Category Archives: Trees

Seen This Week: Late Flowers, Acorns, Crows

Insect on New York aster, Toms Run, 16 Oct 2024 (photo by Kate St. John)

19 October 2024

This week brought:

  • Fall colors and the first piles of fallen leaves
  • Late flowers and insects
  • “See Your Breath” cold mornings
  • The first juncos … and …
  • Several thousand crows in Oakland.

In photos, late asters attracted an insect at Toms Run and morning sun slanted through the trees in Schenley Park.

Fall colors and fallen leaves, Schenley Park, 18 Oct 2024 (photo by Kate St. John)

Many trees are changing color. The oaks aren’t there yet but they have dropped their acorns leaving empty acorn cups on the branches. It’s a big mast year for red oaks in Pittsburgh.

Red oak leaves and acorn cups, 13 October 2024 (photo by Kate St. John)

A rhododendron in Shadyside is confused. Is it spring?

Confused rhododendron blooming in Pittsburgh, 13 Oct 2024 (photo by Kate St. John)

This week crows were absent from Oakland during the day but arrived in huge flocks at dusk, staging on rooftops before flying to the roost. I fumbled to photograph them on the RAND Building last Sunday. This is only a fraction of the flock that flew away.

Crows make a stop on the RAND building before sunset, 13 Oct 2024 (photo by Kate St. John)

Obviously they’ve been roosting on Pitt’s campus. I found evidence below trees at the Pitt Panther statue. The Crows Slept Here Last Night.

Evidence at Pitt that The Crows Slept Here Last Night, 17 October 2024 (photo by Kate St. John)

What is a Wolf Tree?

White pine “Wolf Tree” in Red Rocks Park, South Burlington, Vermont, 2006 (photo from Wikimedia)

10 October 2017

When Europeans arrived in Pennsylvania the first thing they did was clear the forest for farms. 150 years ago the focus changed from chopping for farmland to clear-cutting to sell the wood. Clear-cutting ended in the complete deforestation of Pennsylvania in 1900-1920. Other than small patches of old growth forest, such as the one at Cook Forest, the Pennsylvania woods you see today is just 100+ years old.

A few old trees remained in unlikely places. Farmers sometimes left one tree in a field as shade for the animals or left a tree standing at the boundary line.

A future wolf tree: Lone tree in a field provides shade for the cattle (photo from Wikimedia Commons)

When the farm was abandoned the forest grew back and surrounded the lone tree. At top an ancient white pine is surrounded by a younger Vermont forest. Lone trees in Pennsylvania tend to be oaks.

In the late 20th century foresters dubbed them “wolf trees” because they believed that these huge older trees were “exhausting forest resources and should be eradicated to make way for profitable wood.” Eventually perceptions changed and wolf trees are now appreciated.

In 2015 I took a picture of a wolf tree at Cedar Creek Park in Westmoreland County. Nine years ago it had already been dead a long time and pieces of it were falling.

An old dead "Wolf Tree" at Cedar Creek Park (photo by Kate St.John)
An old “Wolf Tree” at Cedar Creek Park, Sept 2015 (photo by Kate St.John)

In subsequent visits to Cedar Creek I didn’t pay attention to this tree. I wonder how much of it still stands. I’ll have to go and see. (p.s. UPDATE on 15 Oct 2024: Mark Bowers checked and the tree is still there!

Read more about the changing attitudes about wolf trees at Berkshire Natural Resources Council: Debunking Wolf Trees

Appalachia’s Mango Ripens Next Month

Pawpaw fruits on the tree (photo from Wikimedia Commons)

27 August 2024

I came up with today’s slightly inaccurate title when I heard WESA’s piece on Pennsylvania’s secret tropical fruit, the pawpaw or “hillbilly mango.” In fact, pawpaws are not mangoes — they just taste like it — and their range is much wider than Appalachia. However it is true that they ripen in September.

Pawpaw range map from Wikimedia Commons

Pawpaws (Asimina triloba) are the quintessential wild fruit for browsing animals that eat the only ripe fruit on the branch and then move on. The fruit tastes like mango and has the consistency of banana. But don’t eat the seeds. They are poisonous.

Pawpaw cut open to show the fruit and seeds (photo from Wikimedia Commons)

Pawpaws defy commercial agriculture.

