Sorbus torminalis (L.) Crantz, Wild Service-tree
Account Summary
Introduction, neophyte, very rare and probably extinct or possibly a mis-identification.
1939; Faris, R.C.; roadside, Magheraveely, ENE of Newtownbutler.
S. torminalis is a small to medium-sized, rare or local, uncommon tree, usually with a short, stout trunk and ascending branches forming an oval crown. The large, oval (not pointed), greenish buds are prominent in winter and the leaves are maple-like, but are alternately borne and not palmately veined like true maples (Hadfield 1957).
There is just the one old record for Fermanagh, detailed above, which was communicated by Praeger (1939). Charles Faris was an important Co Cavan contributor of records of both plants and insects (Praeger 1949). His is the only known Irish record for this medium-sized tree in the wild anywhere in the whole island. As was often the case with older records, the site is extremely vague. We would dearly like there to be a voucher somewhere to support it, but otherwise we can only very tentatively accept it as a First County Record.
Elsewhere in Ireland, a large S. torminalis tree has been recorded from demesne land in Co Sligo (H28) (Praeger 1939). These two records published by Praeger (1939) do not feature in the Cen Cat Fl Ir 2, nor in Cat Alien Pl Ir, which suggests they have not met the necessary criteria for acceptance. Arboretum specimens of S. torminalis are listed for Glenveagh Gardens, West Co Donegal (H35) and the J.F. Kennedy Park, New Ross, Co Wexford (H12) (Forrest 1985).
S. torminalis is another of the three sexually reproducing Sorbus species that occurs in these islands, but while it is native at the great majority of its sites in S England and Wales, it is planted, or spread from introduced populations further north beyond its native range and, of course, it is an extremely rare alien in Ireland (New Atlas). Even in its native area, Wild Service-tree is nowadays often local and scarce. Previously, the tree was much more common in ancient woods and old hedges over a wide area of lowland England and Wales as far north as the Lake District.
In these areas, and beyond them, it might also have been cultivated for its "pleasantly acid-tasting" (Vickery 1995, p. 399) small fruit, which is orange at first and a distinctive olive-brown colour when frosted and ripe in late October and November (Rackham 1980, p. 358-9; Roper 1993; Mabey 1996, pp. 204-5). Although elsewhere described as "rather gritty to taste" (Milner 1992), it made prune-flavoured jams, preserves and liqueurs and was certainly also used medicinally. Another account describes the fruit as being, "hard, with rather scant dry flesh, and precious little flavour" (Lang 1987), which suggests the sample collected was not yet ripe and 'bletted' by frost and subsequent partial decay (Mabey 1996).
In common with Whitebeams, S. torminalis is very variable in its flowering and fruit production. The species is considered to probably have evolved in dry, open woodland and its reproductive performance is strongly controlled by local climate (Termena 1972). Most trees come into flower towards the end of May, but some are earlier, consistently flowering from the end of April. In the warmer, drier parts of Britain, many trees only fruit every other year and, in more marginal habitats and at the edge of its geographical range, it fruits even more irregularly than this. Towards the northern edge of its English distribution in Derbyshire (VC 57), only 5% of S. torminalis seeds proved fertile (Wilmott 1977).
Although seedlings are very seldom recorded, this is considered due to seed and seedling predation by birds and a range of small mammals and invertebrates, rather than sterility. Birds avidly consume the fruit, but the tree appears only rarely bird-sown, probably on account of the noted levels of infertility and seed predation (Roper 1993).
Vegetative reproduction by suckering from the roots is common, especially if the roots in question are only shallowly buried or have been subjected to any form of damage. Suckers can arise at considerable distance from the base of the parent tree, even at 110 m from it (Rich et al. 2010).
Being very often solitary, Wild Service-tree is easily over-looked and it may well be under-recorded and especially so in Ireland where recorders are not on the lookout for it.
Identification
S. hibernica is a shrub or small, deciduous tree up to 10 m tall with a broad, open crown and a trunk up to 30 cm in diameter. Leaves are un-lobed, elliptic to obovate and are clearly toothed along the whole of their margin except at the extreme base. The leaf teeth are straight, symmetrical and crowded in the upper half, acuminate, even and almost like a fine comb. The blade usually has 18-20 veins and the petiole is about 1.4 cm long. In Ireland, the leaves of S. hibernica most resemble those of S. aria (Common Whitebeam), although the leaves of the latter are slightly larger and their under-surfaces are densely white tomentose, rather than pale greyish-white with silky hairs beneath as in S. hibernica (Rich et al. 2010; Parnell & Curtis 2012).
