Ramble Report November 3 2016

Magnificent Ginkgo leaves

Today's Ramble was lead by Dale Hoyt.

Here's the link to Don's Facebook album for today's Ramble. (All the photos in this post are compliments of Don.)

Today's post was written by Dale Hoyt.

Attendees:31

Announcements:

Rosemary made a wonderful donation to the Friends of the State Botanical Garden in honor of the leaders and members of the Nature Ramblers.

Linda read for Sue about the workshop sponsored by the Memorial Park Weed Warriors, next Thursday night, 6:00 p.m. to 8:00 p.m. at the public library. . The topic will be about invasive plants and their management. . Russel Funderburk,  horticulturist at the Highlands Biological Station Botanical Garden will be the speaker. . He will bring examples of the most invasive plants in the area and give practical advice on how to control them. . Pre-registration is recommended but not required. For more details visit the Announcements page (use the link below).

Visit this page to see the current Announcements.

Today's reading: Dale read the entry for October 26 from An Almanac for Moderns, by Donald Culross Peattie.

It is nearly impossible to be sad, even listless, on a blue and gold October day, when the leaves rain down, rain down, not on a harsh wind, but quietly on the tingling air. They fall and fall, though not a breeze lifts the drooping battle flags of their foliage. You stand a moment before a late, last ash, watching. It seems as though the tree were actively engaged in shedding its attire, snipping it off, cutting it adrift. Pick up a leaf fallen at your feet, and examine the base of the leaf stalk. It feels hard to the touch; it is hollowed out. Had you a microscope, and a cut section of the leaf, you would see that indeed it had been cut off. The growth of a ring of callous cells, in a perfect ball and socket articulation, has predestined the fall. Wind need not tear the foliage down, nor decay set in. The tree itself passes invisible shears through its own auburn crown.

Linda read a Wendell Berry poem from New Collected Poems, Counterpoint, 2012.

October 10

Now constantly there is the sound,

quieter than rain,

of the leaves falling.

Under their loosening bright

gold, the sycamore limbs

bleach whiter.

Now the only flowers

are beeweed and aster, spray

of their white and lavender

over the brown leaves.

The calling of a crow sounds

Loud – landmark – now

that the life of summer falls

silent, and the nights grow.

Today's route: Starting with the Sugar Maple at the edge of the lower parking lot we made our way up the stairs to the upper parking lot. Then down the Orange trail to the bridge across the creek and back to the Visitors Center where Andrea Fischer met us with already made coffee. Among the Ramblers contributing snacks were Avis with her apricot bars and Steve and Rona Cook with some heirloom apples. Yummy!

Today we focused on identifying trees. There are several things to be aware of about trees and tree identification books. The first is variation. Like people, trees change with age. A sapling will not always have the same bark that a mature tree has. The leaves will often vary in shape in saplings vs. adult trees. Some of this variation is due to the saplings growing in the shade of taller trees. Leaves growing in the shade tend to be thinner, wider and less lobed than leaves growing in full sunlight. In addition, leaves are just plain variable. Books illustrate a "typical" leaf and that often doesn't match very closely the random leaf you pull off a tree. The more trees and leaves you examine the more proficient you'll become in recognizing them.

Sugar maple leaves

A Sugar maple stands at the corner of the lower parking lot, near the sidewalk going to the Administration building. The leaves have five lobes, three very prominent and two smaller, basal lobes. The margin (edge) of the lobes is smooth (without teeth). Linda suggested a mnemonic for this feature: "The Sugar maple has no teeth – they've rotten away from all the sugar."

Sugar maple with sapsucker wells

The lower trunk of this tree is dark with sap flowing out of the wounds inflicted by a woodpecker, the Yellow bellied sapsucker. The sapsuckers are back for the winter from their breeding range further north. They excavate rows of small holes in the bark of several kinds of trees and drink the sap that exudes from the openings. The sap also attracts insects and the sapsucker feeds on them as well.

Black gum leaves

Perpendicular branches of Black gum

Near the Sugar maple is a small Black gum tree (also known as a Tupelo). The leaves seem to lack distinctive features, but a few will have two small projections on either side of the pointed tip. If you find such a leaf, it is diagnostic, i.e., no other tree in our area has one like it. The problem is that they seem to be in the minority among the leaves on most Black gum trees. There is another feature that will help you identify this tree, though. Many of the branches are perpendicular to the trunk. In most trees the branches are angled upward.

