Tag Archives for lost

Thousands of city trees have been lost to development, when we need them more than ever


Thami Croeser, RMIT University; Camilo Ordóñez, University of Melbourne, and Rodney van der Ree, University of Melbourne

Climate change is on everyone’s lips this summer. We’ve had bushfires, smoke haze, heatwaves, flooding, mass protests and a National Climate Emergency Summit, all within a few months. The search is on for solutions. Trees often feature prominently when talking about solutions, but our research shows trees are being lost to big developments – about 2,000 within a decade in inner Melbourne.

Big development isn’t the only challenge for urban tree cover. During the period covered by our newly published study, the inner city lost a further 8,000 street trees to a variety of causes – vandals, establishment failures of young trees, drought, smaller developments and vehicle damage.

Still, thanks to a program that plants 3,000 trees a year, canopy growth has kept just ahead of losses in the City of Melbourne.



Read more:
Our cities need more trees, but some commonly planted ones won’t survive climate change

Canopy cover is crucial for keeping urban areas liveable, shading our streets to help us cope with hot weather and to counter the powerful urban heat island effect. Trees can also be a flood-proofing tool.

Trees add beauty and character to our streets, and (so far) they’re not a political wedge issue in the ongoing culture war that is Australian climate policy. In short, they’re a very good idea, at just the right time.

Counting the trees lost to development

The thing is, this good idea happens in the midst of a construction boom. In Melbourne alone, this includes thousands of new dwellings and billions of dollars of new infrastructure. Many of the new buildings are very large – there’s a handy open database that shows these developments.

This map shows the scale of development under way in the inner city.
City of Melbourne

Next time you’re walking past a large construction site, look for empty tree pits – the square holes in footpaths where trees have been removed. Maybe you’ve already seen these and wondered what all the construction means for our trees. Well, now we know.

Our study puts a number on the impact of major development on city trees. In the City of Melbourne – that’s just the innermost suburbs and the CBD – major developments cost our streets about 2,000 trees from 2008-2017.

Using council databases and a mapping tool, we tracked removals of trees within ten metres of hundreds of major developments. We found much higher rates of tree removal around major development sites than in control sites that weren’t developed.

An example of our analysis, comparing tree losses around sites with major development (orange) to control sites (blue). Trees within 10m of major developments were much more likely to be removed.
https://doi.org/10.1016/j.scs.2020.102096

Even with the City of Melbourne’s robust tree-protection rules, trees can be removed or damaged due to site access needs, scaffolding, compacted soil, root conflicts with services access, and even the occasional poisoning.

The City of Melbourne invited artist Louise Lavarack to create a roadside memorial to a poisoned plane tree, which was then shrouded in gauze bandages.
Tony & Wayne/Flickr, CC BY-NC



Read more:
We’re investing heavily in urban greening, so how are our cities doing?

Tree protection limits losses

The silver lining in this story is that the city council’s tree-protection policy seems to be quite effective at saving our bigger trees. The vast majority of removals we saw were of trees with trunks less than 30cm thick. Only one in 20 of the trees lost was a large mature tree over 60cm thick.

This may partly reflect the fact that the council charges developers for not only tree replacement but also the dollar equivalent of lost amenity and ecological values. It gets very expensive to remove a large tree once you factor in all the valuable services it provides. When a tree is a metre thick, costs can exceed $100,000 – and that’s if there are no alternatives to removal.

The protection of bigger trees means Melbourne retained canopy fairly well, despite losing over 2,000 trees. Only 8% of city-wide canopy losses during our study period happened near major development sites. This modest loss is still serious, as removals are having more of an impact on future canopy growth than current cover.



Read more:
How tree bonds can help preserve the urban forest

Lessons for our cities

While Melbourne-centric, there are lessons in this study for cities everywhere. Robust policies to protect and retain trees backed up by clear financial incentives are valuable, as even well-resourced councils with strong policy face an uphill battle when development gets intense.

