December 18, 2021

This Week's Tour...

...met at 9:00AM Saturday on the Beltline Eastside Trail near Parish (R.I.P...soon to reopen as "Painted Park"!). We walked for 1 1/2 hours, covering 1 mile of the Beltline, ending at Ponce City Market.

"The Tourists"...
...shouting out to this week's tourists, another good sized group braved the rainy forecast, including Trees Atlanta volunteers and docents!

Thanks for a great tour!

Map of the week...
...is the "Georgia Fall Line". The change in elevation that it indicates is significant in several ways;  ships can navigate upstream to it and as the river flows downstream, the drop in height gives the water potential energy used to power industrial plants, making it the ideal location for 2 former Georgia State Capitals, Augusta and Milledgeville (sorry Louisville...you are located a little south of this).

From the New Georgia Encyclopedia:  "The fall line is a geological boundary, about twenty miles wide, running northeast across Georgia from Columbus to Augusta. It is a gently sloping region that rapidly loses elevation from the north to the south, thereby creating a series of waterfalls. During the Mesozoic Era (251-65.5 million years ago), the fall line was the shoreline of the Atlantic Ocean; today it separates Upper Coastal Plain sedimentary rocks to the south from Piedmont crystalline rocks to the north. The fall line’s geology is also notable for its impact on early transportation in Georgia and consequently on the state’s commercial and urban development"

Thanks for the pic, 

GPB!!

Tree of the week...
...singling out one of the hundreds of specimens from the dozens of collections along the arboretum.

This week is a repeat shout out to my dad's favorite tree, the mighty beech, which this month began it's transition from summer green to wintery copper. Because of a process called "marcescence", or the retention of dead plant material, these amazing native trees retain their dead leaves throughout the winter, sheltering birds as well as their own tender spring shoots. 

In the spring, beeches will experience "abscission", or the shedding of dead plant material, that most trees went thru the previous autumn, allowing the dead leaves to finally fall, decay around the base of the tree, and form humus, the organic matter in soil so vital to the tree for nutrition and water retention.

Fagus grandifolia  

American Beech

"Stump" of the week...
...featuring a question raised during the tour that Jeff couldn't answer.

Q: How can I tell different oak species apart?

A: The short answer is the same as getting to Carnegie Hall..."practice"! In all seriousness, other than telling the 2 oak families apart - white oaks have rounded lobes while red oaks have pointier lobes - it can be tough. On top of that, our knowledgeable docent-in-training pointed out that leaves can different on different parts of the trees. 

Here is a great posing in Forestry Forum comparing "Northern Red Oak" with "Scarlett Oak", both differences between the species as well as differences between their lower/shade leaves and upper/sun leaves! 

Scarlet oak acorns are usually about 1" long, 

with a bowl-shaped cap that encloses 

about half of the acorn