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November 2008 Galls and Conifers

 Galls

When leaves drop off of trees, shrubs and herbaceous plants it's a great time to look for gall formations. Gall insects use more than 50% of plant species on which to lay their eggs. There is 2000 kinds of American gall insects with 800 species using the Oaks. Most gall insects are host specific, and also fussy about which part of the plant they lay their eggs. Various galls can be found on the stem, flower, bud, bark, leaf and root and are caused by gall insects, gall mites, nematodes, gall fungi and bacteria.

The gall insect is usually named for its association to a specific plant such as : Oak Apple Gall, Goldenrod Bunch Gall, Willow Pine Cone Gall, Sumac Flower Gall, etc.

When the adult gall insect lays its egg or eggs on a plant, certain hormones she produces encourages the plant to grow plant cells around the egg. When the egg hatches, the irritation of the larva continues the plant growth. Soon a small house is fashioned and the young insect is protected from drying out and spends the winter snug and safe from predators.

Quite a few of our local galls are found on the stems of plants. The Goldenrod Bunch Gall, mentioned above, causes the leaves to bunch together at the top of the stem. This is noticeable even in the dried state of standing twigs. The insect responsible is a tiny fly (Cecidomyia solidaginis).

Also effecting the Goldenrod are the Goldenrod Ball Gall, a round swelling on the stem, caused by a different gall fly ( Eurosta solidaginis), and the Goldenrod Elliptical Gall, caused by a gall moth (Gnorimoschema gallaesolidaginis). Quite a handle for an insect less than ¼ inch long.

Other plants that develop stem galls are the dogwood, cherry, oak, willow, spicebush and alder. The plant is not adversely affected, though sometimes the twig dries up and falls to the ground. Often the gall insect will continue its life cycle.

An unusual gall formation is the Black Knot Gall that forms on cherry trees. It looks for all the world like a burnt black blob and is caused by a fungus (Plowrightia morbosa). Does this suggest morbid?

Another distinct growth is found on the twigs of the Witch Hazel tree. It's called the Spiny Witch Hazel Gall, an egg shaped gall about ¾ of an inch long with green or red spines. This is caused by an aphid (Hammamelistes spinosus).

Other plants often having galls are the rose, Black Locust, Red Cedar, Tulip Poplar, grape and birch.

Keep your eyes open for unusual shapes on familiar plants and see if you can spot some galls as you walk the Greenway.

 

11/19/08 Conifers

The Greenway has a nice variety of evergreen trees along its trails.

The stately White Pine (Pinus strobus) is found along Tartan and Walasi Trails. The White Pine can easily be identified by its straight trunk and whorled branches, each set denoting one years' growth. Its slender needles are about 5 inches long and are in bundles of 5. The cones are 5 to 10 inches long, cylindrical, and often slightly curved. Taking two years to form they often litter the ground when mature.

Due to power line restrictions the Eastern Hemlock (Tsuga canadensis) is not prevalent along the northern parts of the trail, but a small one can be found at Salali parking lot. The Hemlock needles are soft to the touch, about 2/3 of an inch long and grow in a flattish arrangement along the twig. They are shinny on top and have two white lines on the underside of each needle. Their tiny cones hang from the ends of the twigs and dangle in the breeze.

Arbor vitae or Northern White Cedar (Thuga occidentalis) is a beautiful evergreen. There is a nice row of them at the Salali Lane entrance to the Greenway. Their very different evergreen “leaves” are overlapping scales on twigs that are fan-shaped, holding tiny urn-shaped cones in upward clusters near the ends of the branches. The American Indians used to call this tree “feather leaf”.

A small specimen is in the butterfly garden where you can see its unique growth.

The Eastern Red cedar, sometimes called the Virginia cedar, is really a Juniper (J. virginiana) and is found along open sunny spots of the Greenway. Its bark is reddish-brown and shreddy. The wood is often used in closets and storage chests as it deters clothes moths. The needles are found in two forms. On young growth they are very prickly ½ inch pointed needles. On older growth they develop short sprays of overlapping needles similar to the Arborvitae. Needles grow in great quantities, making the tree look quite dense. The “cones” are actually fleshy, purplish-blue berries with a whitish bloom, much relished by birds.

The Red cedar often has orange jelly-like growths on its twigs, the result of the Cedar Apple Gall. Because of this relationship with apple trees, farmers often remove the Red cedar from their fields.

