Smart city planning can preserve old trees and the wildlife that needs them

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Mature trees have horizontal branches that are attractive to wildlife and birds.

Philip Gibbons, Australian National University

Australia’s landscapes are dotted with mature eucalypts that were standing well before Captain Cook sailed into Botany Bay. These old trees were once revered as an icon of the unique Australian landscape, but they’re rapidly becoming collateral damage from population growth. Mature eucalypts are routinely removed to make way for new suburbs.

Good planning can ensure many more mature eucalypts are retained in urban developments.
Philip Gibbons

This has a considerable impact on our native fauna. Unless society is prepared to recognise the value of our pre-European eucalypts, urban growth will continue to irrevocably change our unique Australian landscape and the wildlife it supports.

Read more:
Trees are a city’s air conditioners, so why are we pulling them out?

Why are old eucalypts worth saving?

In urban landscapes, many consider large and old eucalypts a dangerous nuisance that drop limbs, crack footpaths and occupy space that could be used for housing. But when we remove these trees they are effectively lost forever. It takes at least 100-200 years before a eucalypt reaches ecological maturity.

Birds use old eucalypts as places to perch or nest.
Philip Gibbons

As trees mature, their branches become large and begin to grow horizontally rather than vertically, which is more attractive to many birds as perches and platforms where they can construct a nest.

Wildlife also use cavities inside ageing eucalypts. These are formed as the heartwood – the dead wood in the centre – decays. When a limb breaks it exposes cavities where the heartwood once occurred.

This is such a ubiquitous process in our forests that around 300 of Australia’s vertebrate species, such as possums, owls, ducks, parrots and bats, have evolved to use these cavities as exclusive places to roost or nest.

Mature trees also support high concentrations of food for animals that feed on nectar, such as honeyeaters, or seed, such as parrots.

Read more:
Concrete jungle? We’ll have to do more than plant trees to bring wildlife back to our cities

One study found that the number of native birds in an urban park or open space declines by half with the loss of every five mature eucalypts.

How can we keep old trees?

Decaying heartwood in older eucalypts leads to some large branches falling. This is when most eucalypts are removed from urban areas. So we remove trees at the exact point in time when they become more attractive to wildlife.

Plantings around the base of a mature eucalypt discourage pedestrian traffic or parked cars.
Philip Gibbons

A well-trained arborist knows that old — or even dead — eucalypts don’t need to be removed to make them safe. A tree is only dangerous if it has what arborists call a target. Unless there is a path, road or structure under a tree, then the probability of something or someone being struck by a falling branch is often below the threshold of acceptable risk.

Progressive arborists first focus on eliminating targets. For example, they might plant shrubs around the base of dead or rapidly ageing trees to minimise pedestrian traffic, rather than eliminating trees.

Where targets can’t be managed, trimming trees can remove branches that have a high risk of falling. Trees can also be structurally supported (braced) to remain stable. Such trees remain suitable as habitat for many native species.

Developers can plan around old trees.

How to design around trees

The removal of mature eucalypts is, in part, due to urban developers not considering these trees early in the planning process.

I have worked with one developer on the outskirts of Canberra to identify important trees. The developer then planned around, rather than in spite of, these trees.

The outcome has been around 80% of mature trees have been retained. This is much greater than the proportion of mature trees retained in other new urban developments in Canberra.

Read more:
Trees versus light rail: we need to rethink skewed urban planning values

The ConversationAustralia’s population is projected to double in 50 years, so our suburbs will continue to infill and expand. This will result in the continued loss of our mature eucalypts unless our approach to planning changes.

Philip Gibbons, Associate professor, Australian National University

This article was originally published on The Conversation. Read the original article.


