American Fringetree (Chionanthus virginicus) is blooming this week in Schenley Park.
On Throw Back Thursday read more in this 2011 post: Fringetree.
Fringetree In Bloom
Category Archives: Trees
The Sweet Smell Of Trees
This week the air in my neighborhood smells so sweet. The black locust trees are in bloom.
Black locusts (Robinia pseudoacacia) are common in Pittsburgh because they’re one of the first trees to grow in poor, disturbed soil. Our area has a lot of habitat for them, generated by people and nature — bulldozers and landslides.
Black locusts are ugly in winter with gnarly bark and twisted branches but they are sweet in May. The trees are in the pea family and it is evident in their flowers. Here’s what they look like in bloom.
The flowers are attractive to bees and birds. I’ve seen rose-breasted grosbeaks use their large beaks to grab the base of the flowers, then twirl to make the petals fall off. They swallow the nectar end.
Black locusts usually reach their peak on May 12 but they’re late this year. Look for these beautifully scented trees before the flowers fade in about 10 days.
Enjoy the sweet smell of trees.
(photos by Kate St. John)
Catkins And Tiny Flowers
Every year I see these yellow catkins in March and every year I forget their name. But this year will be different. I’m identifying them ahead of time as American hazelnuts (Corylus americana).
The catkins are the male flowers, so full of pollen that your fingers become dusty yellow if you touch them. They swing and flutter in the breeze to disperse their pollen to …
… to fertilize this tiny flower. The red female flowers, located on the branches, are easy to overlook because they’re so small. They don’t stand out because they don’t need to attract insects for pollination.
Here are some additional tips on identifying American hazelnut:
- This nut-bearing plant is often cultivated. It produces more nuts in full sun but it grows in the shade as well.
- American hazelnut trunks grow in clumps like a shrub.
- The clumps are on average about 10 feet tall.
- Its long yellow catkins indicate it’s in the birch family.
- The bark is smooth and speckled.
- Many of the catkins sprout alone instead of in bunches.
- The catkins are as long — or longer — than my fingers.
- The leaf buds are alternate on the branches.
- The female flowers bloom from the leaf buds before the leaves appear.
Because it’s often cultivated, you’ll find American hazelnut along trails and in easy to reach places. Its nuts provide food for wildlife.
(photos credits: top photo by Kate St. John, closeups by Marcy Cunkelman)
The Trees Get An Early Start
Even though March came in like a lion, the trees remember that it felt like summer last month so they’re waking up for spring.
American elms (Ulmus americana) are one of the first trees to bloom and have already begun in my city neighborhood. Right now it’s easy to recognize young elms from afar because their twig arrangement resembles a fish skeleton dotted with reddish flower buds. The skeleton isn’t perfect though. The “ribs” (twigs) alternate up the branch.
The trees with opposite twigs and fat red buds are red maples. They’re blooming, too.
On the last day of February at Raccoon Creek Wildflower Reserve, the top bud on this pignut hickory was pushing out tiny leaves. This is so premature that it reminds me of the early leaf out we had in March 2012.
And though the sycamores looked dormant next to Raccoon Creek …
… their seed balls are ready to disintegrate in the wind.
Will this weekend’s cold weather delay the trees? I hope so!
(photos by Kate St. John)
Lace Among The Trees
At this time of year the forest is brown but it still contains a muted beauty.
A lacy beech tree stands out among the gray.
(photo by Kate St. John)
Sweetgum Balls
Sweetgum seed pods are hated or loved, depending on your point of view.
On Throw Back Thursday read about their pros and cons in this vintage post: Gumballs
(photo by Dianne Machesney)
It Just Fell Over
Sometimes soggy ground is too weak to hold a mature tree.
On Friday January 12 it rained 2 inches in 24 hours in Pittsburgh. Then it got very cold.
This red oak was rooted in a hillside in Panther Hollow but it began to lean after so much rain. By January 16 it blocked the Upper Trail in Schenley Park. The Park Ranger vehicle can’t come through.
Alas, it just fell over.
(photo by Kate St. John)
Hackberries
Last Sunday in Schenley Park I found these small hard berries littering the trails … and then one fell on my head. I looked up to see a flock of robins knocking berries to the ground as they reached to eat them.
It’s easy to identify the berries by the bark of their tree. The common hackberry (Celtis occidentalis) has distinctive layered ridges.
Here’s a closeup of one ridge, photographed on a frosty morning.
Birds eat the berries. Deer eat the twigs.
Hackberry trees provide lots of food for wildlife.
(photos by Kate St.John)
Making a Carpet of Yellow Leaves
In autumn ginkgo trees (Ginkgo biloba) turn bright yellow and can lose all their leaves in as little as one day.
Yesterday morning I saw these ginkgos “snowing” so I stopped to film them (11 seconds). The scene is so bright that it’s hard to see individual falling leaves … but there are many.
I returned six hours later to see if the trees were bare. Not yet, but close.
Here’s the before and after.
Before: 11 November 2017, 10:30am
After: 11 November 2017, 4:30pm:
If you want to see ginkgos make a carpet of leaves, I know of two places to go: Schenley Drive near Phipps Conservatory and Highland Avenue near the entrance to Highland Park. But watch them soon. They may be bare by the end of the day.
(photos by Kate St. John)
Hope For What We’ve Lost
Two weeks ago I lamented that fall color is disappointing this year but I should have waited. The trees in Schenley Park looked better last week with red maples, yellow hickories, and this small tree reminding me of what we’ve lost.
Those pale green, yellow, orange and violet leaves are on a small ash tree whose trunk diameter is too small to be plagued by emerald ash borer … and now I’ve found out why.
Before the emerald ash borer (EAB) invasion, mature ash trees added pastel violet to the splash of color on our hillsides but now only the saplings are left.
Just across the trail from the ash sapling stands a mature ash that’s alive, though struggling. Some upper branches have died back and there are sucker branches below them. An old emerald ash borer hole shows what the mature tree was dealing with.
The old tree is alive because it received insecticide treatments during the height of the EAB invasion from a program of the Pittsburgh Parks Conservancy and the City of Pittsburgh. Beginning in 2011, 158 specimen ash trees were treated in the city parks. This one is #76 according to the metal tag.
Years later it appears that emerald ash borer numbers have dropped and it wasn’t because we used insecticides.
Scientists working on EAB biological control in Michigan found that many factors contributed to the emerald ash borer population collapse there.
“Woodpeckers, native and introduced parasitoids, intraspecific competition, disease, innate tree defenses, and reduced ash abundance contributed to the collapse of EAB populations.”
Notice that woodpeckers are at the top of the list!
Second on the list are four tiny parasitic insects that kill emerald ash borer larvae. Two native insects target emerald ash borers through the thin bark of saplings and at Michigan study sites scientists introduced two more parasitic insects from China, the emerald ash borer’s homeland, to get through the bark of mature ash trees.
Thanks to the hard work of scientists and arborists we may hope that our ash saplings will grow into mature ash trees.
Read more about ash tree biological controls at this U.S. Forest Service webpage.
(photos by Kate St. John)