Timber fortifications are the quickest to raise where trees are plentiful and the weakest against time and fire: wood rots where it meets the ground, and it burns. A timber wall is also far lighter than an earth or stone wall of the same thickness, so it works as a barrier and a screen but cannot be assumed to give the kind of cover that a massive wall does.
Timber fortification is the use of logs and sawn wood for palisades, cribs and frames that make a position hard to enter, climb or see into.
Wood Is Quick, Light And Short-Lived
Where there are trees and axes, timber goes up faster than any masonry. Its three weaknesses should decide how you use it.
- It rots at the ground line. The parent article gives pine and spruce a life of about 3 to 5 years in the ground without treatment, and cedar, locust and oak decades; a palisade as a whole lasts 5 to 20 years depending on species and moisture.
- It burns. A palisade, a thatched roof inside a wall, and a store of fuel are all fire problems. See the fire section below.
- It is light. Compare mass per square metre of wall face (areal density). A solid softwood wall 0.175 m thick at an assumed 500 kg/m³ is 0.175 x 500 = 88 kg/m². A rammed earth wall 0.45 m thick at 1,800 kg/m³ is 0.45 x 1,800 = 810 kg/m², about nine times more. Round logs standing side by side leave gaps and are lighter still.
That last point is why timber is a barrier and a screen, not cover. This corpus holds no penetration tests: it cannot say what any timber wall stops, and a threat must be named by cartridge and range to say anything. The ballistic table in Defensive Architecture marks the softwood log row unproven for exactly this reason.
Three Forms
| Form | What it is | Use |
|---|---|---|
| Palisade | Vertical logs set in a trench | Barrier, screen, deterrent; see Palisade Construction |
| Log crib | Notched horizontal logs filled with earth or rubble | Thick wall; see Log Crib Walls |
| Timber frame | A skeleton of posts and beams carrying a roof | Carries load; infill does the work; see Timber Framing for Defense |
Fire Is The Design Problem
- Keep fuel away from the wall. Clear vegetation and stacked firewood back from a timber wall; how far depends on the fuel, wind and slope, and this corpus gives no safe distance.
- Do not put a thatched roof inside a timber wall. Thatch ignites from sparks and burns fast; see Thatching for the material, and use a non-combustible roof for anything that matters.
- Store fuel apart. If you keep gasoline or similar inside or near a timber enclosure, the hazard is vapour, which is heavier than air and travels along the ground to an ignition source; Fire Prevention covers petroleum vapour specifically, not fire safety in general.
- Earth faces help. A timber face with an earth fill or an earth bank behind it burns slower than bare timber; the fill is what carries the fire resistance.
What To Choose
Use timber where you need a barrier quickly, where trees are the plentiful material, and where you accept replacing it. Use earth or stone where the wall has to be heavy or must last, and combine them: a log crib filled with earth uses timber for the forms and earth for the mass.
Felling, lifting and fire
Felling trees and lifting logs kill and cripple: a single log of 15 to 20 cm diameter and 2.5 to 3 m long weighs roughly 20 to 65 kg (assumed density 500 to 700 kg/m³). Cut and lift as a team with a clear plan, and keep everyone out of the fall line. A timber wall in a fire can collapse inward onto the people sheltering behind it, so plan an exit that does not depend on passing the burning wall.
What’s Next
- Learn next: Palisade Construction — the standard timber wall
- Combine with: Log Construction — selecting and notching logs