Monday, May 29, 2017

Trees and Fungi

Right now, like me, you are probably noticing the increasing number of fungi appearing in our gardens, parks and reserves, etc.

Russula sp.
What we are seeing is just the fruiting body of the organism, (fungi are not plants, they have their own kingdom called … fungi). Most of the organism is under the ground, or under the bark, or below the surface of the leaf litter or the mulch, etc.

Mycelium under some bark
Below the surface, the fungus consists mostly of a root-like structure called the mycelium. The mycelium is the part of the fungus that 'consumes' the dead organic matter in the soil, giving fungi their title of decomposers or waste recyclers. Without fungi and other organisms performing this role, our world would be buried under dead leaves, logs, animal carcasses, faeces, etc.

Trametes versicolour, a log decomposing fungus
Another log rotting fungus - Sterum ostrea (I think).
In the process of consuming dead material, fungi release other nutrients for the plants to use. Some fungi have a mycorrhizal association with some plants. Without being too complicated, they exchange materials through their root systems.  
Diagrammatic representation of tree/fungi connections at the root zone.
Many Australian plant species have complex and essential connections with fungi. Most of our orchids will not survive without a mycorrhizal association with a fungus. Many of our forest tree species need fungi to help them grow healthily, particularly during the first few years of growth.
Healthy forest ecosystems need a healthy fungi population.
Spider Orchid on Mt Cannibal. All terrestrial orchids have a symbiotic relationship with fungi.
Trees, indeed all plants, absorb carbon dioxide from the atmosphere. Research has now confirmed that most of the carbon is passed down to the root system of the tree where it is used by the fungi. When we declare that trees are carbon sinks, it really means that most of the tree's carbon is locked up by the fungi in the root zone.

Individual trees in an ecosystem can have their root systems linked by the mycelium network of fungi. It is now believed that this root network below the ground is the means of trees being able to 'communicate' with one another. Trees can secrete soluble chemicals into their roots where fungi can transport them to other nearby trees.

Of course, as far as trees are concerned, there are some bad or parasitic fungi but that might be a topic for a later conversation.


Sunday, May 21, 2017

The Railway Giant

No, not a large steam engine (Gazette). What we here at the Friends of Drouin's Trees call the Railway Giant, is the majestic remnant gum tree at the corner of Albert Rd and Francis Ave.

The Railway Giant is so called because it grows beside the railway line and is truly a giant with a girth of 7.75m and an estimated height of 30+m, (not our biggest giant by the way). 

This grand specimen is a Mountain Grey Gum or Eucalyptus cypellocarpa and is probably around 300 years old and would most certainly have witnessed Drouin's first steam engine passing beneath its outstretched limbs.

Like many of our old 'eucs', the Railway Giant has numerous large and small hollows that offer excellent homes for a variety of native fauna species. Many birds use the canopy for cover and for a source of insects and nectar.

This magnificent tree has locked up many tons of carbon, absorbed untold amounts of atmospheric pollutants, soaked up gallons and gallons of storm water, breathed out litres and litres of oxygen, cooled the air for years, etc.

We revere many other 'giants' – the giant Blue Whale, giant Sequoias, even a Giant Earthworm – and we at the Friends of Drouin's Trees most definitely admire and treasure Drouin's giant trees.

Thursday, May 11, 2017

Drouin's Valuable Remnant Bushland #2

The value of patches of remnant vegetation in an urban setting cannot be overstated.

The old Drouin Nature Reserve in Pryor Rd

A 'bush block' in Roberts Ct
Urban patches of bush obviously provide valuable habitat for a range of native wildlife – birds, mammals, reptiles and invertebrates and this quality has been espoused previously in this blog.

John Lardner reserve beside the freeway
Some perhaps less obvious benefits of urban bushland include ….
·       Visual relief from urban sprawl
·       Places of solitude and tranquillity
·       Provision of cultural and historical links
·       Recreational sites for walkers, photographers, nature study, etc
·       Ecological niches for a range of flora and fauna
·       Cooling and cleaning of the surrounding atmosphere
·       Absorption of noise
·       Mitigating the effects of run off and protecting ground water
·       Genetic resource for indigenous flora species
·       Conserving natural landforms
·       Biological indicators of the effects of climate change
·       Cheap to maintain versus mowing grass, spraying and weeding garden beds, etc.

Even roadside and rail-side bush is valuable, weedy as they often are
Drouin's patches of remnant bushland are significant for many reasons and we should value them highly.

PS: Apologies for the dearth of posts recently. Endeavours are being made to rectify the situation.