Feeding Trees: Biochar and Sugar Drenching

by Stacey Haag

RCMGA would like to thank National Pollutant Discharge Elimination System (NPDES) Stormwater Arborist Chaz Griffith for spending a beautiful Sunday afternoon with us at Ridgetop Arboretum. Chaz spoke about his role at Metro Water Services and their ambitious goal of restoring much of Davidson County's canopy by planting 500,000 trees by the mid-century. He discussed a variety of topics, including preferred species, site selection, soil quality, and proactive care and maintenance.

We also learned about two new topics that garnered much attention from members: biochar and sugar drenching. Biochar is a lightweight, carbon-rich residue made from organic waste material or biomass that is partially combusted in the presence of limited oxygen. It is an amendment that improves the physical and chemical properties of soil, acting like a sponge and serving as a habitat for beneficial soil microorganisms. Sugar drenching is the application of diluted sugar as a soil drench to supplement feeding and improve root vigor of struggling trees.

Chaz was kind enough to answer many questions from members on a variety of topics. Following his presentation and a short meeting, we took a walking tour of Ridgetop Arboretum. We identified unique properties of several species, discussed the new tree tags that will soon be ordered, and possibilities for future plantings.

If you haven't visited the arboretum lately, make sure to do so. It's a peaceful spot for a walk in nature. You can view a Google map of the arboretum here.

Farmer Randy

by Jeanie Moll

While summer’s harvest for 2023 is in the rearview mirror, the hard work and product of that labor is not forgotten by many people in need of food across Davidson and Robertson Counties. The first seed of a small portion of this bounty was planted in April when Lori Birkhead, owner and operator of By Faith Farm, was invited to speak at RCMGA and tell her story and that of the farm. Randy McMoran was touched by this talk and by the opportunity to give so much to others through this basic task of planting a seed and giving it his time. And that he did!! And a big part of that was in our “RCMGA Backyard” at Highland Rim!

Most of the Master Gardener members at some point probably saw the rows and rows of plants growing in the “vegetable garden” and wondered what was happening out there. Several of you even put time, sweat and maybe a few curse words into the weeding of it! In preparation for the Tobacco, Beef and More seminar and the spring garden tours, Randy planted corn, as was requested, but then just kept on going. As time moved on and no formal plans went into play for use of the space near the corn, he planted leftover veggies from the Plant Sale, donated plants from By Faith, his garden, and other members' gardens. He also planted from seed. The opportunity to keep growing and giving just kept GROWING. In the end, this plot of land generated just under 1000 pounds of food for our surrounding communities!

In late summer, the total number of pounds of produce from Highland Rim was at 857, and more was still brought later in the season. All of this produce was harvested and taken to By Faith Farm where it was weighed and separated by type. It was all picked up within 2 days of harvest and distributed to those in need by organizations such as United Ministries in Springfield, The Nashville Food Project, who cooked the produce to serve meals to the hungry, and Second Harvest Food Bank, just to name a few. By Faith donated over 19,000 pounds of food all together, and it has gone out to four different counties surrounding Nashville.

Lori Birkhead contributed gratefully, “Randy worked countless hours at By Faith Farm. He encouraged us and enabled us to expand our growing space by several more 100-foot rows. We added crops like rattlesnake pole beans and okra to our donation gardens. Also, we could not have had the crop we did if it had not been for the work of Master Gardener Kevin Moll, with the help of Jeff Bayer, who installed drip irrigation to all of those crops, including an app to control all of the irrigation process remotely.”

Highland Rim Garden has some big plans in play for 2024, and we can all look forward to the launch of that exciting next chapter, moving beyond the front Circle Garden! I wanted to be sure to share these blessings that came from an otherwise dormant year of the gardens as our group worked on a future plans for the space. An amazing gift from the soil of Highland Rim that can make us all proud.

