Oak tree in bloom with dangling pollen flowers (photo by Kate St. John)
25 April 2023
If your pollen allergies have gotten worse there’s a good reason for it. A study of North American pollen trends in the last 30 years, led by William R. L. Anderegg, found that pollen season is starting earlier, lasting longer and has higher pollen counts than in the 1990s because of climate change.
Yale Climate Connections reports “In Anderegg’s research on pollen in North America, he saw pollen seasons starting about 20 days earlier than they did in the 1990s” and pollen concentrations increased by 21%. The higher temperatures and carbon dioxide in today’s atmosphere make plants more productive and allergies worse.
Right now in Pittsburgh we are at the height of pollen season. Recurring hot weather, 15+ degrees above normal, caused the oaks to bloom early and pollen so intense that my car turned yellow while parked at Anderson Playground for just an hour last Friday.
Allergy sufferers get a double whammy here because the pollen is added to Pittsburgh’s poor air quality making it particularly dangerous for children and people with asthma and respiratory illness.
Bluets, Knob Hill Community Park, 14 April 2023 (photo by Kate St. John)
15 April 2023
More flowers bloomed and more trees leafed out as hot summer weather continued this week.
I saw a few bluets (Houstonia) and spring beauty (Claytonia) at Knob Hill Community Park yesterday.
Spring beauty, Knob Hill Community Park, 14 April 2023 (photo by Kate St. John)
In Frick Park on Thursday this box elder (Acer negundo) was blooming and leafing out at the same time.
Box edler flowers and leafout, Frick Park, 13 April 2023 (photo by Kate St. John)
But many native trees still looked bare, such as the oaks on this hillside.
Progress of leafout at Frick Park, 13 April 2023 (photo by Kate St. John)
The slowness of native trees made last weekend the perfect time to see the invasive extent of Callery pears (Pyrus calleryana). Native white-flowering trees, such as serviceberry and wild cherry, were not blooming yet so the only white trees in the landscape were the Callery pears.
On 8 April at the Ridge Road interchange on the Parkway West (I-376) I found thick stands of Callery pears as far as the eye could see (first 2 slides below). The trees gained a foothold in disturbed soil after construction of the Ridge Road interchange in 2006 and Settlers Ridge shopping center in 2009. The third slide shows Callery pears in the woods at Wingfield Pines.
p.s. This weekend the downy serviceberries are blooming (white) and the Callery pears are growing leaves (white+green) so it’s no longer possible to pinpoint the invasive species.
A redbud branch in full bloom, Frick Park, 12 April 2023 (photo by Kate St. John)
13 April 2023
Hot weather this week is speeding up spring and Pittsburgh’s redbuds are bursting into bloom. Yesterday at Frick Park I found most buds ready to burst with a few branches in full bloom.
Redbuds seem to be everywhere now but this wasn’t always the case.
Seven years ago the Western Pennsylvania Conservancy launched Pittsburgh’s Redbud Project to beautify Pittsburgh’s riverfronts. Envisioned by landscape architect Frank Dawson, the goal was to make Pittsburgh as beautiful with native redbud trees as D.C. is during the Cherry Blossom Festival.
They originally planned for 1,200 trees but by now they’ve planted three times that many along the Allegheny, Monongahela and Ohio riverfronts. The project also inspired redbud plantings in Pittsburgh’s parks and neighborhoods by Pittsburgh Parks Conservancy and Tree Pittsburgh.
Seven years ago today I wrote about the Pittsburgh Redbud Project as I was about to participate in the launch event on 19 April 2016. We gathered for tree planting on the North Shore near the Mister Rogers statue and learned why our assignment — digging holes! — was so important for a tree this size.
Pittsburgh Redbud Project: Volunteers watch how it’s done, Pittsburgh’s North Shore, 19 April 2016 (photo by Kate St. John)
The trees have now been in place for seven years and they are beautiful. This stand near the Frick Environmental Education Center drew attention yesterday even though they were still in bud.
Redbuds drawing attention at Frick Park, 12 April 2023 (photo by Kate St. John)
With temperatures in the low 80s this weekend will be the perfect time to see redbuds at their best.
While traveling in Ecuador last month I saw balsa trees growing in the wild and learned that Ecuador supplies 95% of the world’s commercial balsa wood. The driving force behind these exports is an environmental paradox.
Balsa (Ochroma pyramidale) is a pioneer tree of tropical forest clearings, native to Central and South America. It is so fast growing that it can grow 6-9 feet a year and reach full height of about 100 feet in only 10-15 years. The trees are short-lived, lasting only 30-40 years.
Inside the living wood the cells are large, thin-walled and full of water so that the tree stands upright. When cut and kiln dried the wood is very lightweight and sturdy.
In the wild balsa trees are widely spaced at about one tree per acre (2-3/hectare) but to meet commercial demand balsa is grown in plantations containing 400 trees/acre (1000/hectare). Plantation trees are cut at 6-10 years old because much of the wood in older trees — the core and outer layers — is commercially useless.
Ecuadorans made ocean-going rafts of balsa logs long before the Spanish arrived in the 1500s and it is still used for rafts today. (Balsa is the Spanish word for raft.)
But none of these uses are the driving force behind increased Ecuadoran balsa exports.
Balsa wood is a component in wind turbine blades. According to GE which manufactures wind turbine blades at Castellon, “Workers make the blades from fiberglass fabric and balsa wood. Then, the blade is covered with an airtight foil and the team installs a network of tubes that pumps in and distributes the resin that will hold it together.”
