Bushfires are regular event in our fire-prone country.  Unfortunately,  communities are sometimes devastated and, sadly, these tragic events sometimes lead to significant loss of human life, as well as loss of livestock, livelihoods, remnant bushland, wildlife and property. In true Australian spirit, fire-ravaged communities promise to rebuild, from the ground up. Part of this re-building process is, of course, the re-planting and re-greening of these affected places. From the regeneration of natural bushland, the restoration of public parks and amenity gardens, the re-establishment of community gardens and the very personal task of renewing home gardens and veggie patches, this process plays an important part in helping these stricken communities to recover.

Rising From the Ashes – The Role of Sustainable Gardening in Bushfire Recovery

It is highly likely that the restoration of gardens in fire affected areas is the last thing on the minds of most Australians at that time, and with good reason. But gardens certainly have a role to play in bushfire recovery in the longer term, on both an individual, and a community scale. Gardens have long been regarded as places of healing, of contemplation, of meditation and of remembrance. Gardens have the ability to alleviate stress, to soothe, to calm, and to rejuvenate or restore mental and emotional health. Communities will, as they rebuild, need to connect with these spaces of remembrance, reflection and quiet contemplation.

The restoration of gardens on a small scale, in the home environment, has the added benefit of a “return to normality” after a traumatic event. The first burst of seeds through the soil is symbolic, not just of a “re-birthing”, but as a sign of hope, of life rising from devastation, a sharp and welcome contrast of living green on black. As Paul Kelly, that most famous of Australian songsmiths has told us, “from little things, big things grow”, and the sowing of new gardens is a representation of hope and optimism, for individuals and entire communities.

Soil and Vegetation after fires – What to expect

The unprecedented intensity and temperature of these particular fires, coupled with long term drought and the unlikely occurrence of decent rain in the short term means that setting up gardens in affected areas may be more difficult than usual. The temperature of the bushfires reaches, at times, 1200ºc. The effect of this type of high intensity fire on property, vegetation and utilities, is readily apparent but what about the damage to the soil? After all, soil is the building block of life, the foundation of all required to nurture new life.

Soil is a living, breathing entity, teaming with essential life forms eg fungi, worms, microbes, insects and much more besides. Healthy soil is a porous mixture of minerals, air, water, organic matter, including leaf litter, tree roots, humus (broken down organic matter) and plant material.  All fires, regardless of intensity, alter the structure and behaviour of soil, but, in many cases, the impacts are short lived and the surrounding ecosystems recover rapidly.  However, this is not always the case as in the 2009 Victorian bushfires. In such extreme temperatures and severity of the fires, coupled with the low soil moisture content, the amount of vegetation affected and the pre- and post fire conditions, soils in the areas impacted are severely damaged, and will take some time to recover.  Add to this the extreme amount of ash then present on the surface of the soil, much of which is probably contaminated, and landholders in this area face a tough slog to revegetate and commence growing again.

So, what can fire affected areas expect from their soil? The short answer is not much, at least not for a fair while. The most obvious and significant issue immediately apparent is the volume of ash coating the soil surface. In some areas, it has been reported that the ash is in excess of 30cm deep. Wood ash is, in small amounts, beneficial for gardens and soil, with the recommended dosage being a shovel full per metre square. Ash is generally utilised as a liming agent, due to it’s high alkalinity, and is also a beneficial source of potassium, calcium and magnesium. However, such large volumes of ash exceeds any recommended maximum, and the temperature of the bushfires will have rendered this ash almost completely useless.

Ash also has another unfavourable characteristic, in that, due to its small particle size, it will repel water, and thereby act as a barrier to rain and any other irrigation from permeating the soil.  Known as hydrophobicity, this water repellent characteristic of ash, coupled with the existing hydrophobic nature of many drought-affected soils, leaves landholders despondent for some time.

Ash is also incredibly light, and easily shifted in light as well as gusty winds. This was been evidenced by much of Victoria on the 3rd March 2009 when extreme winds saw much of the state covered in what appeared to be fine dust. This was, in large part, due to dispersing ash from the bushfire areas. Heavy rains (although needed) would see much of the ash in these areas become a sludge, moving amoeba-like down slopes, and coming to rest in dams, waterways and low lying areas. Landholders attempting to protect water resources in these areas need to consider the construction of “ash barriers”. These are low net-like constructions erected around water ways, especially those that connect to larger water courses, or those that are used to supply water to stock. Ash generally contains a high level of potassium  and as such, has the potential to turn a pristine dam into a blue-green algal nightmare. In addition water for livestock should be kept as free from ash contaminants as possible.

So, is the solution to send in machinery, and scoop away the voluminous quantities of ash to give our soil a fighting chance? And, if so where will this ash end up, as much of it, especially from built areas is potentially contaminated with all manner of nasties.  Asbestos is the most obvious contaminant, but consider the less obvious “baddies”. The popularity of treated pine in gardenscapes, for edging, surrounds and play equipment has never been greater, and it’s termite-resistant properties make it an excellent choice for bush areas. However, it is these very properties that can provide contaminants in soils and ash. Treated pine, also used by the construction industry, is generally impregnated with a potent mix of copper, chromium and arsenic (CCA)….all of which then lie inherent in the ashes of damaged landscapes.

So what to do with the ash? In the short term the answer may be nothing. There is the potential for some areas to recover naturally, especially as seed and leaf litter become embedded in the ash over the following few months. Allowing as natural a recovery as possible is ideal, with the exception being areas that are to be utilized as vegetable gardens. In small areas, ash removal can be done, after taking some practical and sensible precautions. DO NOT ATTEMPT to remove any surface ash without wearing appropriate protective equipment. Long sleeved clothing, gloves and a good quality face mask are all absolutely essential. Choose a still day (not windy) and advise all others not involved in the ash clearing operation to stay well clear, particularly children, animals and those with respiratory conditions. Then carefully scrape up the cold ash (but not the soil beneath), and place in large 44-gallon drums with lids. This is probably the best short-term solution for small spaces, including residences, schools and community gardens. For larger properties… I am still waiting for the light bulb to go on. If anyone has any suggestions for this, as wild as they may seem, please let us know.

Part of the healing process that communities need is the process of re-building and re-connecting.  Establishing gardens, be they private, school or community, will be part of this process of re-connecting and of finding a way to work in harmony once again with the Earth.