AVM Infrastructure
TerraValue prices canopy, soil, and natural assets at parcel level — with USPAP-grade rigor, citation-traceable methodology, and a published model card. License the residual layer your AVM is missing.
Founded out of P&X — Phloem & Xylem.
Inside the Engine
TerraValue ingests parcel boundaries, assessed value, and canopy coverage from live municipal ArcGIS endpoints. It runs each parcel through a USPAP three-approach reconciliation (cost / sales-comparison / income) with an ecosystem-services overlay computed from peer-reviewed USDA and EPA methodologies.
The output is a per-parcel ecosystem residual — the dollar value attributable to natural assets — delivered as JSON via API, with full data-quality flags and citation traces. The same call powers the calculator below, the institutional API, and the field-verified case-study reports.
Address → Nominatim geocode → cascading ArcGIS lookup (city endpoint first, county fallback). Returns boundary, assessed value, lot size, canopy %.
Cost approach, sales-comparison approach, and income approach computed in parallel with documented weighting. O.C.G.A. § 48-5-7 assessment ratio coded for Georgia.
Six service rates (carbon, stormwater, air quality, energy, habitat, property premium) applied per canopy-acre. EPA SC-GHG, iTree, BenMAP, McPherson, Kovacs, Netusil — all engine-level.
JSON response with reconciled valuation, ecosystem residual, per-service breakdown, dataQuality flags, and citation traces. PDF report optional.
Integration Surface
One REST endpoint, JSON in / JSON out, parcel-level. Drops in next to your existing AVM stack as a residual-improvement layer or a standalone natural-asset score.
Request
POST /v1/parcel
{
"address": "7840 Roswell Rd, Sandy Springs, GA",
"options": { "includeProjection": true }
}
Response
{
"ecosystemResidual": 4580,
"services": { ... },
"valuation": { "reconciled": 482000, "approaches": {...} },
"dataQuality": { "confidence": "high", "flags": [...] },
"citations": [...]
}
Add the ecosystem residual to your existing AVM output as an additive adjustment. Zero changes to your core model.
Surface natural-asset value as its own consumer-facing or underwriting field, distinct from your AVM estimate.
Async batch endpoint for portfolio scoring, climate-resilience underwriting, and TCFD/SBTi disclosure pipelines.
Residual Signals
Each service is a separately-computed signal in the per-parcel residual. AVM integrators can consume the totalAnnual residual (the five recurring annual services), the one-time property-value premium reported alongside it, or any subset of the six fields — with citation traces and data-quality flags returned per field. Per-service rates and methodology are documented in the model card.
Trees absorb CO2 and store it as biomass. We calculate annual sequestration per canopy acre and price it at the EPA social cost of carbon.
2.6 t CO2/acre/yr (Atlanta iTree Eco) × $190/tonne (EPA SC-GHG 2023, 2% near-term)
Canopy intercepts 35% of rainfall. We calculate gallons diverted from the storm system and price at municipal avoided treatment costs.
Benefit transfer from USDA CUFR / iTree Eco urban canopy valuation literature
Trees filter PM2.5, ozone, NO2, and SO2. Atlanta's PM2.5 concentration makes this one of the highest-value services.
Nowak et al. 2014, BenMAP-CE health valuation ($117K/ton PM2.5 national median)
Strategic canopy reduces cooling loads in summer and wind exposure in winter. Avoided kWh per canopy acre.
McPherson 2003, Atlanta iTree Eco: 1,800 kWh/acre/yr × $0.14/kWh (GA Power avg)
Canopy provides nesting, foraging, and corridor habitat. Priced using willingness-to-pay studies for urban biodiversity.
Troy & Wilson 2006; Brander & Koetse 2011 (benefit transfer, approximate)
Mature canopy coverage adds a measurable premium to assessed property values. Often the single largest dollar amount.
Kovacs et al. 2022; Netusil et al. 2014: ~— premium (capped at 12%)
Sensitivity Analysis
Adjust home value, current and projected canopy score, and time horizon to see how the per-parcel residual responds. For AVM integrators, this is a quick visualization of the same dose-response curve the engine applies in production.
Illustrative model. Projection assumes a 15,000 sqft typical lot and derives canopy from the score slider (canopy % ≈ score × 0.4). For parcel-specific results, use the calculator above with your actual lot size.
Projections use linear scaling from Soil Score to canopy coverage change. Actual results depend on species, placement, maturity, and local conditions. This is a directional estimate, not a guarantee.
Who This Is For
Primary buyers are the institutions that underwrite, value, and surface residential property at scale. Operating-market and case-study customers below.
License the canopy and ecosystem residual layer your model is missing. CFPB AVM-rule compatible model card, citation-traceable methodology, USPAP-defensible.
Quantify natural-asset collateral value with audit-grade methodology. Useful for portfolio monitoring and climate-resilience underwriting.
Add a defensible green-premium feature without standing up new geospatial or appraisal infrastructure. API-first delivery.
