Low
Moderate
High
Extremely High
Unscored
A.T. Corridor
Reference only. Scoring Guide does not replace training or professional judgment.
Likelihood of Failure (1–4 pts)
1 · Low
Minor branch/crown dieback; minor defects or wounds.
2 · Mod.
Stem decay/cavity within safe shell limits (>1 in. sound wood per 6 in. stem diameter); crack(s) without extensive decay; defect(s) affecting 30–40% of circumference; crown damage (hardwoods to 50%, pines to 30%); weak union with included bark; girdling roots <40%; root damage <40% within critical root radius (CRR).
3 · High
Stem decay/cavity at or exceeding shell safety limits (<1 in. sound wood per 6 in. diameter); cracks in contact with soil or other defects; defect(s) >40% of circumference; crown damage (hardwoods >50%, pines >30%); weak union with crack/decay; girdling roots >40%; root damage >40% CRR; leaning tree with recent root breakage/soil mounding, crack, or extensive decay; standing dead tree, no other significant defects.
4 · Ext. High
Stem decay/cavity exceeding shell limits with severe crack; stem/branch split in half; defect(s) >40% with extensive decay or crack(s); weak union with crack and decay; leaning tree with recent root breakage and crack/decay; broken hanging dead branches or with a crack; standing dead tree with other defects; visual/physical obstruction of traffic.
Size of Defective Part (1–3 pts)
1
Parts less than 4 inches in diameter.
2
Parts 4 to 20 inches in diameter.
3
Parts greater than 20 inches in diameter.
Target Exposure (1–3 pts, A.T. context)
1 · Occas.
Low-use side trails; boundary lines.
2 · Interm.
Informal-use campsites, vistas, trail segments; secondary access roads.
3 · Frequent
Shelters, formal overnight sites, privies, trailheads, bridges, high-use vistas — any area of congregation.
Appendix A below determines the Tier 2 / Tier 3 line for campsites specifically: a site meeting any of its criteria is a formal overnight site (Tier 3); an opportunistic, user-created site that meets none of them is a Tier 2 moderate-use campsite instead.
Appendix A: Formal Overnight Site Identification
Use the following to differentiate formally managed overnight sites (Frequent Use, Tier 3) from opportunistic, user-created overnight sites (Moderate Use, Tier 2):
FMSS
The land manager has determined it to be a formal site, and it exists in the Facility Management Software System (FMSS) inventory.
Signage
The site has an agency-recognized name and signage referencing it as an overnight site.
Improve.
Site improvements have been approved by agencies and implemented by A.T. managers, such as a shelter, privy, constructed tent pads or platforms, food storage infrastructure, sign board, kiosk, or site map.
ATC Map
May also be referenced on ATC's Interactive Map, built cooperatively by the Appalachian Trail Conservancy (ATC) and National Park Service using Esri's ArcGIS Online mapping technology: appalachiantrail.org/explore/hike-the-a-t/interactive-map.
Defect Codes (USDA Community Tree Risk Evaluation Form)
D
Decay
CR
Crack
Root
Root problems (general)
WBU
Weak branch union
CA
Canker
PTA:LT
Leaning tree
PTA:TT
Topped tree
EE
Excessive epicormics
DEAD
Dead tree, top, or branches
VO
Visible obstruction (signs/lights/intersections)
PO
Physical obstruction (pedestrian/vehicular traffic)
The full USDA code set (including root-specific codes RSG, RS, RPD, RGC, RSB) is reserved for detailed office review. Note specifics in Notes as needed.
ATC Hazard Tree Decision Workflow
Step 1
Trained personnel complete assessment (every 5 yrs, or after storms, reports, or forest health changes).
Step 2
No hazard → monitoring. Defect confirmed but below threshold → monitor at a frequency matched to severity. Hazard confirmed (imminent risk to a congregation area/structure) → recommend management action.
Step 3
Land manager reviews: declines (may recommend closure/further assessment) or approves removal.
Step 4–6
If removal can't happen immediately, land manager may direct site quarantine: flagging, signage, trailhead notices, online updates.
Step 7–9
Qualified personnel remove the tree per team requirements; reopen site if closed; resume monitoring.
Removal Team Requirements
Team
Minimum of two people per removal.
First aid
At least two team members trained in first aid.
Sawyer
At least one B- or C-Feller-certified sawyer required; sawyers don't exceed their comfort/certification level.
Rigging
If rigging is required, at least one member trained in tree risk assessment and arborist rigging must be present.
Bat Conservation Parameters (APPA Programmatic BA)
Threshold
Suitable NLEB/bat roost trees: live trees and snags ≥ 3" DBH with cavities, cracks, or exfoliating/loose bark.
Safe window
Nov 1 – Mar 31 (bat inactive season). Removal outside this window requires deferral or the imminent hazard exception.
Inspection
A roost inspection must be completed within 72 hrs prior to removal for any suitable roost tree removed outside the safe window.
Exception
A suitable roost tree posing an imminent hazard may be removed outside the window without waiting, if documented and, where applicable, USFWS/resource staff are consulted.
Sources
ATC
Guidance on Appalachian Trail Hazardous Trees, Final, April 2026.
USDA FS
Urban Tree Risk Management: A Community Guide to Program Design and Implementation (NA-TP-03-03, 2006).
APPA
Programmatic Biological Assessment, bat conservation measures.
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Risk Rating Distribution
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Trees by State
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Top Species
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Field Determination
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