Future ‘ocean cities’ need green engineering above and below the waterline

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Artificial islands can cause huge environmental issues for coastlines.
The Forest City Project

Katherine Dafforn, UNSW; Ana Bugnot, UNSW; Eliza Heery, National University of Singapore, and Mariana Mayer-Pinto, UNSW

Population growth has seen skylines creep ever higher and entire cities rise from ocean depths. The latest “ocean city” is the Chinese-developed Forest City project. By 2045, four artificial islands in Malaysia will cover 14km² of ocean (an area larger than 10,000 Olympic swimming pools), and support 700,000 residents.

Often overlooked, however, is the damage that artificial islands can cause to vital seafloor ecosystems. But it doesn’t have to be this way. If proper planning and science are integrated, we can develop the design strategies that will help build the “blue-green” ocean cities of tomorrow.

Read more:
Concrete coastlines: it’s time to tackle our marine ‘urban sprawl’

Colonising the ocean frontier

Ever growing numbers of human-made structures are occupying our oceans. Cities built on artificial islands in the ocean are providing a solution for urban planners trying to manage the population squeeze.

And yet, so-called “ocean sprawl” dates as far back as Ancient Egypt. Over the past few centuries, artificial islands have been built through land reclamation. Land reclamation is the process of creating new land from existing water bodies.

Atlantis, The Palm Hotel in Dubai, United Arab Emirates is built on an entirely artificial island.

The Netherlands, for instance, has been draining lakes and expanding its coastline to fight the advance of the sea since the 1500s. The Dutch actually built one of the first and largest artificial islands, which is now home to some 400,000 people. Japan’s third-busiest airport, the Kansai International Airport, was built on an artificial island in 1994. China has also been building into the oceans, reclaiming more than 13,000km² of seafloor and an estimated 65% of tidal habitat since the 1950s.

The artificial Eden Island in Mahe, Seychelles.

Using Google maps, we were able to identify more than 450 artificial islands around the world, including the famous Palm Islands of Dubai. These are often celebrated as engineering marvels, but at what cost to the marine environment?

We can’t ignore what lies beneath

Marine habitats have always been essential for human life in coastal regions. They provide food, building and crafting materials, and less-known services such as coastal protection, nutrient cycling and pollution filtration.

One of the World Map islands in Dubai, United Arab Emirates.

The creation of artificial islands causes large changes to the seabed by permanently smothering local habitats. In many parts of the world, existing habitats provide the foundation for artificial island construction. For instance, artificial islands in the tropics are often built directly on top of coral reefs. This leads to considerable destruction of already threatened ecosystems.

Land reclamation also impacts nearby habitats that are particularly sensitive to murky waters, such as coral reefs and seagrass beds. In Singapore, land reclamation is associated with coral reef decline due to sedimentation and resulting light reductions. Singapore has lost nearly 45% of the country’s intertidal reef flats and almost 40% of intertidal mudflats.

When the ecological, economic, and social value of marine habitats are considered, artificial islands and ocean sprawl seem to be indulgences that we cannot afford. The effects would be akin to the suburban sprawl of the 20th century. To avoid this cost, we need to address the complexities of the underwater world in urban planning and development.

“Blue urbanism”

In his book Blue Urbanism, Timothy Beatley calls for urban planners to consider and value ocean ecosystems. He argues that we need to recognise the psychological value of human connections to blue space, and extend green practices on land into marine environments. While some artificial island developments such as the Forest City project are touted as “eco-cities”, more could be done both to minimise impacts below the waterline and integrate underwater environments into city life.

Why not combine a “Forest City” with the principles of a “Sponge City”? While native plantings in a forest city could help to reduce air pollution, sponge cities seek to “absorb” and reuse rainwater, thus reducing pollution entering the oceans through stormwater runoff. Around artificial islands, developers could also embrace the water filtration powerhouse of the oceans: active oyster reefs.

The location of future constructions should also be carefully evaluated to ensure the preservation of important marine habitats. Artificial islands have the potential to create fragmented seascapes, but with careful spatial planning and smart designs, they could create corridors for some climate migrants or those threatened species most at risk from habitat loss.

