REPORT: Post Bushfire Condition of Dry Rainforest

Background

In November 2019, the Liberation Trail bushfire decimated the Nymboida area, destroying more than 50 homes. The environmental damage was enormous, made worse by what is arguably the worst drought in the close to 200 years of white occupation of the area. That prolonged drought, combined with record high temperatures and heatwaves, saw moisture content of vegetation at such low levels that living trees were reduced to charcoal.

If the above was the result in Dry Sclerophyll Forest, it is clear that the Dry Rainforest communities which grow in the deep gullies all along the range to the east and west of Nymboida, would likely fare even worse.

Even the Dry Sclerophyll forests, renowned for their bushfire tolerance, were decimated and in some cases killed outright, as at this Glens Creek Road property. 

Background

In November 2019, the Liberation Trail bushfire decimated the Nymboida area, destroying more than 50 homes. The environmental damage was enormous, made worse by what is arguably the worst drought in the close to 200 years of white occupation of the area. That prolonged drought, combined with record high temperatures and heatwaves, saw moisture content of vegetation at such low levels that living trees were reduced to charcoal.

Even the Dry Sclerophyll forests, renowned for their bushfire tolerance, were decimated and in some cases killed outright, as at this Glens Creek Road property. 

If the above was the result in Dry Sclerophyll Forest, it is clear that the Dry Rainforest communities which grow in the deep gullies all along the range to the east and west of Nymboida, would likely fare even worse.

10 months after the fire, and with high rainfall occurring across the region, the total loss of canopy saw massive regrowth occur. In the Dry Sclerophyll across the ridgetops and slopes, a combination of Eucalypt seedlings and a variety of pioneer shrub species, formed an impetrative mass of vegetation.

 

In the gullies, regrowth was dominated by a variety of vines, covering the fallen trees and fire debris and smothering all else, at least in the short term. In gullies that had minimal pre-bushfire disturbance, these vines are mostly native, but in gullies where there had been previous disturbance, exotic vines have also proliferated.

 

Three years on

In November 2022, the Clarence Environment Centre undertook an assessment of another fire impacted property off the Armidale Road. This property was also badly impacted by the fire, not quite to the same extent as the above case, and we were keen to explore one steep gully line that seemed to have previously supported Dry Rainforest, and potentially a number of rare and endangered species known to occur in similar locations nearby.

However, on closer inspection, we found the same canopy-loss problems applied. With the gully clogged with fallen trees and debris from the fire, the additional sunlight has promoted dense regrowth including vines which, unlike the previously described site where water vines dominated, was found to include “unfriendly” climbing shrubs like Cock’s Spur Thorn (Maclura cochinchinensis); Molucca Bramble (Rubus moluccanus), and the thorny Queensland Sarsaparilla Vine (Smilax australis).

Needless to say, progress was extremely slow, even with loppers to cut through the worst of the thicket, taking in excess of 1.5 hours to progress the last 300m, before finally running out of time and giving up.

Regenerating species noted in that 300m confirmed the presence of dry rainforest, with close to 60 rainforest species recorded. However, most were in very small numbers, so recovery will be slow, if at all. Factors such as what trees will regrow to form the canopy, and when the next fire comes, will all have a bearing on the end result.

Report by John Edwards
Clarence Environment Centre