Our findings highlight that retaining and establishing young trees is especially difficult. This is troubling given these are the trees that must deliver the canopy that will in future shelter the streets in which we live and work.



Read more:
Keeping the city cool isn’t just about tree cover – it calls for a commons-based climate response

Improved investments in how young trees are planted and how long we look after them can help. For example, in a promising local study, researchers showed that trees planted in a way that catches rainwater run-off from roads grow twice as fast, provided planting design avoids waterlogging.

Finally, in the context of rapid development, buildings themselves can play a positive role. Green roofs, green walls and rain gardens are just a few of the ways developments can help our cities deal with both heat and flooding.

There are plenty of precedents overseas. In Berlin, laws requiring building greening have resulted in 4 million square metres of green roof area – three times the area of Melbourne’s Hoddle Grid. In Singapore, developments must include vegetation with leaf area up to four times the development’s site area, using green roofs and walls. Tokyo has required green roofs on new buildings for nearly 20 years.

The solutions are out there, and urban greening is rising in profile. Recent commitments in Melbourne, Canberra and Adelaide are promising. Our study findings are a reminder that, even for the willing, we’ll have to take two steps forward, because there’s inevitably going to be one step back.



Read more:
For green cities to become mainstream, we need to learn from local success stories and scale up


The Conversation

Thami Croeser, Research Officer, Centre for Urban Research, RMIT University; Camilo Ordóñez, Research Fellow, School of Ecosystem and Forest Sciences, University of Melbourne, and Rodney van der Ree, Adjunct Associate Professor, School of BioSciences. National Technical Executive – Ecology, WSP Pty Ltd, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Islands lost to the waves: how rising seas washed away part of Micronesia’s 19th-century history



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Laiap, to the west of the site of the now-disappeared Nahlapenlohd.
Author provided

Patrick D. Nunn, University of the Sunshine Coast

At first glance it may not seem so, but the story of the now-vanished island of Nahlapenlohd, a couple of kilometres south of Pohnpei Island in Micronesia, holds some valuable lessons about recent climate change in the western Pacific.

In 1850, Nahlapenlohd was so large that not only did it support a sizeable coconut forest, but it was able to accommodate a memorable battle between the rival kingdoms of Kitti and Madolenihmw. The skirmish was the first in Pohnpeian history to involve the European sailor-mercenaries known as beachcombers and to be fought with imported weapons like cannons and muskets.

Today the island is no more. The oral histories tell that so much blood was spilled in this fierce battle that it stripped the island of all its vegetation, causing it to shrink and eventually disappear beneath the waves.

Read more: Sea level rise has claimed five whole islands in the Pacific: first scientific evidence

Like many oral tales, this one tries to explain island disappearance post-1850 by making reference to an historical event. But in light of what we know today, the more plausible cause of the island’s disappearance is the sea-level rise in the western Pacific since the early 19th century, which has accelerated significantly over the past few decades. The disappearance of islands in the Solomon Islands in the southwest Pacific has recently been attributed to sea level rise. Further north, the same is true of several reef islands off Pohnpei.

Pohnpei and its surrounding islands, both past and present.
CREDIT, Author provided

Surveys of 12 of these islands have shown that not only have some – like Nahlapenlohd – completely disappeared, but that most others have shrunk over the past decade. Islands such as Laiap and Ros, which have lost two-thirds of their land area over this time, are likely to disappear completely within the coming decade.

The island of Laiap has shrunk since 2007.
CREDIT, Author provided

Why are islands in the western Pacific becoming the earliest casualties of sea-level rise? Partly because sea levels in this region have risen at two to three times the global average over the past few decades.

In parts of Micronesia, sea level has risen by 10-12mm each year between 1993 and 2012, far outpacing the global average of 3.1mm a year. While this rate is unlikely to be sustained indefinitely, the current trend would raise sea levels by a further 30-40cm by mid-century if it were to continue.

