Australian Garden Rescue

Restoring a Damaged Garden

Mary Horsfall

• Publisher: CSIRO PUBLISHING
• Year: 2014
• ISBN:
  9781486300020
• Topic: Ciencias biológicas
• Subtopic: Horticultura

Whether you have a garden suffering from lack of attention, damaged from weather events or suffering pest attacks, Australian Garden Rescue will guide you through practical solutions, helpful tips and preventative tactics to minimise future harm.

Best-selling author Mary Horsfall explores how our harsh climate can impact gardens, including the effects of bushfires, floods, frost, storms and heatwaves. She also addresses various pests from possums, snails and caterpillars to fungal problems and weeds.

With an emphasis on environmentally friendly strategies and simple advice, this highly illustrated guide will provide tactics for gardeners repairing recent damage or tackling prolonged neglect. Regardless of your garden's size or location, this book should be part of your gardening toolkit.

Part One

Preparation prevents problems

Many of the problems that can beset our gardens, and these are likely to become worse in the future, can be avoided or minimised with a little planning. Check the predictions for your state in the next chapter to see the conditions you are likely to have to contend with and prepare accordingly.

The chapters that follow will help you to set up a new garden that will better withstand a range of changing circumstances, from droughts to floods. They will also offer suggestions for practical and workable methods to make existing gardens more resilient.

Yes, you will have to put in some work and probably spend some money. However, setting up and maintaining a healthy, resilient garden does not involve much more effort or money than setting up a less adaptable garden. As well, you are likely to find that there will be fewer plant deaths and less need, over time, to pay for replacements.

Chapter One

Changing times

Change is an inevitable part of life. We can close our minds and stubbornly deny it. We can rage against it and resist. We can ignore it and hope it goes away. We can shrug and accept it. Or, we can anticipate, plan, adapt and thrive. This is as true of our gardens as it is of other aspects of our lives. A change in lifestyle or a change in pest populations can bring us a garden that is in need of rescue, but the biggest change of recent times, and one that affects us all, is our changing climate.

The world’s climate has always been in a continuous state of change; life forms of all types have always either adapted to the changes or become extinct. There have been times in the past when the climate has changed relatively quickly, resulting in mass extinctions, but, by and large the rate of change has been very slow and ecosystems usually have adapted successfully.

In recent decades, the rate of change has accelerated, giving less time for ecosystems to adapt. A major driver of the change is human activity that causes the emission of greenhouse gases. I do not intend to spend time proving this to you; hundreds of scientists with much more knowledge and authority on the subject than I have already made the case. The scientific evidence from a variety of sources is overwhelming.

For the purposes of this book, it doesn’t matter whether or not you accept that human activities are a major cause of climate change. The climate is changing, it is changing now, it is changing fast and we must adapt in many ways, including in the ways we manage our gardens, if we are to thrive in the future.

Mass extinctions and global warming

Researchers from Curtin University have linked the two great extinction events of the Triassic period (200 million years ago) and the Permian period (250 million years ago) to global warming triggered by rises in atmospheric carbon dioxide levels. During the Permian mass extinction, 96% of all species on Earth died out, meaning that all the life forms that now populate our planet have descended from the surviving 4%.

Find out more at: http://news.curtin.edu.au/media-releases/similar-global-warming-conditions-associated-with-two-mass-extinctions/

A global issue

The Intergovernmental Panel on Climate Change (IPCC) has concluded that: ‘It is virtually certain that increases in the frequency of warm daily temperature extremes and decreases in cold extremes will occur throughout the 21st century on a global scale.’ In other words, there will be more heatwaves and fewer frosts. As well, the IPCC has stated that there is a 90% to 100% probability that heatwaves will increase in length, frequency, and/or intensity over most land areas.

Evidence that the global climate is changing comes from several different studies. These include long-term instrumental records of air and ocean temperatures, changing sea levels, changing atmospheric water vapour measurements and melting glaciers and icecaps.

In late 2012, Michel Jarraud, head of the World Meteorological Organization said: ‘Climate change is taking place before our eyes and will continue to do so as a result of the concentrations of greenhouse gases in the atmosphere, which have risen constantly and again reached new records.’ He added that naturally cooling La Niña events ‘do not alter the underlying long-term trend of rising temperatures due to climate change as a result of human activities’.

In December 2012, at a conference in Qatar aimed at extending the Kyoto Protocol, United Nations Secretary-General Ban Ki-moon said that extreme weather was the new normal and that it posed a threat to the human race.

What to expect around Australia

We have all seen the damaging effects on our gardens of prolonged drought, heatwaves, sudden downpours and other weather-related phenomena. Most people think of climate change in terms of global warming, but the changes involve much more than increased temperatures. Rainfall patterns are changing, storm intensity and frequency are changing, droughts are becoming more frequent and more prolonged and coastal regions everywhere are experiencing rising sea levels.

Average temperatures around Australia are expected to rise by from 1°C to 5°C by 2070, compared with temperatures in recent decades. Though rising temperatures for all areas of Australia seem to be inevitable, different areas of the nation will experience the changing climate in a variety of ways. It might seem as if there is no way of knowing what to expect, and therefore no way of planning for it, but some quite firm predictions have been made. The following summary of expected impacts comes from information published by the Federal Department of Climate Change and Energy Efficiency. I have concentrated here on those that are likely to be relevant to gardens. For more information on environmental, agricultural, health and other impacts visit: www.climatechange.gov.au/climate-change.

All the predictions below are based on an assumption that greenhouse gas emissions are not reduced. If, by some miracle of international cooperation, global emissions are reduced, the projected impacts will lessen.

Australian Capital Territory

• Residents of Canberra and environs can expect rainfall to decrease by about 10% by 2030 and 25% by 2070, relative to 1990, along with reduced run-off in the catchments of up to 20% by 2030 and 50% by 2070.

• Rising temperatures and more days of extreme heat can be expected. The average number of days each year with temperatures above 35°C could increase from five (currently) to 26 by 2070.

• Higher temperatures and increased evaporation are likely to increase the bushfire risk, resulting in more days of very high or extreme fire danger. The number of such days could rise from 23 (currently) to 26–29 by 2020 and up to 38 by 2050.

• An increase in the number and intensity of bushfires is possible.

New South Wales

• There is potential for a decrease in the annual rainfall and run-off in inland catchments and for minor increases in coastal catchments by 2030.

• The evaporation rate is expected to increase by up to 22% in inland areas and 9% in coastal areas by 2070.

• Days of extreme heat over 35°C in Sydney could increase from 3.5 (currently) to 12 by 2070.

• Extreme bushfire risk days are expected to increase in parts of the state.

• In the Sydney region extreme fire danger days could rise from nine per year (currently) to 15 by 2050. By 2020, fire seasons are likely to begin earlier and end later and fires will be more intense. We have already seen this predicted trend happening, with severe bushfires in the Blue Mountains and other areas in October 2013.

• Higher temperatures and lower rainfall and relative humidity are likely to increase the fire danger in the south-eastern forests, resulting in more frequent fires and a greater area being burnt.

Northern Territory

• Territorians might live in one of two quite different climate zones. The Top End, which includes Darw...

Table of contents

• Cover
• Title
• Copyright
• Contents
• Acknowledgements
• Introduction
• Part One Preparation prevents problems
• Part Two Rescue rollout
• Appendix 1: Suppliers and information
• Appendix 2: Bibliography
• Index