Tree Ferns Are Older Than Dinosaurs. But There's a More Interesting Fact
By Gregory Moore
With massive fronds creating a luxuriously green canopy in the understory of Australian forests, tree ferns are a familiar sight on many long drives or bushwalks. But how much do you really know about them?
First of all, tree ferns are ferns, but they are not really trees. To be a tree, a plant must be woody (undergo secondary plant growth, which thickens stems and roots) and grow to a height of at least three meters when mature. While tree ferns can have single, thick trunk-like stems and can grow to a height of more than 15 meters, they are never woody.
They're also incredibly hardy — tree ferns are often the first plants to show signs of recovery in the early weeks after bushfires.
The unfurling of an almost iridescent green tree fern fiddlehead amid the sombre black of the bushfire ash is almost symbolic of the potential for bushfire recovery.
Ferns are often the first plants to grow back after bushfires. Greg Moore, Author provided
Ancient Family Ties
Tree ferns are generally slow growing, at rates of just 25-50 millimeters height increase per year. This means the tall individuals you might spot in a mature forest may be several centuries old.
However, in the right environment they can grow faster, so guessing their real age can be tricky, especially if they're growing outside their usual forest environment.
As a plant group, tree ferns are ancient, dating back hundreds of millions of years and pre-dating dinosaurs.
They existed on earth long before the flowering or cone-bearing plants evolved, and were a significant element of the earth's flora during the Carboniferous period 300-360 million years ago, when conditions for plant growth were near ideal. This explains why ferns don't reproduce by flowers, fruits or cones, but by more primitive spores.
In fact, fossilized tree ferns and their relatives called the fern allies laid down during the carboniferous then have provided much of the earth's fossil fuels dating from that period. And tree ferns were a great food source, with Indigenous people once eating the pulp that occurs in the center of the tree fern stem either raw or roasted as a starch.
Until recent times, ferns were quiet achievers among plant groups with an expanding number of species and greater numbers. Today, human activities are limiting their success by the clearing of forests and agricultural practices. Climate change is also a more recent threat to many fern species.
Species You’ve Probably Seen
Two of the more common tree fern species of south eastern Australia are Cyathea australis and Dicksonia antarctica. Both species have a wide distribution, extending from Queensland down the Australian coast and into Tasmania.
They're often found growing near each other along rivers and creeks. They look superficially alike and many people would be unaware that they are entirely different species at first glance. That is, until you look closely at the detail of their fronds and run your fingers down the stalks.
C. australis has a rough almost prickly frond, hence its common name of rough tree fern, and can grow to be 25 meters tall. While D. antarctica, as the soft tree fern, has a smooth and sometimes furry frond and rarely grows above 15 meters.
Both contribute to the lush green appearance of the understory of wet forests dominated by eucalypts, such as mountain ash (Eucalyptus regnans).
Stems That Host a Tiny Ecosystem
The way tree ferns grow is quite complex. That's because growth, even of the roots, originates from part of the apex of the stem. If this crown is damaged, then the fern can die.
At the right time of the year, the new fronds unfurl in the crown from a coil called a fiddlehead. The stem of the tree fern is made up of all of the retained leaf bases of the fronds from previous years.
The stems are very fibrous and quite strong, which means they tend to retain moisture. And this is one of the reasons why the stems of tree ferns don't easily burn in bushfires — even when they're dry or dead.
In some dense wet forest communities, the stems of tree ferns are a miniature ecosystem, with epiphytic plants — such as mosses, translucent filmy ferns, perhaps lichens and the seedlings of other plant species — growing on them.
These epiphytes are not bad for the tree ferns, they're just looking for a place to live, and the fibrous, nutrient-rich, moist tree fern stems prove brilliantly suitable.
Engulfed by Trees
Similarly, the spreading canopies of tree ferns, such as D. antarctica, provide an excellent place for trees and other species to germinate.
That's because many plants need good light for their seedlings to establish and this may not be available on the forest floor. Seeds, such as those of the native (or myrtle) beech, Nothofagus cunninghamii, may germinate in the crowns of tree ferns, and its roots can grow down the tree fern trunks and into the soil.
As time passes, the tree species may completely grow over the tree fern, engulfing the tree fern stem into its trunk. Decades, or even centuries later, it's sometimes still possible to see the old tree fern stem embedded inside.
Still, tree ferns are wonderfully resilient and give a sense of permanence to our ever-changing fire-affected landscapes.
