Trapper area piles

Live site: https://jburdick-m.github.io/trapper-area-piles/

Interactive map and disposal planner for the large burn piles left by fuels treatments in the Pike-Magnus, Graveyard, Sleighville and Alaska Peak units, Tahoe National Forest.

The page maps 212 piles 40 ft and wider: 205 from the first pass and 7 the automated pass below found that it missed, 2 of them in NE Sleighville units (322 and 666) that were flown in Feb 2026 but lay north of the first pass's analysis extent. Sliders set packing ratio, wood density, grind-and-haul and carbonator rates, and the totals, project table and map update as they move. The "all project ground" figures carry each project's flown totals onto its unflown unit acres at the same piles per acre (flown × unit acres / flown acres), an allowance for piles outside the 2026 lidar; 33% of unit acres were not flown.

Data

File	Contents
data/piles.json	One row per pile: project, unit, footprint, diameter, height, gross volume and 95% sampling interval, footprint outline. Rows with added: true (ids 1001+) come from the automated pass and carry a 90% volume range, pile probability, stability and pulse count
data/piles_30_40ft.json	The 13 piles 30–40 ft the automated pass found, same fields. Not shown on the page: too incomplete to count yet
data/units.json	Treatment units with acres and the share covered by the 2026 lidar
data/layers.json	Project boundaries, Feb 2026 lidar footprint (from the ASO tiles: 25 m cells with at least 0.5 points per m², gaps up to 200 m filled), National Forest System land (USFS basic ownership, Tahoe and Plumas NF, across the whole map), analysis extent
data/assumptions.json	Slider defaults and ranges, with their sources
data/hillshade.jpg	Hillshade background from USGS 3DEP, 25 m, covering all four projects
data/piles/pile_<id>.webp	Lit 3-D view of each pile at true scale with a chip van and tractor beside it, shown when a pile is clicked

Coordinates are NAD83 / UTM zone 10N (metres).

Method

• Piles are opaque mounds in the Feb 4, 2026 ASO lidar that were not there in 2022, measured against the 2022 TNF 1 m bare-earth DEM and canopy height model.
• Volume is gross (including air space), the 2026 surface minus 2022 bare earth over each footprint.
• Dry tons = volume × packing ratio × wood density (Hardy 1996, PNW-GTR-364). Defaults: 0.20 and 380 kg/m³.
• Cost defaults come from the Siskiyou County biochar demonstration (2020–21), Earth Foundries (2024), the Central Sierra feedstock report (2023), Yoshioka et al. (2017) and CAL FIRE (2023). They are planning estimates, not quotes.

What the costs include

Grind and haul	Carbonator
Grind and load ($/dry t), chip-van haul (round trip + 1 h load/unload), contractor markup	Contract rate per run-hour (machine, operator, feeding loader, margin)
Grinder and loader move-in per project	Carbonator and loader move-in per project, per machine
Fire support: Forest Service's own, not costed	Contracted fire support (water tender) per machine per working day
Plant gate payment or tipping fee (default: no credit)	Biochar value not credited

Diesel: the slider sets the on-road pump price and starts at the California average, $8.46/gal (AAA, Oct 24, 2026). Chip vans, lowboys and the carbonator's fire support pay that price. The grinder, carbonator and their loaders burn dyed off-road diesel, priced from the slider: take out California's diesel excise (48.2¢/gal, outside the sales tax base), the 13% diesel sales tax and the federal excise (24.4¢), then add the 7.25% sales tax dyed diesel pays off-road (CDTFA rates from July 2026; district taxes apply to both and are left out). That gives $7.31/gal at today's price. The other default rates are taken as priced when diesel was about $5.00/gal ($4.03 off-road; AAA average $5.12 a year earlier), so the slider adds or removes only their fuel share, using assumed fuel use in data/assumptions.json: grinder and loader 40 gal per productive hour, chip vans 5.5 mpg plus 1 gal idling per load, carbonator and loader 10 gal per run-hour, carbonator fire support 25 gal per day, and 100 gal per move-in. Each $1/gal on the slider adds about $105k to grind and haul and $30k to the carbonator at default settings; today's price adds about $360k and $100k over $5.00 diesel.

Grind-and-haul working days are set by the slower of the grinder (dry t/h × hours) and the trucks (whole round trips per 11 h driver day). Not included: agency contract preparation and oversight, road maintenance or reconstruction for chip vans, permits, and cleanup of pile sites.

Chip destinations

Routed road miles from the units (OpenStreetMap routing):

Destination	One-way
Rio Bravo Rocklin, Lincoln (default)	69 mi
Sierra Pacific cogeneration, Quincy	75 mi
Woodland Biomass, Woodland	106 mi
Buena Vista Biomass, Ione	112 mi
Honey Lake Power, Wendel	150 mi

Pile views

tools/pile_views.py draws the image shown when a pile is clicked (no title; the panel heading names the pile). It grids the Feb 4, 2026 returns (gs://aso-august-w1/pc_work_10212026/pike_view2/tiles) against 2022 bare earth from the USGS CA_SierraNevada 2022 ground returns (public EPT), inside each pile's footprint. The 2026 points are shifted onto the 2022 ground by the Feb flight's ground offset (+0.18 m, as in the pile mapping), standing trees are filtered out, and heights are capped at the mapped pile height. The chip van is a 53 ft × 8.5 ft × 13.5 ft trailer behind a day-cab tractor, about 69 ft overall. Tree filtering and smoothing make the drawn surface a little low: image volumes run a median 8% under vol_m3. The 2022 ground for each pile is cached in gs://aso-august-w1/pc_work_10212026/pile_views/ground22/ so the render runs from the bucket alone.

This is the beginning of the README. Read the rest at the original. Read the full README ↗