What’s more, reef islands are particularly vulnerable to erosion by rising seas, being made almost entirely of sand and gravel. Whole islands – even some island nations with which we are familiar today – are likely to be rendered uninhabitable or even disappear within the next 30 years. These include islands in nations like Kiribati, the Marshall Islands, Tokelau and Tuvalu, as well as some in other island nations that comprise mostly larger islands, such as the Federated States of Micronesia, of which Pohnpei is one.

Armoured islands

Yet we should note that not all of Pohnpei’s reef islands are disappearing, at least not at the same rate, and some have fortuitously evolved protection that will likely help them outlive their neighbours.

The coasts of some islands – like Kehpara and Nahlap – are “armoured” by beaches of huge boulders left there by large storms, often along their most exposed coasts. Other reef islands off Pohnpei’s leeward coast, such as Dawahk, are becoming “skeletonized” as waves wash across the island removing the sand and leaving only rocks, held in place by a maze of giant mangrove roots.

Whether or not the islands themselves succumb or survive, sea-level rise is a clear threat to their habitability for humans. Short-term interventions – either natural fortifications such as boulder beaches, or human-built defences such as seawalls – are unlikely to change the long-term outcome.

This underscores the fact that low-lying reef islands are transient – most Pacific reef islands formed only in the past 4,000 years after sea levels fell and sediment began to pile up on exposed reef platforms. The sea will remove today’s islands, just as it has washed away countless others before.

But of course we cannot ignore the human dimension. While only a few dozen people today call the reef islands of Pohnpei home, they are similar to many larger reef islands in Micronesia from which people may well be involuntarily displaced during the next few decades. Where these people might go, and how they can be accommodated in ways that preserve their dignity as well as their unique cultures, are very real questions for community leaders.

Read more: Australia doesn’t ‘get’ the environmental challenges faced by Pacific islanders

People first reached the islands of Micronesia from the Philippines, about 3,500 years ago after an unbroken ocean crossing of 2,300km. It’s an extraordinary achievement when you consider that people in most other parts of the world at that time rarely sailed out of sight of land. To have survived on islands in the middle of the ocean for more than three millennia, Micronesians and other Pacific islanders must have developed considerable resilience.

On high islands in Micronesia, the evidence for this is manifest. Ancient stonework constructions line many parts of the coastline, testament to a long
history of resisting shoreline change, and sometimes of manipulating it for human advantage.

Perhaps nowhere is more evocative of this today than Nan Madol, a megalithic complex built 1,000 years ago on 93 artificial islands off southeast Pohnpei. There are many explanations about why Nan Madol was created. Perhaps the truth is that it is an expression of dogged human resilience – one of hundreds along Micronesian coasts – in the face of an unruly nature.

The ConversationI thank my co-researchers on the project focused on Pohnpei’s reef islands, Augustine Kohler from the Department of National Archives, Culture and Historic Preservation of the Government of the Federated States of Micronesia, and my colleague Roselyn Kumar from the University of the Sunshine Coast’s Sustainability Research Centre.

Patrick D. Nunn, Professor of Geography, Sustainability Research Centre, University of the Sunshine Coast

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

Found: ‘lost’ forests covering an area two-thirds the size of Australia


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A coolabah forest in Western Australia – one of the world’s previously unrecognised dryland forests.
TERN Ausplots, Author provided

Andrew Lowe, University of Adelaide and Ben Sparrow, University of Adelaide

A new global analysis of the distribution of forests and woodlands has “found” 467 million hectares of previously unreported forest – an area equivalent to 60% of the size of Australia. The Conversation

The discovery increases the known amount of global forest cover by around 9%, and will significantly boost estimates of how much carbon is stored in plants worldwide.

The new forests were found by surveying “drylands” – so called because they receive much less water in precipitation than they lose through evaporation and plant transpiration. As we and our colleagues report today in the journal Science, these drylands contain 45% more forest than has been found in previous surveys.

