Archive for the 'Trees' Category

Jun 04 2014

What Made This Tree Fall Over?

Published by under Quiz,Schenley Park,Trees

Black cherry tree toppled at Schenley Park, 30 May 2014 (photo by Kate St. John)

When I see a tree snapped in half like this I have to ask: What made this tree fall over?

I did some detective work but I don’t know the answer yet.  Maybe you can help.  Here are the clues:

  • The tree is a black cherry (Prunus serotina)
  • It was alive when it fell.  It grew leaves this spring so the structural weakness wasn’t evident until the tree broke.
  • This is the only broken tree at this location in Schenley Park.  Even if a strong wind snapped the trunk it wasn’t strong enough to damage other trees.
  • The trunk is not hollow inside the break though there are air gaps between the light outer wood and dark inner core.
  • There’s a white flaky substance inside the trunk that coats the light wood layers.  Is it a fungus?
  • Did the white stuff weaken the trunk?  Is it responsible for the break?

The trunk isn’t hollow, but…
Black cherry break, 30 May 2014 (photo by Kate St. John)

Here’s a close look at the white flaky fungus.  It reminds me of the white correction tape I use on paper.
White flaky fungus. What is it? (photo by Kate St. John)

Do any of you know what this is?  Is it the reason the tree fell over?

Leave a comment with your answer.

Thanks!

(photos by Kate St. John)

UPDATE on June 5 with the ANSWER!   It’s a species of Armillaria or honey fungus.  (See Maureen Hobma’s comment below.)   Well, I feel a little dumb.  I wrote about Armillaria on 16 January 2014 because I was fascinated that it’s the largest living organism.  I even included a photo of the white sheets inside the heartwood but, having never seen the white sheets before, I did not remember them.  Until now I had only seen the black rope-y strands and the honey mushrooms so that’s all I knew of Armillaria.  The white sheets are the newer growth, the mycelium, and can be bio-luminescent!   I learn something new every day.

10 responses so far

May 03 2014

Leaf Out!

Published by under Schenley Park,Trees

Tulip tree leaves unfurling, 28 April 2014 (photo by Kate St. John)

Very soon southwestern Pennsylvania will reach the moment when most of the trees have leaves.  This usually happens around May 5.

Leaf out seems a bit delayed this year but it’s making progress.  On Monday (April 28) I found a tulip tree unfurling its leaves one by one.  By Thursday the same branch looked like this:

Tulip tree leaf-out, 1 May 2014 (photo by Kate St. John)

There’s probably another leaf inside that big bud, and then there will be a flower.

When will “Most of the Trees Have Leaves?”

For Schenley Park, I’ll let you know.

 

(photos by Kate St. John)

Later:  “Full Leaf” was late this year.  It didn’t happen until May 13 in Schenley Park.

2 responses so far

Apr 30 2014

April Showers Bring…

Published by under Phenology,Plants,Trees

Great chickweed (photo by Kate St. John)

While it feels like it’s been raining forever, last weekend’s weather was sunny and so were the flowers. Here’s a selection I found at Raccoon Creek Wildflower Reserve and Friendship Hill National Historic Site on Saturday and Sunday.

Above, a very close look at Great Chickweed (Stellaria pubera), also called Star Chickweed.  The flower is only 1/2″ across and it has only five petals but they’re so deeply cleft that they look like ten.

Below, inch-long Virginia bluebells (Mertensia virginica) in bloom at Raccoon Wildflower Reserve.  I love how they change color as they open.

Virginia Bluebells (photo by Kate St. John)

 

Toad Trillium or Toadshade (Trillium sessile) is rarely seen from this angle because the plant is only four inches tall.  (I got muddy taking this picture.)  The dark, closed petals look boring from above but graceful from the side.  Perhaps they open like this so the pollen can disperse more easily.  It’s dusting the leaf at front left.
Sessile trillium (photo by Kate St. John)

 

Today’s April showers will bring May flowers. It’s hard to believe that May begins tomorrow.

 

(photos by Kate St. John)

5 responses so far

Apr 28 2014

The Trees Take On Color

Published by under Phenology,Trees

Redbuds in bud, 18 April 2014 (photo by Kate St. John)

Last week Pittsburgh’s trees took on color and shape after a long brown winter.

A week ago the redbud trees had closed pink buds that made their branches look magenta from a distance.

Now the flowers are open and the trees are lighter pink.
Redbud flowers open, late April 2013 (photo by Kate St.John)

 

Meanwhile the hillsides have changed from uniform winter brown to individual, spring-green trees as seen from Downtown on Saturday.
Spring green trees in Mt. Washington, Pittsburgh (photo by Kate St. John)

 

The earliest colors are usually pale green flowers.

If you haven’t been paying attention, your nose knows the trees are blooming.  Welcome to pollen season.

