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Glossary

Tree Survey Terms,
Plainly Defined

DBH, TRAQ, BS5837 categories, RPA — the terms that show up in arborist reports and planning submissions, defined the way practitioners actually use them, not the way a dictionary would.

Fundamentals

What is a tree survey?

Inventory, BS5837, risk assessment, condition survey — and who commissions each.

Measurement

DBH

Diameter at breast height — the standard stem measurement, single- and multi-stem.

Crown spread

Measuring canopy width N-S and E-W, and deriving canopy area.

Multi-stem tree

When a tree is multi-stem, and how to measure and record each stem.

Risk & Assessment

TRAQ

The ISA tree risk assessment qualification and its likelihood/consequence matrix.

Tree condition rating

Good, fair, poor, dead — what each rating looks for.

CTLA trunk formula

Valuing a tree from trunk area, species rating, condition, and location factor.

UK Planning & Preservation

BS5837 categories

Category A/B/C/U grading and what each means for a development site.

Root protection area (RPA)

The 12x stem diameter formula and what it means for construction.

Tree Preservation Order (TPO)

What a TPO protects, what counts as an offence, and how to check for one.

Want the full field workflow, not just the definitions? Start with thetree inventory guideor browse thedownloadable templates.

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