Category Archives: Trees

Listening to the Secret Sounds Of Trees

Trees, Winter Weeds & Trees
Woman listening with headphones (photo from Wikimedia Commons)
Woman listening (photo from Wikimedia Commons)

18 March 2015

When the trees leaf out six weeks from now we’ll once again hear the sound of rustling leaves.  Did you know that trees also make secret sounds we cannot hear?

Last year an article by Sarah Zhang in Gizmodo caught my attention.  Eavesdropping On The Secret Sounds Of Trees describes the art and science of a Swiss research team, headed by Marcus Maeder, who recorded the internal sounds of trees.

The project, fittingly called trees, attached sensitive microphones to trunks, branches and even leaves, then recorded the sounds and analyzed them in light of simultaneous environmental factors such as drought.  Click here to hear the clicks, pops, hisses and taps made by a Scots pine (Pinus sylvestris).

Closer to home our trees are getting ready for spring, the sap is running, and it’s maple sugaring time in North America.

Maple sugar bucket hanging on a tree (photo from Wikimedia Commons)
Maple sugar bucket hanging on a tree (photo from Wikimedia Commons)

And so I wonder …

If we had those special microphones could we heard the sap rising in the maples? 

Yes!

In 2010 Alex Metcalfe installed headphones on a copper beech at Oakville Galleries in Oakville, Ontario. Anyone could listen to the tree using his installation — and so can you with this video. Wow!

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

Take A Look Outdoors

Beyond Bounds, Trees

Cone of a Japanese larch (photo from Wikimedia Commons)

Feeling cooped up by winter weather?  Tired of staring at four walls?

Put on your hat and coat and take a walk outside.  Even though it’s cold, nature has beauty on display.

Take a look outdoors. … Then you can reward yourself with hot chocolate.

 

(photo of a Japanese larch cone at John J. Tyler Arboretum in Media, Pennsylvania. Click on the image to see this Featured Picture on Wikimedia Commons.)

The Link Between Hemlocks And Birds

Trees

Eastern hemlocks shading Tom's Run, Cook Forest State Park (photo by Nicholas Tonelli via Wikimedia Commons)

As I mentioned two weeks ago, a Pennsylvania hemlock project needs volunteers to report hemlock woolly adelgid in the Allegheny High Plateau so that the trees can be protected against this deadly pest.

Many of us want to help because we love the hemlock’s beauty, but for some birds the trees are more than beautiful, they’re essential.

At the project kickoff seminar Dale Luthringer told us about hemlocks and their link to birds.

Eastern hemlocks are the most shade tolerant tree in the U.S. and can thrive in pure stands or in damp areas of deciduous forests.  Wherever hemlocks grow their dense evergreen canopy creates a cool, shady habitat that’s used by 90 species of birds.

Studies have shown that six species depend so much on hemlocks that they decline when the woolly adelgid kills the trees.  Here are the six who go missing:

Black-throated green warbler (photo by Steve Gosser)
(1) Black-throated green warblers are obligate to hemlock stands. They experience a 93% decline when the trees die off. (photo by Steve Gosser)

Blackburnian warbler (photo by Chuck Tague)
(2) Blackburnian warblers like all hemlocks but prefer old growth stands. They’re found 40 times more often among old growth hemlocks than younger trees. (photo by Chuck Tague)

Ovenbird with nesting material, May 2014 (photo by Marcy Cunkelman)
(3) Ovenbird populations go down when hemlocks die (photo by Marcy Cunkelman)

and… (4) hermit thrushes, (5) blue headed vireos and (6) Acadian flycatchers decline where the woolly adelgid takes its toll.

 

With hemlocks covering 19 million acres in the eastern U.S., we’ll lose a lot of habitat — and birds — if we do nothing to combat the hemlock woolly adelgid.

Read more here on how you can help the Allegheny High Plateau adelgid project. (See where on this map — from Cooks Forest northward to NY).

 

(photos:
Eastern hemlocks shading Tom’s Run in Cook Forest by Nicholas Tonelli, via Wikimedia Commons, Creative Commons license. Click on the image to see the original.
Black-throated green warbler by Steve Gosser
Blackburnian warbler by Chuck Tague
Ovenbird by Marcy Cunkelman)

p.s. Magnolia warblers are also affected. They’re 45 times more likely to be found in old growth hemlock forests than in stands of younger trees.

