Category Archives: Trees

The Largest Living Organism is Dying of Deer

Pando in October snow, 2021 (photo by Beth Moon via Flickr Creative Commons license)

29 November 2022

In 1976 Jerry Kemperman and Burton Barnes discovered that 106 acres of quaking aspens (Populus tremuloides) in the Fishlake National Forest of Utah were actually all the same male plant, one root with thousands of suckers that grew into trees. It came to be known as Pando — “I spread.”

Quaking aspen, Pando, in fall (photo from Wikimedia Commons)

Pando weighs 6,600 tons making it the heaviest known organism on Earth and it is very old, though no one is sure whether it’s 10,000 or 80,000 or even a million years old.

Aerial image of the location of the single aspen tree, Pando (highlighted in green) at Fishlake National Forest, Utah (photo from Wikimedia Commons)

However, almost as soon as Pando was discovered researchers found that sections of it were not rejuvenating because new sprouts were being overbrowsed by deer. In that part of the U.S. the species is mule deer (Odocoileus hemionus).

Mule deer in Colorado (photo from Wikimedia Commons)

So they fenced it — twice — one fence in 2013, another in 2014.

Map of 2018 Pando study partially funded by U.S. Bureau of Land Management, Grant/Award Number: L21AC10369 (map downloaded from Wiley Online Library)

Then in 2018 Paul Rogers and Darren McAvoy of Utah State University conducted a followup study sampling Pando’s health inside and outside the deer exclosure fences and concluded that the fencing was not working.

According to September 2022 Sci.News “The unfenced areas are experiencing the most rapid aspen decline, while the fenced areas are taking their own unique courses — in effect, breaking up this unique, historically uniform, forest. … Fencing alone is encouraging single-aged regeneration in a forest that has sustained itself over the centuries by varying growth.”

“One clear lesson emerges here: we cannot independently manage wildlife and forests.”

Sci.News, October 2018: Pando, World’s Largest Single Organism, is Shrinking

Aldo Leopold’s experience in his early career when he worked to eradicate wolves from the American West changed his perspective on trees and deer. At one point he shot an old female wolf and was there to see the green fire go out of her eyes as she died. He wrote …

I thought that because fewer wolves meant more deer, that no wolves would mean hunters’ paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.…

I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail of replacement in as many decades.

Aldo Leopold: Sand County Almanac, “Thinking Like a Mountain”

Pando’s days are numbered because new trees are not growing up to replace the old ones. This is how a forest dies.

(photos from Wikimedia Commons, map from Wiley Online; click on the captions to see the originals)

Most of the Trees Are Bare

Most of the trees are bare on this Schenley Park hillside, 6 Nov 2022 (photo by Kate St. John)

10 November 2022

In Pittsburgh the wind blew all day last Saturday with gusts as high at 35 mph. By Sunday morning, 6 November, most of the trees were bare.

I confirmed this at my favorite “leaf gauge” hillside in Schenley Park, above, after hiking at Hays Woods where bare trees sheltered the still-green leaves of invasive honeysuckle.

Most of the trees are bare inside Hays Woods, 6 Nov 2022 (photo by Kate St. John)

Deciduous conifers are finally showing their own fall colors. Larches are yellow, dawn redwoods (Metasequoia glyptostroboides) are orange.

Deciduous needles on a dawn redwood, 7 Nov 2022 (photo by Kate St. John)

The needles were dropping fast from this one in front of Phipps Conservatory.

Dawn redwood at Phipps, 7 Nov 2022 (photo by Kate St. John)

Meanwhile half of the ginkgos (Ginkgo biloba) along Schenley Drive still had leaves.

Ginkgos along Schenley Drive, 7 Nov 2022 (photo by Kate St. John)

Last year they weren’t bare until 20 November, below, but I predict they will be earlier this year.

Ginkgo trees lost their leaves later in 2021. This is 20 Nov (photo by Kate St. John)

Even if I couldn’t see them I can hear a clue that most of the trees are bare. The sound of leaf blowers fills my neighborhood. Maybe yours, too.

Sound of a leaf blower, Pittsburgh, 8 Nov 2022 (recorded by Kate St. John)

(photos and audio by Kate St. John)

Fall Color This Week

Sunrise in Pittsburgh, 28 October 2022 (photo by Kate St. John)

29 October 2022

Fall color was brilliant this week, especially at sunrise.

Bright red was gone from our hillsides as the maples faded but other leaves took up the slack in yellow and orange. Below:

  • Bottlebrush buckeyes are yellow in Schenley Park.
  • Japanese knotweed is yellow-orange at Duck Hollow.
  • Blue-green porcelain berries were eagerly eaten by migrating robins.
  • Red honeysuckle berries attracted cardinals and house finches.
  • Confused flowers! Forsythia bloomed along the Nine Mile Run Trail even though its leaves were a deep purple-red.
  • Red oaks are red-orange in Schenley Park.
Bottlebrush buckeye leaves turn yellow in Schenley Park, 25 October 2022 (photo by Kate St. John)
Fall color, Japanese knotweed, Duck Hollow, 27 October 2022 (photo by Kate St. John)
Porcelain berry fruit, Nine Mile Run Trail, 27 October 2022 (photo by Kate St. John)
Honeysuckle fruit, Nine Mile Run Trail, 27 October 2022 (photo by Kate St. John)
Forsythia blooming in late October, NMR Trail, 27 October 2022 (photo by Kate St. John)
Fall color, Schenley Park from Panther Hollow Bridge, 25 October 2022 (photo by Kate St. John)

A week from now the trees will be half bare.