  • The skin is thin and bruises easily so they cannot be shipped.
  • Pawpaws don’t ripen all at once. You must come back later for the next batch because …
  • If you pull a hard, unripe fruit from the tree it will never ripen.
  • Pawpaw fruits lose their flavor if you heat them.
  • The bark, leaves, fruit and seeds of pawpaw trees contain the disabling and potentially lethal neurotoxin annonacin so …
  • Do not dry or cook down the fruit because that concentrates the compound that — fortunately — makes you vomit. (see more in the WESA article).

However, the neurotoxin is a benefit for zebra swallowtails (Eurytides marcellus) whose only host plant is the pawpaw tree. Zebra swallowtail caterpillars eat pawpaw leaves, become toxic themselves and are protected from predators.

Zebra swallowtail in spring (photo from Wikimedia Commons)
Pawpaw Festivals in September

If you want to eat a pawpaw and learn more about them, your best bet is at an upcoming Pawpaw Festival. The complete schedule of 12 festivals plus additional events are at Heppy.org: 2024 Pawpaw Festivals and Events. Here are a few close to Pittsburgh on the Heppy.org list in order of occurrence.

  • Ohio Pawpaw Festival in Albany, Ohio, 13-15 Sept
  • Paw Paw Festival in Duncansville, PA, 22 Sept, 9a-4p
  • West Virginia Pawpaw Festival, Core Arboretum, Morgantown, WV, 28 September
Pittsburgh has two notable pawpaw enthusiasts:

Andrew Moore wrote the book on pawpaws in 2015. Pawpaw: In Search of America’s Forgotten Fruit. If you want to know about pawpaws this is the book to read!

Book cover. Pawpaw: In Search of America’s Forgotten Fruit by Andrew Moore

Gabrielle Marsden is restoring zebra swallowtail butterflies to southwestern PA by planting pawpaw trees and encouraging others to do the same. Her YouTube channel is here. She also has two upcoming events:

Pawpaw Pathways poster (image from Wikimedia Commons)

Still curious about pawpaws? Learn more at this vintage blog.

p.s. Thanks to John English for pointing out the WESA article.

Planning Ahead for Pittsburgh’s Warmer, Wetter Climate

Quaking aspen vs Eastern cottonwood (photos from Wikimedia Commons)

30 July 2024

Today in Pittsburgh we’re looking forward to a week of heavy downpours.

HAZARDOUS WEATHER OUTLOOK, Pittsburgh, PA, 30 July 2024
Scattered showers and thunderstorms could produce heavy rainfall that creates localized flooding concerns, favoring low lying or urbanized areas.
National Weather SErvice Hazardous Weather Outlook for Pittsburgh, PA, July 30 through August 5,2024

It’s hard not to notice that Pittsburgh’s climate is changing fairly rapidly into hotter, wetter weather. Climate predictions indicate that 60 years from now, Pittsburgh weather will feel a lot like McCormick, South Carolina does today.

This is bad news for trees that are on the southern edge of their range. Not only do they live a long time but they cannot adapt as fast as our climate is changing. For example, quaking aspens, which prefer cooler weather, will disappear from Pittsburgh by the end of this century. Meanwhile eastern cottonwoods will do just fine.

Comparing range maps of Quaking aspen vs Eastern cottonwood (maps from Wikimedia Commons)

Pittsburgh’s urban forest and parks are feeling the heat, too. If we do nothing we’ll have fewer and poorer trees in the city 100 years from now.

Fortunately the Pittsburgh Parks Conservancy is planning for our future forest by testing southern tree species at Fezziwig Grove in Schenley Park. Read about the tree nursery project and Kentucky yellowwood, pictured below, at TribLive: Pittsburgh Parks Conservancy forges forest of the future in face of global warming

Kentucky yellowwood flowers, Schenley Park, 20 May 2019 (photo by Kate St. John)

To visit Fezziwig Grove, use the map at this link.

Wondering what our climate will feel like in the future? Check out this vintage article.

Seen This Week: A Visit to the Woods

Beaver Meadows Recreation Area, 24 June 2024 (photo by Kate St. John)

29 June 2024

Early this week a group of us drove north to go birding at Heart’s Content, Beaver Meadows and Piney Tract in Warren, Forest and Clarion counties. For two days the weather was pleasantly cool and the sky was gorgeous. Here are a few things we saw this week.