The ConversationDesigns based on ecological principles can reduce the impacts of artificial islands on natural habitats. However, applications of “blue-green” infrastructure remain largely untested at large scales. New designs, building strategies and spatial planning that integrate seascapes and landscapes are an opportunity for both “smarter” cities and experimentation for the development of successful blue-green technologies.

Katherine Dafforn, Senior Research Associate in Marine Ecology, UNSW; Ana Bugnot, Research Associate, UNSW; Eliza Heery, Research Fellow in Marine Ecology, National University of Singapore, and Mariana Mayer-Pinto, Senior Research Associate in marine ecology, UNSW

This article was originally published on The Conversation. Read the original article.

Floods don’t occur randomly, so why do we still plan as if they do?

Anthony Kiem, University of Newcastle

Most major floods in South East Queensland arrive in five-year bursts, once every 40 years or so, according to our new research.

Yet flood estimation, protection and management approaches are still designed on the basis that flood risk stays the same all the time – despite clear evidence that it doesn’t.

We analysed historical flooding data from ten major catchments in South East Queensland. As we report in the Australasian Journal of Water Resources, 80% of significant floods arrived during five-year windows, with 35-year gaps of relative dryness between.

Read more:
Old floods show Brisbane’s next big wet might be closer than we think

The early 1970s brought a succession of severe floods to South East Queensland. This was followed in the 1980s by a raft of floodplain development projects, together with extensive research on floodplains and flooding risk, carried out by a group of researchers who described themselves as the “Roadshow” because of their frequent visits to flood-prone regions.

Throughout the 1980s, some Roadshow members noticed that large floods in South East Queensland seemed to follow a 40-year cycle, with five-year periods of high flood risk separated by 35 years of lower flood risk. They speculated that the next “1974 flood” (a reference to a devastating flood that hit Brisbane and South East Queensland that year) would arrive some time around 2013 .

Sure enough, South East Queensland was once again hit by large floods in January 2011 and January 2013.

Evidently, large floods in South East Queensland are not random. This is a problem, given that development policies and engineering practice, by and large, still assume that they are.

History repeating

In 1931, the Queensland meteorologist and farmer Inigo Jones linked the Brisbane River’s floods to the Bruckner Cycle of solar activity, which he determined to be 35 years long, but which has since been found to vary from 35 to 45 years.

In 1972, flood engineer John Ward argued that flood frequency distributions differ in space and time because higher flows originate from a variety of different rainfall mechanisms. At the time, minimal insight was available into what those different rainfall mechanisms were.

In the 1990s, drought research in Queensland by, among others, researchers Roger Stone and Ken Brook and John Carter identified cyclical variations in Queensland rainfall associated with the Southern Oscillation Index (SOI), supporting the idea of non-random occurrence of floods.

In 1999, Australian hydrologist Robert French also noticed that irregular clustering of flood events was associated with the SOI, and pointed out that flood planning needed to take into account more than just seasonal or year to year variability.

More recently, flood incidence has been strongly linked to large-scale ocean processes such as the El Niño/Southern Oscillation (ENSO) and the Interdecadal Pacific Oscillation (IPO). These phenomena seem to have a marked effect on eastern Australian rainfall variability, and therefore on the risk of both floods and drought.

Is the 40-year cycle real?

We compiled records of major floods in South East Queensland between 1890 and 2014. As the table below shows, roughly 80% of large historical floods happened within a series of five-year flood-prone periods, despite these periods together representing only 16% of the study period.

The South East Queensland study area (approximately indicated by the orange box) and the 10 catchments analysed in this study.

Timing of the largest flood events within the 40-year cycles. Superscripts next to each flood event indicate the ranking of that flood event in that catchment (that is, the largest flood in each catchment is ranked 1).

On average, the number of large floods per year was 4.9 times higher within the five-year flood-prone periods.

