An initiative of Earthwatch Institute

  1. E._mollucana_flower_l._von_richter__the_royal_botanic_gardens___domain_trust E. moluccana flower by L. von Richter © The Royal Botanic Gardens & Domain Trust
  2. E.molucanna-flower-bud-euclid E. moluccana flower bud - EUCLID
  3. Eucalyptus_moluccana_leaves-wikipedia E. moluccana leaves - Wikipedia
  4. Eucalyptus_moluccana_fruit-wikipedia E. mollucana fruit - seed capsule - Wikipedia
  5. Dsc00785 E. mollucana bark - Earthwatch - Nadiah Roslan

Grey Box or Gum-topped Box (NSW, QLD)

Eucalyptus moluccana


Tree to 25 m high. Also known as Gum-topped Box. The presence of adult and juvenile psyllids (jumpling plant lice) are being monitored on this ClimateWatch species as an indicator of ecosystem health.

Bark: rough on part or all of trunk, thin, box-type or tessellated (mosaic-like), grey or mottled with grey and white patches; smooth bark white, cream or pale-grey, often shiny

Adult leaves: alternate, broadly lance-shaped, 7-17 cm long, 2-5 cm wide, green, glossy, concolorous (both sides of the leaf blade are the same colour)

Flowers: are white and usually clustered in groups of 7. Sometimes there are more than 7 or there may appear to be less as flowers have dropped off. They occur in multiple groups at the end of small branches.

Flower buds: ovate (egg-shaped) to fusiform (spindle shaped; tapering at both ends), 5-9 m long, 3-4 mm diameter; scar absent.

Mature flower buds: occur in groups of 7 (as with flowers there is sometimes more or less). They are ovate (egg-shaped) to fusiform (spindle shaped; tapering at both ends), 5-9 mm long, 3-4 mm diameter; scar absent.

Fruit: cylindrical or ovoid (egg or barrel-shaped)


What to Observe


  • First fully open single flower 
  • Full flowering (record all days)
  • End of flowering (when 95% of the flowers have faded)
  • Not flowering
  • Fruiting

Insect outbreak:

  • Average number of adult psyllids  
  • Average number of juvenile psyllids
  • Average number of psyllid eggs

ClimateWatch Science Advisor

We expect plants to start shooting and flowering earlier in the year as a result of climate change warming the Earth. They may also start appearing in new areas, as warmer temperatures enable them to live in environments that were previously too cold or unsuitable.

In addition, the frequency and severity of insect outbreaks in forest ecosystems are predicted to increase with climate change. Some insects may result in having the advantage over trees, such as the psyllids (jumping plant-lice) that defoliate adult Grey Box. A psyllid outbreak could be an example of the unexpected consequences of climate change on native ecosystems. 

Help scientists answer the question: "How are our animals, plants and ecosystems responding to climate change?"

When To Look

All year for flowering and insect outbreaks (psyllids). Flowering has been recorded during most months of the year. This is a widespread species and flowering time is location dependent. In general, this is attributable to variation in climate and geographical influences at sites.

Where To Look

NSW and QLD. Widespread, community dominant, in grassy woodland or forest on loamy soils of moderate to high fertility; on the coastal plains and ranges northwards from Jervis Bay in New South Wales to the area between Rockhampton and Mackay in Queensland, then with a substantial gap to the northern occurrences in the ranges from west of Paluma to the southern part of the Atherton Tableland; also two small disjunct patches east of Clermont near Eungella Dam. 

Note: ClimateWatch is looking for any changes outside of their known ranges so remember to keep a lookout beyond these regions too!

Grey Box or Gum-topped Box distribution map - EUCLID

Grey Box or Gum-topped Box distribution map - EUCLID



See links on species’ ClimateWatch page

Brooker, M.I.H. & Kleinig, D.A. Field Guide to Eucalyptus, Bloomings, Melbourne 2001

Gherlenda et al  2016 Boom and busy: rapid feedback responses between insect outbreak dynamics and canopy leaf area impacted by rainfall and CO2



  1. Search Species

  1. What Else?

    It is closely related to the Narrow-leaved Box or Grey Box, E. microcarpa (also a ClimateWatch species), which is a more inland species with rough bark higher up the stem and smaller leaves, buds and fruit. 

    Fruits of E. moluccana are barrel-shaped and resemble those of the related New South Wales tableland and western slopes species, E. albens. The latter species differs, however, in having a greyish to glaucous crown and larger, often glaucous, buds and fruit.


  1. Did You Know?

    Eucalyptus moluccana is named after the Moluccas islands of South-east Asia, a misnomer.


    The Grey Box (E. moluccana) is a dominant tree species of the endangered Cumberland Plain Woodland Community. 


    Grey Box defoliation is known to be caused by the family of Psyllidae (jumping plant-lice). A psyllid outbreak in Western Sydney has attacked hundreds of hectares of mature Grey Box in parks, reserves and backyards from Blacktown to the foot of the Blue Mountains. 


    The Cumberland Plain Woodland communities (dominated by E. moluccana) have been heavily impacted by urban development and only about 5 percent remain in the Sydney region.