  • Beaver Meadows Recreation Area near Marienville, PA
  • Allegheny River as seen from Rt 62 south of East Hickory
  • Old growth hemlocks at Heart’s Content
  • A fallen tree completely covered by moss. It was cut because it blocked the path when it fell long ago.
  • Looking through the trees at Heart’s Content
  • A view of Piney Tract, SGL 330
  • The Wall of Rocks at the Microtel parking lot in Clarion
Allegheny River south of East Hickory, PA, 24 June 2024 (photo by Kate St. John)
Old growth hemlock at Heart’s Content, 24 June 2024 (photo by Kate St. John)
Fallen tree coated in moss, Heart’s Content, 24 June 2024 (photo by Kate St. John)
Heart’s Content forest, 24 June 2024 (photo by Kate St. John)

The next day we visited a very different habitat: the grasslands at Piney Tract, SGL 330. This scene is close to where we saw the clay-colored sparrow I wrote about on 25 June.

Piney Tract, SGL 300, 25 June 2024 (photo by Kate St. John)

The Wall of Rocks:

We stayed at the Microtel in Clarion (nice and new) where I was fascinated by the Wall of Rocks that formed one side of the parking lot. It looked impressive at dusk, lit by streetlamps.

Wall of Rocks closeup at Microtel parking lot, Clarion, 24 June 2024 (photo by Kate St. John)

The next morning it was not so fascinating. It looks this way because the excavated hillside is too steep to mow. It is landscaped with large stones.

Rocky hillside at Microtel parking lot, Clarion, 25 June 2024 (photo by Kate St. John)

Seen This Week: Warblers and Tulips in the Trees

Blackpoll warbler, Presque Isle, 12 May 2024 (photo by Charity Kheshgi)

18 May 2024

Best birds this week were seen at Presque Isle State Park on Sunday 12 May while birding with Charity and Kaleem Kheshgi. At Leo’s Landing many of the birds were at eye level including this blackpoll warbler and the barn and bank swallows.

Barn and bank swallows, Presque Isle, 12 May 2024 (photo by Charity Kheshgi)

Even the treetop birds, like this yellow-throated vireo, cooperated for photographs.

Yellow-throated vireo, Presque Isle, 12 May 2024 (photo by Charity Kheshgi)

Was this redstart was looking askance at us? Or eyeing a bug?

American redstart, Presque Isle, 12 May 2024 (photo by Charity Kheshgi)

I had high hopes for the Bird Banding at Hays Woods on Wednesday 15 May but we were in for a surprise. No birds to band! Bummer. 🙁 This restart, banded earlier in the week, shows what we could have seen.

American redstart at Bird Lab banding (photo by Kate St. John)

After we left the banding station we had good looks at a scarlet tanager and found this Kentucky flat millipede (Apheloria virginiensis). It’s colored black and orange because it’s toxic.

  • It secretes cyanide compounds as a defense. Don’t touch it!
  • You might find one perched and dying on top of a twig. That’s because it can host the parasitic fungus Arthrophaga myriapodina which causes infected individuals to climb to an elevated spot before death (per Wikipedia). Eeeew.
Centipede Aphelosia virginiensis, Hays Woods, 15 May 2024 (photo by Kate St. John)

This week there were flowers in the tulip trees (Liriodendron) obscured by thick leaves. This flower came into view when a squirrel bit off the twig and didn’t retrieve the branch.

Tulip tree flower and leaves, 16 May 2024 (photo by Kate St. John)

Instead of rain on Wednesday we had a beautiful sunrise.

Sunrise 14 May 2024 (photo by Kate St. John)

To make up for no rain on Wednesday it’s pouring right now on Saturday.

Putting Fluff to Good Use

Warbling vireo using cottonwood fluff to build its nest in St. Louis, MO, 19 May 2019 (photo by Andy Reago & Chrissy McClarren via Wikimedia Commons)

12 May 2024

Eastern cottonwoods (Populus deltoides) rely on the wind for both pollination and seed dispersal. In the spring the male and female trees each produce an inflorescence.

The males produce catkins which drop off the tree when the pollen is gone. The females produce flowers whose seeds are embedded in fluff to carry them away on the wind.

Eastern cottonwood inflorescences: male and female (photos from Wikimedia Commons)

By the time the cottonwoods have gone to seed warbling vireos (Vireo gilvus) have returned to the trees on the shore of Lake Erie. Though the birds look nondescript their song is the sound that fills the air in the parking lot at Magee Marsh in May.

Yesterday at Presque Isle State Park we watched a warbling vireo building a nest in a cottonwood. The nest is a cup that hangs from the fork of two small branches. Both sexes help build it.

