The importance of brashing plantations

By Donal Magner

13 Aug 05 : Regular inspection of plantations are important as they allow growers to monitor crop performance and to plan management operations such as fire protection, forest roading, first thinning and pruning. Inspection is relatively easy for the first few years after planting but in fast growing coniferous plantations, access can be difficult as early as year six when trees compete vigorously for space and side branches, and foliage meet between tree rows.

Around year 10, canopy (tree crown branches) begins to close and at that stage it is impossible to fully monitor a crop's performance without cutting or brashing inspection paths through the plantation.

Brashing

Brashing involves the removal of the lower branches between two lines of trees, up to 1.8 metres or head height. It is recommended to brash lines at regular intervals. The number of lines that need to be brashed will depend on the size of the plantation and the uniformity of the crop. Parallel paths should be brashed at least every 100 metres or every 50th line in crops planted at 2.0 metre spacing.

In small mixed species, plantations growers are advised to brash every 25th line or every 50 metres in crops planted at 2.0 metre spacing. Brashed lines should also be connected by brashing parallel rows at right angles every 50 or 100 metres.

Timing

The time of brashing will depend on growth rates and species. Some growers cut pathways as soon as side branches touch and the plantation becomes inaccessible. It is essential to carry out the operation at least two to three years before thinning which can be anytime from year 11 onwards. At that stage, the lower branches are dead but remain intact and the plantation is almost impenetrable without brashing access paths.

Brashing is a straightforward operation and requires little equipment. In light branched stems it can be carried out with a hook or strong secateurs, although for most species the preferred equipment is either a pruning saw or light chainsaw.

Branches need to be cut cleanly and close to the stem. Operators should take necessary safety measures, especially when using chainsaws.