The Virginia Pine ( Pinus virginiana) has needles in clusters of two that grow from 1 ½ to 2 inches long. Its growth is kind of haphazard and deserves its alternate name of Scrub Pine. The dark limbs show up as the needle groups seems to be above the limbs. Cones are small, only about 3 inches long and without stems, so they appear to squat on the branches. They have small spines on the immature one year cones as well as the mature two year cones. The opened cones often remain on the tree for years.

Have fun looking for these evergreens along the Greenway.

 NEWS

11/12/08 Ordinance Review

Reminder to all: Jack Johnston will lead our Discovery Walk on Friday, November 14 th . Please meet at Frog Quarters, 573 E. Main St. , at 10 am rain or shine.

We continue to have incidents with dogs and dog owners. It was reported on Monday that a man with seven dogs, all unleashed, were walking the Tartan Trail.

Not only is this very inconsiderate of this dog owner, but it goes against the Little Tennessee River Greenway Regulatory Ordinance, adopted by the County, and a similar ordinance adopted by the Town of Franklin, in 2002. The following is excerpted from the regulations of the County Ordinance which allows for imprisonment and fines for persons who:

•  place objects in toilets that impair its function

•  leave refuse in an exposed or unsanitary condition

•  bring refuse from home and dump on Greenway property ( including placing in Greenway waste cans)

•  allow animals in the river, streams, or ponds of the Greenway

•  bring onto the Greenway or possess any animal...on said property unless it is crated, caged or restrained by a leash at all times

•  failure to remove their pet wastes and dispose of it properly

•  to kill, injure or disturb any bird, mammal or reptile on the Greenway

•  to fish except in designated spots and in accordance with current rules

•  to possess firearms (except for law officers) or fire a gun within 150 yards of the Greenway

•  to possess any alcoholic beverages on Greenway property

•  to solicit funds or other contributions

•  to use skateboards where prohibited (in shelters, playgrounds and adjacent paths)

•  to operate a motor vehicle, except in designated parking areas, unless necessary to provide maintenance or emergency service, or motorized wheelchairs or scooters designed for the handicapped.

•  to operate any vehicle over 11 mph (bicycles included)

•  leaving vehicles that obstruct traffic or are left overnight

Copies of the complete ordinances may be obtained at County or Town offices.

Citizens have absolutely no right to create unsafe conditions for others while using public lands. We trust the Town and the County law officers will continue their vigilance.

11/05/08 Plant Buds

If you're interested in the little details of the plants around us, here are some facts about the buds that plants produce from which the new life of the coming season emerges.

There are two major kinds of plant buds; the leaf bud and the flower bud. Because the flower structure is usually larger than the leaf, the flower buds are often the larger of the two. Nature sometimes places the flower bud on the stem just above the leaf bud, but not always. In order to protect both kinds of buds there are small scales or special leaves that wrap around the bud to keep it from freezing, drying out or unwrapping in early warm spells. A few plants have a single cap-like bud scale.

Most buds sit on the stem just above a leaf scar. Where the leaf has fallen off in the winter will be found a little shelf-like protrusion on the stem and inside the leaf scar itself you will find tiny dots. With a lens you can readily see anywhere from 1 to seven or eight dots, called leaf bundle scars. This is where the veins from the leaf were attached and how the leaf got its nourishment during the growing season. Bundle scars are very diagnostic for the various genera of trees and shrubs, and some have very interesting shapes. The Butternut leaf and bundle scars look for all the world like a camel face!

It's not very common to see trees flowering at this time of year, but the Witch Hazel (Hamamelis virginiana) will surprise us during a walk in the woods anytime between September and November with its spidery, thin yellow flower petals. These flowers will be followed by small acorn-like seed pods about one half inch in diameter. Occasionally you might be present when a pod or two forcefully expels its one quarter inch black elongated seeds. They have been known to travel up to 45 feet away from the mother tree.

Witch Hazel bark has been known for many years for its medicinal uses in salves and lotions in the treatment of minor skin irritations.

The tree is considered an understory tree, growing only to 30 feet with a diameter of maybe 10 inches. Its leaves are recognized by their roundish shape with wavy edges and an uneven base. It has 5 to 7 prominent leaf veins. If the yellow fall leaves are gone, three bundle scars and yellowish, hairy buds will help to identify the Witch Hazel. It often grows to the tops of the higher mountains in WNC, but is common along the Greenway.

Many animals rely on this tree for food. Seeds, twigs, and buds are eaten by the whitetail deer, rabbit, beaver and ruffed grouse.