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Figure 1. Eucalyptus obliqua seedlings
dutifully rising from the ashes. (Image: Des Stackpole)
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Figure 2. Before and after the fire at
Wallaby Creek. The view from 50 m above the ground in what was the
tallest forest in Victoria (Wallaby Creek catchment, Kinglake
National Park). (Images: Steve Sillett)
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Figure 3. A rare view of the Watts River from
the Maroondah Highway at Fernshaw. This was burnt in the week
following Black Saturday under very mild conditions allowing the
fire sensitive E. viminalis and E. regnans forest
to survive. The fire origin was a lightning strike near Healesville
that occurred on the evening of Black Saturday. (Image: Des
Stackpole)
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While the Royal Commission enquiry
into the Victorian bushfires (February 2009) continues, forest
researchers and managers are in the field, assessing the damage to
Victoria’s forests. Michael Ryan (VicForests) is one such
manager who is assessing the impact of the fires on
Victoria’s public forests. He remains optimistic that,
despite the large areas of mature and regrowth forests that have
been killed, recruitment of new seedlings will be good. The
2009 fires coincided with excellent seed crops in most of the
forests, so only the youngest forests will require active
intervention in the form of supplementary seed. Already, with
a small amount of follow-up rain, forest floors are covered with
tiny seedlings (Fig. 1).
It is estimated that the fires on 7th February killed 100% of the
mature and old growth ash forests within the Wallaby Creek
catchment and 50% of the mature and old growth ash forests within
the O’Shannassy catchment, including the Australian
mainland’s top ten tallest trees. Brett Mifsud, one of
Australia’s tall tree experts, reports that there are no
trees taller than 90 metres remaining in Victoria. At Wallaby
Creek, an area renowned for it’s spectacularly tall and lush
old growth forests, there are possibly over 100 trees that
survived: one 87.5 m tall tree that is just alive and 2 others over
85 m are the tallest (Fig. 2). In the days after 7th
February, much of the regrowth in the Armstrong Creek catchment was
killed, half of Tarago catchment and 75% of Maroondah catchment was
burnt, but at a lower intensity. The fires have caused a
patchwork effect of forest survival in the landscape.
Generally, stands burnt on the Black Saturday itself destroyed
stands completely (ie, 100% dead trees). Stands burnt after
Black Saturday when conditions had moderated received a respectable
“reduction burn” in the understorey, allowing close to
100% survival of the trees (Fig. 3). Sometimes very young
regrowth stands did survive on the Black Saturday due to a lack of
fuel while the nearby mature and old growth forests were
devastated. |
