A vertical fissure 30 feet up. The Level 2 visual assessment that couldn’t make the structural call — and the decision to escalate.
Before the climber goes up, the ground-level read happens. This March 2023 field clip is the Level 2 visual assessment on a mature Dawn Redwood that had developed a vertical fissure in its trunk — the assessment that prompted the subsequent aerial inspection and ultimately the removal decision. Worth walking through what an arborist sees from the ground on a tree with this kind of defect, and why it sometimes isn’t enough to make the call.
View from the Field · Paul Biester · Tree Awareness
Dawn Redwood (Metasequoia glyptostroboides) is one of the more interesting specimens in residential landscapes. A deciduous conifer — needles in summer, bare branches in winter — that grows fast (3–5 feet per year on a good site), reaches mature heights of 70–100+ feet, and has fluted, buttressed trunk structure that’s visually distinctive. The species was thought extinct until living specimens were discovered in central China in 1944. Most of the Dawn Redwoods in American landscapes today trace back to seed material distributed in the late 1940s and 1950s.
The downside, structurally, is that the species’ rapid growth doesn’t always produce the strongest wood. Mature Dawn Redwoods can develop trunk splits, included bark in fluting, and structural cracks — usually in the upper portions of the trunk where the canopy load is concentrated.
The visible signal from the ground was a vertical fissure on the trunk, identifiable from a distance with binoculars or a long lens. The defect’s position — well above the second story of the house — meant that closer inspection from ground level wasn’t going to add data. The fissure could be 6 inches long and superficial, or 10 feet long and structural. The ground read couldn’t distinguish between those.
That’s the test for whether a Level 3 assessment is justified. If the Level 2 leaves the structural call ambiguous, and the consequences of being wrong are unacceptable (a tree over the house and the neighbor’s house, in this case), the right next step is escalation.
The Plant Healthcare technician’s recommendation was to bring Paul out for an Aerial Tree Risk Assessment — climb the tree, look at the defect from inside the canopy, make the data-driven structural call.
That’s exactly what happened. The follow-up post on this tree is the ATRA itself, with Paul aloft documenting a 10-foot crack, decay column, and structural compromise that justified a removal recommendation.
Three possible paths after the Level 2 ground read identifies a structural concern:
Monitor only. If the ground assessment can confidently classify the defect as superficial — old, fully compartmentalized, no expansion signs — the call may be to monitor on an annual cycle without aerial intervention.
Escalate to Level 3. If the defect’s nature can’t be confirmed from the ground, and the target zone makes the consequences of being wrong unacceptable, escalate to ATRA, resistograph, or sonic tomography — whichever Level 3 tool fits the defect type.
Pre-emptive removal. If the defect is severe enough on visual that the structural call is already obvious from the ground, removal can be the recommendation without escalation. This is rare on heritage specimens — usually the question is data-supportable, and the data should be collected before the chainsaw is brought out.
A heritage Dawn Redwood on a residential property is a meaningful asset. Mature specimens are 70+ years old at this point, often beautiful focal points of the landscape, and meaningful enough that owners are reluctant to remove them on a vague concern. The right way to honor that reluctance is to bring the right tools to the assessment — and to make the keep-or-remove call based on data, not first impression.
The Level 2 visual that prompts an ATRA escalation isn’t a finding of fault. It’s a finding of insufficient information from this assessment level. The right answer is more data, not faster decisions.
For a TRAQ Level 2 visual on a tree with a suspected structural defect, request a Tree Risk Assessment →
