Goodbye tree friends

After five years of having the privilege of documenting Pittsburgh’s parks and sharing stories about them with all of you, this is my last blog post for the Pittsburgh Parks Conservancy.  I moved back home to Memphis last week (to borrow the politicians’ phrase) to be closer to my family.  Saying goodbye was tough, especially since I was surrounded by such a warm and wonderful community of people who have taught me so much.  But it wasn’t just the people.  I think when you’ve spent so much time in the parks, especially slowing down to really get to know them, you realize you’re going to miss the trees too.  And so it was that I found myself, over the last few weeks, visiting some favorite trees to say a final farewell.  (At least until my next visit…)

Not all these special trees were blooming or leafing out yet (you picked a nice year to delay spring, Pittsburgh!), but there were plenty that were eager to show off.  In a lot of cases, I photographed a tree one day and then came back about a week later to watch it progress from flower to fruit to leaf (not necessarily in that order).  And in a switch this spring, I shot exclusively with a 100mm macro lens to get as much detail as possible.  This stymied Phil when I came back to the office and asked him for ID help; “I’m a silhouette guy!” he would exclaim.  “Come back when you photograph the whole tree.”  So these IDs are good guesses–thanks very much to both Phil and Erin for sharing their expertise.

So enjoy the final batch of tree photos.  I will miss these trees–and interacting with all of you–more than I can say.  Take good care of them for me.

I spent a good deal of time over by Westinghouse Pond, which has a nice assortment of trees that flower and leaf out early. Here’s a sweetgum whose leaves look like tiny stars.

Sweetgum tree

Redbuds near the Frick Environmental Center.


One of the earliest bloomers of spring, the Cornelian cherry dogwood, at Mellon Park.

Cornelian cherry dogwood

This one’s pretty but unfortunate: a honeysuckle vine that’s twisted itself around a spicebush in Frick Park.

Spicebush and honeysuckle

Now we start with the trees-in-progress shots.  Here is a horsechestnut tree in Highland Park that’s just started to leaf out.


And here’s a horsechestnut the following week.  These were beginning to flower–probably right now the flowers will be standing up in white and pale pink stalks if you pass one of these trees.


Back at Westinghouse Pond, everything was pink.  Here’s a saucer magnolia and some cherry blossoms that haven’t opened yet.

Magnolia and cherry

And now a magnolia that’s in full bloom…

Magnolia blossom

…and a cherry blossom.   Some on the tree had petals, others (like this one) didn’t.  I don’t know whether that was because of all the recent wind, or if that just happens sometimes.  Either way, I thought it made for an unusual photo.

Cherry blossom

Another beautiful kind of magnolia tree grows right around the basin of Westinghouse Pond–the sweetbay magnolia.  Here it is before the flowers have opened.

Sweetbay magnolia

And a week later, delicate white flowers.

Sweetbay magnolia

The hawthorn tree is lovely, but you probably shouldn’t play tag anywhere near it.


Here it is beginning to flower (they’ll be pretty and white–check this one out over by the Bartlett Meadow, where the daffodils are blooming):


And now we come to the maples.  Last year, my fascination was with redbuds; this year, it’s been maples.  I was a little disheartened that it seemed like so many of the trees I was asking Erin and Phil about turned out to be invasive Norway maples…but I have to give it up, they are pretty fascinating in the spring.  The trees that look like they’re covered in neon green popcorn balls are Norway maples–probably the first trees you saw flowering this year.  The photo on the left is a native sugar maple, and the one on the right is a Norway maple for comparison.

Sugar and Norway maple

This one is also a Norway maple, although it sure looks different.  Popcorn of a different variety?

Norway maple

And here’s another Norway maple that’s begun to produce leaves.

Norway maple

This one in the Westinghouse woods in Schenley Park appears to be a sycamore maple–another tree considered by some to be invasive, although it’s not nearly as prevalent as the Norway maple in Pittsburgh’s forests. (Thanks Burlton for the ID!)

Mystery tree

Finally, we come to four different red maple trees.  I think these are such beautiful harbingers of spring, especially the big trees that just light up with red flowers.  So I decided I’d track one red maple tree every couple of days for a month to watch its progression.  While it is a pretty tree, I happened to pick one that wasn’t producing seeds, and I had to leave town before the leaf was fully formed.  But here’s the tree (at the corner of Bartlett St. and Panther Hollow Road) on March 22…

Red maple flowers

…and on April 23.

Red maple leaf bud

Since that tree wound up not being particularly showy, I supplemented with some other red maples.  This one was across the street, near the drive up to the Schenley Oval.  It was my original choice to document, but all the branches were too high to get close to.

Red maple and spider

This one (and many others like it) was putting on quite a show lining the Bob O’Connor Golf Course in Schenley Park.  You can see the winged seeds starting to take shape.

