FINDINGS

Analysis of the photoseries showed some clear and consistent trends:

No	Event	Management Implications
1.	Grass cover after the fire quickly entered a non-fire-affected sequence that reflected the drought level. Biomass peaked before the 1997 drought, and has stayed lower since. The heavily drought-affected state is not dissimilar to the one-year post-fire state.	Grassland management effort should reflect the wetness of a season, as is established practice.
2.	Small shrub layers are patchy and inconsistent.	Small shrubs have little direct impact on fire risk. No effort is needed.
3.	Tall shrubs exhibit three strong sequences: A) the pre-fire tall shrub layer was either killed off by the fire or became senescent after the fire.	The dead tall shrub biomass may, if bulky, produce a transient risk surge, requiring their removal. Remove within Asset Protection Zones (APZs).
4.	B) a post-fire, Acacia-dominated tall shrub layer was rapidly established from seed, and became senescent about 10 years post fire. It capitalised on the opening of the eucalypt canopy, and suffered when the canopy closed again about three years post-fire. Final loss also coincided with peak drought.	The Acacia layer is major risk from year 3 to year 10, especially Cootamundra Wattle and similar species. Dead biomass also produces risk for two years after die-off. Remove in APZs.
5.	C) a later tall-shrub layer appeared after the Acacia layer died off. This usually came from eucalypt seedlings suppressed in the low shrub layer. These are still growing, and may become a replacement canopy, or may simply be recruited into the existing canopy. Some areas had a repeat of the Acacia layer.	The eucalypt surge should be promoted in the outer APZs, as it assists with long-term maintenance of fuel moisture levels. For their first seven years they are NOT sufficiently seperated from the ground cover to prevent them contributing to fire behaviour, and thus being killed. Removal or protection from fire are thus the goals during this period.

The role of Drought

If the time series is reviewed at many sites, it is clear that the drought cycle has a far greated impact of fuel load than does time-since-last-fire (both wildfire and prescribed burns.
In 2019-2020, across south-east Australia, the drought was as a bad as has been seen, and fuels largely disappeared. And then worst fire season ever seen occurred.

Urban edge

Another area where interesting findings arise from the photoseries is the urban edge.
Some features of note are:

The steady loss of trees from urban lands. When a fire comes from timbered lands onto non-timbered lands, it oftens carries an ember storm ahead of the headfire. The distance over which these embers can be a problem depends on many factors, including the nature of the air flow ahead of it. Timbered urban lands cause much more disruption to air flow than a purely built environment. They may thus, in a well-designed area of interface, reduce the risk.
Without trees we may see spotfires further past the interface than the two rows of houses seen in 1991.
When dominant trees are removed or die, shrubs can increase their dominance of the urban edge. These may paradoxically act to catch embers, and thus increase risks.
Recurrent removal of fuel in parts of the urban edge keeps fire hazards down in the inner APZs. This is exactly what is intended.
Cars are still occasionally parked on the edge of the timbered lands, as was done in 14 Feb 1991. They are vulnerable to fire if parked close to fire fuel.