Irish and British occurrence
The distribution in Ireland of S. hibernica is widely scattered, trees generally occurring in small numbers or as solitary individuals, in a wide variety of soils in both semi-natural and artificial habitat types, chiefly in Midland Ireland (Rich et al. 2005, 2010). Unlike many other species in the Subgenus Aria in Britain, S. hibernica occurs in a range of habitats on mountains and on lowland rocks and cliffs, rocky lake shores and islets, river gorges, open rock pastures and roadsides, hedges, open woods and copses (Rich et al. 2010).
Fermanagh occurrence
Since RHN first found specimens of this endemic apomictic Irish whitebeam on the shoreline and the scrub margins of plantation woodlands on the Castle Caldwell estate at the W end of Lower Lough Erne, he has since discovered it in a total of five Fermanagh tetrads, four of them around the same small area. The original discovery was made quite early on in Robert's recording career when he was naturally unsure as to exactly what he had found. Fortunately, he had the good sense to keep herbarium vouchers of unrecognised plants. During a fleeting visit to Fermanagh in August 2007, Dr Tim Rich, the BSBI Sorbus referee, confirmed the identification of the S. hibernica vouchers.
Spurred by the knowledge that this interesting, rare Whitebeam was indeed present in the county, in the autumn of 2007 RHN and HJN searched the scrub shoreline and sections of two peninsulas on the Castle Caldwell estate where the tree had first been encountered. Sixteen trees were discovered in two tetrads on Rossergole Peninsula, 14 specimens on the northern shore and two on the southern shore. A solitary tree was located near the eastern end of the adjacent larger Rossmore peninsula on the same estate. Both peninsulas were planted up with conifers sometime in the 1930s and the 17 specimens of S. hibernica are growing rather randomly scattered on the strip of shoreline that became exposed when the water level in Lower Lough Erne was lowered by drainage works in the 1870s. This strip was enlarged in the 1950s by further lake drainage. The latter adjustment was a desirable consequence of the development of the River Erne hydroelectric generation scheme, situated between Belleek, Co Fermanagh and Ballyshannon, Co Donegal and constructed between 1942-57.
The lake level reduction helped drain farmland around both parts of Lough Erne, ground which previously had been subject to unmanageable flooding despite the 19th century drainage efforts. The rocky limestone ground around the new shoreline has since been colonised by dense, almost impenetrable scrub, which made the task of surveying for S. hibernica extremely difficult. The survey is incomplete for this reason and perhaps dozens more trees might stand undetected, particularly on the long Rossmore peninsula where access is the most difficult. The trees discovered on the Castle Caldwell estate were 4-7 m in height and some were fruiting sparingly.
Certainly, the main area where this endemic species occurs is in the Irish Midlands, but the 17 individuals now known to occur at Castle Caldwell in Co Fermanagh make this the most important site for this endemic rarity in the whole northern province of Ulster.
Additional Irish Whitebeam specimens were subsequently discovered in Fermanagh at a second site lying on the S shore of Lower Lough Erne, 1 km E of Hill's Island in 2004. Three specimens were found at the end of a path from a small car park. They appear to have been deliberately planted in a line behind a wire fence. A fourth tree stands isolated further along the path. Apart from accompanying native willows, another definitely introduced tree at this site was Acer campestre (Field Maple). This secondary S. hibernica site is approximately 2 km south of the Rossmore peninsula, so the possibility of the specimens being of bird-sown origin should not be completely ruled out.
A third local station was discovered in 1989 lying about 6 km SSW of Enniskillen. Here, a solitary tree of S. hibernica is growing amongst birch on a cut-over bog at Gransagh, not far from the shore of Upper Lough Erne. Very probably this tree is another bird-sown individual.
It is very clear from this account that S. hibernica has been previously overlooked in Fermanagh, almost certainly because it has only recently been properly described (Warburg 1957), identification is not easy and relatively few Irish field workers can confidently recognise it from S. aria (Common Whitebeam). Thus, although there are many more plants and sites of this endemic recorded than previously was the case and there now are records from 31 of the 40 Irish VCs (the main exceptions being in the far SW), at the moment S. hibernica still remains under-recorded throughout Ireland (Rich et al. 2010).