(photos by Kate St. John)

One response so far

Apr 22 2014

Schenley Oak Wilt Status

Published by under Schenley Park,Trees

Schenley Park clearcut to stop oak wilt (photo by Kate St. John)

The scene is ugly but it’s therapeutic.

These trees at Prospect Drive in Schenley Park were removed because they were infected with oak wilt.  The eradication project was scheduled for February but didn’t get rolling until early April.

Last Friday it was partly complete.  The oaks were gone but their stumps remained.  These stumps will be removed, too, so the disease cannot spread.

Clearcut to remove oak wiltat Prospect Circle, Schenley Park, 18 April 2014 (photo by Kate St. John)

How old were the oaks?  The rings on one of them tallied 87 years.

It takes more than a lifetime to grow a tree and less than a day to chop it down.  Alas, these oaks would still be here if they had not become victims of highly infectious oak wilt fungus.

When the ground is ready and the time of year is right volunteers and the Pittsburgh Parks Conservancy will plant new trees.

 

(photos by Kate St. John)

UPDATE 2 June 2014: Click here for the most recent update.

4 responses so far

Apr 13 2014

Flowering Trees

Published by under Phenology,Trees

Red maple flowers, 10 April 2014 (photo by Kate St. John)

Spring is getting a boost on this warm and sunny weekend but we still don’t have blooming cherry trees, dogwoods or hawthorns.  If you look closely, though, you’ll see one native tree has small red flowers.

Shown above are the male flowers on a red maple.  The sepals and petals are only half as long as the stamens that stick out to catch the wind or tap the backs of bees. The flowers are a favorite with bees but red maples are so versatile they can be pollinated by both insects and wind.

Individual red maple trees can have all male, all female, or both sexes of flowers.  The female flowers have no “fuzz” because they have no stamens (of course).

Look closely to see the tiny flowers.

 

(photo by Kate St. John)

One response so far

Feb 04 2014

Schenley’s Oak Wilt Trees Are Coming Down

Published by under Schenley Park,Trees

Oak stump upended to prevent the spread of oak wilt (Joseph O'Brien, USDA Forest Service, Bugwood.org)

Don’t be surprised when you see trees being felled this month at Prospect Drive in Schenley Park.  An acre of diseased trees must be clear-cut to protect the park’s healthy oaks.

Councilman Corey O’Connor held an informational meeting last night where we learned about the project from City Forester Lisa Ceoffe and Pittsburgh Parks Conservancy’s Erin Copeland.  They described oak wilt, its treatment, and the affected area in Schenley Park which I’ve drawn on the tiny map below.  Click on the map for a better view in Google.

Location of the Oak Wilt zone in Schenley Park, February 2014 (screenshot of shared Google map)

Here are some of the 55-60 trees that will come down, marked with blue logging paint last summer. Many of them are 100 years old.
Oak wilt trees marked for removal from Schenley Pak (photo by Kate St. John)

Why is the area so large and why must it be clear cut?

Oak wilt is caused by a fungus that doesn’t spread easily but can kill a tree in 30 days.  The fungus travels in the oak’s vascular system and when the tree detects it it blocks those vessels — the arboreal equivalent of a stroke.  Watch the 13 minute video here to see how this happens.  You know the oaks are sick when you see browning leaves in mid-summer.  This is the only sign.

Oak leaves showing oak wilt (Joseph O'Brien, USDA Forest Service, Bugwood.org)

The infection travels through an entire stand because the oaks are joined underground.  When their roots touch, they graft to share nutrients and, sadly, disease.  We only see the symptoms in summer so a large area can become infected before anyone notices.

Oak root graft (photo by Ronald F. Billings, Texas Forest Service, Bugwood.org)

 

Once the fungus has taken hold, an infected tree is doomed.  The only way to save nearby healthy trees is to trench the perimeter of the infection(*) and remove all the trees inside the circle.  Sap beetles can carry the infection so the logging must be done in winter when the sap isn’t running.  (Note!  Don’t prune your oaks in spring and summer.  This opens them to oak wilt.)

When the logging begins in about 10 days, Prospect Drive will be closed each morning when the equipment arrives and reopened when Davey Tree is done for the day.  Signs will be posted explaining what’s going on and Davey Tree will have brochures for those who want to know more.  The site is easily visible from the Boulevard so the City expects a lot of questions.  Now that you know what’s going on, spread the word.

By the end of February the area will be empty, but not for long.  Site restoration begins March 22 with a tree planting conducted by the Pittsburgh Parks Conservancy.  Who’s going to plant the trees?  Volunteers!

Schenley Park needs you on Sunday March 22, 10:00am to 2:00pm, rain or shine.  Click here or call 412-682-7275 to learn more about signing up.

