A tree to 30 m, but becoming a small, dense, thicket-forming shrub at high altitudes and in exposed places. Bark grey, smooth, with some horizontal banding; ultimately cracking shallowly into plates. Shoot slender (1-2 mm thick), grey-brown, with short erect persistent hairs; buds red-brown, less pointed than in most Nothofagus, c. 6 mm long. Leaves broadly ovate to broadly elliptic, 2-4 × 1.2-2 cm, obtuse to rounded at the apex, the base usually obliquely cuneate, sometimes rounded or even cordate, upper surface medium green, slightly glossy, almost glabrous, underside paler, lustrous, with appressed hairs on the midrib and main veins, margins ciliate, bluntly but neatly double-toothed (except between the lowest 2 pairs of veins where there are usually 3 teeth); lateral veins in 5 or 6 pairs, straight and parallel, raised beneath, each running out to a sinus; petiole 5-7 mm long. Autumn colour orange and yellow. Male flowers solitary. Cupules with only 2 valves, dark brown, linear and twisted, c. 10 mm long, without any lamellae. Nutlets single, 3-angled, twisted, dark brown, slender and c. 10 mm long. (Bean 1976); (Nothofagus 2007–2008).
Distribution Argentina Along the southern Andes Chile Maule, Ñuble, Bío Bío, La Araucaría, Los Ríos, Los Lagos, Aysén and Magallanes regions
Habitat Mountain and coastal forests, from sea level in the south and extending to the tree-line at around 2000 m in central Chile; the commonest Nothofagus on the Argentine side of the mountains.
USDA Hardiness Zone 7
RHS Hardiness Rating H5
Conservation status Least concern (LC)
Nothofagus pumilio grows alongside N. antarctica to the southernmost tip of the Americas; the two species resemble each other, but N. pumilio is capable of growing into a taller straighter tree, yielding good timber - even though its specific name means ‘dwarf’. The smooth bark of N. pumilio into maturity is another distinguishing feature, as is the single nutlet carried in a very slender, bald, twisted husk. The leaf is remarkably neat, with two rounded teeth in between each lateral vein, which itself, most unusually, runs to a sinus instead of a tooth; the typically 6 pairs of veins place the leaf between those of N. antarctica and N. obliqua in terms of size.
N. pumilio seems not to have been grown in Europe until 1950, when a tree from seed collected or received by Dr Wilfrid Fox was planted at Kew (Clarke 1988); if Fox had also planted trees at his own arboretum at Winkworth in Surrey, they must have failed before any records were made. The Kew tree has grown well in the shelter of the Bluebell Wood - it was 22 m × 55 cm dbh by 2001 (Tree Register 2020), and is probably the only mature example in Britain to have a good, single bole. Another handsome if distinctly bushy tree was measured in 2000 (Tree Register 2020) in the Surrey garden of the late Desmond Clarke, on whose revision of the species in his 1988 Supplement to W J Bean’s Trees & Shrubs Hardy in the British Isles parts of this account are based; oddly, Clarke chose to make no reference to his own specimen in his entry for Nothofagus pumilio, to confirm whether it, too, was a gift from Wilfrid Fox.
Trees from subsequent introductions have also thrived across the UK, though a huge specimen accessioned in 1963 at the Benmore Botanic Garden in Argyll was moribund by 2017 (Tree Register 2020); the species is likely to be vulnerable to Phytophthora pseudosyringae and seems bound, like N. antarctica, to prove short-lived in cultivation anyway, although in the wild it can live for up to 350 years (Nothofagus 2007–2008). One of the Forestry Commission’s trials of the species, planted in 1981-2 at quite a high altitude at Dalmacallan in south-west Scotland, showed a good early survival rate (Mason et al. 2018), and the tree is also happy at the Royal Botanic Garden Edinburgh, where a specimen 11 m tall in 2004 (Tree Register 2020) had been grown from seed collected by G. Schlätzer in 1967. Another large example, this one of unknown provenance, grows at Dawyck Botanic Garden in the Scottish Borders, it was 12 m × 1.92 m dbh (at 50 cm on the short bole) in 2014 (Tree Register 2020); it is the only Nothofagus to survive as a mature tree in this collection which is situated in one of the coldest and most continental microclimates in Scotland.
Like most Nothofagus, N. pumilio probably prefers high humidity and plenty of summer rainfall, but may not prove sufficiently long-lived in Europe for this predilection to become clear. Some of the largest in England were planted at the Forestry Commission’s Lynford Arboretum in Thetford Forest in Norfolk in 1973 (Tree Register 2020), where summer rainfall totals can be very low but where the sandy woodland soil is quite water-retentive; these had, however, all been lost by 2020. A 5 m tree at Bute Park in Cardiff in 2004 was growing reasonably well in significantly alkaline alluvium, while two examples at Lord Heseltine’s arboretum at Thenford in Northamptonshire have thrived in loam over Jurassic limestone (Tree Register 2020).
Nothofagus pumilio has also been grown from introductions made in the 1960s and 70s in south-west Norway and in Denmark, where there are a few trial forestry plantations; some trees here appear intermediate with N. antarctica and may represent hybrids (see further under N. antarctica), and there has been some damage in cold winters (Søndergaard 1997). This species is one of several Nothofagus grown in the Washington Park Arboretum in Seattle (Washington Park Arboretum 2013).