Not only were floods more frequent, they were also more severe, with flood heights 41% higher during the five-year flood-prone periods than at other times.

Even though a few large floods occurred outside the five-year flood-prone periods, the 40-year cycle of flooding in South East Queensland appears to be a genuine phenomenon.

What drives the cycle?

The most likely physical explanation for cyclic or non-random flooding is the IPO, which is rather like the ENSO cycle except on longer time scales. The IPO influences eastern Australia’s climate indirectly, by affecting both the magnitude and frequency of ENSO impacts.

Recent “negative phases” of the IPO – meaning warmer than average Pacific Ocean temperatures north and south of the tropics – happened roughly during 1870–95, 1945-76, and 1999–present.

If we compare these with the five-year flood-prone periods in the table above, we can see that with the exception of 1930–34, all five-year flood-prone periods happened during these negative IPO events. Interestingly, the large floods in the 1950s and 1960s happened outside the five-year flood-prone periods identified by the 1980s Roadshow, but do align with IPO negative conditions.

Read more:
Planning for a rainy day: there’s still lots to learn about Australia’s flood patterns

In spite of all this evidence, most engineers and flood planners still assume that floods occur randomly and that flood risk is the same all the time. Phrases like “one in 100-year event” or “1% annual exceedance probability” are routinely used to describe floods, despite the fact that for some years and decades the risk is significantly higher. This gives a false sense of security during times when major floods are much more likely.

If this approach continues, then every few decades our flood defences will not be as reliable as we thought – a fact to which many Queenslanders can now attest.

We need new approaches to deal with the reality that large flood events do not occur randomly. It would arguably be more sensible to separate flood records into two (or more) categories – one for times when flood risk is “normal” and another for periods where the risk is higher – and then reevaluate flood frequency distributions and flood risks for each category. Decision makers then get a more realistic estimate of the true risk of flooding which leads to more informed and more resilient flood planning and defences.

This new approach might also help plan for the changes to flood risk expected in the future, whether from climate change, land use change, or whatever else the oceans and skies throw at us.

The ConversationThis article was coauthored by Greg McMahon, a Brisbane-based independent consultant on flood risks and Academic Chair at Rhodes Group Australia.

Anthony Kiem, Associate Professor – Hydroclimatology, University of Newcastle

This article was originally published on The Conversation. Read the original article.

Planning and Organising a Holiday Using Evernote

The link below is to an article that looks at planning and organising a holiday by using Evernote.

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Gas crisis? Energy crisis? The real problem is lack of long-term planning

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The long view: energy policy needs to stay firmly focused on the horizon.
Mattinbgn/Wikimedia Commons, CC BY-SA

Alan Pears, RMIT University

If you’ve been watching the news in recent days, you’ll know we have an energy crisis, partly due to a gas crisis, which in turn has triggered a political crisis. The Conversation

That’s a lot of crises to handle at once, so lots of solutions are being put forward. But what do people and businesses actually need? Do they need more gas, or cheaper prices, or more investment certainty, or all or none of the above? How do we cut through to what is really important, rather than side details?

The first thing to note is that what people really care about is their energy costs, not energy prices. This might seem like a pedantic distinction, but if homes and businesses can be helped to waste less energy, then high prices can be offset by lower usage.

The second thing to note is that energy has become very confusing. A host of short- and long-term problems have developed over decades of policy failure, meaning that there is no single solution.

Take gas prices, which were indirectly responsible for South Australia’s blackouts last month. Last week, SA Premier Jay Weatherill responded by unveiling a A$550-million plan including a new state-owned gas power station, while Prime Minister Malcolm Turnbull claimed to have secured a promise of secure domestic supply from gas producers.

Short-term thinking

It is crucial to keep the ultimate goals in focus, or else our short-term solutions could exacerbate long-term problems.

For electricity, we want to avoid blackouts and limit prices and overall costs. We need to do this in ways that allow us to meet our climate constraints, so we need solutions with zero or very low greenhouse emissions.

