ozark chinquapin root system revealed through root excavation
Bert Hart, Hobbs State Park, AR
In 2023, Bert Hart led a group of volunteers on an exploration at Hobbs State Park to uncover the secrets of the Ozark chinquapin root system. Several trees at a planting site on the park had succumb to drought in spite of watering bags being placed on the trees. Bert wanted to understand why the trees, which were about 10 years old, had died. The article below was created using notes and pictures from a presentation Bert did about the root excavation and what they learned.
Preparing the site for root excavation
The area first had to be prepared to work with. The thin grass layer had to be removed. Had to be careful because some of the lateral roots were only about 2” of dirt. The team began by clearing a semi-circle on the downward side of the Ozark chinquapin stump with a 4-foot radius.
The team carefully took a few inches of soil off as a start. Then they uncovered roots down from the stump as the root system expanded outward to get a more precise idea of how for laterally the root system went. Grass was loaded up and put on a tarp for replacement later. The team ended up exposing an area about 7’ x 8’.
(Photo above) Initial laying out of the root extraction area. Kylie and Tom measuring the work area while Caitlyn takes notes on the team progress. First roots found at 2” deep.
Unveiling the Root System
Working close quarters with small tools and carefully with a rake. Lateral roots were first found at 2 inches. Some smaller lateral root at 3-4 inches. The entangled lateral root system was right at 8” thick. Lateral roots seem to cling to larger rocks with root hairs slurping as much water as they could from crevices in the rocks. Large lateral roots close to the surface. Most lateral roots continue outward, some past the drip line. Many others go straight down. Both facts are very important. The large, forking, diving down lateral roots were within 4’ of the trunk. Newer lateral roots took on an orangey color. Deeper lateral roots have thicker and darker skin. Older/larger lateral roots have the voluminous array of root hairs that seek water near the surface. 5” circumference on the largest root or approx. 1.6” diameter on a tree that was probably 5” in diameter.
The team of 6 volunteers were down on their bellies for 6 hours!
Key Findings
USDA Webs Soil survey results:
The soil type was identified as Clarksville – Extremely gravely silt loam to 80” depth, or 6.7 feet before hitting “Restrictive features”, and classified as “excessively drained”. This is why our larger trees died. Moisture from above goes straight down! The water from the water bags dripped out slowly, as the bags are designed to do, and the water went straight down, missing a lot of the root hairs on the lateral roots that absorb moisture. Essentially, THE WATER DID NOT GO WHERE THE TEREE ROOT SYSTEM COULD ABSORB IT.
Photo above shows what the team was digging in; more gravel than dirt.
The slow work progresses. Photo below, from left to right: Kylie, Caitlyn, Ellen, Bert.
Happy Ozark chinquapin root excavators, removing rock/soil and putting it on a tarp to make it easy to fill in after their work. Sandra, who took this photo, said that because of the friendships they have made volunteering at the Hobbs Ozark chinquapin restoration plots, this has been the most fun she ever had digging in dirt.
Lateral Roots
We discovered the tree has many, stacked lateral roots emerging from the base of tree.
Photo above shows lateral roots uncovered at 2” near the trunk of the tree.
(Photo Above) Carefully removing larger stones. Larger lateral root in upper right forking. This begins to tell the story of the Ozark chinquapin remarkable root system. Hairy roots to absorb water.
(Photo Above) Most of the ground had small rock, but a few were baseball size. The roots ran over man of the larger stones and sometimes seem to cling to them.
(Photo Above) 3.5 hours is a long time to stay at this task. No time was put on the volunteers. They kept digging on their own until they got the answer to the question about the Ozark chinquapin root system. Dedication!
(Photo Above) Drawing by A.J. Hendershott of an experiment. The tap root drawing was from an experiment Steve Bost did growing a seed in a tube from January to mid spring. He then cut the tube to look at the root. It was a LONG thin tap root. This gave the idea that this is how the root system grows, but one main tap root. Maybe the tap root got the tree going, but the secret is up here. (point to the growth under the seed.) “this” (the upper growth” becomes the Ozark chinquapin’s secret. The reason I show this is to show how the root system morphs.
(Photo Above) Massive root system as a two-year-old tree! A lot of roots supporting the tree. Had to have been pulled from a pot. See it on the ground. Misleading when you see this. You must understand how the Ozark chinquapin alters it root system as it grows. Looking at these limp roots does not explain how the OC root system grows. You really are not seeing what this root system is trying to do.
