a Forestry Commission REPORT ON FOREST RESEARCH MW* - ■ Forestry Commission HMSO ARCHIVE REPORT ON FOREST RESEARCH for the year ended March 1990 LONDON: HMSO ® Crown copyright 1991 First published 1991 ISBN 0 11 710282 2 ODC 232.31:(021) The abbreviated title of this fleport Rep. Forest Res., Edin. 1990 CONTENTS Introduction byD.A. Burdekin, DirectorofResearch v PART I THE WORK OF THE FORESTRY COMMISSION RESEARCH DIVISION Seed 1 Silviculture (South) 3 Silviculture (North) 13 Site Studies (South) 26 Site Studies (North) 32 Tree Improvement 36 Physiology 43 Pathology 47 Entomology 56 Wildlife and Conservation 61 Mensuration 67 Wood Utilisation 70 Statistics and Computing 72 Communications 79 DEVELOPMENT DIVISION Work Study 82 Capercaillie in commercial forests PART II WORK DONE FOR THE FORESTRY Woodland management practices by non­ COMMISSION BY OTHER AGENCIES governmental organisations Forest edge management to conserve wild Silviculture 87 plants Herbicide evaluation for forestry uses Wood utilisation 97 Factors affecting nutrient source/sink relations Research on British-grown timber on restock sites Research on British-grown softwood Site studies 88 Timber preservation Soil erosion on land cultivated and drained for afforestation Prevention and treatment of decay in utility poles The nature and pattern of soils under ancient woodland Fertilisation and wood quality The role of the soil microbial community in Development 100 areas reclaimed to forestry after opencast The aggregate value of the non-priced mining recreation benefits of the Forestry Commission Effects of afforestation on water resources estate Effect of clear felling on stream sediment The impact of forestry on output and employment in the UK and its member Ambient pollution and tree growth at three countries sites in Britain Detection of any widespread and APPENDICES unprecedented changes in growth in European conifers I Publications by Forestry Commission staff 103 Tree improvement 91 II Research Division organisation 119 Seasonal cambial activity and root III Research Division branches and their development in cuttings in oak project groups at 31 March 1990 120 Physiology 92 IV Net expenditure of Research Division An apparatus to apply dynamic loads to trees 1989/90 122 V Contracts for work undertaken Pathology 93 by Research Division 123 Viruses in beech VI Staff engaged in research as at Beech health in southern Britain 31 March 1990 124 Entomology 94 VII Addresses of research locations 128 Predators and the pine beauty moth INDEX 130 Wildlife and conservation 95 GLOSSARY 135 Nightjar research in Thetford Forest in 1989 Latin names of trees cited by common name Woodlark ecology in Thetford Forest in this report INTRODUCTION by D. A. B u rd ek in Director of Research Forestry research has, during the course of the Protection at the Institute of Horticultural year, maintained a high profile in both the public Research Station at Wellesbourne) chaired the and the scientific spheres. Two areas have attrac­ Pathology Visiting Group and other members ted particular attention, carbon fixation by trees were Dr D. H. Phillips (retired Forestry Commis­ and the effect of trees on water quality. Con­ sion Chief Research Officer) and Dr M. Griffin siderable progress has also been made in many (Senior Officer, Plant Pathology, ADAS). The other research areas and I draw attention to some Group was particularly impressed by the research of these below. programme on Heterobasidion annosum but was The public debate on global warming has concerned that the balance between advisory and focused on the control and containment of the research work based at Alice Holt was tilted too emissions of ‘greenhouse gases’ especially carbon much in favour of the former. dioxide, methane and chlorofluorocarbons. The Mr David Johnston (retired Director Research), only identified anthropogenic activity that acts as together with Gavin Ross (Statistics Department, a ‘sink’ for carbon dioxide is forestry. The Fore­ Rothamsted), chaired the Visiting Group to the stry Commission and the Research Division in Mensuration Branch. A total of 14 recom­ particular have been publishing information on mendations were made, perhaps the most impor­ the rates at which trees sequester carbon dioxide. tant being the need to review the distribution of The proportion of total emissions (some 3-4%) of sample plots and also to incorporate data col­ carbon dioxide absorbed by trees is small but not lected over the past 20 years into current and insignificant. Further planting of trees can help future yield models for use by forest managers. increasingly to ameliorate the position. Fervours have been aroused by the water qual­ ity debate. On the one hand trees are blamed for H ig h l ig h t s o f t h e R e s e a r c h P r o g r a m m e causing acidity in our freshwater streams. On the other, foresters are vigorously defending their I cannot state that the items below represent