The Five-Bin Structure Is the Methodology
The ratio (live crown : tree height) field runs from 0-20 through 80-100 in five ordinal bins. That's not a simplification — it's the Bond methodology's scoring scale operationalized as a structured choice field rather than a handwritten estimate. When you're assessing 40 street trees across a municipal block during a single afternoon survey, that bin structure lets you score consistently without recalibrating your mental reference point every three trees.
The same five-bin logic applies to opacity (% light blockage), vitality (% no dieback), quality (% no abnormal), and the inverted-scale growth (shoot extension), where higher shoot extension — 8 cm or more — represents the healthiest score. The decision to keep all five metrics on the same ordinal scale means you can compare across metrics within a single tree record without normalizing scores afterward.
What Street-Level Assessment Actually Looks Like
You're on the sidewalk, July heat radiating off concrete, looking up through the canopy of a silver maple that was planted in a tree pit that's about 60% smaller than it should be. The ratio reading is clear — maybe 40-60, crown is suppressed relative to height, classic infrastructure competition. Opacity is harder. You're angle-sighting through the canopy against a flat gray sky, trying to distinguish 60-80 from 80-100 light blockage when there's no direct sunlight to give you shadow reference. This is where the take pic field earns its place: you shoot straight up into the canopy, which later resolves the ambiguity when you're reviewing the record in better light.
Vitality — percentage of crown with no dieback — is a walking assessment. You're circling the tree, looking for dead limbs, tip dieback, crown thinning from the apex down. On a large specimen you're missing the upper crown entirely from ground level, which is why the shoot extension (growth) field matters: recent terminal shoot extension of less than 2 cm is frequently visible lower on the crown and tells you what's happening systemically.
The dual location fields — location 1 for address and site context, location 2 for tree number and distance/direction — handle the municipal inventory situation where trees are tagged by a grid coordinate or sequential ID that doesn't map neatly to a street address. You need both to reconstruct which exact tree you were standing under when the city engineer asks about the one with the compacted root zone at the corner of Oak and Third.
The Data Picture After a Full Survey Block
Run a seasonal survey across a 200-tree urban forest segment and filter by vitality in the 0-20 range. That filtered set is your triage list — the trees most likely to need intervention before next summer's heat events compound the stress. Cross-reference against ratio below 40-60 and you've isolated the specimens where crown suppression is occurring alongside active dieback: probable infrastructure conflict, root zone damage, or both.
Quality in the 20-40 range across multiple adjacent trees — abnormal growth patterns like epicormic sprouting, witches'-broom, or persistent tip chlorosis affecting more than 60% of the canopy — signals a block-level pathogen or soil contamination problem rather than individual specimen failure. That distinction changes the intervention recommendation entirely.
Growth tracking at the shoot extension level gives you the long-term vigor trend. A tree scoring 6-8 cm terminal extension in year one that drops to 0-2 cm in year three, holding all other variables constant, is telling you something specific about root zone degradation or systemic stress accumulation that no canopy photograph alone would catch.