• Alden, J. & Hermann, R. K. (1971). Aspects of the cold–hardiness mechanism in plants. Botanical Reviews, 37, 37142.
  • Ashenden, T. W. & Mansfield, T. A. (1978). Extreme pollution sensitivity of grasses when SO2 and NO2 are present in the atmosphere together. Nature, 273, 142143.
  • Ashmore, M., Bell, J. N. B. & Rutter, A. J. (1985). The role of ozone in forest damage in West Germany. Ambio, 14, 8187.
  • Bell, J. N. B. (1986). Effects of acid deposition on crops and forests. Experientia, 42, 363371.
  • Binns, W. O. & Redfern, D. B. (1983). Acid Rain and Forest Decline in West Germany. Forestry Commission Research and Development Paper 131.
  • Blank, L. W. (1985). A new type of forest decline in Germany. Nature, 314, 311314.
  • Cannell, M. G. R. & Sheppard, L. J. (1982). Seasonal changes in the frost hardiness of provenances of Picea sitchensis in Scotland. Forestry, 55, 137153.
  • Cannell, M. G. R. & Smith, R. I. (1983). Thermal time, chill days and prediction of budburst in Picea sitchensis. Journal of Applied Ecology, 20, 951963.
  • Davison, A. W. & Bailey, I. F. (1982). SO2 pollution reduces the freezing resistance of ryegrass. Nature, 297, 400402.
  • Fowler, D. & Cape, J. N. (1982). Air pollutants in horticulture and agriculture. In: Effects of Gaseous Air Pollution in Agriculture and Horticulture. Proceedings of School of Agricultural Science, University of Nottingham (Ed. by M. H.Unsworth, & D. P.Ormrod), pp. 326. Butterworths, London .
  • Freer-Smith, P. H. (1984a). The influence of SO2 and NO2, and their mixtures on the growth and physiology of conifers. In: Air Pollution and Stability of Coniferous Forest Ecosystems (Ed. by E.Klino, & R.Saly), pp. 235247. University of Agriculture, Brno , CSSE .
  • Freer-Smith, P. H. (1984b). The responses of six broadleaved trees during long–term exposure to SO2 and NO2. New Phytologist, 97, 4961.
  • Freer-Smith, P. H. (1985). The influence of SO2 and NO2 on the growth, development and gas exchange of Betula pendula. New Phytologist, 99, 417430.
  • Garsed, S. G. & Rutter, A. J. (1982). Relative performance of conifer populations in various tests for sensitivity to SO2, and the implications for selecting rees for planting in polluted areas. New Phytologist, 92, 349367.
  • Godzik, S. (1984). Air pollution problems in some central European countries. In: Gaseous Air Pollutants and Plant Metabolism (Ed. by M. J.Koziol, & F. R.Whatley), Butterworths, London .
  • Hellkvist, J., Richards, G. P. & Jarvis, P. G. (1974). Vertical gradients of water potential and tissue water relations in sitka spruce trees measured with the pressure chamber. Journal of Applied Ecology, 11, 637667.
  • Levitt, J. (1980). Responses of Plants to Environmental Stresses, vol. 1, chapter 8, ‘Factors related to freezing tolerance; morphology, anatomy, organelles, physiological factors’, pp. 163222. Academic Press, London & New York .
  • Malcolm, D. C. & Freezaillah, B. C. Y. (1975). Early frost damage on sitka spruce seedlings and the influence of phosphorus nutrition. Forestry, 2, 139145.
  • Mansfield, T. A., Davies, W. J. & Whitmore, M. E. (1986). Interactions between the Responses of Plants to Pollution and other Environmental Factors such as Drought, Light and Temperature. In the proceedings of CEC COST; Workshop entitled ‘How are the effects of air pollutants on agricultural crops influenced by the interactions with other limiting factors?’ March 1986.
  • Nihlgard, B. (1985). The ammonium hypothesis – an additional explanation of the forest dieback in Europe. Ambio, 14, 28.
  • Prinz, B., Krause, G. M. M. & Stratmann, H. (1982). Waldschaden in der undesrepublik Deutschland. Bericht nr. 28, Landesanstalt fur Immissionsschutz des Landes Nordrhein-Westfalen, Essen.
  • Redfern, D. B. & Cannell, M. G. R. (1982). Needle damage in sitka spruce caused by early Autumn frosts. Forestry, 55, 3945.
  • Roberts, T. M. (1984). Long-term effects of sulphur dioxide on crops: an analysis of dose-response relations. Philosophical Transactions of the Royal Society of London (B), 305, 299316.
  • Tyree, M. T. & Jarvis, P. G. (1982). Water in cells and tissues. In: Physiological Plant Ecology. II. Encyclopedia of Plant Physiology, vol. 12b. (Ed. by O. L.Lange, P. S.Nobel, C. B.Osmond, & H.Ziegler), pp. 3537. Springer-Verlag, Berlin , Heidelberg .
  • Whitmore, M. E. (1982). A study of the effects of SO2 and NO2 pollution on grasses, with special reference to Poa pratensis L. Ph.d. thesis, University of Lancaster.