Manchurian ash is a tall ash tree from the river valleys and wetlands of northeast Asia, growing up to about 100 ft (30 m) tall. It does not grow wild in the US, but it is planted now and then in the northern US and Canada as a hardy ornamental or windbreak tree. North American scientists are studying it as a possible source of resistance to the emerald ash borer, the beetle that has killed huge numbers of ash trees in the US.
Appearance
- Growth form
- A medium to large deciduous tree, up to about 100 ft (30 m) tall.
- Leaves
- Opposite, compound leaves 10–16 in (25–40 cm) long, usually with 9 or 11 toothed leaflets (sometimes 7 or 13). The leaflets have almost no stalks, and there are tufts of brown hairs where they join the central leaf stalk. Leaves turn golden yellow in early fall.
- Flowers
- Small, petalless flowers in tight clusters appear in early spring before the leaves and are wind-pollinated. Male and female flowers grow on separate trees.
- Fruit
- Each fruit is a : a single seed with a flat wing about 1–1.5 in (2.5–4 cm) long, borne in clusters on female trees.
Look-alikes
The two are very close relatives with similar leaves, and they are hard to tell apart from photos. Black ash is a native North American tree, while a Manchurian ash in the US is almost always planted; black ash trees can also carry both male and female flowers.
Why they get mixed upBoth have stalkless leaflets and are thought to be each other's closest relatives.
Where it lives
- Typical habitats
- river valleys
- wet lowland forests
- planted in yards and windbreaks (US/Canada)
- Range
- Native to northern China, Korea, Japan, and the Russian Far East including Sakhalin. Not native to the US; it is grown occasionally as an ornamental in Canada and the northern US.
- Preferred conditions
- Tolerates many soils, including wet ones, but does poorly in very alkaline soil. It likes full sun and a continental climate with cold winters, hot summers, and no late spring frosts.
Growing it
- Care
- Male cultivar 'Mancana', selected in Manitoba, Canada, is very cold-hardy and has a dense oval to rounded crown. It tolerates city pollution but suffers in mild, oceanic climates, where it leafs out too early and gets hit by late frosts.
Name and classification
- About the name
- It is very close to black ash (Fraxinus nigra) of eastern North America, and some botanists treat it as a subspecies or variety of black ash.
Conservation
- IUCN Red List
- LCLeast ConcernLow risk of extinction
- Status
- It is listed in at Russia's request, so exports of its logs, sawn wood, and veneer from Russia need permits.
- Threats
- The emerald ash borer is native to the same part of Asia. Manchurian ash has more natural resistance than most North American ashes, which is why it is being tested for breeding, but wild trees in China have also died in significant numbers from the beetle.
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