Sycamore
Aceraceae (maple) family - Acer pseudoplatanus
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What does it look like?

Sycamore is a large tree up to 20m tall, with a smooth trunk.  It is deciduous but leaf fall is moderately protracted.  Leaves are five-lobed, up to 20cm long, green but with reddish petioles up to 15cm long.  Dense clusters of small, green flowers occur during October-November, with fruit in late summer-early autumn.  Seeds are 0.5-1cm long with wings up to 4cm long.

Preferred habitats include open or regenerating forest/scrub and forest margins (including pine plantations as well as native vegetation).  Also, short-stature plant communities, and road and rail corridors.  It colonises predominantly open sites, growth is slower in shade. High fertility, high pH soils are preferred.  It tolerates range of soil moisture from damp gullies to moderate drought, and is fairly frost tolerant.

Sycamore is present in the region but its distribution has never been formally surveyed.

Why is it a problem?

Sycamore seedlings grow rapidly, and it is a competitive coloniser of open sites.  A persistent seedling bank can form under shade.  There is potential for the seedling bank to rapidly exploit future canopy openings but growth rates remain very slow under intact canopy. It is less competitive on low fertility soils.  Possible allelopathic effect, suppressing other plants.

Copious seed production (over 10,000 seeds/tree/year).  Synchronous germination in spring; dormancy broken by winter chilling.  The seed bank is unlikely to persist beyond a single season. Vectors of spread: Locally wind and gravity dispersed (mostly up to 50-100m), also some downstream dispersal by water.

Control Methods

Physical control:

  • Dig out small patches (all year round): dispose of at refuse transfer station, burn or bury.

Drill & fill / stem injections:

  • Make 1 hole every 100 mm around the trunk and fill or saturate each hole with 2g metsulfuron-methyl 600g/kg; or 1.5ml glyphosate; or 5g picloram gel.

Stump paint:

  • Cut trunk and paint stump (summer-autumn): cut trunk near to the ground, and swab freshly cut stump with metsulfuron-methyl 600g/kg (5g/L); or Tordon BK (50ml/L); or picloram gel

Overall spray (full leaf stage only):

  •  metsulfuron-methyl 600g/kg (5g/L).

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