(photos by Kate St. John)

Seen This Week

Fall leaves, Schenley Park, 12 Oct 2022 (photo by Kate St. John)

15 October 2022

Fall colors were looking good in the City of Pittsburgh this week. A maple in Schenley Park turned shades of orange and red while the sunrise worked to match it.

Sunrise on 12 Oct 2022 (photo by Kate St. John)

This acorn in Schenley Park is a squirrel’s dream come true, the largest acorn native to North America. Bur oaks (Quercus macrocarpa also spelled burr oak) were planted in several places in the park more than 100 years ago, most notably at the main trail entrance near Bartlett Playground. This species withstands harsh conditions and is one of the most drought resistant oaks.

Bur oak acorn, Schenley Park, 9 Oct 2022 (photo by Kate St. John)

Goldenrods are blooming in the small meadow near Bartlett Playground.

Goldenrod in meadow, Schenley Park, 12 Oct 2022 (photo by Kate St. John)

During my walk to Schenley Plaza on 11 October I saw a peregrine fly toward Heinz Chapel’s scaffolding and disappear among the dense rods.

Heinz Chapel scaffolding, 11 Oct 2022 (photo by Kate St. John)

If he hadn’t moved I would not have found him. Ta dah! (See inside red circle.)

Peregrine falcon perched (circled) on Heinz Chapel scaffolding, 11 Oct 2022 (photo by Kate St. John)

Amazingly he was easier to see through binoculars from Schenley Plaza tent. Too far for a photo.

(photos by Kate St. John)

Fluff Like Snow in June

Pile of cottonwood fluff in the hand (photo from Wikimedia Commons)

9 June 2022

It usually “snows” in late May in Pittsburgh but this year it happened in early June.

On 3 June a light breeze carried snow-like fluff above Nine Mile Run in Frick Park. I found a source in this open catkin that had fallen on the trail.

Eastern cottonwood pods burst open, Frick Park Nine Mile Run, 3 June 2022 (photo by Kate St. John)

Another had not fully opened before it fell.

Eastern cottonwood female catkin gone to seed, Frick Park Nine Mile Run, 3 June 2022 (photo by Kate St. John)

Both came from an eastern cottonwood tree (Populus deltoides) whose leaves look like this. There are only a few of cottonwoods in the Nine Mile Run valley but their seed dispersal is prodigious.

Eastern cottonwood leaves (photo from Wikimedia Commons)

Pittsburgh is barely inside the eastern edge of the cottonwood’s range so the trees and their fluff are not common here. Read more about them in this vintage article.

(photos by Kate St. John and from Wikimedia Commons)

Invasive Princess

Princess tree (Paulownia tomentosa) in bloom (photo from Wikimedia Commons)

This gorgeous tree with large violet flowers is blooming now in Allegheny County. It grows fast, provides shade, looks beautiful and smells sweet. What could go wrong?

One paulownia blossom with my hand for size comparison, Schenley Park, 23 May 2022 (photo by Kate St. John)

The princess tree (Paulownia tomentosa), also called empress tree or royal paulownia for Anna Pavlovna of Russia (1795-1865) is — or was — popular in ornamental gardens. It was first introduced to the U.S. from China in 1840 and planted in the eastern U.S. and Washington state.

Initially it was a gardener’s dream. It is easy to grow in full sun, thrives in many soil types including disturbed soil, is tolerant of drought and pollution and grows 15 feet per year. It also reproduces like crazy. One tree can produce 20 million winged seeds that are dispersed by wind and water.

Seed pods and seeds of Paulownia tomentosa (photo from Wikimedia Commons)

And …

Paulownia tomentosa’s ability to sprout prolifically from adventitious buds on stems and roots allows it to survive fire, cutting and even bulldozing in construction areas; making it difficult to remove from established areas.

Texas Invasive Species Institute: Paulownia tomentosa

This one was chopped down but it came back stronger than ever. Notice the huge leaves.

Paulownia tomentosa sprouts from a stump. Huge leaves! (photo from Wikimedia Commons)

Eventually botanists and gardeners realized that P. tomentosa is invasive. This map of paulownia’s occurrence in the U.S. …

Distribution of Paulownia tomentosa by county in U.S. (from EDDMapS)

… nearly matches the map of its State Invasive listings. Maryland and Massachusetts have outlawed it.

State Invasive Listings for Paulownia tomentosa (map from Invasive.org)

Years ago I knew of only one princess tree in Pittsburgh, this one next to the Schenley Bridge near the corner of Frew Street and Schenley Drive.

