Blue-winged teal, Moraine State Park, 27 March 2024 (photo by Charity Kheshgi)
30 March 2024
A Wednesday trip to Moraine State Park was cold and gray but quite worthwhile. We saw 300(!) red-breasted mergansers, many ring-necked ducks, blue-winged teal and a rare bird — a trumpeter swan. Charity Kheshgi’s photos show off the teal and swan.
Trumpeter swan, Moraine State Park, 27 March 2024 (photo by Charity Kheshgi)
Trumpeter swans (Cygnus buccinator) are “the heaviest living bird native to North America and the largest extant species of waterfowl.” They were nearly extinct in 1933 — only 70 remained in the wild — but several thousand were then found in Alaska. “Careful re-introductions by wildlife agencies and the Trumpeter Swan Society gradually restored the North American wild population to over 46,000 birds by 2010.” The trumpeter at Moraine is one of their descendants. (quotes from Wikipedia)
Comparing two springs, yellow buckeyes’ early leaf-out, Schenley, March 2012 and 2024 (photos by Kate St. John)
Early spring is the hungriest time of year for deer in Pennsylvania because they’ve already eaten all the easy-to-reach food. When the deer population is greater than the area’s carrying capacity they seek out food in unusual places. Thus I was amazed but not surprised to see a deer browsing the bushes next to our highrise at 5:30am. There is nothing to eat down there. There is nothing to eat anywhere near here.
A deer browses at a highrise in Pittsburgh, 5:30am 24 March 2024 (photo by Kate St. John)
Despite the popularity of The Christmas Song, you’ll never find nuts of the American chestnut in the wild. By the time The Christmas Song was written in 1945 mature American chestnuts were nearly gone from North America. Today there are so few surviving mature trees that Wikipedia lists only 25 locations though people are always searching.
American chestnuts (Castanea dentata) used to be more abundant than oaks within their native range.
Then in the late 1800s someone imported Japanese chestnut trees that had chestnut blight. Asian chestnuts are immune, American trees are not. First noticed at the Bronx Zoo in 1904, chestnut blight spread quickly and nothing could stop it. By 1950 mature American chestnut trees were gone throughout their range.
Chestnut blight is caused by a fungus that kills the above-ground portion of the tree by getting under the bark and girdling the trunk.
The stump lives and sends up seedlings though they die as saplings. The process repeats — seedlings, sapling, death. Most stumps are at least a hundred years old.
To find a chestnut in the woods I look for the leaves at knee height. The photo below shows a typical American chestnut stump with seedlings. This one has a dead sapling as well.
For over 70 years arborists have been searching for a cure for chestnut blight and trying to breed immune American chestnuts. They have crossed the American chestnut with Chinese chestnuts, then back-crossed the hybrid to another American chestnut. These efforts, supported by The American Chestnut Foundation among many others, take decades to realize any success.
There are several experimental orchards in Pennsylvania. All are protected from deer.
As potentially successful hybrids become available, they are planted more widely — still in protected areas — to test their immunity and build back the chestnut population.
Perhaps in one to two hundred years the nuts of American chestnuts will be easy to find and we’ll appreciate the first phrase of The Christmas Song again.
You’ve probably noticed that in humid weather table salt clumps in the salt shaker and sticks to the top. That’s because at the molecular level salt’s ions have a net positive charge that attracts atmospheric water which has a net negative charge. Salt literally pulls water out of the air and builds crystals. This process can make the top of the salt shaker moist or dampen a salted road on a humid day.
Can salt’s natural means of pulling water from the air be used to gather water in a larger way? Researchers led by Marieh B. Al- Handawi investigated Athel tamarisk (Tamarix aphylla), a desert plant native to Africa and Asia that takes up saline water with its roots and secretes excess salt through its leaves.
The tiny leaves are arranged alternately, almost wrapping the branches. The salt crystalizes on the leaves. Look closely and you can see tiny crystals.
The smaller crystals stay on the plant and attract more water, especially overnight as shown on this branch in the early morning (8 a.m.) with condensed water droplets.