(Photo Above) This is what the root system is doing. The main lateral roots are stacked on top of each other. This tree must be strongly anchored in the ground. The lateral root stack was about 8” deep from the base of the tree…There is not one lateral root that goes straight down but rather many lateral roots that begin outward from the base of the tree, fork, and then go downward. All the largest lateral roots took a 90-degree angle dive within 6 feet of the tree trunk. Some of the largest lateral roots continued along the contour of the hill to at the least the drip line. Smaller lateral roots went downhill 2 to 3 feet, branched, and them took a 90-degree dive down.
(Photo Above)A 2’ lateral root forks with both branches of the fork heading down for water.
It was as slow going like an archaeological dig to uncover, but not cut the small roots while excavating the roots of an Ozark chinquapin tree. The ‘F7’ is the “house” location of that deceased tree on the main Plot at Hobbs State Park. Care is taken to note the seed source of each tree in the plot. This large lateral root came out about two feet and BOTH forks headed down for water. Beginning to see how the entire root system grows!
The secret begins to be revealed. The large, stacked lateral roots don’t go very far before they fork two to four times and then head straight downward towards moisture. (Photo above)
(Photo Above) Little ones branching off larger lateral roots and going down to moisture.
The roots are big, small, and hairy. Large lateral roots fork. Some of the forks keep heading out laterally. Some of the forks immediately head downward looking for moisture. The roots are flush with root hairs – which gather as much moisture as they can as levels just under the surface of the ground. (Photo above)
(Photo Above) Very important! The key! The man lateral roots fork and become tap roots.
Are you beginning to visualize the entire root system?
(Photo Above) A lateral root growing over a larger rock. This is important! This was interesting to see.
The lateral roots seem to like the larger rocks, and the root hairs are looking for moisture in the cracks. In the second photo above, you can see where a rock was removed and the root hairs seeking moisture in the cracks of the stone.
(Photos Above) Chunky roots from the base of the trunk of the tree – forking – looking for water. Note not just the large lateral root is going down, but also smaller shoots off this lateral root are going down…resulting in dozens of “tap roots”. Picture a 5’ diameter, 8” thick, tightly woven lateral root system with dozens of tap roots.
A Second Ozark Chinquapin’s Root System Uncovered Through Excavation
(Photo Above) This was a different Ozark chinquapin that was pulled from the ground and of course the tap roots were all ripped off. The lateral roots of this species of tree are thick, complicated, and have one thing on their mind – WATER
Complicated lateral root system basically about 8” thick…exactly what the root extraction team found…confirmation
(Photos Above) Amazing root system! Lateral roots fork like squid tentacles…over each other…looking for water. If there was one tap root in the beginning, it did not become the major part of the root system. The major parts of the root system are the large lateral roots emanating from the trunk base.
(Photo Above) VERY LIMPORTANT. Very hairy lateral roots – these hairy roots absorb all the moisture that is available in the surrounding ground. This tree was made to be drought tolerant.
What Did The Root Excavation Team Discover?
(Photo below is an artistic rendering of a mature Ozark chinquapin root system, by AJ Hendershott)
We (the volunteer group at Hobbs) have been watering our older trees improperly because we did not understand the root system.
The water didn’t go where it was supposed to because we did not understand the root system of an older Ozark chinquapin.
Water bags placed on the trees did not work. The water slowly seeped out of the bags in the “excessively drained” soil, so the water went straight down and was not absorbed by the tree. Another important dig finding: an Ozark chinquapin has a convoluted, complicated, 8” thick, upper lateral root structure extending past the drip line with very active root hairs looking for any water they can find.
The bottom line: We now understand the root structure of an older Ozark chinquapin.
Thick mass of convoluted, lateral roots emanate from the base of the trunk of the Ozark chinquapin that have LOTS of root hairs to gather moisture at the upper levels…a very active upper lateral root system. These lateral roots extend beyond the drip line. At the same time, those lateral roots that fork and head down looking for moisture at lower levels…a very active, multi-tap root system.
This is why the Ozark chinquapin is drought tolerant.
Perhaps the most important thing that the team discovered was the dozens of large and small tap roots to an Ozark chinquapin. No one has ever known this!
The drawing done by AJ (photo above) is but a SLICE of the whole picture – There are dozens of tap roots on the Ozark chinquapin. Picture slice after slice after slice and tap roots going down at each slice.
Question: Why have the Hobbs trees died of drought even though they have been watered?
1.Watered older trees improperly
2.Excessively drained soil
3.Extremely harsh environment with full sun in the late afternoon.
I believe, based on the new information, we should be watering our older trees out away from the trunk where the root hairs can absorb the water. Watering heavily each time we water so as to NOT encourage shallow root growth.
Bert Hart pictured above with interpreter Chris at the Hobbs State Park Ozark chinquapin restoration planting where he volunteers.