The trees are gone. We and our society have lost them. They stood as silent sentinels for decades and some a century or more, providing environmental and ecological services. They cooled us in summer, filtered the air we breathe, quietened the noise of the hustle and bustle around us and their presence increased the value of our homes. They did all of this at little cost and with less recognition. They helped us live better lives, but now they are gone; cut down in their prime – they are not the only things that have been lost.
Trees and green space are vital for a proper human existence. Can we really have forgotten that the planet that we know as Earth is the Earth we know because of plants, trees and greenspace? Without plants there would be no life as we know it, and certainly no human life. Gone are the trees under which children played with parents and grandparents on balmy summer days. The memories of important family milestones in so many lives persist still, but in a generation or two they too will be lost – they are not the only things that have been lost.
It is curious that despite knowing that the presence of trees and greenspace in the vicinity of where you live leads to longer human longevity, better human health and lower state and national health costs, we are still removing trees in our cities and towns. From a mega-data study on women’s health in the USA, we know that in treed greenspaces, women live longer, use fewer prescribed medications, give birth to babies with higher birth weights and are hospitalised less and for shorter durations. These are huge benefits to the women who live in these places and they save billions in health care costs. When trees are removed they are not the only things that are lost.
Australian research tells us that if there were more treed open spaces available to those living in urbanised areas, a massive $5 billion could be saved from the nation’s annual medical bill for type-2 diabetes, blood pressure and cardiac related diseases. The researchers pointed out that the reason for the savings is not rocket science: if treed openspaces are available more people will exercise and these illnesses relate to a lack of physical activity, weight gain and obesity. When trees are removed unnecessarily, they may not be the only ones who are lost.
Treed open space meets basic human physical, mental and psychological health needs that have their origins in human evolution. Navigating a large and connected greenspace engages many senses –sight, hearing, smell, and perhaps taste and touch – at once, which activates various parts of the brain and hones a suite of spatial problem solving skills. Finding your way requires purpose, planning, patience and memory if you have travelled there before – it is multi-tasking par excellence. These experiences facilitate full human development from infancy to adulthood as the brain’s dopamine secreting neurones are stimulated impacting on motivation, attention and persistence. Without treed greenspaces can we even imagine what else is lost?
Trees sequester carbon and provide diverse microhabitats that may accommodate fifty or more other species. They are essential to biodiversity and allow humans to connect with nature in urban sites. Without trees the futures of native birds, insects, reptiles and fungi are put at risk too. When trees are removed they are not the only things that are lost.
The health and social benefits of recreation are well-known and the venues for such activities are public open spaces under local government control. It is easy to think that these facilities bolster urban green space and provide opportunities for greater canopy cover. However, more club rooms, car parks and hard surfaces are seeing a gradual erosion of green space, even within older recreation reserves. With the increase in the demand for ovals and pitches and the massive increases in women’s sport, there is enormous pressure on public open space to remove trees for more playing surfaces and facilities. There is no argument against fostering greater participation in recreation, but why is there no strategy for preserving or increasing open green space due to these pressures as climate changes. When trees are removed the value of our greenspace is lost.
There is a strong correlation between the degree of tree canopy cover and the socio economic status (SES) of where people live. Greener, leafier suburbs tend to have a higher SES. People who live in these suburbs are healthier and live longer. We know it is a correlation not simple cause and effect, but in these greener and leafier suburbs, crime rates are lower, there is less violence, vandalism and graffiti and educational outcomes at all levels are higher. Greater health benefits accrue to disadvantaged sectors of communities from the provision and use of treed open space which can be a mechanism for addressing social inequality. When trees and greenspace are lost who knows what else we have lost?
From the air it is painfully obvious that not every suburb, town or region is equally served by treed open space. Worldwide the most impoverished sectors of societies with lower SES are the most disadvantaged in their access to and use of treed open space. This is true of Australia’s cities, regional centres and many country towns where some places seem to be completely devoid of green. We can see how disconnected the green patches and corridors of our landscapes and urban environments have become. It is astonishing to see developments of small blocks and large houses that could have been plucked from the new suburbs of any major Australian city fringing hot, inland towns. When trees are lost, the potential for coping with climate change is also lost.
Trees have a vital role to play in making cities sustainable and liveable as the climate changes, warms and dries. The subdivision of older homes involves the loss of mature trees on private land, but there is an assumption that these losses will be compensated by street tree planting. This is pure fantasy – the large old house and block transforms into four townhouses with four driveways which leave little, if any, space in the nature strip for the planting of sizeable trees. There is a spiral into greater canopy decline. When trees are lost on private land some of the potential to deal with climate change is lost.
The urban heat island (UHI) effect means that parts of cities, regional centres and even smaller towns can experience much higher day and night temperatures than the land that surrounds them. These higher temperatures, particularly during heatwaves, can contribute to higher rates of ambulance call outs, hospitalisations and heatwave related deaths. The simplest, easiest and cheapest way to cool cities is by increasing tree canopy cover. However, despite knowing the value of tree canopy cover in reducing UHIs, in most Australian cities canopy cover is declining. In Melbourne, the loss is at a rate of 1-1.5% per annum, mostly due to the removal of trees on private land – front and back yards – for more intense housing development. This is a serious concern for cities and towns anticipating population increase and future densification. When trees are lost during climate change and future heatwaves, lives will be lost.
During the covid-19 lockdowns, high level concerns about peoples’ physical health, capacities for coping with stress, increased risks of self harm and domestic violence and the learning environments of children, saw people flock to local parks, gardens and riverside reserves in unprecedented numbers. Such places were vital assets in coping with the pandemic. It also became clear that the most disadvantaged members of the community were further disadvantaged and subjected to higher levels of stress, because of the lack of accessible treed open space. There will be future pandemics and one wonders when trees are lost whether the hard lessons of covid and the importance of treed open space have also been lost.
Research tells us that to maximise the benefits provided by trees and their canopy cover, we should be aspiring to a canopy cover of 30%. However, there is insufficient public space in many Australian municipalities to achieve 30% tree canopy cover, and this is further threatened by tree removals. There must be contributions from trees growing on private front and back yards, but that too is put at risk by redevelopment and housing infill. How is it possible, given rising temperatures, that state planning laws continue to ignore the value of trees and open space? When trees are lost at the time we need them most, is it a sustainable, liveable future that is lost.
Public parks and gardens served their purpose admirably during covid-19 lockdowns and given the opportunity and proper planning they will do so again, enabling cities to cope with climate change. Providing large and well-connected treed green space is essential urban infrastructure under conditions of increased urban populations and climate change, not as a luxury for a privileged minority, but as a vital component of a sustainable economy for the majority and a right of all. Treed green space is not an option but essential as societies cannot afford it to be otherwise! When trees, open space, green space and canopy cover are lost from cities and suburbs society as a whole has lost.
The trees are gone. They are lost. The trees are gone we are lost.
– Dr Greg Moore OAM
Remembering trees lost to road construction, November 2022