Sample Plot Strategic Review
At the request of FC Forestry Group, FR Mensuration has been carrying out a fundamental review of the holding of permanent sample plots as well as policy for their establishment, maintenance and abandonment. A Working Group involving internal and external experts and stakeholders was formed to assist Mensuration project leaders in carrying out this review. The main conclusions were that:
- The objectives of the Forestry Commission sample plot network should be focussed specifically on providing data for development of models of forest growth and yield; any role of sample plots in providing data for other purposes or as a forest monitoring network should cease.
- The main objective of permanent mensuration sample plots should be to provide data for validation of models of forest growth and yield. Permanent sample plots should be maintained only in stands composed of tree species identified as 'principal' or 'contingency' in the context of British forestry.
- The network of permanent plots should include more mixed-species, mixed aged stands so as to better represent the range of forest types across Britain, as well as representing increasingly diverse silvicultural and management objectives.
- In addition to permanent sample plots, a programme of tactical assessments should be made in periodic and temporary sample plots to provide data for the formulation and calibration of improved forest growth and yield models. A succession of such 'integrated experiments' could be carried out to support the development of specific aspects of models to deliver progressive improvements in accuracy of forecasts.
Having considered these findings, the FC Forestry Group has asked FR Mensuration Branch to draw up proposals for a revised research programme and for the realignment of the existing national sample plot network.
As a prelude to the realignment exercise and also to assist with the decision making process required to identify which of the existing sample plots should be retained in 'principal' and 'contingency' species Mensuration staff will be discussing the existing network with Forest Districts and private estates. By the end of the current Forest Year it is expected that discussions will have been held with all but three Forest Districts. The remaining Forest Districts and the private estates will be contacted during FY 04/05.
The twin objectives of the discussions has been to agree, in principle, which sample plots can be felled with a full final measure and when. In nearly every case it has been possible to schedule the final measurement of a plot to coincide with harvesting operations in the near vicinity thus ensuring that the timber from the felled plots is not wasted. Where it has not been possible to schedule a plot for felling within a reasonable time-span, usually for stability or landscape reasons, a compromise solution has been arrived at. In a few instances it may be necessary to achieve the final measure by climbing the trees.
The second objective of the meetings has been to explain to local staff the rational behind the decision to fell much of the existing sample plot network and to inform them of the proposals for the future of the network. The reaction from local staff has been uniformly positive and the co-operation that Mensuration has received when putting together the felling and abandonment programme is greatly appreciated.
In addition to the proposed felling programme being formulated a costing exercise is being carried out which will be put to the TSUs early in the new FY for their consideration.
Establishment of New Sample Plots
As a result of the Strategic Sample Plot Review no new sample plots have been established during FY 03/04. However, Mensuration has been involved in the establishment and initial field work for the ten new EU Level II monitoring plots each of which contain a sample plot. This project is managed by Environmental Research Branch who finance any involvement by Mensuration.
Sample Plot Re-measurement Programme
The proposed re-measurement programme for FY 03/04 has, as was anticipated, been heavily revised as a result of the Strategic Sample Plot Review. The original programme consisted of 37 plots being scheduled for re-measurement during the FY. The revised programme consisted of 17 plots being felled with a full final measurement, all of which had been approved for abandonment by Robert Matthews. A further four plots were abandoned without a final measurement. All four plots were extensively windblown and the cost of obtaining a final measurement would have been prohibitive and the operation would have been dangerous to undertake. Seven plots from the original programme were re-measured, and when required, thinned. Additionally, three plots heavily infected with red band disease were re-measured at the request of East Anglia FD. These plots had been measured during the previous FY and the re-measurement a year later indicated that two of the plots had put on much less volume increment than would be expected whilst a third plot being managed under the standard Thetford thinning regime recorded a negative volume increment. A further 14 plots which are expected to be felled in the near future were given a girth only measurement.
Updated summaries for all the plots measured during the FY have been provided to the Forest Districts or private estates and where appropriate to the TSU which undertook the work.
Advisory Services
Advisory services accounted for 5 days during the FY. The service provided was in most cases to the FE and were in the form of visits to Forest Districts to assist with problems concerned with thinning or in the control of thinning on the ground. In addition a number of advisory telephone calls were received from the FE and the general public covering a wide range of issues and were generally resolved in less than five minutes.
Additionally funded advisory services were provided by the sample plot project leader being a member of the FE OSU Thinning Project Group. This required attendance at meetings and carrying out work on behalf of the group. Funded work was also carried out to support the WEB branch of Forest Research in their work on the impact of grey squirrels in the Forest of Dean. The work required of Mensuration involved the full re-measurement of a sample plot established some years ago on behalf of WEB and reporting on the reduction in volume increment and timber quality that was being caused by the squirrels. The re-measurement of this plot is not included in the total given in the Sample Plot Re-measurement Programme.