For gas, we need to ensure enough supply for local demand, at reasonable prices, and give large consumers the opportunity to negotiate contracts over reasonable time frames.

This means we need to allocate more of our gas to local consumers, because increasing overall gas production would just add to our long-term climate problems.

Peak gas and electricity prices are entangled. In our electricity markets, the most expensive generator needed to maintain supply in a given period sets the price for all the generators. So if an expensive gas generator sets a high price, all of the coal and renewable energy generators make windfall profits – at the consumer’s expense.

So either we need to ensure gas generators don’t set the price, or that they charge a reasonable price for the power they generate.

Quick fixes

Demand management and energy storage are short-term fixes for high peak prices. Paying some electricity or gas consumers to use less at peak times, commonly called “demand response”, frees up electricity or gas, so prices don’t increase as much.

Unfortunately, policymakers have failed to introduce effective mechanisms to encourage demand response, despite the recommendations of numerous policy reviews over the past two decades. This is a serious policy failure our politicians have not addressed. But it could be fixed quickly, with enough political will.

Energy storage, particularly batteries and gas storage, can be introduced quickly (within 100 days, if Tesla’s Elon Musk is to be believed). Storage “absorbs” excess energy at times of low demand, and releases it at times of shortage. This reduces the peak price by reducing dependence on high-priced generators or gas suppliers, as well as reducing the scope for other suppliers to exploit the shortage to raise prices.

The same thinking is behind Turnbull’s larger proposal to add new “pumped hydro” capacity to the Snowy Hydro scheme, although this would take years rather than weeks.

Thus South Australia’s plan, which features battery storage and changes to the rules for feeding power into the grid, addresses short-term problems. Turnbull’s pumped hydro solution is longer-term, although his handshake deal with gas suppliers may help in the short term.

The long view

When we consider the long term, we must recognise that we need to slash our carbon emissions. So coal is out, as is any overall expansion of natural gas production.

Luckily, we have other affordable long-term solutions. The International Energy Agency, as well as Australian analysts such as ClimateWorks and Beyond Zero Emissions, see energy efficiency improvement as the number-one strategy – and in many cases, it actually saves us money and helps to offset the impact of higher energy prices. Decades of cheap gas and electricity mean that Australian industry, business and households have enormous potential to improve energy efficiency, which would save on cost.

We can also switch from fossil gas to biogas, solar thermal and high-efficiency renewable electricity technologies such as heat pumps, micro-filtration, electrolysis and other options.

Renewable energy (not just electricity) can supply the rest of our needs. Much to the surprise of many policymakers, it is now cheaper than traditional options and involves much less investment risk. Costs are continuing to fall.

But we need to supplement renewable energy with energy storage and smart demand management to ensure reliable supply. That’s where options such as pumped hydro storage, batteries and heat-storage options such as molten salt come in.

This is why the crisis is more political than practical. The solutions are on offer. It will become much more straightforward if politicians free themselves from being trapped in the past and wanting to prop up powerful incumbent industries.

Alan Pears, Senior Industry Fellow, RMIT University

This article was originally published on The Conversation. Read the original article.

Uluru Road Trip

Over the last few years I have planned to travel to Uluru (Northern Territory, Australia) and then those plans have failed reach reality, for a whole bunch of reasons. Now I am planning yet another road trip to Uluru for later this year. I have been before, as part of a much larger trip through the Top End of Australia in 1998, but the time I had available at Uluru was limited to just the one day. This time I am planning a stay of a bit longer than that. So nothing too much to report on the actual planned trip at this stage, except to say that it does appear to be definitely on this time round.

For more information visit:
Uluru-Kata Tjuta National_Park

ABOVE: Uluru at Sunset

Bushwalking: Plan Your Trip

The link below is to an article that looks at some of the basics of bushwalking/trekking. In this particular article the emphasis is on planning the trip.

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