Sycamore
Aceraceae (maple) family - Acer pseudoplatanus

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, regenerating forest or scrub and forest margins (including pine plantations as well as native vegetation).  Also, short-stature plant communities, road and rail corridors.  It colonises predominantly open sites, growth is slower in shade. Highly fertile and high pH soils are preferred.  It tolerates a 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, with a possible allelopathic effect that suppresses other plants.

Copious seed production (over 10,000 seeds per tree per year).  Germination occurs in spring as dormancy is broken by winter.  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 plants (all year round): dispose of at refuse transfer station, dry and burn or compost.

Herbicide Control

  • Drill & fill / stem injections - Make 1 hole every 200 mm around the trunk and fill with undiluted glyphosate.
  • Stump paint - Cut trunk and paint stump (summer-autumn): cut trunk near to the ground, and swab freshly cut stump with 5g metsulfuron-methyl (600g/kg) per 1L water; or 50ml Tordon Brushkillerper 1Lwater; or picloram gel
  • Over spray - (full leaf stage only): 5g metsulfuron-methyl (600g/kg) per 10L water.

CAUTION: When using any herbicide or pesticide, PLEASE READ THE LABEL THOROUGHLY to ensure that all instructions and safety requirements are followed. 

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