Science of Fall Colors

by USDA Forest Service

For years, scientists have worked to understand the changes that occur in trees and shrubs during autumn. Although we don't know all the details, we do know enough to explain the basics to help you enjoy nature's multicolored display. Three factors influence autumn leaf color: leaf pigments, length of night, and weather.

The timing of color changes and the onset of falling leaves is primarily regulated by the calendar as nights become longer. None of the other environmental influences – such as temperature, rainfall, food supply – are as unvarying as the steadily increasing length of night during autumn. As days grow shorter, and nights grow longer and cooler, biochemical processes in the leaf begin to paint the landscape with Nature's autumn palette.

Leaf Pigments

A color palette needs pigments, and there are three types that are involved in autumn color:

Carotenoids: Produces yellow, orange, and brown colors in such things as corn, carrots, and daffodils, as well as rutabagas, buttercups, and bananas.

Anthocyanin: Gives color to such familiar things as cranberries, red apples, concord grapes, blueberries, cherries, strawberries, and plums. They are water soluble and appear in the watery liquid of leaf cells.

Chlorophyll: Gives leaves a basic green color. It is necessary for photosynthesis, the chemical reaction that enables plants to use sunlight to manufacture sugars for food.

Trees in the temperate zones store these sugars for the winter dormant period.

Both chlorophyll and carotenoids are present in the chloroplasts of leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells.

During the growing season, chlorophyll is continually being produced and broken down and leaves appear green. As night length increases in the autumn, chlorophyll production slows down and then stops and eventually all the chlorophyll is destroyed. The carotenoids and anthocyanin that are present in the leaf are then unmasked and show their colors.

Certain colors are characteristic of particular species:

Oaks: red, brown, or russet

Hickories: golden bronze

Aspen and yellow-poplar: golden yellow

Dogwood: purplish red

Beech: light tan

Sourwood and black tupelo: crimson

The color of maples leaves differ species by species:

Red maple: brilliant scarlet

Sugar maple: orange-red

Black maple: glowing yellow

Striped maple: almost colorless

Some leaves of some species, such as the elms simply shrivel up and fall, exhibiting little color other than drab brown.

The timing of the color change also varies by species. For example, sourwood in southern forests can become vividly colorful in late summer while all other species are still vigorously green. Oaks put on their colors long after other species have already shed their leaves.

These differences in timing among species seem to be genetically inherited, for a particular species at the same latitude will show the same coloration in the cool temperatures of high mountain elevations at about the same time as it does in warmer lowlands.

Length of Night

In early autumn, in response to the shortening days and declining intensity of sunlight, leaves begin the processes leading up to their fall. The veins that carry fluids into and out of the leaf gradually close off as a layer of cells forms at the base of each leaf. These clogged veins trap sugars in the leaf and promote production of anthocyanin. Once this separation layer is complete and the connecting tissues are sealed off, the leaf is ready to fall.

How does weather affect autumn color?

The amount and brilliance of the colors that develop in any particular autumn season are related to weather conditions that occur before and during the time the chlorophyll in the leaves is dwindling. Temperature and moisture are the main influences.

A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most spectacular color displays. During these days, lots of sugars are produced in the leaf but the cool nights and the gradual closing of veins going into the leaf prevent these sugars from moving out. These conditions – lots of sugar and light – spur production of the brilliant anthocyanin pigments, which tint reds, purples, and crimson. Because carotenoids are always present in leaves, the yellow and gold colors remain fairly constant from year to year.

The amount of moisture in the soil also affects autumn colors. Like the weather, soil moisture varies greatly from year to year. The countless combinations of these two highly variable factors assure that no two autumns can be exactly alike. A late spring, or a severe summer drought, can delay the onset of fall color by a few weeks. A warm period during fall will also lower the intensity of autumn colors. A warm wet spring, favorable summer weather, and warm sunny fall days with cool nights should produce the most brilliant autumn colors.

What does all this do for the tree?

