SelectFor Continuous Cover Forestry Research Programme
In plantation forestry in Britain, performance in timber production terms is only actually confirmed at the liquidation of the stand. Before then the mensurational framework of management tables and the yield class system developed by the Forestry Commission allows the manager to determine which trajectory of productive capacity a stand is likely to be on and provides guidance on the interventions necessary to maximise volume production. This maximisation is directed at the stand as a whole and management is directed at achieving stand-wide target parameters such as total stand volume and average stem volume.
In permanently irregular stands, the focus is on optimising the individual elements of the stand; this optimal production level is achieved by distributing the available timber increment onto the quality stems and by creating a sustainable framework in which an appropriate distribution of size groups is combined with sufficient regeneration and recruitment of smaller stems into the main stand.
Theoretically there will be an ideal structure that will deliver continuously the highest value increment. In practice, however, the complexities of species composition and seasonal climatic variation mean that for a particular stand such an ideal can only be defined in fairly broad terms. The manager can ask ‘are we moving forwards or backwards’ and aim by iterative movements over a long period to approach a quasi-optimal state.
This process requires not only knowledge of what the structure and composition of the stand is, and how it is changing over time, but also the measurement of the performance of that stand as the structure changes. So eventually information on the timber increment of whole stands and their constituent parts is required.
Extracting such information requires long time-series of data and such data exist in central and north-western Europe, largely for coniferous and beech stands but increasingly for broadleaved stands as well; repeated periodic inventories using some form of the Check Method to measure increment are commonplace and other methodologies using sampling have also been developed.
Results from this type of monitoring can be used to guide management locally as well as forming part of integrated research networks which seek to measure a wider range of silvicultural parameters designed to provide more detailed insights into the effect of silviculture and allow comparisons between sites and climatic regions. Over time such data also enables managers to be able to learn where successful silvicultural journeys have led others, on comparable sites to their own.
In Britain direct measurement of increment in Continuous Cover stands for management or research purposes is very rare.
The aim of the SelectFor Continuous Cover Forestry Research Programme is to address this lack of data with regard to more developed, permanently irregular stands in the UK and Ireland and also to establish a link with one of the most successful European Continuous Cover Forestry Research Networks, that one created by the French “Association Futaie Irrégulière” in association with the L’Ecole Nationale du Genie Rural, des Eaux et des Forests at Nancy, the leading forestry university and forest research centre in France.