FEMA Hazardous Tree, Hanger, and Stump Screen with Extraction Volume

ScopeAfter a storm, tree crews on public property work to FEMA's thresholds, and this calculator applies them in the order a reimbursement reviewer will. A tree is hazardous when the disaster caused its condition, it is an immediate threat, it is at least 6 in at breast height, and it has more than 50% of the crown damaged, a split trunk or broken branches exposing heartwood, has fallen or been uprooted in a public-use area, or leans more than 30 degrees. The lean is the one criterion that needs arithmetic: a top displaced 6 ft at a point 8 ft up the trunk is atan(6/8), about 36.9 degrees, so it qualifies -- and with only 30% of its root ball exposed it is cut flush and the stump stays, not separately paid. A hanging limb qualifies over 2 in at the break, on improved public property, threatening a public-use area. A stump with half or more of its root ball exposed, over 24 in in diameter measured 24 in above ground, on public property or right-of-way, is extracted, and the volume paid is the stump and its root ball from FEMA's conversion table: a root ball 3.6 times the stump diameter and 31 in deep. The table does not state the stump length it includes; 24 in reproduces every row, and the calculator says so. A 36 in stump is 9.3 cubic yards -- 94% of it root ball -- and a 48 in stump is 16.5; the same volume is the fill for the hole. It does not assess tree risk as an arborist would, cover private-property trees except limbs over a public right-of-way, or price the work. FEMA Public Assistance, the state, and a qualified arborist govern.

Formula or tabletree: disaster-caused, immediate threat, DBH >= 6 in, and any of crown damage > 50%, split trunk or exposed heartwood, fallen or uprooted in a public-use area, lean = atan(offset / height) > 30 degrees; < 50% root ball exposed -> cut flush; hanger > 2 in at the break over a public-use area; stump >= 50% root ball exposed, > 24 in at 24 in above ground, on public property -> extract; volume = [D^2 x pi/4 x 24 + (3.6 D)^2 x pi/4 x 31] / 46,656 cy.

Source and editionFEMA-325, Public Assistance Debris Management Guide (July 2007), hazardous trees, hazardous limbs (hangers), and hazardous stumps, and Appendix G, DAP9523.11 Hazardous Stump Extraction and Removal Eligibility, stump conversion table (root ball 3.6 times the stump diameter, 31 in high). The current Public Assistance Program and Policy Guide carries the criteria forward and governs where they differ.

Free accessFEMA-325 and the Public Assistance Program and Policy Guide are free federal publications on fema.gov.

What governsEstimate. AHJ and licensed professional govern.

API field namesdisaster_threat, dbh_in, crown_damage_pct, split_trunk, fallen_in_public_use, lean_offset_ft, lean_height_ft, root_ball_exposed_pct, hanger_dia_in, hanger_over_public_use, stump_dia_in, stump_on_public_property, extraction_volume_cy, fill_volume_cy

• Stump length 24 in not stated in the conversion table; it reproduces every row (36 in -> 9.3 cy, 48 in -> 16.5 cy)FEMA-325 Appendix G, DAP9523.11 (inferred)
• Root ball 3.6 x the stump diameter, 31 in high the field findings behind the conversion tableFEMA-325 Appendix G, DAP9523.11
• Extraction volume is the fill volume the documentation asks for the quantity of material needed to fill the holeFEMA-325