About

Forestry transactions rely on the distinction between the gross dimensions of a wood stack and the actual volume of timber contained within it. When logs are stacked, air gaps create a significant volume discrepancy. Invoicing based on gross dimensions without applying a specific stacking coefficient leads to financial inaccuracies and inventory errors. Professional scalers and mill operators use the solid content factor to determine the net wood volume.

This tool computes the Solid Volume by applying industry-standard coefficients to the Stacked Volume. Factors influencing this coefficient include log straightness, delimbing quality, diameter variety, and stacking density. Accurate conversion is essential for transport logistics (calculating truckloads) and fair payment in the pulp, paper, and sawmill sectors. The calculator handles metric and imperial inputs, allowing cross-border estimation.

Formulas

The calculation relies on determining the gross volume of the bounding box and reducing it by the air-to-wood ratio.

Stacked Volume = L × W × H

Solid Volume = Stacked Volume × k

Where L, W, and H represent the external dimensions of the stack. The coefficient k (Solid Content Factor) represents the ratio of wood to total space, where 0 < k < 1.

Reference Data

Timber Type & Condition	Stacking Quality	Solid Volume Factor (k)	Air Gap %
Conifer Sawlogs (Straight, >3m)	High (Machine)	0.70	30%
Conifer Sawlogs (Straight, >3m)	Average	0.66	34%
Pulpwood (Pine/Spruce, 3m)	Well Stacked	0.64	36%
Pulpwood (Pine/Spruce, 3m)	Loose / Crossed	0.58	42%
Hardwood (Birch/Aspen)	Straight	0.60	40%
Hardwood (Crooked/Knotted)	Average	0.52	48%
Firewood (Split, Throw-in)	Loose	0.40	60%
Firewood (Round, Stacked)	Hand Stacked	0.65	35%
Small Poles (< 10cm dia)	Tight Bundle	0.72	28%
Branches / Brushwood	Loose Pile	0.15	85%
Industrial Chips	Compacted	0.38	62%

Frequently Asked Questions

Moisture content technically affects weight, not volume. However, fresh green wood typically has tighter bark and may stack differently than dry wood where bark has fallen off. The coefficient focuses on geometry (air gaps), but if weight-based billing is used, a density factor must be applied separately.

In large-scale operations involving thousands of cubic meters, a deviation of 0.05 in the coefficient represents a 5% value discrepancy. For a standard logging truck carrying 40 stacked cubic meters, this error equals 2 cubic meters of solid wood, directly impacting profitability.

It depends on the standard used (Over-bark vs. Under-bark). Most general stacking coefficients estimate volume "over-bark". If "under-bark" volume is required for sawmill processing, the coefficient usually needs to be reduced by an additional 10-12% depending on the species.

Thrown (loose) firewood has a much lower coefficient, typically around 0.40 to 0.45. Hand-stacked split firewood creates fewer gaps, raising the coefficient to approximately 0.60 to 0.70. Buying "loose" volume often requires purchasing 1.5x the volume to get the same amount of wood as "stacked".