a cause and point out that the acidity does not comprehensive list of the activities of the originate in the forest but in the fuel burning Research Division, nor are they intended to be the industries. It is hoped that the outcome of this most important achievements. They are merely a will include a reduction in emissions (though selection from the many items discussed in the there will be many reasons for these reductions), body of the Report which perhaps give some a treatment for severely affected areas, perhaps by flavour of the whole. I strongly commend those liming, and a rational agreement on the critical with interests that are not listed here to delve loads of pollutants in acid-sensitive areas (which deeper into the following pages. are of limited size in Britain) where trees may exacerbate the situation. Weed control. The long-term interest in ‘the need to weed’ for the successful establishment of trees has continued in both lowland and upland research projects. For the first time, this year A d v is o r y C o m m it t e e o n F o r e s t r y comparisons have been made between the effects R e s e a r c h of different weed flora including grass and herb­ aceous weeds. Both types had deleterious effects I regard the Advisory Committee on Forestry on the survival and subsequent growth of newly Research and the Visiting Groups that it estab­ planted trees. lishes as a vital part of the monitoring and Farm forestry. Interesting weed problems have critique of the Research Division’s activities. Two arisen on one of the farm forestry trials and a new Branches were investigated during the year, the experiment has been laid down to allow tractor Pathology Branch and the Mensuration Branch. access for the application of a trial range of Dr Roy Burchill (Head of Crop and Environment herbicides. INTRODUCTION Poplars. The poplar clonal trials established 3 were taken. At the same time more and more use years ago at Bedgebury (Kent) and Ampthill is being made of data capture devices for (Bedford) are already showing marked site recording data in forest experiments. differences, probably associated with the lower Growth models. Great strides have been made rainfall and greater droughtiness at Ampthill. in the development of the Sitka spruce growth Water storage for sawlogs. Several species of model. The model’s parameters are being opti­ both conifers and boadleaves have now been mised to obtain the best forecast for particular successfully stored under constant water sprink­ sample plots. ling for more than 18 months with little sign of Carbon storage. New and original models have blue stain. All species continue to saw easily after been developed to simulate the absorption and water storage. Studies showed that delays of 9-10 release of carbon by forest plantations and forest weeks before water storage allowed blue stain products. This information has been published in fungi to gain entry before treatment. Research Information Note 160 and further The pine weevil. Hylobius abietis is a major papers are in preparation. concern in restocked areas. Treatment of trans­ Reclamation sites. One of the reasons why it is plants with permethrin using the Electrodyn difficult to establish vegetation, including trees, Sprayer has been sucessful but there are still on reclaimed land is the harsh chemical and some situations where the treatment is not giving physical environment in the soil. A study of adequate control. spoils has shown that young unweathered mater­ Windthrow prediction. The Windthrow ial with a high pH is often associated with poor Hazard Classification provides a means for forest tree growth whereas spoils on older sites may managers to predict windthrow in their crops. A have a lower pH and tree growth is better. network of monitoring sites has been established Water quality. Trials with pelletised lime at to enable the hazard classification to be validated Llyn Brianne have led to a limited effect after 10 and refined. months on soil and drainage water chemistry. Vegetative propagation. Two to three million Forestry Research Co-ordination Com­ cuttings of genetically improved Sitka spruce are mittee. The role of The Forestry Research Co­ being propagated annually in Britain. The feasib­ ordination Committee, chaired by Forestry Com­ ility of producing these rooted cuttings in con­ missioner Roger Bradley, has been applauded by tainers is being investigated and shows promise. the House of Lords Select Committee on Science Natural regeneration in upland oak- and Technology. An excellent example of co­ woods. The lack of natural regeneration in ordination was pursued during the year in the upland oakwoods is a matter of concern especi­ form of a Special Topic on Farm Forestry. The ally in Wales. A review of current knowledge has Committee provided funds for a special topic on been completed and this will act as a base for environmental and socio-economic aspects of future research.