Volume Estimation

Description

Calculates timber volume using Pacific Northwest (PNW) volume equations. Supports multiple log rules (Scribner, Doyle, International 1/4") and applies defect deductions. Expands plot-level volumes to per-acre estimates and aggregates by species for salvage planning.

Triggers

When should the agent invoke this skill?

•User asks about timber volume or board feet
•Query mentions "volume estimation" or "MBF"
•Request for per-acre volume calculations
•Questions about log rules or volume equations
•Plot data analysis requests
•Salvage volume assessment

Instructions

Step-by-step reasoning for the agent:

•
Load Tree Data: Parse individual tree measurements (species, DBH, height)
- •Support FSVeg species codes (PSME, TSHE, THPL, etc.)
- •Validate DBH and height ranges for realism
•
Calculate Individual Tree Volume: Apply PNW volume equations
- •Use species-specific equation parameters
- •Support Scribner, Doyle, and International log rules
- •Return gross volume before defect deduction
•
Apply Defect Deductions: Reduce gross volume by defect percentage
- •Fire damage, rot, sweep, crook
- •Typical salvage defect: 15-40%
•
Expand to Per-Acre: Convert plot volume to per-acre basis
- •Variable radius: Use BAF and tree count
- •Fixed radius: Use plot area
•
Aggregate by Species: Sum volumes and categorize
- •Commercial species (Douglas-fir, hemlock)
- •Secondary species (true firs, pine)
- •Low-value species (lodgepole)

Inputs

Input	Type	Required	Description
fire_id	string	Yes	Unique fire identifier (e.g., "cedar-creek-2022")
plot_id	string	No	Specific plot to analyze
trees	array	No	Tree measurement data (species, DBH, height, defect)
baf	number	No	Basal area factor for variable radius plots (default: 20)
log_rule	string	No	Volume log rule: "scribner", "doyle", "international" (default: "scribner")
include_defect	boolean	No	Whether to apply defect deductions (default: true)

Outputs

Output	Type	Description
fire_id	string	The analyzed fire identifier
plot_id	string	Plot identifier (if provided)
total_volume_mbf	number	Total net volume in thousand board feet (MBF)
volume_per_acre_mbf	number	Expanded per-acre volume in MBF
trees_analyzed	number	Count of trees in analysis
species_breakdown	object	Volume by species with percentages
log_rule	string	Log rule used for calculations
reasoning_chain	array	Step-by-step volume calculations
confidence	number	Calculation confidence (0-1)
data_sources	array	Sources used (PNW equations, log rules)
recommendations	array	Volume utilization guidance

Reasoning Chain

Step-by-step reasoning for the agent:

•First, load tree measurement data from plot or fixture
•Then, calculate gross volume for each tree using PNW equations
•Next, apply defect deductions based on fire damage and quality
•Then, expand plot totals to per-acre estimates using BAF or plot area
•Finally, aggregate by species and generate salvage recommendations

Resources

•resources/volume-tables.json - PNW volume equation coefficients by species
•resources/species-factors.json - FSVeg species codes and bark ratios
•resources/log-rules.json - Scribner, Doyle, International conversion factors

Scripts

•
scripts/estimate_volume.py - Python implementation of volume estimation
- •Function: execute(inputs: dict) -> dict
- •Inputs: {"fire_id": "cedar-creek-2022", "plot_id": "47-ALPHA"}
- •Returns: Complete volume analysis with species breakdown

Examples

Example 1: Single Plot Volume Estimation

Input:

json

{
  "fire_id": "cedar-creek-2022",
  "plot_id": "47-ALPHA",
  "baf": 20,
  "log_rule": "scribner"
}

Output:

json

{
  "fire_id": "cedar-creek-2022",
  "plot_id": "47-ALPHA",
  "total_volume_mbf": 32.4,
  "volume_per_acre_mbf": 32.4,
  "trees_analyzed": 6,
  "species_breakdown": {
    "PSME": {
      "volume_mbf": 26.8,
      "percentage": 82.7,
      "tree_count": 4,
      "avg_dbh": 28.0
    },
    "TSHE": {
      "volume_mbf": 2.9,
      "percentage": 9.0,
      "tree_count": 1,
      "avg_dbh": 18.4
    },
    "THPL": {
      "volume_mbf": 2.7,
      "percentage": 8.3,
      "tree_count": 1,
      "avg_dbh": 22.3
    }
  },
  "log_rule": "scribner",
  "reasoning_chain": [
    "Loaded 6 trees from plot 47-ALPHA",
    "Tree #1 PSME 28.5\" DBH × 145' height = 1.82 MBF gross, 1.55 MBF net (15% defect)",
    "Tree #2 PSME 24.2\" DBH × 132' height = 1.24 MBF gross, 0.93 MBF net (25% defect)",
    "Tree #3 PSME 32.1\" DBH × 158' height = 2.45 MBF gross, 2.20 MBF net (10% defect)",
    "Tree #4 TSHE 18.4\" DBH × 98' height = 0.67 MBF gross, 0.44 MBF net (35% defect)",
    "Tree #5 PSME 26.8\" DBH × 140' height = 1.58 MBF gross, 1.26 MBF net (20% defect)",
    "Tree #6 THPL 22.3\" DBH × 112' height = 1.12 MBF gross, 0.95 MBF net (15% defect)",
    "Plot total: 32.4 MBF, BAF 20 expansion = 32.4 MBF/acre",
    "Douglas-fir dominates (82.7%) with high salvage value"
  ],
  "confidence": 0.94,
  "data_sources": ["PNW-GTR volume equations", "Scribner log rule"],
  "recommendations": [
    "High-value Douglas-fir salvage potential: 26.8 MBF/acre",
    "Monitor defect progression in western hemlock (high defect)",
    "Prioritize this plot for immediate salvage operations"
  ]
}

Example 2: Custom Tree List

Input:

json

{
  "fire_id": "test-fire",
  "trees": [
    {"species": "PSME", "dbh": 30.0, "height": 150, "defect_pct": 12},
    {"species": "PSME", "dbh": 28.0, "height": 145, "defect_pct": 18},
    {"species": "PIPO", "dbh": 26.0, "height": 120, "defect_pct": 15}
  ],
  "baf": 20,
  "log_rule": "international"
}

Output:

json

{
  "fire_id": "test-fire",
  "total_volume_mbf": 15.8,
  "volume_per_acre_mbf": 15.8,
  "trees_analyzed": 3,
  "species_breakdown": {
    "PSME": {
      "volume_mbf": 11.6,
      "percentage": 73.4,
      "tree_count": 2
    },
    "PIPO": {
      "volume_mbf": 4.2,
      "percentage": 26.6,
      "tree_count": 1
    }
  },
  "log_rule": "international",
  "reasoning_chain": [
    "Analyzing 3 custom trees",
    "Tree PSME 30.0\" × 150' = 2.12 MBF gross, 1.87 MBF net (12% defect)",
    "Tree PSME 28.0\" × 145' = 1.82 MBF gross, 1.49 MBF net (18% defect)",
    "Tree PIPO 26.0\" × 120' = 1.65 MBF gross, 1.40 MBF net (15% defect)",
    "Total net volume: 15.8 MBF"
  ],
  "confidence": 0.88,
  "data_sources": ["User-provided tree data", "International 1/4\" log rule"]
}

References

•Brackett, M. (1973) "Notes on Tarif Tree Volume Computation"
•PNW-GTR-019: "Volume Equations for Commercial Species"
•Scribner Decimal C Log Rule
•International 1/4-inch Log Rule
•Cedar Creek Timber Plots: data/fixtures/cedar-creek/timber-plots.json