Two weeks ago we spent a lot of time looking at trees in the upper parking area, so today we just briefly reviewed them before we entered the Orange trail.

Sweet gum leaves; possibly confused with maple leaves but leaves are alternate on the stem, not opposite, as in maple; lower-most lobes are larger

Tulip tee leaves; unique shape; no other leaves are like them.

Sourwood leaves; much longer than broad.

Sourwood seed capsules

Twisted growth form typical of a Sourwood tree

Winged elm; corky ridges are called "wings"

Winged elm bark; the plates of bark lie next to one another, like the pieces of a jigsaw puzzle.

Winged elm leaves

Red maple leaf (L) with teeth on lobes; 3 lobes
Sugar maple leaf (R) lacks teeth on lobes; 5 lobes

Beech leaf with wavy edges

Hophornbeam leaf with double toothed edges (teeth have teeth)

 Hophornbeams are one of those trees where the bark changes a lot as the tree ages. The young saplings have a smooth bark that resembles that of the young cherry trees -- dark, smooth, with lighter horizontal markings. As the tree ages the bark becomes rougher and eventually breaks apart into very narrow vertical strips. It has the appearance of being used as a cat's scratching post.

Beech leaves have a smooth, papery texture with wavy edges (remember: you see waves at the beach). Their smooth, gray bark and long, sharp-pointed buds are other unique characteristics.

Beeches have the habit of root sprouting, so when you find a number of beeches growing in the same area you may be seeing a group of genetically identical plants.

Someone asked if Beeches were allelopathic, a word that refers to the ability of some plants to produce a substance that inhibits the growth of other plants, either of the same or different species. Allelopathy is hard to prove. If you don't find one species growing near another there could be many different reasons: shade avoidance, inability to compete for water or soil nutrients, or even random chance. To demonstrate allelopathy you need to be able to show that there is an inhibitory substance produced and that is difficult to do. Black walnuts are the classic example of allelopathy. They produce a substance in their leaves that is washed down by rain and inhibits a wide range of plants from growing in the soil beneath them.

Script lichen; no one has been able to translate the message.

We noticed a Script lichen on one of the beeches and encouraged everyone to look at with a hand lens or magnifying glass. It was fun listening to all the "Oh, wow!" as Ramblers discovered the surprising beauty of this nondescript gray patch. 

Lichens are dual organisms. They are a symbiotic association between a fungus and a photosynthetic organism, called the photobiont, which can be either an algal cell or a photosynthetic bacterium. They are probably the first multicellular organisms to colonize dry land. Lichens can reproduce asexually by fragmenting or by producing spores that contain pieces of fungus and photobiont. But the sexual reproductive process leaves the photobiont behind and the sexual spores need to find a new photobiont after they germinate. 

A very recent study found that there is a third partner in some lichens, a yeast. It is still not known if this is common to all, most or just a few lichens.

The dark structures of the Script lichen resemble so sort of hieroglyphic or cuneiform writing, but they are really reproductive in nature. Each black line produces the sexual spores of the fungal partner in the lichen symbiosis.

Black cherry bark; piece in upper left shows surface of younger bark

As the Black cherry tree ages its bark changes from smooth, reddish brown to a fragmented, dark and rough texture. Emily likens it to "smashed, burnt potato chips." In some of the bark fragments you can see vestiges of the earlier condition.

Hook moss on Hophornbeam trunk

One thing we often notice on Hophornbeans is lots of Hook moss growing on the barks. This moss seems to be most abundant on both Hophornbeam and Musclewood, a related species.

Shortleaf pine bark with pitch pockets

Two weeks earlier we looked at the pitch pockets on the bark of Shortleaf pine. Today there were dark smudges around these small pits that looked as if they might have produced some pitch. But the dark color wasn't sticky, as you would expect if it were pine pitch. Another unsolved mystery!

Serviceberry bark

Serviceberry leaves

We were stumped for a while by a smooth-barked tree with oval leaves that had tiny, tiny teeth on the margin. But Linda saved the day -- it was a Serviceberry, an early blooming tree in the Rose family (as are apple and cherry).

