Diary of a Red Gum – February 2015

In late January and through February the river red gum in front of our house revealed a very welcome secret – it is carrying dual crops. The cycle of seed development usually lasts 2 years, from bud to seed fall, and healthy trees have two alternate cycles running simultaneously. That means the tree will always be producing seed each year in the peak seed production period. Our tree has mature fruit with open valves, indicating that the tiny pinhead-sized seeds have already been shed, while at the same time tiny buds are forming to develop into the next crop which will flower next summer and mature into seed in 2 years, in summer 2016. The flowers of November and December 2014 have transformed into immature fruit which will ripen on the tree during the year and mature into seed in summer 2015.

Summer is the season for red gums to shed bark, leaves and spent fruit

Summer is the season for red gums to shed bark, leaves and spent fruit

Healthy thriving red gum in an urban Adelaide street

Healthy thriving red gum in an urban Adelaide street


Summer (November to March) is generally the peak production season for red gums; in the Mid-North of South Australia it is November – December, and in the South Australian River Murray Valley it varies from November to March across individual trees and sites.
Healthy red gum with a dual crop of new buds and maturing fruit

Healthy red gum with a dual crop of new buds and maturing fruit

Mature red gum fruit shed their pinhead-sized seeds immediately if they break off the tree Mature red gum fruit shed their pinhead-sized seeds immediately if they break off the tree[/caption]
During the Millenium drought 2000-2010 in South Australia, river red gums reduced their reproduction, firstly only carrying one crop through a 2-year cycle, and then reducing the amount of seed produced by at least 10 times. The healthy growth on our local urban red gum gives hope for improved production and regeneration in river red gums across Australian landscapes this year.

Spent mature red gum fruit with their valves fully open have already released their seeds while still on the tree

Spent mature red gum fruit with their valves fully open have already released their seeds while still on the tree

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About redgumgirl

Dr Anne Jensen is an environmental consultant with a passionate interest in sustainable management of our natural resources, particularly the River Murray and wetland environments. She is particularly interested in using photographs and stories to explain issues around water and protecting natural ecosystems in terms that are understood by the wider community, so that we can manage our environment sustainably for our common future.
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