Red maple seeds

And finally, a closer look at the seeds of another maple along Bartlett Street.

Red maple seeds

Thanks again for reading and commenting, and for generally sharing the park love over the last few years.  If you want to keep in touch, you can still find me online at, where you can bet you’ll see some of the superstar trees of Zone 6.

Top 15 Trees in the Parks – Part 5

It’s time for the last installment of our Top 15 Trees in the Parks series.  The final four trees include some natives you may not be familiar with, as well as the brightest star in the winter landscape.

12. Eastern hophornbeam (Ostrya virginiana)

Hophornbeam fruit
Photo by Steven Katovich

This is a small tree in the birch family with an extremely durable wood (which explains another of its common names, “ironwood”).  It grows well in many types of soils and can tolerate living under the shade of taller trees.  When it matures, its bark appears shredded because it forms narrow strips that are loose at the edges.  Leaves are simple, shaped similarly to elms, and doubly toothed at the edges.  The fruit, which resembles hops, is a cluster of papery oval sacs each containing a tiny nut. 

Like the northern pin oak, this tree has both male and female flowers.  Its male flowers are brown “pre-formed” catkins, in clusters of three like birds’ toes, that are visible throughout the winter and open in spring.  Female catkins are light green and only appear in the spring.  This is a good way to distinguish this species from the American hornbeam (Carpinus caroliniana), whose catkins all appear in the spring. 

Phil Says: These trees are often confused with elms because they look very similar with bark characteristics, form, and the nature of the twigs.  But upon close inspection, you’ll see subtle differences in leaf shape and seed set.  Hophornbeam is a great native that is definitely underutilized in both landscape and urban woodlands.  It performs very well as a street tree if planted.

13. Hackberry (Celtis occidentalis)

Hackberry bark
Photo by Paul Wray

The hackberry tree is a member of the elm family.  It has a distinctive bark—it’s mostly smooth, light brown or gray, but wart-like knobs disrupt the surface.  It’s well-suited to the urban environment, tolerant of air pollution and many different temperatures and soil types.  It can also be planted near waterways to help reduce the risk of flooding. 

The hackberry is a fantastic tree for wildlife, hosting bees, birds, and butterflies.  The birds love its sweet fruit, and butterflies (like the hackberry emperor) drink its sap.  Humans can eat the berries too, and although they’re fairly thin and dry, they have a taste similar to dates.  Another good quality for wildlife is that the hackberry has fairly weak wood, so late in its lifespan it begins to split and form cavities that provide shelter. 

Phil Says: Another great native.  Definitely underutilized in our landscape and streetscape.  They are beneficial in both those settings, and it’s a great woodland tree as well.  It has an interesting bark that grows in bumpy ridges.  I liken it to the Velcro tree—if you were to run and jump and grab onto it, it would be difficult to slide down the tree because the ridges are so rough they’d hold you there. 

14. Yellow buckeye (Aesculus flava)

Yellow buckeye
Photo by William Ciesla

The yellow buckeye is a close relative of the Ohio buckeye (Aesculus glabra), but can be distinguished by its flowers.  In the yellow buckeye, the stamens are shorter than the petals, and in Ohio buckeye they are longer.  Both trees have an unpleasant odor, but the Ohio buckeye’s is much stronger, which has led to the yellow buckeye sometimes being termed “sweet buckeye.”  The yellow buckeye is also a larger tree. 

Its leaf is distinctive, usually having five leaflets.  It’s similar to the horse chestnut, which is in the same family of trees.   (The leaf buds of the horse chestnut are very sticky, which is a helpful way to distinguish them.)  The yellow buckeye’s flowers are yellow and form upright clusters.  The fruit, a smooth nut enclosed in a thick husk, is poisonous to humans but beloved by squirrels. 

Phil Says: There are native and non-native buckeyes here; there are probably a half-dozen non-natives that have been hybridized in horticulture and brought to this area.  They do grow in the parks as well.  I don’t plant them in the landscape because there’s a pretty common leaf blight that affects them, so often they get pretty brown by July.  But they’re part of the ecosystem, so they’re appropriate for growing in the woods. 

15. Witch hazel (Hamamelis virginiana)
Witch hazelUnlike most other trees, the witch hazel is easiest to identify in the winter months.  It begins showing its small, thread-like yellow flowers in late fall and retains them throughout the winter.  In very cold weather the petals might curl up close, but they usually last until spring, when everything else begins to bloom.  Then the small buttons that contain the seed pods burst and shoot out the seeds that have been ripening over the past year.  

The witch hazel is a small, shrubby tree, well-suited to the understory.  Its scientific name Hamamelis means “together with fruit,” which refers to the fact that its fruit, flowers, and leaf buds all appear at the same time (making it unique among trees native to North America).  

