The document summarizes the inspection of a large oak tree with multiple cavities and cracks. It finds that the tree has grown additional support structures like buttress roots and woundwood to cope with the cavities. While the openings affect some buttress roots and interior decay is present, the tree's response growth has walled off the spread of decay. The document recommends pruning to reduce strain on the tree and improve its structure and health.

1. Hollow Public Trees

3. Town Manager, PW Director, Urban Forester etc. Approved

4. The fattest oak in Europe has a cavity large enough to hold a council meeting. Trees have many
strategies for coping with cavities, like shedding unneeded limbs and adding support.

5. To the left, a new root grows at the margins of the cavity.
To the right, a column of new wood is formed inside the cavity.

6. The Crying Tree, Marion VA
Inspecting the structure, pruning
branches, and invigorating roots
improves health, safety, and longevity.

7. Open cavities between buttress roots are not uncommon in old oaks, and interior decay is
typical. Healthy trees are supported by their buttress roots, and wall off the spread of decay.

20. The cavity is in a sinus and strong response growth,
woundwood, is visible (orange lines). The yellow lines
indicate a second line of defense.
The open areas appear to be 3" x 5" and 2" x 4“, in a non-
supporting sinus area.
This activity is starting to affect one buttress root.
.
Using a trowel to get a look below ground on the Crying
Tree may reveal this type of response growth.
This type of inspection can provide an idea of the structural
significance of those openings.
•

22. On the north side of the
trunk, trunk tissues have
cracked apart after the
loss of limbs.
The crack stops at a
growth point, where
tissues are strengthened.
Even after the branches
are cut off, the
protection zone remains.
A small hole in the upper
left appears to be one of
several access points for
squirrels and other
creatures.
These are typical in older
oaks.

23. The loss of limbs on this one vascular column of this tree restricts the flow of nutrients
to the area around the crack. This starvation contributed to the cracking, and slows closure.

24. The BMP and the TRAQ form guides the assessor to
document response growth. The tree’s response
growth is an important factor.
The ANSI A300 standard calls for inspection before
pruning, or installing lightning protection.
The crack and the openings were probably observed
at those times or before.
•

25. Response growth
is visible on both
sides of the tape
measure.
Its thickness
indicates the
crack has been
there for 5+
years.

26. The Crying Tree sprawls toward the parking lot. This imbalance puts a lot of strain on the
supporting tissues on the opposite side of the trunk that faces the building.

27. Reducing the sprawl will reduce the strain on the trunk, and risk of failure.

28. The red line shows
a gap in the
crown. It could be
related to the loss
of a limb in 2012.
The yellow line may
point to the wound
created by the
removal of a
broken limb.
Closer inspection
will guide the
adjustment of
pruning
specifications.

29. Reducing branches will reduce the distance that water and nutrients must travel, redirecting the
tree’s energy to foliage that is easier for the tree to support .

30. CONCLUSION: The reduction of branches will reduce the risk associated with this tree to or
below the level of risk associated with the average mature tree in the urban landscape.
SPECIFICATIONS for Care:
Flare: Remove soil >6” away from the trunk. Avoid damaging roots. Expose and measure
any roots that arise near wounds. Replace soil with stalite or another sterile aggregate.
Roots: Eliminate turf >6’ from trunk by spraying contact herbicide per need and suffocating
with cardboard. Spread woodchip mulch 4” deep. Beyond 6’, modify soil by aerating and
inoculating per need.
Trunk: Clean dead material away from wounds. Document and monitor response growth—
”scar tissue”-- in the form of woundwood. Assess strength.
Branches: Reduce horizontal and downward growth to improve crown symmetry and
lessen crown movement. Make cuts <4”, to laterals that grow upright or in a favored
direction. Remove 10%-15% of the crown.
Monitoring: Review images of the crack and the cavity and the crown annually. Return in 3
years to inspect the tree and perform other treatments as specified.
Invasive testing causes excessive damage to structure and health. Future inspections will
involve sounding, probing, and recording images of the interior with a camera.