Large gully formed by headward erosion

The upper end of the Orange trail creek is found in a large gully. This gully is not formed by surface runoff; it is an example of headward erosion. Subsurface water emerges at the bottom of the gully, eroding the soil above it. When sufficient soil has been removed the dirt above slumps into the bottom of the gully. Over time this cycle of erosion from the bottom and slumping causes the head of the gully to migrate uphill. In the 30+ years I've lived in Georgia I've seen this gully migrate perhaps 20 feet uphill.

Holes excavated by a woodpecker (Pileated?) to get carpenter bee larvae.

There is an old bench next to the gully and the wood is cratered with woodpecker excavations. The birds were not trying to build nests in the bench, instead they were looking for food -- the larvae of carpenter bees. Carpenter bees chew long tunnels in wood which they then, starting at the end of the tunnel, they provision it with a pollen ball.  A single egg is laid on the ball and that part of the tunnel closed off. This process is repeated until the tunnel is full. How the woodpeckers found out that tasty bee larvae were in a tunnel in the wood is a mystery. Perhaps they could hear them moving inside the wood. But find them they did, pecking the tunnels open from the side and feasting on what they found.

You can see a Pileated woodpecker seeking out carpenter bee larvae in a large board in this short video. (Apologies for the sound track -- I had the radio on while I was filming and couldn't stop to turn it off.)

Someone asked about the difference between White oaks and Red oaks. First, these terms are a little confusing because they refer to either two species of oak or two groups of oak species. First, the characteristics of the two groups:

Trees in the white oak group have leaves with rounded lobes and the lobes do not end in small points or prickles. Red oak group leaves have pointed lobes that end with prickles. There are other important ecological differences between these two groups of trees. Acorns of white oaks mature in a single year and are "sweet," i.e., they have a low tannin content. They also germinate in the fall, if conditions are suitable. Red oak acorns take two years to mature and have a high tannin content -- they are bitter. Red oak acorns overwinter before germinating.

Squirrels treat the two types of acorn differently. They eat the white oak acorns immediately and don't bury them. (If they did bury them they would germinate and the growing tree embryo would start using the food in the acorn to produce a root. This would decrease the amount of food available to the squirrel. But, when there is an abundance of white oak acorns the squirrels will often bite off the tip of the acorn where the embryo is and then bury the nut.Red oak acorns are buried.

The difference in germination time gives white oaks a head start. When spring comes they can have an established root system which gives them a head start on producing their shoots. And if that shoot is attacked by a herbivore, the presence of a good root system makes recovery easier.

Another hornbeam species grows in the garden, the American hornbeam or musclewood. The latter name refers to the appearence of the trunk. It has smooth, gray bark that covers what looks like rippling, sinewy muscles. Musclewood is related to Hophornbeam and has the same extremely dense wood and leaf shape. The bark and trunk are the easiest features to use to separate the two species.

Beech drops; a root parasite of Beech

On the way back to the Visitor center we found a large group of Beech drops, a type of parasitic plant, surrounding a large beech tree. Beech drops have no chlorophyll, having given up photosynthesis. Instead they rely on the photosynthetic capabilities of a beech tree. Their roots connect to those of the beech and they conduct their life a permanent vegetable vampires, an appropriate costume for next years halloween party.

SUMMARY OF OBSERVED SPECIES:

Common Name	Scientific Name
Sugar maple	Acer saccharum
Black gum/Black tupelo	Nyssa sylvatica
Tulip tree	Liriodendron tulipifera
Sweetgum	Liquidambar styraciflua
Sourwood	Oxydendrum arboreum
Callery pear	Pyrus calleryana
Winged elm	Ulmus alata
Red maple	Acer rubrum
Hophornbeam	Ostrya virginiana
American beech	Fagus grandifolia
Black cherry	Prunus serotina
Hook moss	Leucodon sp.
Shortleaf pine	Pinus echinata
Serviceberry	Amelanchier arborea
Grape vine	Muscadinia rotundifolia
Eastern carpenter bee	Xylocopa virginica
Pileated woodpecke)	Hylatomus pileatus
White oak	Quercus alba
Northern Red oak	Quercus rubra
Southern Red oak	Quercus falcata
Musclewood	Carpinus caroliniana
Beechdrops	Epifagus virginiana