Calculation Methodology & Technical Standards

The physics, USDA forestry data, and agricultural extension standards behind our tools.

1. Legal Cord Definition & Packing Density

In the United States, a legal cord equals 128 cubic feet of stacked wood ($4' \times 4' \times 8'$). However, solid wood accounts for only approximately 70% to 85% of that volume due to natural curvature and bark:

Neatly Stacked Wood: ~85% packing density • Loosely Tossed Wood: ~62% packing density

2. Moisture Content & Weight Multipliers

Freshly felled trees can consist of over 50% water by total weight. Wood is considered "seasoned" and ready to burn when its moisture content drops below 20% on a dry basis:

Green Oak: ~60–65 lbs per cubic foot solid (~5,000 lbs/cord)
Air-Dried Seasoned Oak: ~45–48 lbs per cubic foot solid (~3,800 lbs/cord)

3. Poultry Ventilation & Convective Draft Avoidance

Moisture is the primary vector for frostbite in backyard chickens. Birds expel water vapor continuously through their lungs and droppings. Agricultural extension standards require minimum air exchange without direct draft:

Vent Area = Floor Area (sq ft) ÷ 10 • Minimum 1.0–1.5 CFM per bird in winter