowers dying off, squirrels being crazier than ever and loving the falling acorns.
This is geographically specific observations. If I told you that the arrival of the first blackberry means that autumn has arrived, some would respond the blackberries appeared in July, and other people would say they ripen when the trees have lost their leaves in December.
Did you have a wet summer? Then you are likely to have a long, colorful autumn. Of course, a warm, dry spring could have prevented the sugars forming in trees which create those beloved autumn colors.
The maple trees usually turn first and then the beeches and finally the oaks give in November.
The trees know – or feel – that summer is over and stop producing the chlorophyll that gives them their green color. That lets the yellow to red pigments rule. Dry weather means more sugar which means more anthocyanins that make leaves red.
Observing nature in your area should be more accurate than any prediction about broader areas like the Northeast or very general ones about the United States.
Want to do some basic citizen science? Pay attention.
Now, it’s not strong scientific phenology but do the squirrels and raccoons have thick tails? That is supposed to mean a rough winter. Are spiders spinning larger than usual webs and trying harder to get in your house? More bad winter foreshadowing along with bees taking to the hive earlier. The popular predictors, the woolly bear caterpillars, better have narrow rather than wide middle brown bands so that winter will be less severe.
How about posting a comment on this post about your own personal sign of winter being “official” in your neighborhood? My mom used to say it was after the third frost. It’s certainly not when Christmas decorations appear in stores or holiday lights get turned on in the neighborhood.
For a few weeks in February, it sure felt like spring was very near in Paradelle – or maybe it had arrived early – even if the calendar and Earth’s tilt said otherwise. I saw crocuses and daffodils up and blooming. Tree buds seemed to be starting their bud burst.
Then the thermometer reversed itself and we had our biggest snow of the winter.
The news reported that the cherry blossoms in the nation’s capital are threatened, and the ones in New Jersey, which generally peak in early April, might also be affected. [Not So Trivial Fact: New Jersey has more cherry trees than Washington D.C. – the largest cherry blossom collection in the United States. But the Branch Brook Park cherry blossom webcam in Newark just shows bare trees and snow as I write this.]
I have written before about the study of cyclic, seasonal natural phenomena which is called phenology. The National Phenology Network tracks “Nature’s Calendar” via phenological events. But can we actually predict the seasons with any accuracy?
These nature observations include the ones we all have been observing lately, such as trees and flowers, but also ones that you may not be able to observe or just don’t pay attention to. Those signs of seasonal change include male ungulates, such as elk or deer, growing antlers at the beginning of the rut and breeding season each year, mammals that hibernate seasonally to get through the winter, and bird migration during the year.
Other than the false Groundhog Day forced observations, phenological events can be incredibly sensitive to climate change. That change can be year-to-year, but the timing of many of these events is changing globally – and not always in the same direction and magnitude.
According to a Public Library of Science (PLOS) blog, “From 1982 to 2012, spring budburst (when the leaves first appear) has advanced by a bit over 10 days, while the onset of autumn in the northeast US has pushed back about 4.5 days. No trends were found for other regions. This lengthening of the growing season has profound implications for the ecology of these forests and potentially their ecological evolution. A longer growing season could translate to high carbon storage for increased growth, but higher rates of decomposition and changes in moisture availability. However, these changes in phenology are primarily driven by increasing temperatures. In a warmer world, some species may simply not be able to survive where they are now, creating a dramatic change in the species composition. And this is without considering changes in precipitation.”
The National Phenology Network’s project called Nature’s Notebook collects data from more than 15,000 naturalists across the nation who, using standardized methods, provide information about plant and animal phenology.
Project BudBurst is another citizen science focused project using observations of phenological events and phases through crowd-sourcing. Project like this give you the opportunity to make your observations of nature more conscious, and to contribute to the knowledge base.
Punxsutawney Phil the groundhog predicted another 6 weeks of winter, but on that day I saw a lone dandelion already blooming at the neighborhood park. Maybe it was being bold, or being stupid, to bloom so early. It was covered by snow the following week. But according to estimates by the National Phenology Network, spring has already arrived in much of the Southwest and Southeast. It was about 20 days early for the Southeast. They track Extended Spring Indices which are models that scientists have developed to predict the “start of spring” at a particular location.