Every day the water cycle repeats: (A) branches attract water overnight, (B) water evaporates during the hot day while salt crystals grow, (C) water is gone and crystals are large, (D) during overnight high humidity the crystals attract water from the air and the plant absorbs the water. — paraphrased from PNAS: Harvesting of aerial humidity with natural hygroscopic salt excretions.
The tree is “drinking” from its leaves.
Researchers observed that at least one type of salt, lithium sulfate, forms small crystals that remain on the leaves and absorb water from the air. When the team added colored water to salty leaves, they watched the liquid stick to the crystal crust, then absorb into the plant’s leaves—evidence that the salty coating acts as a bona fide water collection mechanism.
Acorns are complicated because oaks are extremely diverse. There are about 500 species in the Quercus genus (oaks) plus about 180 hybrids, all of them native to the Northern Hemisphere and Asia.
The best I can do in the field is divide them into the red oak or white oak group based on buds, bark and leaves. Knowing this, I balk at identifying acorns down to the species level. There is only so much room in my brain and I’m saving it for birds.
So with that in mind here are a few acorns I’ve found in Pittsburgh recently. What exact species are they? The only one I know for sure is the burr oak.
Pin oak acorns found on Devonshire St sidewalk (photo by Kate St. John) — see comments for IDBur oak acorn, Schenley Park, Oct 2022 (photo by Kate St. John)White oak acorn without its cap (photo by Kate St. John)Red oak acorns and a mix of fallen leaves, Sept 2020 (photo by Kate St. John)
Buckeyes have always been one of my favorite objects because their skin is smooth and shiny fresh out of the husk, perfect to carry in my pocket like a worry stone.
In America, the native Aesculus are commonly called “buckeyes,” a name derived from the resemblance of the shiny seed to the eye of a deer [a buck’s eye]. In the Old World, they’re called “horse chestnuts”—a name that arose from the belief that the trees were closely related to edible chestnuts (Castanea species), and because the seeds were fed to horses as a medicinal treatment for chest complaints and worm diseases.
Let’s go backwards in the growing season from nut to husk, flower and leaf by examining buckeyes planted in Schenley Park more than 100 years ago.
The large nut pictured at top left is from a European horse chestnut (Aesculus hippocastanum) native to Albania, Bulgaria, mainland Greece and North Macedonia. Each husk contains one to three nuts. Sometimes they’re flat on one side. My favorites are the round ones.
They’re produced from the white flowers that have pink (already fertilized) highlights. Notice that each leaf has seven fat leaflets. The number and shape of the leaflets indicate this is a horsechestnut.
Horse chestnut flowers and leaves (photo by Kate St. John)
In winter horse chestnuts are easy to identify by their large, sticky end buds.
The yellow buckeye (Aesculus flava) is native to the Appalachians and Ohio Valley and is North America’s tallest buckeye tree at 70 feet. Planted as an ornamental in Schenley Park it can hybridize with its shorter cousin, the Ohio buckeye (Aesculus glabra), making identification difficult for non-botanists like me.
Yellow and Ohio buckeye nuts look a lot like horse chestnuts. Seeing the husk is a big help because yellow buckeye husks are smooth …
p.s. The small buckeye nut in the top photo is from the shrub-sized bottlebrush buckeye (Aesculus parviflora), planted in Schenley Park near Panther Hollow Lake. Click here to learn more.
(*) Which Flowers? I could not tell whether the flower photo was yellow or Ohio buckeye. Mary Ann Pike suggests Ohio buckeye in this comment.
Sunrise seems to pierce Central Catholic’s steeple, 28 Nov 2023 (photo by Kate St. John)
2 December 2023
Saturday blogs usually show what I’ve “Seen This Week” but I have only one worthy photo, shown above. For the rest I’ve chosen sights that are timely for the season and seen at some point.
This Wednesday the water was low in the Monongahela River at Duck Hollow, just as it is in this photo from Nov 2020. However the sky was not so blue and it was very cold!
