Outside My Window

Standing alone like a “wolf tree” in a farmer’s field, this tree looks quite odd.

Grandidieri’s baobab (Adansonia grandidieri) grows only in the western part of Madagascar, an island off the coast of Africa.   As is typical for baobabs it has a very wide trunk compared to its crown.  Of the eight baobab species on earth, six are endemic to Madagascar.

If surrounded by a forest this tree would not stand out.  At 80 feet tall it’s about the height of a red oak and would blend in from a distance.  But its trunk is 10 feet wide, three times the diameter of a red oak.  This is one fat tree!

The IUCN says that Grandidieri’s baobab probably occurred in dry deciduous forests close to water but is now found in degraded agricultural land.  Sadly this is typical of Madagascar where deforestation is a huge problem.

That’s why this baobab is endangered … and more unusual than it ought to be.

(photo by Bernard Gagnon on Wikimedia Commons.  Click on the photo to see the original.)

As I’ve snapped photographs of bark for my winter tree identification series, I’ve had no trouble finding clean, lichen-free trees in Schenley Park.  It turns out the lack of lichens is bad news for our air quality.

Lichens are two organisms that operate as one, a symbiotic partnership of a fungus with a green or blue-green algae (sometimes all three).  The algae’s photosynthesis feeds the fungus.  The fungus gathers and retains water and nutrients and protects the algae.

This amazing combination allows lichens to thrive in some of the harshest habitats on earth but they’re sensitive to air pollution.  The ones that grow on trees are epiphytes, totally dependent on the surrounding air and precipitation for their nutrition.  Ultimately their tissues absorb elements in concentrations that mimic what’s in the air.

We’ve known for a long time that there’s a correlation between the absence of lichens and poor air quality.  Back in 1866, the Finnish botanist William Nylander showed that lichens were present in the Luxembourg Gardens that had disappeared from the polluted sections of Paris, France.  Sadly, air pollution increased in Paris and within 30 years the Luxembourg Gardens’ lichens had disappeared as well.

Lichens are used in air quality studies today because they are widespread, accurate indicators and far less expensive than man-made monitors.  You don’t have to be an expert to participate.  In the 1960′s schoolchildren in Great Britain gathered data in a nationwide lichen-based air quality study that produced the “Mucky Air” map.  Here’s a list of a few more recent lichen studies:

• A lichen air quality study conducted in Pittsburgh by Matthew Opdyke
• Air pollution-related lichen monitoring by the National Park Service
• The OPAL Air Survey currently underway in the U.K.
• USDA Forest Service air quality lichen survey in Oregon and Washington
• Utah lichen study showing that lichen tissues mimic air quality concentrations

Even if you can’t identify lichens you can make a rough guess of the local air quality by the types of lichens you see.  Basically, “the further it stands out from the tree, the cleaner the air.”  Crusty lichens (crustose) are the hardiest because they have the least surface area, leafy (foliose) lichens are in the middle, shrubby (fruticose) lichens are the most sensitive.  Hypogymnia physodes, a foliose lichen pictured above, is often used as an indicator species because it’s widely distributed and it “stands up.”  I’ve seen lichens like this in Maine but not in Pittsburgh.

Lichens are especially sensitive to sulfur dioxide (SO2).  So are people.  In Pennsylvania most of our SO2 is produced by coal-burning power plants and coking facilities.   High SO2 causes respiratory distress and triggers asthma so it’s been regulated since the Clean Air Act of 1970.  Lichens have rebounded in many areas of the U.S. since then.

In June 2010 EPA issued tighter 1-hour SO2 standards (75 ppb, measured hourly) to protect public health from high short term exposures ranging from 5 minutes to 24 hours.  Because we’ve been measuring SO2 for so long, we already know that the Pennsylvania counties of Allegheny, Beaver, Indiana and Warren have exceeded the new SO2 standard.  Coal-burning facilities in these counties will have to control their SO2 emissions even further.  As they do, we’ll all breathe a little easier.

And we’ll have more lichens in the future.

(photo in the public domain from Wikimedia Commons. Click on the photo to see the original.)

I discussed epiphytes a couple of days ago because I wanted to use this beautiful photo as a quiz. 

Though this looks like an artistic squiggle it’s actually a close-up of a plant. 

Here are some hints to its identity:

• It’s an epiphyte.
• It’s native to the southeastern U.S. where the climate is warm with high humidity.
• It has tiny inconspicuous flowers.  (As many times as I’ve seen this plant I’ve never noticed any flowers.)
• Its leaves are alternate, thin, heavily scaled and curved.  These are its leaves. 
• The leaves appear to form long chains.
• Big hint: It’s commonly found hanging from southern live oaks and bald cypress trees.

Can you guess what it is?

Leave a comment with your answer.

(photo by Ernest V. More in the public domain on Wikimedia Commons)

“Upon plant”

That’s what epiphyte means in Greek (epi=upon, phyte=plant) and that’s what an epiphyte is:  a plant upon a plant.

I never thought about this word until I saw some interesting epiphytes in the forest while visiting my family in southeastern Virginia.

True epiphytes are sometimes called air plants because they collect their water and nutrients from rainfall, mist, dust and the surrounding air.  Though they’re held aloft by a host plant they aren’t parasites and never directly harm their host.