Princess tree next to the Schenley Bridge at Frew Street and Schenley Drive, 23 May 2022 (photo by Kate St. John)

Then a few years ago a volunteer sprouted in Schenley Park near the tufa bridge over Phipps Run. When it reached 20 feet it was cut down and its roots were dug up. However, this spring there are four paulownias near the tufa bridge. The genie is out of the bottle. Uh oh!

Learn more about the invasive princess in this video from University of Maryland Extension, posted at invasivespeciesinfo.gov.

p.s. P. tomentosa has been suggested as a plant to use in carbon capture projects. Nooooo! Don’t do it!

(photos from Wikimedia Commons and by Kate St. John, maps from EDDMapS; click on the captions to see the originals)

What Tree Is This?

Hosechestnut in flower (photo from Wikimedia Commons)

19 May 2022

Trees with stacks of white flowers are drawing our attention this week in Pittsburgh. Perhaps you’re wondering “What tree is this? “

Horsechestnuts (Aesculus hippocastanum) originated in Greece but have been planted around the world for their beautiful flowers. When fertilized the flowers become the familiar shiny buckeyes I played with as a child.

Fruit of the horsechestnut (photo from Wikimedia Commons)

In Pittsburgh we call the tree a “buckeye” though it is just one of many buckeyes (Aesculus) in our area including natives of North America: yellow, Ohio, and bottlebrush.

A close look at horsechestnut flowers reveals that some have yellow centers, others red.

Closeup of horsechestnut flowers (photo from Wikimedia Commons)

Bees see and are attracted to yellow, not red, so when a horsechestnut flower is fertilized it turns red. The flowers are …

Are there red flowers on the tree? Come back in early fall to collect the buckeyes.

(photos from Wikimedia Commons; click on the captions to see the originals)

Denuded Pine Cones

Central stem of a white pine cone missing all its seed scales, bracts & seeds, Moraine State Park, 24 March 2022 (photo by Kate St. John)

27 March 2022

On a walk last week in Moraine State Park we found a pile of pine cones in various stages of undress. Some were uneaten, some were half eaten and many were stripped bare like the stem above.

White pine cones at the red squirrel’s midden: uneaten to completely gone

The large debris pile called a midden included woody seed scales, pine straw, bract scales, and central stems but few seeds.

Close up of the midden shows many discarded seed scales, Moraine State24 March 2022

It was created while eating the seeds inside the cones.

Anatomy of a woody pine cone (image from Wikimedia Commons)

The midden was made by an individual red squirrel (Tamiasciurus hudsonicus), working alone.

We can know this because of the focus on pine cones, how the cones were denuded, and the sizeable midden. Conifer seeds make up the majority of the red squirrel’s diet and he defends his midden territory year-round against every other red squirrel.

Red squirrels are highly territorial and asocial with very few non-reproductive physical interactions. The majority of physical interactions are in male-female matings and between females and their offspring before the offspring disperse to their own territories. The non-reproductive physical interactions recorded (0.6% of all recorded behaviors in one 19-year study) were all instances of chasing an intruder from a territory.

Wikipedia Account: American Red Squirrel

The red squirrel is small and cute, but always eats alone.

Red squirrel on a tree branch (photo from Wikimedia Commons)

(photos by Kate St. John and from Wikimedia Commons; click on the captions to see the originals)

Listening to the Sap Rise?

Yellow-bellied sapsucker in Central Park, Feb 2021 (photo from Wikimedia Commons)

17 March 2022

Spring is here and tree sap is rising in western Pennsylvania. This month yellow-bellied sapsuckers (Sphyrapicus varius) are migrating through our area, pausing to drill holes in the trees to sip the welling sap.

How does a sapsucker know a tree is a good candidate for a meal? Can he hear the sap rising? Maybe so.

Seven years ago I learned that with special microphones we can hear the secret sounds of trees. Here’s an example from a Scots pine, recorded by Marcus Maeder’s trees project.

Auditory emissions of a Scots pine (recording by Marcus Maeder)

On Throwback Thursday learn more about the secret sounds of trees and listen to one in the video.

(photo from Wikimedia Commons, audio from Marcus Maeder’s trees project; click on the captions to see the originals)

Finding Food in the Cold

Snow scene on 19 January 2022

22 January 2022

I’ve often noticed that in winter there are more birds in the city than the countryside. Though we may not have “quality” birds we make up for it in quantity with large numbers of fruit-eating birds drawn to our ornamental trees.

In the past two weeks hundreds of American robins have been feasting in Oakland. Some of the fruits were inedible until the deep freeze softened them so the robins circled back to finish the Bradford pears last weekend. This week they started on pyracantha berries and the red fruits of this (hawthorn?) tree next to the Cathedral of Learning.

Was half the fruit wasted when birds and squirrels knocked it out of the trees?

Look closely and you can see that deer walked among the fallen fruit. They must have crossed Forbes or Fifth Avenue after dark to browse on the Cathedral of Learning lawn.

Nearby, the sweetgum balls were coated in snow on Monday, all melted by Wednesday.

American goldfinches arrived to pull seeds out of the balls. Some fell on the snow.

And a crow walked by to check it out.

Birds are finding food in the cold.

(photos by Kate St. John)