 

(photos from Bugwood.org by Joseph O’Brien, USDA Forest Service, Bugwood.org and Ronald F. Billings, Texas Forest Service. Screenshot of shared Google map. Click on the map to see details on Google.)

(* Trenching prevents healthy roots from growing into the infected zone.)

UPDATE 2 June 2014: Click here for the most recent update.

12 responses so far

Jan 27 2014

Schenley Park Oak Wilt Meeting, Feb 3

Back in July I mentioned that there’s oak wilt in Schenley Park.  In the weeks ahead those trees will come down.
Councilman Corey O’Connor is holding an informational meeting about the project on Monday February 3, 6:00pm – 7:30pm at the Jewish Community Center, Levinson Hall B.  (The main entrance is at 5738 Forbes Avenue in Squirrel Hill.)

See Councilman O’Connor’s flyer below for more information.

Schenley Park Oak Wilt meeting, 3 Feb 2014, 6:00pm

One response so far

Jan 16 2014

The Largest Living Organism

Published by under Plants,Trees

Armillaria ostoyae (photo from Wikimedia Commons)

On my way to somewhere else I found…

It’s hard to believe these mushrooms represent the largest living organism but they’re the outward and visible sign of a subterranean and sub-bark network.

The network can be quite large, as described here on Wikipedia:  “The largest living fungus may be a honey fungus of the species Armillaria ostoyae [now called Armillaria solidipes].  A mushroom of this type in the Malheur National Forest in the Blue Mountains of eastern Oregon was found to be the largest fungal colony in the world, spanning 8.9 km² (2,200 acres) [and] estimated to be 2,400 years old.  … If this colony is considered a single organism, then it is the largest known organism in the world by area.”

And so it was named the “Humongous Fungus.

There are many species of Armillaria, all with dark shoestring-like rhizomorphs that grow through the soil or under bark and white mycelial fans which spread under bark via root contacts and root grafts.  Here’s what they look like: rhizomorphs on the left, mycelia on the right.  (For a sense of scale, these are tree trunks)

Armillaria rhizomorphs and mycelia (photos from Bugewood.org)

Sometimes the mycelia are luminescent and cause foxfire!

Armillaria spreads widely. Click on the image below to see an animation from an article on Armillaria root rot by J. Worrall at APSnet.org.

Animated disease cycle of Armillaria infection. (Courtesy J. Worrall, copyright-free)

 

Fascinating as their huge size may be, Armillaria infects trees and can either kill them outright or be a contributing factor to their demise.  I have seen Armillaria in Schenley Park without realizing what it was: rhizomorphs, mycelia and mushrooms.

So now I understand how a live tree can just fall over…

Bur oak toppled by armillaria root rot (Joseph O'Brien, USDA Forest Service, Bugwood.org)

… when infected by Armillaria root rot.

 

(photo credits:  mushrooms by Walter J. Pilsak via Wikimedia Commons (click on the image to see the original).  Rhizomorphs and dead tree on grass by Joseph O’Brien, USDA Forest Service via Bugwood.org.  White mycelial fan by Borys M. Tkacz, USDA Forest Service via Bugwood.org)

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Jan 05 2014

Two Resins For Tomorrow

Published by under Musings & News,Trees

Frankincense from Yemen (photo from Wikimedia Commons)

Back in December when I wrote about amber, I learned about other tree resins important to humans.  Two of them are celebrated tomorrow on the traditional anniversary of the visit of the Magi who brought gold, frankincense and myrrh to the infant Jesus.

Frankincense, native to the Arabian peninsula and the Horn of Africa, is a hardened resin used in religious ceremonies around the world. It’s been traded for at least 5,000 years, burned as incense or steamed to release its essential oils.

The resin is produced by slashing the bark of trees in the Boswellia genus as often as two to three times a year.  Some say that Boswellia sacra produces the best.  Ironically frankincense trees are declining because agricultural pressure is clearing the land and the remaining trees can’t produce viable seeds if they’re slashed too often.

Frankincense tree, Boswellia sacra (photo from Wikimedia Commons)

 

Myrrh is the resin of thorny trees in the Commiphora genus, valued for its religious and medicinal uses.  Just like frankincense it’s produced by slashing the tree’s bark to make it ooze sap.

Myrrh (photo from Wikimedia Commons)

Commiphora myrrha is one of the species favored for myrrh and because it is native to Yemen, Somalia, Eritrea, and eastern Ethiopia Biblical scholars say that the wise man who gave that gift came from one of those countries.

Commiphora myrrha produces myrrh (image from Wikimedia Commons)

 

Tomorrow these two resins will be in the limelight, though frankincense and myrrh are used throughout the year.

 

(photos from Wikimedia Commons. Click on the images to see the originals)

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