Plantations provide 60% of Ecuador’s balsa wood but the remaining 40% is coming from wild trees in the rainforest. Using satellite images and on-the-ground followup Mongabay and Global Forest Watch have documented deforestation in Ecuador, especially east of the Andes in the Amazon watershed. According to Mongabay:
The Pastaza River Basin is one of the areas most affected by the balsa industry. There, the Pastaza, Bobonaza, Curaray, Villano, Copataza and other rivers are used as logging access routes, with satellite imagery showing their banks increasingly pockmarked by deforestation. Sources tell Mongabay Latam that the logging has been so intense that balsa has been completely removed from some areas.
…[And now] loggers are starting to harvest other timber species in areas that have been denuded of balsa.
“The same loggers and traders that one year ago arrived from [the cities of] Quevedo, Esmeraldas or Guayaquil are now arriving to look at what else is there,” Páez said.
“There is an ongoing process of deforestation of valuable tree species in Indigenous territories” with no monitoring by the authorities, she added.
The deforestation shows up as pink dots in Global Forest Watch’s map, below left. Are these places where birders go? The eBird map of Ecuador hotspots at right is red at sites where birders reported more than 500 species. There seems to be overlap southeast of Quito.
NOTE about the eBird map: eBird maps show where birders have found birds and reported them on eBird. The blank spots on the Ecuador map do not indicate an absence of birds but instead an absence of birders or an absence of Internet access.
(photo and map credits are in each caption; click on the captions to see the originals)
Woodland crocus or Tommasini’s croscus, 21 Feb 2023 (photo by Kate St. John)
25 February 2023
For seven days this week the temperature stayed above freezing and hit 71 degrees F on Thursday. At 26 degrees above normal, flowers opened on plants and trees.
My favorites were the early crocuses. Native to Bulgaria, Hungary, Albania and the former Yugoslavia, these woodland crocuses (Crocus tommasinianus) are often seen in gardens but someone in my neighborhood planted them in a grassy front yard. Because the flowers bloom before the grass grows they are in no danger of being mowed.
Tomasini’s crocuses blooming in the grass, Neville Ave, 21 Feb 2023 (photo by Kate St. John)
On Pitt’s campus Cornelian cherry trees (Cornus mas) produced yellow flowers.
Flowers of Cornelian Cherry, 20 Feb 2023 (photo by Kate St. John)
Red maples (Acer rubrum) bloomed next to Carnegie Museum …
Red maple flowers near Carnegie Museum, 20 Feb 2023 (photo by Kate St. John)
… and at Frick Park the maple branches looked thick with tiny flowers, including yellowish pollen-bearing ones.
Maple trees against a blue sky. Branches look thick with small flowers and pollen anthers, Frick Park, 23 Feb 2023 (photo by Kate St. John)
This week, tiny leaves opened on jetbead (Rhodotypos scandens) and a few honeysuckle bushes. Unfortunately invasive plants are first to leaf out.
New leaves opening on jetbead, Frick Park, 23 Feb 2023 (photo by Kate St. John)
The coming week will be like a wet blanket: above freezing, gusty wind, lots of rain.
The sunrise was gorgeous and cold last Wednesday when a group of us decided to walk at Jennings in Butler County. We saw few birds but there were ice heaves, buttress roots on an elm, and the seeds of old man’s beard (Clematis drummondii).
Ice heave at Jennings, Butler County 11 Jan 2023 (photo by Kate St. John)Elm tree with buttress roots, Jennings, Butler County, 11 Jan 2023 (photo by Kate St. John)
When old man’s beard is in bloom it’s called virgin’s bower, transforming it from a young woman to an old man in a matter of months.
Seeds of Virgin’s bower, a.k.a. Old man’s beard, Jennings, Butler County, 11 Jan 2023 (photo by Kate St. John)
My friends who live north of the city have not seen many dark-eyed juncos at their feeders this winter, but juncos are definitely present at the Frick Park Environmental Education Center. Charity Kheshgi posted photos of our recent trip to Frick.
A red oak felled at Anderson Playground in Schenley Park, 30 Dec 2022 (photo by Kate St. John)
7 January 2023
This week’s rain dampened outdoor activities but there were still some things to see.
Chainsaw tree “trimming” continues in the city. This red oak had a hollow core so it was chopped down in late December at Anderson Playground in Schenley Park. Can you count the rings and determine its age?
On 3 January rain flecked the camera as Ecco stopped by for a visit. Notice how wet his head is!
On 4 January the rain finally stopped and the moon shone at 8pm.
When the cold snap ended on 28 December the ice thawed and the creeks began running again. Listen to the sound of Panther Hollow Run in Schenley Park on 30 December 2022.
Tall columnar arborvitae along an alley in Kutztown, PA, 27 Nov 2022 (photo by Kate St. John)
12 December 2022
At Thanksgiving in Kutztown, PA I was stunned to see a solid wall of arborvitae bordering a neighborhood. In Pittsburgh’s East End, arborvitae is always bare from the ground to 4-5 five feet up, eaten by our overpopulated deer. Here’s a row of arborvitae at Schenley Park golf course.
Deer damage on arborvitae at Schenley Park golf course, 11 Dec 2022 (photo by Kate St. John)
Why didn’t deer browse the Kutztown trees? My guess is that they are the Green Giant variety of Western arborvitaes. Davey Tree explains:
Deer don’t care for Western arborvitaes, like green giant, steeplechase or spring grove. So, if you plant these, they may leave them alone.
Though, when deer are starving, they become less picky and will eat almost anything, including those deer-resistant arborvitaes. If deer are a big problem in your yard, avoid arborvitae altogether.
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.”
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.
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).
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.”
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.
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)