Paperbark poplar
Myrtaceae - Melaleuca quinquenervia
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What does it look like?

Paperbark poplar is an evergreen tree up to approximately 20-30m tall.  The bark is shed in pale, papery layers.  Leaves are aromatic, simple, and up to 12cm long.  It has prolific roots capable of penetrating to depths of over 1m.  When inundated, it produces a fibrous sheath of roots around the base of the trunk.  Flowers are white with pronounced stamens.  Seeds are minute, borne in woody capsules.

Wetlands, including freshwater and saline, and open canopy terrestrial habitats including grasslands and open forest.  It tolerates a wide range of soil types and conditions. Inundation and exposed ground are tolerated, but it prefers moist soils or fluctuating hydrology to either sustained drought or immersion.  Native and exotic range includes tropical and subtropical locations.  It is frost sensitive, though it can tolerate occasional light frost.  Limited shade tolerance.

Why is it a problem?

Invasive overseas in a variety of ecosystems.  The deep and extensive root system provides a competitive advantage in accessing water under fluctuating hydrological conditions.  Foliage is highly flammable and can fuel fires which may damage co-occurring vegetation; seedlings recruit vigorously following fire.  Possibly allelopathic, inhibiting growth of other species.

It can reach sexual maturity in under two years, and exhibits multiple flowering episodes within a growing season.  Capsules are retained on the tree where seed may remain viable for years.  Capsules open in response to frost, fire or desiccation.  Therefore a large proportion of seeds will be released synchronously from the canopy seed bank, while the remainder are released in a continuous low level seed rain.  The canopy of a mature tree may hold > 56 million seeds.  Soil seed bank remains viable for less than two-three years.  Recruits dense cohorts of seedlings following disturbance. Germination is favoured by moist soil conditions.

Control Methods

Cut the tree down to below the lowest green leaves and immediately paint the cut stump with 100g/L glyphosate.

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