We found new dryland forest on all inhabited continents, but mainly in sub-Saharan Africa, around the Mediterranean, central India, coastal Australia, western South America, northeastern Brazil, northern Colombia and Venezuela, and northern parts of the boreal forests in Canada and Russia. In Africa, our study has doubled the amount of known dryland forest.

The world’s drylands: forested areas shown in green; non-forested areas in yellow.
Bastin et al., Science (2017)

With current satellite imagery and mapping techniques, it might seem amazing that these forests have stayed hidden in plain sight for so long. But this type of forest was previously difficult to measure globally, because of the relatively low density of trees.

What’s more, previous surveys were based on older, low-resolution satellite images that did not include ground validation. In contrast, our study used higher-resolution satellite imagery available through Google Earth Engine – including images of more than 210,000 dryland sites – and used a simple visual interpretation of tree number and density. A sample of these sites were compared with field information to assess accuracy.

Unique opportunity

Given that drylands – which make up about 40% of Earth’s land surface – have more capacity to support trees and forest than we previously realised, we have a unique chance to combat climate change by conserving these previously unappreciated forests.

Drylands contain some of the most threatened, yet disregarded, ecosystems, many of which face pressure from climate change and human activity. Climate change will cause many of these regions to become hotter and even drier, while human expansion could degrade these landscapes yet further. Climate models suggest that dryland biomes could expand by 11-23% by the end of the this century, meaning they could cover more than half of Earth’s land surface.

Considering the potential of dryland forests to stave off desertification and to fight climate change by storing carbon, it will be crucial to keep monitoring the health of these forests, now that we know they are there.

Ground-based observations were a crucial part of the survey.
TERN AusPlots, Author provided

Climate policy boost

The discovery will dramatically improve the accuracy of models used to calculate how much carbon is stored in Earth’s landscapes. This in turn will help calculate the carbon budgets by which countries can measure their progress towards the targets set out in the Kyoto Protocol and its successor, the Paris Agreement.

Our study increases the estimates of total global forest carbon stocks by anywhere between 15 gigatonnes and 158 gigatonnes of carbon – an increase of between 2% and 20%.

This study provides more accurate baseline information on the current status of carbon sinks, on which future carbon and climate modelling can be based. This will reduce errors for modelling of dryland regions worldwide. Our discovery also highlights the importance of conservation and forest growth in these areas.

The authors acknowledge the input of Jean-François Bastin and Mark Grant in the writing of this article. The research was carried out by researchers from 14 organisations around the world, as part of the UN Food and Agriculture Organization’s Global Forest Survey.

Andrew Lowe, Professor of Plant Conservation Biology, University of Adelaide and Ben Sparrow, Associate professor and Director – TERN AusPlots and Eco-informatics, University of Adelaide

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

Gorillas: Rarest Have Lost Half Their Habitat in 20 Years


The link below is to an article that reports on the loss of half the habitat for the world’s rarest Gorillas in the last 20 years. 

For more visit:
http://news.mongabay.com/2012/1001-great-apes-habitat.html

Article: Australia’s Battle for the Great Barrier Reef is Being Lost


The link below is to an article that reports on how Australia is loosing the battle for the Great Barrier Reef.

For more visit:
http://www.news.com.au/news/australia-losing-the-war-to-save-reef/story-fnehlez2-1226421775358

Article: Lost Toad Found in Sri Lanka


Not seen since 1876, the Kandyan Dwarf Toad has been found once more in a stream in Sri Lanka. Thankfully the discovery took place in a protected area, the Peak Wilderness Sanctuary, so the toad should be free from most threats. Even so, the species is still considered extremely rare.

For more, visit:
http://news.mongabay.com/2012/0618-hance-kandyan-dwarf-toad.html

South Africa: Rhino Poaching Continuing to Kill Many Rhinos


The article below reports on the large number of Rhinos lost to poaching this year in South Africa.

For more, visit:
http://www.cbsnews.com/8301-501710_162-57399946/135-endangered-rhino-killed-in-south-africa/