Cylchgronau Cymru

DISCUSSION. The following tree species are represented ASH, Fraxinus excelsior L. HAZEL, Corylus avellana L. OAK, Quercus robur L. s. 1. probably Q. robur L. s. s. Rosaceae, probably HAWTHORN, Crataegus monogyna. Interest centres partly on the occurrence of ash, partly on the quantity of hawthorn. More ash charcoal was found in the central deposit (Late Bronze Ago c. 700-400 B.C.). than has been reported on by the writer from any excavation in South Wales. The wood may have been derived from several trees or all may have come from a single tree. Ash, even when green, is such good firewood that it may have been deliverately chosen and felled expressly for the pyre. One is not justified in concluding from the abundance of ash in the sample that it was the dominant tree thereabouts at the time or, from its poor quality as timber, that ash trees though present did not flourish very well. When one turns to the earlier deposit (? Late Neolithic,' c. 1800-1400 B.C.), the evidence as to local forest composition is far from clear. Ash is present among the charcoals (though here in relatively small quantity) along with a little oak and some hazel, from which one might argue the probable exis- tence of ash-oak-hazel wood but that these charcoals are greatly outnumbered in the deposit by haw- thorn. The last-named is a smallish tree which readily springs up in clearings and neglected pastures thickets of this and other (often spiny) species thus come to occupy the site of former woodland and form a seral stage preceding reoccupation by the climax woodland type. Hawthorn (in the form of twigs and small branches) is unpleasant to handle and is unlikely to have been used for firewood if any other tree species were present in sizes suitable for the purpose some amount of local deforestation seems certain. The woods in Pantyrhyll to the south of Mount Pleasant Farm were almost entirely clear- felled about a century ago and replanted they consist today mainly of elm, sycamore and other species, and provide no evidence as to the composition of natural woodland in the neighbourhood. These woods, however, to judge from the extant woods on Lias limestone in other parts of Glamorgan must at some time in the recent past have been largely composed of ash. But the existence of natural or semi- natural ash woods at the present epoch does not warrant a presumption that this type of woodland has occupied the ground (in the absence of disturbance) from (say) Boreal time on. Despite recent work it still remains true that of the history of ash in our flora we have too little knowledge (Tansley, 1939). That this species has a long history in Britain might perhaps be presumed from its wide occurrence and its dominance on certain soils, but in view of the paucity of dateable remains any actual proof of the presence of ash in Wales in the Neolithic period or the Early Bronze Age is welcome. At one time ash pollen was said not to be preserved in peat (Godwin, 1934). Until recently it was not included among the tree pollens customarily recognised in analyses of fossil pollen thus Jessen does not mention ash pollen in his great work on Irish peats (Jessen, 1949) although he refers to finds of ash timber. Conway (1947) includes ash pollen in her analyses of peats from Ringinglow Bog, Yorkshire all date from after the Boreal-Atlantic transition (c. 6200 B.C. according to Godwin, 1945) and ash pollen is seen in her diagrams to rise from very low values at the base of the peat to a value (in her transition zone, VII-VIII, which lies between horizon RY IV = C. 1200 B.C. and horizon RY III = c. 500 B.C., both as dated by Godwin, 1945) which on the average is equivalent to about 12 per cent of the total tree pollen (as usually understood) and then to fall again to low values at RY IV, finally rising to its highest average values in her highest zone (VIII Mod). Ash pollen makes up the equivalent of about 12 per cent of the tree pollen deposit on the Breconshire moorland today, just as it did on the Pennines at some period between 1200 and 500 B.C., from which it may be argued that during the Late Neolithic period (c. 1800-1400 B.C., well inside Dr. Conway's zone VIIb, in which ash pollen forms a much lower proportion of the tree pollen than 12 per cent) ash, though present, had not attained its present importance in the flora. The evidence of the Mount Pleasant charcoals, too, is consistent with the supposition that ash, though present, had not yet at this period become dominant on Lias limestone. REFERENCES. Conway, V. (1947). Ringinglow Bog, near Sheffield. Part I. Historical. J. Ecology. 34. 149-81. Godwin, H. (1934). Pollen Analysis. An outline of the problems and potentialities of the method. Part I. New Phytol. 33. 278-305. ■ (1945). Coastal peat beds of the North Sea Region as indices of 'TanoT-arid "sea-level i;" changes. New Phytol. 44, 29-69. Jessen, K. (1949). Studies in Late Quaternary deposits and flora history of Ireland. Proc. R. Irish Acad. 52. 85-290. Tansley, A. G. (1939). The British Islands and their vegatation. Cambridge. *Information from Mrs. G. C. Blundell.