Nine Mile Run outflow at Duck Hollow, 29 Nov 2020 (photo by Kate St. John)
Wednesday’s low was 21°F but today will warm to nearly 60°F. No frost today like the bit shown below from Nov 2021.
Frost on the grass, 4 Nov 2021 (photo by Kate St. John)
The trees are bare now and showing off their silhouettes. Here are three typical sights on the cusp of December.
Bare trees at dusk, Schenley Park, 15 Nov 2012 (photo by Kate St. John)
You can identify young American elm trees by their twig arrangement that look like fish skeletons.
Twigs on young American elms look like fish bones, 2 Dec 2012 (photo by Kate St. John)
Black locust trees are always gnarly but this one was made worse when it was trimmed away from the utility wires in 2012.
Black locust tree looks twisted after powerline cutback, 28 Jan 2012 (photo by Kate St. John)
The thick green husks began to turn brown immediately and peel off in quarter-moon sections. This piece of husk sat indoors for more than a month before I took a photo of its interior. The dark brown exterior is visible at the bottom edge.
Section of a shagbark hickory husk, Nov 2023 (photo by Kate St. John)
If a nut lasts through the winter its husk looks quite worn out by March. This one was probably uneaten for a good reason.
Shagbark hickory nut that overwintered, March 2021 (photo by Kate St. John)
Shagbark nutshells are slightly oval with a remnant stem and four ribs. When I cracked open the nut I collected, it was a dud. Maybe an insect got to it. This Wikimedia photo of a sawed nut shows the meat.
Though shagbark hickory nuts taste good and can substitute for pecans, shagbarks are not cultivated because …
They are unsuitable to commercial or orchard production due to the long time it takes for a tree to produce sizable crops and unpredictable output from year to year. Shagbark hickories can grow to enormous sizes but are unreliable bearers.
C. ovata begins producing seeds at about 10 years of age, but large quantities are not produced until 40 years and will continue for at least 100. Nut production is erratic, with good crops every 3 to 5 years, in between which few or none appear and the entire crop may be lost to animal predation.
Interestingly, shagbarks (Carya ovata) and pecans (Carya illinoensis) can hybridize in the wild though the hybrids usually don’t produce nuts.
Shagbark hickories are easy to identify by their shaggy bark. Just look up and you’ll see it peeling from the trunk. Young trees can fool you, though, because they have smooth bark (click here to see young bark).
Shagbark hickory tree, Raccoon Wildflower Reserve, March 2021 (photo by Kate St. John)
Shagbarks are one of the first native trees to leaf out so their sap runs early in the spring. Yellow-bellied sapsuckers (Sphyrapicus varius) take advantage of this and drill the trees as they migrate north. The birds move sideways around the trunk as they drill in a ring around the tree. The trees heal the wounds by producing callus tissue that grows outward, almost like lips. These attract the the sapsuckers who then drill the same rings year after year.
Shagbark hickory with yellow-bellied sapsucker drill-rings, Schenley Park, Oct 2017 (photo by Kate St. John)
If you’ve spent a lot of time in the woods chance are you’ve see trees kissing. The fusion of their trunks in what looks like a kiss is called inosculation from the Latin word for kiss.
University of New Hampshire explains how it occurs:
Inosculation happens when the friction between two trees causes the outer bark of each tree to scrape off at the point of contact. The trees respond by producing callus tissue that grows outward, thereby increasing the pressure between the two trees. This pressure, along with the adhesive nature of sap or pitch that exudes from the wounds, reduces the amount of movement at the point of contact. The cambia layers from the two trees come in contact and the vascular tissues become connected, allowing for the exchange of nutrients and water.
Though I’ve seen fused trees several times, I have only one photo of a pair “kissing,” fused twice at Raccoon Creek State Park in February 2015. The date is notable because that hike is also the last time I saw a long-eared owl.
Two trees “kissing” twice, Raccoon Creek State Park, 8 Feb 2015 (photo by Kate St. John)
An extreme case tweeted by Science girl @gunsnrosesgirl3 reminded me of the phenomenon. The smaller tree on the left does not touch the ground and is completely sustained by the larger one that’s holding it up. The embedded tweet below does not show that the smaller tree is cut off so click here to see a larger photo.