Warbling Vireo on nest, Ruby Mountains, Nevada

In s. Ontario [the region of Lake Erie], nest exteriors fashioned with insect and spider silk and cocoons, paper and string, and bits of birch bark; exterior walls composed of grasses, plant fibers, bark strips, plant down, hair, leaves, fine twigs, lichens, and rootlets. Linings were fine grasses, pine needles, plant fibers, rootlets, feathers, and leaves.

Birds of the World: Warbling vireo account

Warbling vireos put the fluff to good use.

p.s. Here’s a mnemonic to help you remember their song:

 The mnemonic of “If I see you, I will seize you, and I’ll squeeze you till you squirt!” is very useful in identifying and remembering this bird’s song.

While easily heard, the Warbling Vireo can be difficult to spot. They tend to perch themselves high in treetops. When they are seen, this common bird is often described as “nondescript”.

— from Indiana Audubon description of warbling vireo

Spring Update: Where Are We Now?

Oak tree in bloom with dangling pollen flowers (photo by Kate St. John)

1 May 2024

Since our last spring checkup six weeks ago, Pittsburgh has galloped into summer. Last weekend we had July-in-April weather with official highs of 83°F and even higher in town.

Pitt peregrine Carla felt the heat at 10am on 29 April as she shaded her chicks and gular fluttered (panted) to cool herself off.

It’s hot at the Pitt peregrine nest, Carla shades the chicks, 29 April 2024, 10am (photo from the National Aviary falconcam at Univ of Pittsburgh)

Pittsburgh is not alone. In a wide swath of the U.S. from Iowa to New York spring was 20+ days early this year. In Pittsburgh nearly half of April was more than 10°F above normal while we had only one cold day at 12°F below normal.

U.S. Daily Spring Index Leaf Anomaly, 1 May 2024 (map generated by USANPN Visualization Tool)

So what temperature should we expect if we’re only 20 days ahead of schedule? April 29th ought to have been like a normal 19 May but it was way beyond that.

The heat prompted the trees to leaf out early and flowers to bloom ahead of schedule. Maples and buckeyes are in full leaf now and our oaks are at flower+leaf stage as shown at top. The leaves are hosting food for birds in the form of tiny caterpillars, so …

Migratory birds are taking advantage of the south winds and early leaf out. Since 27 April we’ve seen our first scarlet tanagers, rose-breasted grosbeaks, Baltimore orioles, indigo buntings and warblers.

Charity Kheshgi has been documenting our good luck with warblers at Frick Park. Notice the size of the leaves in her photos!

p.s. And where am I? Right now I’m at Magee Marsh a week ahead of The Biggest Week in American Birding. I don’t expect to see the swarms of migratory birds that will be here next week (I’m leaving on 3 May) but I’ll learn what happens before the people show up and why everyone waits until next week. 😉

(credits are in the captions)

Seen This Week: Ducks, a Swan and Leaf Out

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)

Spring is 20 days early in Pittsburgh this year. To prove it the yellow buckeye trees were in near-full-leaf on Thursday 28 March in Schenley Park.

Yellow buckeye leaves open and green, Schenley Park, 28 March 2024 (photo by Kate St. John)

They are 8 days later than the astoundingly early spring of March 2012. Click here to read about that year.

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)

American Chestnuts Too Rare to Roast

American chestnut leaves, nut husks and nuts (photo from Wikimedia Commons)

20 December 2023

The Nutty Series: American chestnut

‘Chestnuts roasting on an open fire / Jack Frost nipping at your nose / Yuletide carols being sung by a choir / And folks dressed up like Eskimos.’

NPR: The Story Behind the Christmas Song

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.

Former range of the American chestnut (map from Wikimedia Commons)

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.

Chestnut blight on an American chestnut (photo from Wikimedia Commons)

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.

American chestnut seedlings sprouting from a stump surrounding a sapling that died of blight (photo by Richard Gardner, Bugwood.org)

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.

American chestnut orchard in PA, 2012 (photo from Wikimedia Commons)

Arborists collect the nuts, not to roast but to plant, so we’ll have more chestnuts some day.

American chestnut nuts in husk (photo by USDA Forest Service – Southern Research Station , USDA Forest Service, SRS, Bugwood.org)

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.

Planting an American chestnut orchard at Sky Meadows, VA, 2015 (photo from Wikimedia Commons)

At these locations the leaves are above knee height.

American chestnut leaves (photo from Wikimedia Commons)

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.

(credits are in the captions)