Phil Says: That is a great native plant that blooms during the winter when nothing else blooms.  It does best in wet, riparian areas, but it is adaptable.  It’s a smaller tree, usually multi-stemmed.

We hope you enjoyed this peek into the composition of our forests.  Any other trees you’d like to see spotlighted here on the blog?

Top 15 Trees in the Parks – Part 4

Time to spotlight a few more commonly found trees in our parks:

9. Hawthorn (Crataegus pennsylvanica)

Hawthorn flowers

Photo by David Hawgood

Sometimes called thornapples, hawthorns are small trees with 1-3cm thorns growing from their branches or trunks.  The leaves are variable in shape, but usually have serrated margins.  Their small berry-like fruits are beloved of birds and mammals, and the nectar from their flowers is a food source for insects.  Cedar waxwings are especially fond of these trees.

The tree is distinctive in three seasons—with beautiful clusters of white flowers in the spring, red fruit in late summer, and attractive fall color. 

Phil Says: We frequently don’t put a lot of value on trees which do not attain great height or girth, but our native hawthorn occupies a niche in the overall ecology of Pittsburgh.  In its native state, it is a floodplain and wet areas tree.  And those are frequently areas that are difficult to have large canopy trees succeed, even though boxelder and poplar and sycamores will grow there.  But it is rare to see hawthorn trees fail in flooded conditions, where larger canopy trees are subject to failure.  They are a great habitat tree with a dense branch structure.  The seed set is prized by wildlife—birds, squirrels, deer, raccoons, and opossum all utilize it.  

10. White Oak (Quercus alba)
White oak(We’re focusing on the Quercus alba species here, but this section includes all oaks in the white oak family.  White oaks are generally defined by having leaf lobes whose tips are not bristled, and by acorns that ripen within one season.) 

White oaks, despite not being extraordinarily tall, often project a massive appearance thanks to low branches that reach out parallel to the ground.  White oaks can grow as wide as they are tall, giving them a distinctive silhouette.  They have a light gray bark that peels slightly, and glossy green leaves that are lobed and oval in shape.  In the spring, leaves are downy and silvery pink. 

White oak leaf

Photo by Paul Bolstad

The white oak is an excellent shade tree because of its wide branching and its tendency not to drop its limbs.  It grows well in almost all soils except those that are particularly dry and shallow.  They are fairly slow-growing compared to other oaks, but they tend to have long life spans.  

Phil Says: White oaks are somewhat resistant to oak wilt disease.  They will contract the disease but they generally do not have fatal symptoms, unlike the red oak group.  Like red oaks, white oaks are also a group—white oak, swamp white oak, and bur oak are the most common.  To date, wherever oak wilt has been controlled in the parks, we have removed the white oaks as well as the red oaks, knowing that the white oak could be a host for future infections of red oaks.   

11. Northern Pin Oak (Quercus ellipsoidalis)
Also called Hill’s Oak, this member of the red oak family is often found in dry, sandy soils.  Despite its ability to tolerate poor soil conditions, it is extremely intolerant to shade and so is usually succeeded by other oaks that need less light.  

Northern pin oak

Photo by Paul Wray

Its name suggests that it’s closely related to the pin oak (Quercus palustris), but its nearest relative actually seems to be the black oak (Quercus velutina).  Northern pin oak gets its scientific name from the ellipse shape of its acorns.  The tree is medium-sized and has a bright red color in the fall, making it a good choice for ornamental plantings. 

Northern pin oak has male and female flowers appearing on the same tree, with male flowers taking the form of catkins and females as small hanging flowers either alone or in groups of two or three.  Its leaves can be distinguished from those of the red oak (Quercus rubra) by their shiny surfaces and deep sinuses (the indentations between lobes). 

Check back soon for the final installment in this series!

Top 15 Trees in the Parks – Part 3

Time for the next few trees in our Top 15 Trees in the Parks series: 

6. Elm (Ulmus americana)


Elm stand at the Schenley Park Overlook

Despite the high mortality caused by Dutch elm disease, Pittsburgh’s parks still feature a significant population of elm trees, although many of them are smaller than the elm’s traditional soaring height (often around 100 feet tall).  Because of its strong wood and tolerance of many stress factors like pollution and poor soil quality, the elm is a high-quality tree for an urban park. 

Prior to Dutch elm disease’s reign in the 1950s – 1970s, the elm was the most popular street tree in the country thanks to its elegant Y shape, sturdy build, and ample shade.  Over 100 million elms were felled by the disease, changing the character of cities, from neighborhoods to forests.  But the elm is working its way back into the landscape: to combat the disease, a breeding program has sought to hybridize American elms with Asian elms, which are highly resistant to the disease. 