‘The thinner tree was cut years ago and the big one has been holding and feeding it since then. They "wake up" together in the spring and "go to sleep" together in the autumn’
Inosculation is a natural phenomenon in which parts of two different trees, commonly but not… pic.twitter.com/Ta34iNeEp2
The ginkgo leaves fell all at once, 22 Nov 2023 (photo by Kate St. John)
25 November 2023
On Wednesday I found a yellow carpet on Elmer Street. Ginkgo trees were shedding their leaves all at once.
The ground was gorgeous and so were the branches.
Ginkgo: Many leaves are still on the tree, 22 Nov 2023 (photo by Kate St. John)
Some trees were already bare. Some were yet to come.
Ginkgo trees dropping their leaves in a Pittsburgh neighborhood, 22 Nov 2023 (photo by Kate St. John)
But there were hazards beneath this beauty. Ginkgos are dioecious (with separate sexes) and the females produce fruits that smell like vomit. Landscapers try to plant only male trees but there was a female in this mix.
I didn’t pay attention until I stepped on a fruit and felt it pop beneath my heel. Yuck! The stinky flesh stuck in the treads of my shoe so I searched for a puddle to stomp in, too preoccupied to take a picture of the fruits. These are from Wikimedia.
Ginkgos were planted along Pittsburgh’s street during the Smoky City era because they’re one of the few trees that do well in polluted air. We can expect them continue for 100s of years.
In 2020, a study in China of ginkgo trees up to 667 years old showed little effects of aging, finding that the trees continued to grow with age and displayed no genetic evidence of senescence, and continued to make phytochemicals(*) indefinitely.
(*) Phytochemicals are chemical compounds produced by plants, generally to help them resist fungi, bacteria and plant virus infections, and also consumption by insects and other animals. Gingkos have great immune systems even when more than 600 years old.
By the end of October the fruit had fallen and started to look bruised. Eventually the husks turned black.
Black walnut in husk, 23 Oct 2023 (photo by Kate St. John)
But most black walnuts aren’t abandoned that long. Squirrels gather them for winter food and eat a few along the way.
Fox squirrel opening a black walnut (photo by Donna Foyle)
Squirrels know that they have to open the shell on both sides to get all of the nut meat.
Black walnut shell opened by a squirrel (photos by Kate St. John)
The meat does not come out easily! It usually breaks into small pieces on the way out and is never the perfect shape of grocery store walnuts.
Black walnut shell and meat (photo from Wikimedia Commons)
The ones we buy in the grocery store that are grown in California are English walnuts (Juglans regia) which would not be possible without the life-giving participation of black walnut trees (Julgans nigra).
Non-native English walnuts are susceptible to root diseases in California so walnut farmers plant native black walnut trees to start the orchard. When the black walnuts are a year old with strong roots and vigorous base they are chopped off and an English walnut shoot is grafted to the stump.
All the trees in the orchard below show the wider stump base (highlighted in yellow) that ends at the graft point. Above the graft English walnuts produce their own delicious nuts which are harvested after they fall by sweeping and vacuuming from the ground. FLORY harvesting equipment is pictured below.
Black walnut trees can be identified in winter as a bare tree standing alone with twigs that have alternate (not opposite) small buds above large leaf scars.
Like other walnuts, the roots, inner bark, nut husks, and leaves [of Julgans nigra] contain a nontoxic chemical called hydrojuglone; when exposed to air or soil compounds it is oxidized into juglone that is biologically active and acts as a respiratory inhibitor to some plants. Juglone is poorly soluble in water and does not move far in the soil and will stay most concentrated in the soil directly beneath the tree.
Symptoms of juglone poisoning include foliar yellowing and wilting. A number of plants are particularly sensitive. Apples, tomatoes, pines, and birch are poisoned by juglone, and as a precaution, should not be planted in proximity to a black walnut.
