Basic Information
Abbatis (or variant spellings thereof) is a type of fortification designed to slow and disrupt enemy troop movements. An abbatis is traditionally made from trees and bushes - although some sources may also use it to refer to a barbed wire obstacle. (This usage of the term was a lot more common in the late 19th Century and early 20th Century when barbed wire was relatively new and considered more of an alternative to traditional wooden abbatis by most militaries.)
The term covers a variety of structures, but the default seems to be an area of trees, felled but not completely cut through so that the fallen trunk remains attached to the stump to impede clearance. The resulting mess provides a significant barrier to wheeled vehicles, cavalry and heavy infantry - although light infantry (especially those armed with ranged weapons) have a tendency to use it as cover1. It is also extremely disruptive to the deployment of siege engines - even as low down the scale as ladders, gabions and fascines. Properly used it can be quite effective in disordering assaults on a position.
Other things that have been called abbatis (besides those using barbed wire) include hedges of wooden spikes2 (especially bamboo ones, sometimes called panjis) and thorn-bush obstacles, either as a living hedge or as a mass of cut branches. Sub-saharan Africa traditionally made great use of zariba - thorn bush barriers - circumstances dictating whether such a barrier was a woven fence, a living hedge or a pile of branches.
By its nature, abbatis tends to be a short lived form of obstacle - even if no-one burns or bombards it to clear it away, natural decay will tend to reduce its effectiveness after a relatively short time. Also, unless the obstacle is closely defended, there is the probability that the local population will use it as a source of free timber when the garrison's backs are turned.
Sources
Game and Story Use
- Actually quite good cover for covert ops type people sneaking up on a fortification.
- And a good venue of a battle between skirmishers.
- Where sufficient trees are to be had, abbatis on its own could make for a relatively quick and easy defensive position for an infantry unit plagued by cavalry of the horse-borne, chariot, or even modern wheeled varieties (such as an Armoured Personnel Carrier.
- Obviously this makes a poor choice for a permanent part of a fortification … except for the thorn hedge type, which can make a useful obstacle, not to mention a good filler for a dry moat
- For example, several moderately secure buildings in the UK are surrounded by what appears to be a low, wide thorn hedge - and is actually a ditch, big enough to swallow a car and full of a viciously spiked thorn bush such as burberris. The resulting obstacle does little to impede the view from the building and prevents it looking obviously fortified, but makes access from unexpected directions nearly impossible without using heavy equipment..