Oak Tree FAQs
Oak trees are unique in their ability to remain standing for hundreds of years. And the laws of physics cause mature trees of any species to be more stable than young trees.
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Mature trees become more stable with age
Frank Rinn, a renown German tree physicist and inventor of tools used worldwide to assess decay in trees, wrote that "even strongly hollowed trees can be safer than young intact trees without any defects."
In his article, he describes how hollow trees are often more sturdy than young solid trees due to the laws of physics.
He gives an example of a tree that has stood close to a subtropical coastal shoreline for more than 100 years. The stem has been severely damaged and hollow for decades but has survived dozens of hurricanes while young intact trees in the same area broke.
This illustrates that the older trees are, the higher their basic safety and the more decay they can tolerate without being significantly more susceptible to breakage. The reason is that when the trees stop growing taller, they continue to become thicker with each tree ring they put on each year:
[E]ven when tree height is no longer increasing (typically 60 to 80 years of age for common urban trees), trees still annually put on girth. The continuous addition of new tree rings automatically leads to an increasing load-carrying capacity and, at the same time, to a correspondingly higher basic stability. Consequently, the older mature trees are, the higher their basic stability and the more defects they can tolerate without becoming hazardous. Taking into account these size-related (positive) aging effects allows arborists to determine the gain in safety for mature trees and thus determine what extent of "defects" can be tolerated without having an increased probability of failure.
The practical implication is that many, if not most, mature urban trees of concern have no need for pruning (for wind-load reduction) or for other expensive mitigation measures, resulting in the following benefits:
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Less money needed for pruning and cabling mature trees;
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Less damage to tree vitality and to the tree's ability to resist fungal decay; and
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Longer and less expensive conservation of mature and ancient trees as important natural habitats.
Certified arborist Ray Gleason heard Frank Rinn speak in the past at an event for tree professionals. During that talk, Rinn described being dissatisfied with how people were using his technology to remove trees that did not need to be removed. He explained how his approach is to look at each tree objectively and that retaining the tree is always his primary objective unless the evidence dictates otherwise
Oaks replace decayed wood with much stronger wood
Mature oaks have a special ability to remain stable as they age, whether or not they are hollow (and they usually are). The new wood they form in response to decay or injury is denser and more durable than the original wood.
Mature oaks with hollows can become a sturdy tube, like a brick chimney.
Poet John Dryden wrote of oaks,
The Poetical Works of Dryden, Tales from Chaucer, Palamon and Arcite, Book III, l. 1058, The Riverside Press. 1949.
This ability to replace decayed wood with even stronger wood is part of a tree’s natural defense mechanism. It is known as “compartmentalization.” The new growth is often called “reaction wood” and helps to reinforce the tree structure. See Shigo, A. L. (1986). A New Tree Biology Dictionary: Terms, Topics, and Treatments for Trees and Their Problems and Proper Care. Durham, NH: Shigo and Trees, Associates.
Thus, oaks, especially mature oaks, can live hundreds of years with a hollow stem. They should not be assessed for risk in the same way other trees are assessed for risk. It is like comparing apples to oranges.
The longevity of oaks prompted Norway to create a national law to protect old and hollow oaks, including dead oaks. The law is a model for us to follow.
Three centuries he grows and three he stays,
Supreme in state, and in three more decays.
A gnarled and hollow old oak tree (Quercus robur L) sheltering a shepherd and his sheep. Etching after JG Strutt, 1823. Moccas Court, an 18th-century country house on the river Wye in Herefordshire. Created 1831–36. Contributors: Jacob George Strutt (1790–1864). Work ID: zub6gxsr.
The Davis Meeker oak is in very good health
The irony of the mayor's desire to cut down the Davis Meeker oak is that even the report she relies on states that the tree is in very good health: "[T]he Meeker Oak appears to be in very good health. The crown density, leaf color, leaf size and internode growth all indicate a vigorous tree." See 10/10/2023 Report of Kevin McFarland, at 4.