Start Looking Now

Insects, Trees

Hemlock woolly adelgid at Jacobsburg (photo by Nicholas A, Tonelli via Wikimedia Commons)

Yesterday I mentioned hemlock woolly adelgid, a really bad invasive insect that’s killing our eastern hemlock forests.  It devastated the southern Appalachians (click here to see, here to read) and has moved north into south, central and eastern Pennsylvania.  Has it conquered the Allegheny High Plateau?  Now’s the best time to find out.

Hemlock woolly adelgids (Adelges tsugae) have no North American predators and a very unusual lifestyle.  Originally from Japan, they kill eastern hemlocks in 4-20 years by locking onto the underside of their branches and sucking the lifeblood out of them.

The adults are female, immobile and practically microscopic.  Twice a year they reproduce asexually, laying up to 300 eggs a year in woolly white egg sacs that protect their young.  The larvae, present in April and July, are the only mobile phase and so tiny that they spread easily on the wind or hitchhike unseen on birds, animals and humans.
Hemlock wooly adelgid adults (photo by Ashley Lamb, Virginia Polytechnic Institute and State University, Bugwood.org)

Harsh winters used to protect Pennsylvania’s hemlocks but the climate is warming.  Our worst fears were realized when they were found in Cook Forest in March 2013.  Last winter’s Polar Vortex reduced that infection 90-100% but the bugs are poised to take off again. Unfortunately the only biological control, a tiny beetle, is even less winter-hardy than the pest so the only way to save our hemlocks right now is by treating individual trees with pesticide. (*)

What trees should be treated?  The Nature Conservancy, the U.S. Forest Service and DCNR have teamed up to survey the area from Cook Forest to New York’s Allegany State Park (click on this map to see a larger version).

Priority hemlock conservation areas on the Allegheny High Plateau (map from The Nature Conservancy and US Forest Service)

It’s a big area and they need your help.  Don’t worry, it’s easy.

In the winter hemlock woolly adelgid egg sacs are large and visible (see top photo).  If you’re in this region — even for a quick hike or birding trip — take a moment to notice the underside of hemlock branches.  Birders, you may accidentally find this while looking at a bird.

Report infections by calling or emailing the location to one of the folks on this list of contacts.  (Contact any of them and they’ll forward the information if necessary).

Do you need more information before you begin?  Contact Sarah Johnson at The Nature Conservancy, sejohnson@tnc.org, 717-232-6001 Ext 231.

Start looking now.

 

(photo credits:
top photo, wool sacs: Nicholas Tonelli via Wikimedia Commons
middle photo, adults: Ashley Lamb, Virginia Polytechnic Institute and State University, Bugwood.org
map: courtesy The Nature Conservancy and U.S. Forest Service. Click on the map to see a larger version.)

 

(*) Note: Work is underway to breed winter-hardy biological controls.  It just takes time.

What Made This Tree Fall Over?

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

4 June 2014

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 .  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 fungus inside the trunk that coats the light wood layers.
  • Did the white stuff weaken the trunk?  Is it responsible for the break?

The trunk isn’t hollow but there are white sheets in the layers of the wood.

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)

What do you think? Is this the reason the tree fell over?

Leave a comment with your answer.

Thanks!

(photos by Kate St. John)

UPDATE with the answer!   The white fungus is a species of Armillaria or honey fungus.  (See Maureen Hobma’s comment below.)   I wrote about Armillaria on 16 January 2014 because it’s the largest living organism. Up until now, I had only seen Armillaria‘s black rope-y strands and honey mushrooms.  The white fungal sheets are newer growth, the mycelium.  It can be bio-luminescent!   I learn something new every day.

Leaf Out!

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.

April Showers Bring…

Phenology, Plants & Fungi, Trees
Great chickweed (photo by Kate St. John)

30 April 2014

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)

The Trees Take On Color

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

28 April 2014

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)

Schenley Oak Wilt Status

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.

Flowering Trees

Phenology, Trees
Red maple flowers, 10 April 2014 (photo by Kate St. John)
Flowers on red maple, 12 April 2014 (photo by Kate St. John)

13 April 2014

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)