pyfia 1.1.0b3

High-performance Python library for Forest Inventory Analysis (FIA) data analysis

The Python API for forest inventory data

Part of the FIAtools Python Ecosystem
pyFIA · gridFIA · pyFVS · askFIA

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A high-performance Python library for analyzing USDA Forest Inventory and Analysis (FIA) data. Built on DuckDB and Polars for speed, with statistical methods that match EVALIDator exactly.

Why pyFIA?

Feature	pyFIA	EVALIDator
Speed	10-100x faster	Baseline
Interface	Python API	Web UI
Reproducibility	Code-based	Manual
Custom analysis	Unlimited	Limited options
Statistical validity	✓ Exact match	✓ Reference

Quick Start

pip install pyfia

from pyfia import FIA, biomass, tpa, volume, area

with FIA("path/to/FIA_database.duckdb") as db:
    db.clip_by_state(37)  # North Carolina
    db.clip_most_recent(eval_type="EXPVOL")

    # Core estimates
    trees = tpa(db, tree_domain="STATUSCD == 1")
    carbon = biomass(db, by_species=True)
    timber = volume(db, land_type="timber")
    forest = area(db, land_type="forest")

Core Functions

Function	Description	Example
tpa()	Trees per acre	tpa(db, tree_domain="DIA >= 5.0")
biomass()	Above/belowground biomass	biomass(db, by_species=True)
volume()	Merchantable volume (ft³)	volume(db, land_type="timber")
area()	Forest land area	area(db, grp_by="FORTYPCD")
mortality()	Annual mortality rates	mortality(db)
growth()	Net growth estimation	growth(db)

Statistical Methods

pyFIA implements design-based estimation following Bechtold & Patterson (2005):

• Post-stratified estimation with proper variance calculation
• Ratio-of-means estimators for per-acre values
• EVALID-based filtering for statistically valid estimates
• Temporal methods: TI, annual, SMA, LMA, EMA

Installation Options

# Basic
pip install pyfia

# With spatial support
pip install pyfia[spatial]

# Development
git clone https://github.com/mihiarc/pyfia.git
cd pyfia && pip install -e .[dev]

Documentation

📖 Full docs: mihiarc.github.io/pyfia

Integration with FIAtools

pyFIA works seamlessly with other tools in the ecosystem:

# Use pyFIA data with gridFIA for spatial analysis
from pyfia import FIA
from gridfia import GridFIA

with FIA("database.duckdb") as db:
    species_list = db.get_species_codes()

api = GridFIA()
api.download_species(state="NC", species_codes=species_list)

The FIAtools Ecosystem

PyFIA is part of the FIAtools Python ecosystem - a unified suite of open-source tools for forest inventory analysis:

Tool	Purpose	Key Features
pyFIA	Survey & plot data	DuckDB backend, 10-100x faster than EVALIDator
gridFIA	Spatial raster analysis	327 species at 30m resolution, Zarr storage
pyFVS	Growth simulation	Chapman-Richards curves, yield projections
askFIA	AI interface	Natural language queries for forest data

Explore the full ecosystem at fiatools.org

Citation

@software{pyfia2025,
  title = {pyFIA: A Python Library for Forest Inventory Analysis},
  author = {Mihiar, Christopher},
  year = {2025},
  url = {https://fiatools.org}
}

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fiatools.org · Python Ecosystem for Forest Inventory Analysis
_{Built by Chris Mihiar · USDA Forest Service Southern Research Station}