According to certified arborist Ray Gleason, when a Garry oak is in decline, you would start seeing gaps in the canopy, the leaf size at the top would become smaller, and the tone of the leaf would change. The leaves would become lighter. The canopy density would become less dense. You would start seeing a higher percentage of fruit that is nonviable.
A lot of fruit would be produced but a high percentage would be not completely formed, the nuts would be smaller than normal, and the ones near the bottom of the tree would usually be larger than the ones at the top of the tree. The top of the tree dies first. That’s what shows a tree is physiologically failing.
Gleason wrote in his sworn declaration to the court that the Davis Meeker oak has none of those signs. There are some holes in the tree canopy that are due to lack of tree maintenance, such as pruning, but those are starting to fill in. Small branches are filling in those openings. That’s a normal process that does not indicate any decline.
If the tree were in decline, the tree would not have the energy to fill in those holes in the canopy. The canopy would be ever shrinking. As a branch breaks off, nothing would fill in the hole it left.
Another sign of decay would be an abundance of dead leaves beneath the tree during the growing season. Gleason visited the tree on August 14, 2024, and noticed that the Davis Meeker oak has had virtually no dead leaves beneath it on the ground this summer. If it did, they would be visible because the chain-linked fence around the tree would have prevented the leaves from blowing away.
Photo by Wayne Shreckengosh, June 28, 2024
The City of Tumwater has been derelict in its maintenance
A few years ago, certified arborist Ray Gleason, who provided years of free care for the tree, took the city’s arborist, Kevin McFarland, into the canopy of the Davis Meeker oak and explained to him that a paid tree canopy assessment should be performed rather than Ray continuing to donate his time.
Ray began donating his time in 2008. Since that time, the city never paid for pruning, risk assessments, or long-term maintenance, despite the fact that the tree is on the city’s historic register.
According to Ray, since 2008, the only time the city paid for maintenance on the Davis Meeker oak was after Ray stopped providing free services in approximately 2020. After that, the city hired a contractor one time when it wanted branches overhanging Old Highway 99 cut for vehicle clearance and another time when it wanted the same for vehicle clearance in the parking lot of the historic airplane hangar that is next to the tree.
From Ray's perspective, it was not until City Administrator Lisa Parks was hired in June 2023 that the city started to pay attention to the tree, but then only for the purposes of trying to cut it down.
Ms. Parks came straight from her executive services job at the Port of Olympia, which owns and operates the Olympia Airport where the tree stands. Cutting down the tree would make it easier to upgrade the airport's infrastructure, including widening of the road. The Port’s stated goal is to have 20,000 passengers passing through the airport per month (there are none now).
Veteran trees are an irreplaceable resource
It takes around 400 saplings to match the environmental benefits of one old tree. Prof. Andreas Roloff, a forestry scientist with a wealth of expertise in old trees, did the math several times over, always using different methods. But the results remained the same. In order to match the environmental benefits that an old tree with a crown circumference of 65 feet provides – such as air filtration, shade, cooling and carbon storage – you need about 400 saplings.
But 400 saplings can never make up for the loss of one old tree in some ways. Old trees, because they are rare, contain large numbers of rare and threatened species. Although some of the organisms are generalists, many are extremely specialized. Without a veteran tree, these organisms simply cannot exist.
Specifically, fungal rotting of the heartwood and dead limbs in veteran trees results in a diversity of micro-habitats suitable for other organisms, including a potentially very wide range of invertebrates dependent on such micro-habitats and birds, such as woodpeckers, that prey on them.
And epiphytes, such as mosses and lichens, may require the old bark characteristic of veteran trees to grow on.
The biological importance of a tree is greater if it lives long enough to perpetuate the continuity of habitats for future generations.
According to Veteran Trees: A guide to good management, the term "veteran tree" encompasses trees defined by three guiding principles:
• trees of interest biologically, aesthetically or culturally because of their age;
• trees in the ancient stage of their life;
• trees that are old relative to others of the same species.