Mysterious Oaks and the Value of Trees - Powell Gardens, Kansas City’s botanical garden

Hasn’t the heat wave been dramatic? That’s a pretty poor question for what is at stake for the region as we now are classified as being in a SEVERE drought. EXTREME drought is the next category that Western Kansas and Southeastern Missouri are now experiencing. It’s painful to watch the important agricultural crops wither all around. We are able to water most of the horticultural crops at Powell Gardens and our gardens are holding up well thanks to a hard working and committed horticulture staff. Kudos to them!

I am surprised by how one group of native trees is handling the situation. Oak trees are not withering but putting on NEW growth!

I first noticed the new growth on the two Bur Oaks (Quercus macrocarpa) on either side of the Horticulture Cabin where my office is. See the bright new growth in the above photo? Bur Oak is pretty much the king of oak trees in Greater Kansas City, growing to nearly 100 feet tall and wide but with very strong branches that laughed off the ice load of 2002’s catastrophic ice storm. It also produces large, almost golf ball sized acorns

Then I noticed that virtually all the oaks in the Parking Lot Arboretum on the other side of the garden were doing the same thing. See the bright yellow-green new foliage adorning this Chinkapin Oak (Quercus muhlenbergii)? Chinkapin oak I consider to be the quintessential oak of Kansas City as it once graced the region’s bluffs, including where downtown now stands. Lewis & Clark described it there and you can see it in the magnificent mural of their described scene at the Anita Gorman Discovery Center.

Powell Gardens Parking Lot Arboretum contains 96 oak trees comprising 16 of Missouri and Kansas’s 21 species of native oaks. Virtually all of them are not just enduring the heat and drought but putting on new growth. I noticed that the River Birches (Betula nigra) were shedding leaves to conserve water.

Does this mean anything? Was it caused by conditions earlier in the season or do they know something we do not? I would love to be an optimist and that they foretell a change in the weather pattern that would bring a monsoon flow and returning rains to the region. Time will tell. I can say that oaks are one tough tree once they are established so it’s no wonder they were the dominant tree in the region when the settlers first came here.

My friend Leah Berg said this reminds her of a talk by America’s tree expert, Guy Sternberg, on a recent conference of the Kansas Arborist Association. Guy explained a need to plant more heat resistant trees as our climate warms. He recommended oaks for such and I sincerely concur.

The Value of Trees

The recent HEAT WAVE with temperatures reaching 100F or more for a full week was especially brutal on us and plants because the days are so long near the summer solstice. Trees have enormous value to us in times like this as their shade is the cheapest air conditioner available!

This image is the woodland walk from the Marjorie Powell Allen Chapel to the trolley stop at Powell Gardens. On hot days it is a respite compared to the full sun of the garden’s open prairie landscapes.

It is noticeably cooler in summertime when you enter this walk (and noticeably milder in winter too). But what is the real value of a tree during the year?

In late June the Gardens’ Director, Eric Tschanz, and I attended the American Public Garden Association’s (APGA) national conference in Columbus, OH. I visited the Chadwick Arboretum on the Ohio State University Campus and was thrilled to see this sign that gave an actual dollar value of a shade tree! This particular Hackberry (Celtis occidentalis) was given a value of $265.09 per year. Its energy value in terms of cooling summertime and trapping a bit of warmth in the winter was given as over $80 per year of that value. I was disappointed no value was given to it hosting five species of butterflies and providing fruit for winter birds — many things just can’t be assigned dollar values!

Here’s an image of a tree that helped inspire Powell Gardens. We call it Marjorie’s Oak and it stands in front of the Chapel. It’s a maturing Shingle Oak (Quercus imbricaria) and it survived the catastrophic ice storm of 2002. The image was taken from INSIDE the chapel. The late Marjorie Powell Allen was a leading human force who helped create Powell Gardens and her spirit is still present here as she inspired many and left a lasting legacy. As most trees live for many human generations they leave a lasting legacy of the past that is impossible to assign a value.

This young oak also has significance at Powell Gardens as it was planted on Arbor Day 1990 to honor Chuck Brasher, local tree expert and friend of Marjorie. We are sad to announce that Chuck passed away recently at age 90 and his knowledge of trees and his charity and altruism will be greatly missed. This Swamp White Oak (Quercus bicolor) graces the old (deliveries and staff) entrance to Powell Gardens and is a constant reminder of Chuck and his love for and expertise with trees. He maintained the list of Champion Trees of Greater Kansas City and I had the pleasure of spending many days with him measuring and scouting for champion trees. Chuck wrote a list of the value of trees along with the champions:

Think Trees… Your future depends on their survival!

TREES supply the oxygen we need to breathe.
TREES keep our air supply fresh by absorbing carbon dioxide that we exhale and also that which we emitted by factories and engines.
TREES are natural air conditioners. They lower air temperatures by evaporating water in their leaves.
TREES cut down on noise pollution by acting as sound barriers.
TREES trap and filter out dust and pollen on their hairy leaf surfaces.
TREES shelter us from direct sunlight on hot sunny days.
TREES roots stabilize the soil and prevent erosion.
TREES camouflage unsightly scenes and break the monotony of endless highways, sidewalks and lawns.
TREES slow down strong winds.
TREES give us privacy.

And lastly Chuck included: A country without children would be hopeless… a country without trees would be almost as hopeless!

Trees leave a lasting legacy to the future as well — a Swamp White Oak can easily live 300 years or older.

See Champion Trees of Greater Kansas City at http://www.countryclubtreeservice.com/.

This large shade tree is a White Ash (Fraxinus americana) in front of the Chapel. White Ash are threatened by an imported exotic pest, the Emerald Ash Borer (EAB), which is ravaging ash trees in the eastern Midwest and is spreading our way. I learned at our APGA conference that with treatment as EAB arrives and for several years thereafter, your ash trees can be saved and their appreciating value retained. That’s good news as I thought there was no hope for ash trees and the more than 400 species of insects and other creatures besides ourselves who need them for their livelihoods. Powell Gardens will be spreading the word about what local communities and landowners should do as part of The Sentinel Plant Network that APGA and the United States Department of Agriculture have set up to monitor and advise about threatening pests and diseases.

Just remember from tiny acorns mighty oak trees grow. This is one of our seedlings of the extirpated (locally extinct) Arkansas population of Bigleaf Magnolia (Magnolia macrophylla). Powell Gardens was given five seedlings of these important trees by Dick Figlar as part of our North American Plant Collection Consortium Magnolia collection. A a member of the consortium, Powell Gardens is responsible for preserving and protecting the native magnolias found west of the Mississippi in Missouri, Arkansas and Oklahoma.

These magnolias were once found on Crowley’s Ridge just eight miles south of the Missouri border. They are important because as the western-most survivors by many, many miles they probably offer improved drought resistance. Bigleaf magnolia has the largest leaf of any North American tree and takes about 15 years to bloom. Some day this tree will really inspire visitors with its 3-foot leaves and 12-inch fragrant blossoms!

How does one assign a value to the beauty of trees? I hope you all are inspired to visit Powell Gardens and its extensive collection of trees and to plant a tree yourself for their appreciating dollar value AND for their value beyond human currency designations.