Carole Macmullan, retired biology teacher and North Fulton Master Gardener, presented on tree pandemics and ongoing treatments. She provided leaf, acorn and chestnut packets for a hands-on learning experience.

 

Trees undergoing pandemics (or extinct) are: American Chestnut, Elms, Hemlocks, Dogwoods, Southern Pine. These trees are "keystone species" which are species important to an ecosystem and if extinct dire consequences occur to animals and plants that depend on these keystone species. She gave examples of bison and wolf, in addition to these trees.

 

American Chestnut Blight - a fungus spread via spores on wind from exotic plants introduced by niche gardens years ago. These trees were the predominant species in Appalachia. A total of 4 billion Chestnuts were gone in 40 years, extinct by 1940. The few remaining are being cross bred with Chinese Chestnut and the hybrid is again bred to try to produce more of the American Chestnut gene. Berry College in GA is involved in the effort, fungus is introduced into the trees, the ones showing resistance are continued to be bred. A wheat gene introduced into the chestnut genetics may also provide resistance.

 

Oaks - dominant in the Appalachian Range. There are two species, red oak (spikey leaves) and white oak (rounded leaves). They provide food for 950 moths and butterflies (caterpillars) and 95 species eat the acorns for sustenance.

 

American Elm - common streetscape tree in the U.S. until 1980's. Now Dutch Elm Blight, a fungus from a Netherlands shipment of logs in 1921, has caused their decline. A beetle carries the spores and bores into the tree bark, spreads the fungus which gets into the Xylem and tree cannot transport water from the roots. 1 in 100,00 are resistant, so cross breeding is the best chance.

 

American Hemlock - were common in old growth forests, she gave an example in Pennsylvania. Hemlock Wooly Adelgid sucks on the tree bark. Some chemical treatments can be injected into the tree bark to help thwart this pandemic.

 

Dogwood - affected by Anthracnose disease, a fungus spread by spores, seen in GA in 1987. Treatment is to plant in part sun, mulch trees, water at the soil line, prune diseased leaves, use a fungicide.

 

Southern Pines - affected by Southern Pine Beetle which chews away bark. A variety of beetles each attack a different height area of the tree. Beetles lay eggs which bore through the bark and beetles then grow in the tree. Healthy trees produce resin, called pitch tubes, to try to help protect themselves. Tree may need to be removed or fall on its own.