Operating Market
Pre-construction lot economics that price preservation, not just clear-and-build. Defensible canopy-attributable value at the site-plan stage.
TCFD- and SBTi-aligned natural-asset disclosures across residential portfolios, parcel-level and audit-grade.
Urban canopy asset valuation, stormwater fee-credit programs, and ordinance-grade evidence for tree-fund decisions.
Practitioner Tier
Appraisers, brokers in canopy-rich markets, homeowners running tax appeals or sale-prep, and HOAs are the intended first users at this tier. Minimal revenue contribution by design — the purpose is field evidence, not revenue.
Gate 1 — sales ratio study
Washington, DC residential sales from 2025 onward, held out of training entirely. Ratios are predicted value divided by observed sale price. Both the trimmed and untrimmed bases are reported — not only the flattering one.
Every one of the 4,788 holdout sales is represented; density is binned rather than sampled. The amber trace is the median ratio within each price decile — it is the vertical-equity read, and it is the reason PRD fails untrimmed. 137 sales fall outside the plotted ratio range and are included in every statistic.
Median ratio
0.965
IAAO standard 0.90–1.10. Passes.
COD (trimmed)
10.5
Standard ≤15. Passes. Untrimmed 12.4.
PRD (untrimmed)
1.039
Standard ≤1.03. Fails untrimmed; 1.020 trimmed.
Top decile ratio
0.888
Sales above roughly $2M center low.
Stated limits
Launch Geography
The Fulton County parcel service is verified live at 373,306 parcels — measured by a committed endpoint probe, not asserted. That figure is a live count and moves as parcels split and merge; it was last re-probed 9 September 2026. Every launch jurisdiction below sits inside it. National rollout uses NLCD canopy raster + county-level parcel ingest, with the same engine and the same model card. Pilot-stage integrations available now in launch geography; national availability sequenced to validation-study publication.
Lot size, appraised value and canopy resolve for any parcel in the county. Zoning is joined for Sandy Springs, Johns Creek and Atlanta only — the remaining jurisdictions publish no parcel-level base-zoning layer to join against, so zoning there is returned as unavailable rather than inferred.
Under the Hood
Live public endpoints, peer-reviewed research, and institutional-grade methodology — wired together. Every field in the JSON response is traceable to a source.
Parcel records county-wide · zoning join: Sandy Springs, Johns Creek, Atlanta
Validation
On 4,788 sales from 2025 onward, held out of training entirely: median ratio 0.964, COD 10.5, PRD 1.020, PRB −0.015 (IAAO extreme-ratio trimmed; untrimmed passes three of the four, PRD 1.039 against a ≤1.03 standard). Head-to-head on identical sales, untrimmed, it beats the DC assessor’s roll on uniformity (COD 12.4 vs 13.4) and on both vertical-equity metrics (PRD 1.039 vs 1.056; PRB −0.040 vs −0.069). Trimmed, both systems clear all four and the assessor edges uniformity (COD 10.1 vs 10.5) — we report both bases rather than the flattering one.
Shipped as FittedValuation in engine v1.4.0 (methodology 2.0.0), with a 4,788/4,788 trainer–scorer parity check within 0.0004%. Honest limits: the artifact is Washington, DC only; the >$2M tier still centers low (median ratio 0.894 untrimmed); and it is server-side, not yet what powers the calculator on this page.
We don't claim accuracy lift against incumbents (Zestimate, HouseCanary, CoreLogic) until a head-to-head study against them is on paper and reviewed.
Founded Out Of P&X
TerraValue was founded out of P&X — Phloem & Xylem, an Atlanta-based natural-resource consulting practice. P&X provides parcel-level ecosystem assessments, regenerative landscape design, and tree-preservation planning for engineering firms, developers, and property owners across Georgia. TerraValue productizes the valuation methodology developed across those engagements.
P&X was founded by William Park, the Urban Forester and Sustainability Coordinator for the City of Sandy Springs, Georgia, and the 2024 recipient of the Georgia Tree Council's Outstanding Urban Arboriculture Grand Award. He came to municipal urban forestry by way of Trees Atlanta, the Georgia Department of Natural Resources State Parks Division, and an Andreessen Horowitz–backed sustainability startup (The Rounds). He's an Emory University graduate, an ISA Certified Arborist, holds the Urban Forest Specialist credential and TRAQ qualification, and serves on the Georgia Arborist Association Board of Directors and the ISA Credentialing Council — the body that sets professional standards for the industry.
Why this matters for an AVM buyer
The methodology is built by someone who writes the canopy ordinances most cities use, sits on the body that credentials the appraisers and arborists who would defend any contested valuation, and has shipped product inside a venture-backed startup before. That combination is hard to acquire and harder to fake.
Ready?
Pilots, API access, and validation-study briefings are scoped on request. Atlanta metro live; national pipeline in build.
Reviewing this as a colleague or mentor? This is an MVP and candid notes are the point — send feedback.