Whole Forest Inventory

Phil Morgan of SelectFor has been pioneering the use of an abbreviated version of the AFI Research Network Methodology to derive information on the overall timber production and structure of large upland forest estates in Wales and Ireland.

With the advent of certification there is an increasing requirement to account for the sustainable production from certified woodlands. Regular repeat inventories coupled with good planning and record keeping is a means of accounting for the state of the woodland resource when undergoing certification audits, as well as being an invaluable tool for the forest manager to refine his or her management.

Many forests in Britain are undergoing a phased transition to continuous cover, in part due to the history of woodland management, where late transformations have succumbed to wind and site conditions have constrained a response to fell in small coupes. Different restructuring strategies will create a range of different scenarios where forests have to rebuild capital reserves or where they are overstocked due to neglect and require transformation. Baseline inventories are a record of the forest condition at one particular time; repeat inventories carried out a regular cycle provide the means of monitoring the progress and evolution of the woodland.

Inventories are undertaken on a five or ten year cycle to record the growing stock and to monitor species composition, standing volume, tree size, timber quality, regeneration in all its phases from young seedlings to pole sizes as well as stand biodiversity.

The sustainability of the woodland is determined by the comparison of a baseline inventory and a subsequent repeat inventory, with the addition of harvesting records. The increment from the woodland is calculated and the proportion of increment which is harvested. Depending on circumstances the forest may be in a phase of capitalisation or de-capitalisation, or the forest may be at equilibrium where harvesting removal equals the increment.

The AFI inventory uses the same software as the with the Abbreviated AFI local research stands. Instead of a nest of subjectively located sample plots, a grid is superimposed over the forest area to systematically determine the permanent sample plot locations. The sampling intensity is determined by the size of the woodland so no pre-survey is undertaken to sample the variation within the forest. A measure of the variation between sample plots is recorded and is monitored.