Winter is a certainty that all vegetation in the temperate zones must face each year. Perennial plants, including trees, must have some sort of protection to survive freezing temperatures and other harsh wintertime influences. Stems, twigs, and buds are equipped to survive extreme cold so that they can reawaken when spring heralds the start of another growing season. Tender leaf tissues, however, would freeze in winter, so plants must either toughen up and protect their leaves or dispose of them.

Evergreens: pines, spruces, cedars, firs, and so on are able to survive winter because they have toughened up. Their needle-like or scale-like foliage is covered with a heavy wax coating and the fluid inside their cells contains substances that resist freezing. Thus the foliage of evergreens can safely withstand all but the severest winter conditions, such as those in the Arctic. Evergreen needles survive for some years but eventually fall because of old age.

Broad-leaved trees: These are trees that do not have needles or scale-like leaves. They are tender and vulnerable to damage, are typically broad and thin and are not protected by any thick coverings. The fluid in the cells of these leaves is usually a thin, watery sap that freezes readily, which makes them vulnerable in the winter when temperatures fall below freezing. Tissues unable to overwinter must be sealed off and shed to ensure the plant's continued survival.

What happens to all those fallen leaves?

Needles and leaves that fall are not wasted. They decompose and restock the soil with nutrients and make up part of the spongy humus layer of the forest floor that absorbs and holds rainfall. Fallen leaves also become food for numerous soil organisms vital to the forest ecosystem.

It is quite easy to see the benefit to the tree of its annual leaf fall, but the advantage to the entire forest is more subtle. It could well be that the forest could no more survive without its annual replenishment from leaves than the individual tree could survive without shedding these leaves. The many beautiful interrelationships in the forest community leave us with myriad fascinating puzzles still to solve.

Where can I see autumn color in the United States?

You can find autumn color in parks and woodlands, in the cities, countryside, and mountains - anywhere you find deciduous broadleaved trees, the ones that drop their leaves in the autumn. New England is rightly famous for the spectacular autumn colors painted on the trees of its mountains and countryside, but the Adirondack, Appalachian, Smoky, and Rocky Mountains are also clad with colorful displays. In the East, we can see the reds, oranges, golds, and bronzes of the mixed deciduous woodlands; in the West, we see the bright yellows of aspen stands and larches contrasting with the dark greens of the evergreen conifers.

Many of the Forest Service's 100 plus National Scenic Byways were planned with autumn color in mind. Almost every one of them offers a beautiful, colorful drive sometime in the autumn.

When is the best time to see autumn color?

Unfortunately, autumn color is not very predictable, especially in the long term. Half the fun is trying to outguess nature! But it generally starts in late September in New England and moves southward, reaching the Smoky Mountains by early November. It also appears about this time in the high-elevation mountains of the West. Remember that cooler high elevations will color up before the valleys.

Tennessee Tree Day 2024

Each year, Tennessee Tree Day engages thousands of volunteers in a fun, meaningful, family-friendly, event that results in multi-generational benefits to our environment, communities and public health.

Tennessee Tree Day 2023 engaged 21,706 volunteers in planting 101,900 native trees in all 95 Tennessee counties, as well as 54 counties in neighboring states, encompassing all watersheds that flow through Tennessee. Since 2007, Tennessee Tree Day events have mobilized almost 100, 706 residents in planting 924,760 native trees in Tennessee and surrounding states.

Tennessee Tree Day 2023 involved many stakeholder groups and thousands of volunteers. Some planted trees to replace those lost to development. Others planted trees to help to repair degraded streams and improve water quality or to increase habitat for wildlife and pollinators. Some planted trees for purely aesthetic reasons. No matter the reason, all trees planted will improve the health of our environment by reducing air pollution, and enhancing Tennessee's magnificent tree canopy. 

The Tennessee Environmental Council hopes participation in Tree Day instills public awareness of the value of trees, while nurturing a culture of sustainability in our region. 

You can reserve your trees for the 2024 Tennessee Tree Day now by following this link! Trees can be picked up on the morning of Saturday, March 16, 2024 at the Robertson County UT Extension office in Springfield, TN.