This weekend in Paradelle, we are enjoying temperatures in the 50s and 60s after a windy week in the 20s and 30s. Such is this time of late winter and early spring.
I have written a few times about phenology which is the study of cyclic and seasonal natural phenomena, especially in relation to climate and plant and animal life.
They use historical observations of the timing of first leaf and first bloom of certain plants (for example, cloned lilacs and honeysuckles) and daily observations from weather stations.
Many deciduous plants in temperate systems put on their leaves as temperatures warm in late winter and early spring. Using the Extended Spring Index models, scientists can look at how much the start of spring has varied from one year to the next at a particular location, and whether recent years are dramatically different from the past or not. The models can also be used to forecast when selected plants might bloom or put on leaves in future years.
I have been keeping my own bloom records for my home turf for about 20 years. Though my property is certainly its own “micro-climate” with variations due to shade, soil etc., I have seen earlier springs over the years for certain plants that are my own little “control” group.
The USA National Phenology Network developed Nature’s Notebook, a project focused on collecting standardized ground observations of phenology by researchers, students and volunteers like me.
I think their mission should be everyone’s mission, even if you don’t get as official as doing phenology: Gain a better understanding through considered observation of the plant and animals that surround you and how they relate to your environment and broader environmental change.
Spring is officially still a month away for those of us in the Northern Hemisphere, but that doesn’t mean that you aren’t already observing signs of it in your little corner of the world.
Things are blooming in Paradelle, so I have started recording them in my garden notebook. Have you noticed any changes in when things sprout or bloom in your neighborhood? Maybe flowers tend to bloom a little earlier in the year or birds that used to migrate are hanging around your yard through the winter?
In some ways my garden notebook is a nature notebook as I find myself also recording first and last frosts, snow storms, the appearances of birds, insects and wildlife. Some of those things I report here, both seriously and also as a kind of weather lore. My posts about predicting the weather based on signs in nature seem to get a lot of hits, so I am not alone in my interest, scientific or not.
Most people have never heard of phenology. but if you have ever paid attention to the timing of natural events, like blooming flowers and migrating animals, you have been practicing this -ology. Phenology is the study of the timing of recurring plant and animal life cycle events.
If you want to make those observation to be more “official,” you can become a citizen scientist by connecting with groups like Nature’s Notebook. It is an online project sponsored by the USA National Phenology Network. Americans can practice phenology in their own habitat and share their observations with other members and have their data shared with scientists who will use the data for research and decision-making.
It saddens me how disconnected people are to the natural world of plants, animals, the earth and sky. s a lifelong teacher, it really saddens me to see how disconnected kids become as they get older. The interest is always there in very young children, so it is something that is lost.
We may not all be as observant as Sara Schaffer of Nature’s Notebook who suggests that we notice the “slightest blush on a maple leaf that foreshadows the coming fall” or the “new, more vibrant feathers warblers put on days before mating.”
Do you see the appearance of the first robin on your lawn as a sign that spring has arrived? I grew up hearing and believing that. But I have observed and recorded robins every winter. Once I saw four of them sitting on my fence in a February snowstorm. Robins as indicators of spring is a good example of weather lore.
Most robins do migrate south, but some are probably still around your neighborhood all winter – no doubt better protected in the woods than on your bare lawn. The robins that do migrate to the South in the fall, return in the spring, so then we see many more of them on that soggy lawn and field in search of food.
Geese flying south in Paradelle is a daily occurrence. They fly from the reservoir south to a pond. They never migrate and leave any more. What does that indicate? Perhaps some of it is climate change, but it is also the prime water and grass we provide them in parks, golf courses, school fields and corporate settings. Why leave?
Though thinking a captive groundhog can predict the end of winter is certainly weather lore, paying attention to events like true bird migrations can help us understand long-term trends and predict future events. That is why many observers may be reporting small changes that can help more accurately predict the long-term impacts of climate change and shorter-term events in the near future.
And observing when the smell of smoke from fireplaces changes to the smell of barbecue smoke is a definite indicator of suburban seasonal change!