As proof, here’s a photo of epiphytes growing on telephone wires in Bolivia.

I’ve seen this in Florida too.  I’m sure it annoys the phone company.

We normally think of epiphytes as tropical plants like the red orchid pictured above, but all kinds of plants-upon-plants grow wherever there’s enough humidity or rainfall and clean air.

Mosses, lichens and ferns are the epiphytes I usually see in Pennsylvania.  They seem almost boring because I’m so used to them.

Do you have interesting epiphytes where you live?

(photos via Wikimedia Commons.  Click on each photo to see the originals)

Jonathan Nadle is fascinated by porcelain berry.  He wondered if his cat would be too.

I think it’s safe to say the cat did not catch Jonathan’s enthusiasm. 

Click on the photo of Larry Cat to see the very mild reaction of one imported species (Felis catus) examining another (Ampelopsis brevipedunculata).

(photos by Jonathan Nadle)

As the sunlight shines through this leaf, each vein is illuminated.

Alocasia sanderiana is beautiful up close and from afar.

Its leaves are arrow-shaped, dark green, and very shiny with prominent pale green veins.  The leaf edges are so amazingly wavy that in English it’s called the kris plant, named for the kalis (or kris) daggers of its homeland.

Here’s what the whole leaf looks like:

Alocasia sanderiana is native to the Philippines but is critically endangered in the wild.  It grows in only two locations, both legally protected, but the protection is not enforced.  It’s existence is threatened by logging and by being collected as a house plant.

Ironically, if the kris plant disappears from the wild, its beauty will save it from extinction because it’s been propagated “in captivity” for many, many years.

(close-up of an Alocasia leaf by Joan Guerin; whole-leaf photo from Wikimedia Commons)

Happy Halloween!   Here’s a selection of witchy things to celebrate the day.

Witches hat mushroom (Hygrophorus conicus) (photo by Dave Powell, USDA Forest Service, from Bugwood.org), common in the forest at this time of year.

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Witch-hazel trees are blooming now in Schenley Park (photo by Dianne Machesney).

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Witches Butter fungus (Tremella mesenterica) (photo by Gerald Holmes, Valent USA Corporation, Bugwood.org).  Its gelatinous fruiting body feels greasy or slimy when damp.  Eeeewwwww!

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Witches brooms in a hackberry tree (photo by Whitney Cranshaw, Colorado State University, Bugwood.org).  Witches brooms are ugly but don’t kill the tree.  They’re so common in hackberries that I use them as a clue to identify the tree in winter.

(see photo credits above)

While perusing the Sibley Guide to Trees (which I quote below) I ran across an amazing name for ginkgos:  Stinkbomb Tree.

The name is new to me but I know how they got it.  In autumn the ginkgo’s fleshy, ripe fruit falls from the female trees and is easily crushed underfoot.  If you step on it you’re sorry.  It’s slippery and smells like vomit.

Ginkgo trees (Ginkgo biloba) are living fossils from the Triassic, the only plant in their division to survive into the modern age.  Though classified as trees, ginkgos have a lot in common with ferns.  Their fan-shaped leaves have a fern-like vein system.  Each tree is either male or female and the seeds are “fertilized by motile sperm as in cycads, ferns, mosses and algae.”

There are probably no wild ginkgos left on earth but they survived and re-naturalized in Asia because humans cultivated them for their religious and medicinal significance, especially in China.

Ginkgos cope well with pollution and confined root systems so they’re often planted in cities.   How hardy are they?  Six ginkgo trees were the only living things to survive within a 1-2 km radius of the 1945 Hiroshima atomic blast.

Of course that wasn’t known when they were chosen to beautify Pittsburgh during our Smoky City days.  Both male and female trees were planted in our city parks in the late 1800s.  Nowadays female ginkgos are often banned because of their “stinkbombs” but we have some on Schenley Drive near Phipps Conservatory and on Highland Drive near Highland Park.

Very soon our ginkgos will turn a beautiful bright yellow and their leaves will fall all at once.  If you time it right, you can stand below a yellow ginkgo on a windless day and the leaves will drop around you like snow.   But watch where you step…

(photo by Aomorikuma via Wikimedia Commons, GNU Free license. Click on the photo to see the original.)

The weather was beautiful last Saturday when I took these pictures in Schenley Park.  Even my little cell phone camera was able to capture the colors.  Here are buckeye leaves turning yellow at eye level.

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Blue sky peeks through the trees.

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Golden leaves and green.  The green leaves are porcelainberry.

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The trails were flooded with light.

(photos by Kate St. John)

With berries this beautiful no wonder the plant was imported.

Porcelainberry (Ampelopsis brevipedunculata) is native to China, Korea, Japan and far eastern Russia.  Brought to the U.S. as an ornamental in the 1870′s it grows so well that it’s now invasive in Pennsylvania.

Porcelainberry resembles grapevine except that its stem pith is white, its bark doesn’t peel, and its berries are stunningly beautiful in turquoise, blue and pink.  Birds eat the berries and give the seeds a free ride.

Do nothing and you’ll soon have porcelainberry in your garden.

Want to see it up close?  Visit Schenley Park.

The berries are worth it.

(photo by Jonathan Nadle)