In Pittsburgh, we’re working to become part of the solution.  In 2005, Norway maples were removed from the border of the Schenley Park overlook and replaced with 30 elms from six different cultivars: Accolade, Allee, Frontier, Pioneer, Prospector, and Triumph.  Students from the Penn State Cooperative Extension are studying the trees to observe their development and keep a careful eye on whether the elms exhibit invasive tendencies in the adjacent natural areas (so far, so good!).

Elm leaf

Elm leaf photo by Paul Wray

Phil Says: Even though Dutch elm disease swept through Pittsburgh decades ago, elm is such a strong native tree genetically.  It’s very well adapted to growing here, and so as these mature trees were sickened, they produced tens of millions of seeds that were dispersed throughout the urban forest.  Many of those seedlings grew up, and Dutch elm disease did not find them until they became larger trees.  So we still have lots of American elms left—they’re known as climatic escapees.  It’s a regenerative population that has survived because the disease is not at the level it once was and the insects that spread it aren’t nearly as abundant.  For the most part these newer trees will never attain the height and girth of the elms we were used to seeing in Pittsburgh.  To have thousands of large trees is probably not going to happen.

7. Northern Red Oak (Quercus rubra)Red oak
(We’re focusing on the Quercus rubra species here, but this section includes all oaks in the red oak family.  In this family, the lobes at the ends of the leaves are pointed and acorns ripen over two seasons.  The “red” refers to the wood inside the tree, although many of them also have red leaves in fall.) 

Red oaks are a fast-growing, fairly tall tree with a mature diameter of 2-3 feet.  They are good urban trees because they tolerate pollution and compacted soils.  The red oak is a dominant forest tree throughout the state of Pennsylvania. 

The leaves contain tannin, which makes them leathery and resistant to decomposition.  They are simple, with between 7 and 11 toothed lobes on each leaf.  They are dull green throughout the summer and turn a brick red color in fall. 

Phil Says: When we mention “red oak,” that refers to a group of oak trees.  The trees in the red oak group that are most common in Pittsburgh are red oak, black oak, and pin oak.  Oak wilt disease has directly impacted the red oak group, having claimed several hundred trees last year alone in Riverview, Highland, and Frick Parks.  

8. Black Locust (Robinia pseudoacacia)
Black locustThe dark, deeply furrowed bark of this tree and the twisty character of its upper branches make the black locust easy to distinguish.  They also have paired thorns that can grow to half an inch long.  It has an especially striking winter silhouette.  They are usually medium-sized trees but can grow to 100 feet tall.  

Black locusts are similar to cottonwood trees, but in summer can be easily distinguished by their compound leaves (cottonwoods have simple leaves).  There are between 7 and 19 leaflets on one stem, and all of them are paired except for the leaflet on the end.  They are smooth and oval-shaped, and droop at night.  Locust fruits are dark brown pods up to four inches long.

Black locusts are the host plants for clouded sulphur butterflies and silver-spotted skippers.  They are considered invasive in some parts of the United States, particularly where they have begun to colonize dry prairies and savannas.

Phil Says: Like black cherry, this is an early successional species, so wherever it’s growing, it’s making that site more suitable for other dominant trees—oaks, maples—to move in.  It’s a site colonizer.  Black locust trees have thorns, even though most people never see them.  The thorns occur on new growth, and they are there to protect the tree from being browsed by deer.

Hear Me: Stories from the Park

Hear Me stories in Frick Park

Jen Saffron of the CREATE Lab assists with story collection in Frick Park.

More proof that Pittsburgh is one of the coolest places on the planet: the Hear Me project, from CMU’s CREATE Lab.  Hear Me is an effort to use technology and media to engage children and students in creative conversations about their lives.  These stories–whether they are audio, visual, or written–are collected and archived on the Tell-Port website, where they can be shared with the world.

The Parks Conservancy has been lucky enough to partner with the Hear Me folks to gather stories about the parks.  As part of our High School Urban EcoStewards program, students regularly write in journals during their projects in the parks.  Now, because of the partnership with Hear Me, they can also record their feelings and observations about the outdoors to Tell-Port.  CREATE Lab staff members and interns have begun accompanying High School EcoStewards to the park with audio equipment and capturing their stories on-site.

Saturday Light Brigade

Jeff Baron of the Saturday Light Brigade collects stories at the Pittsburgh Science & Technology Academy (image: Jen Saffron)

The Hear Me folks were on hand for a cold but sunny February work day in Frick Park with EcoStewards from The Ellis School.  The students took turns telling their stories and collecting them, learning how to use the audio equipment to capture clear sound.  They also learned tips like gathering ambient noise from the interview setting to fill blank spaces and lend authenticity.  The stories were then sent back to the studios of the Saturday Light Brigade radio program at the Children’s Museum of Pittsburgh for editing.  And now you can hear them online!

Click here for stories from City High students collected at Schenley Park.

Click here for stories from Ellis School students collected at Frick Park.

We’re so thrilled to be part of this project and to hear from these wonderful students about what parks mean to them.