Gregory Moore is a Doctor of Botany, University of Melbourne.
Disclosure statement: Gregory Moore does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
Reposted with permission from The Conversation.
By Brett Wilkins
Despite acknowledging that the move would lead to an increase in the 500 million to one billion birds that die each year in the United States due to human activity, the Trump administration on Friday published a proposed industry-friendly relaxation of a century-old treaty that protects more than 1,000 avian species.
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By Dolf Gielen and Morgan Bazilian
John Kerry helped bring the world into the Paris climate agreement and expanded America's reputation as a climate leader. That reputation is now in tatters, and President-elect Joe Biden is asking Kerry to rebuild it again – this time as U.S. climate envoy.
Energy Is at the Center of the Climate Challenge<p>The <a href="https://science2017.globalchange.gov/chapter/1/" target="_blank">effects of climate change</a> are already evident across the globe, from <a href="https://theconversation.com/100-degrees-in-siberia-5-ways-the-extreme-arctic-heat-wave-follows-a-disturbing-pattern-141442" target="_blank">extreme heat waves</a> to <a href="https://science2017.globalchange.gov/chapter/12/" target="_blank">sea level rise</a>. But while the challenge is daunting, there is hope. Solar and wind power have become the <a href="https://www.irena.org/publications/2020/Jun/Renewable-Power-Costs-in-2019" target="_blank">cheapest forms of power generation globally</a>, and technology progress and innovation continue apace to support a transition to clean energy.</p><p>In the U.S. under a Biden administration, long-term national climate legislation will depend on who controls the Senate, and that won't be clear until after two run-off elections in Georgia in January.</p><p>But there is no shortage of <a href="https://www.bloomberg.com/features/2020-biden-climate-change-advice/" target="_blank">ideas for ways Biden</a> could still take action even if his proposals are blocked in Congress. For example, he could use executive orders and direct government agencies to tighten regulations on greenhouse gas emissions; increase research and development in clean energy technologies; and empower states to exceed national standards, <a href="https://www.reuters.com/article/us-autos-emissions-california/defying-trump-california-locks-in-vehicle-emission-deals-with-major-automakers-idUSKCN25D2CH" target="_blank" rel="noopener noreferrer">as California did in the past with auto emission standards</a>. A focus on a just and equitable transition for communities and people affected by the decline of fossil fuels will also be key to creating a sustainable transition.</p><p>The U.S. position as the world's largest oil and gas producer and consumer creates political challenges for any administration. U.S. forays into European energy security are often treated with suspicion. Recently, France blocked <a href="https://www.wsj.com/articles/frances-engie-backs-out-of-u-s-lng-deal-11604435609" target="_blank">a multi-billion dollar contract</a> to buy U.S. liquefied natural gas because of concerns about limited emissions regulations in Texas.</p><p>Strengthening cooperation and partnerships with like-minded countries will be critical to bring about a transition to cleaner energy as well as sustainability in agriculture, forestry, water and other sectors of the global economy.</p>
Creating a Global Sustainable Transition<p>How the world recovers from COVID-19's economic damage could help drive a lasting shift in the global energy mix.</p><p>Nearly one-third of Europe's US$2 trillion economic relief package <a href="https://www.bloomberg.com/news/articles/2020-07-21/eu-approves-biggest-green-stimulus-in-history-with-572-billion-plan" target="_blank" rel="noopener noreferrer">involves investments that are also good for the climate</a>. The European Union is also strengthening its 2030 climate targets, though each country's energy and climate plans will be critical for successfully implementing them. The <a href="https://joebiden.com/clean-energy/" target="_blank" rel="noopener noreferrer">Biden plan</a> – including a $2 trillion commitment to developing sustainable energy and infrastructure – is aligned with a global energy transition, but its implementation is also uncertain.</p><p>Once Biden takes office, Kerry will be joining ongoing <a href="https://www.un.org/en/conferences/energy2021/about#:%7E:text=The%20overarching%20goal%20of%20the,2030%20Agenda%20for%20Sustainable%20Development.&text=Accelerate%20delivery%20of%20United%20Nations,related%20issues%20at%20all%20levels." target="_blank" rel="noopener noreferrer">high-level discussions on the energy transition</a> at the U.N. General Assembly and other gatherings of international leaders. With the U.S. no longer obstructing work on climate issues, the G-7 and G-20 have more potential for progress on energy and climate.</p><p>Lots of technical details still need to be worked out, including international trade frameworks and standards that can help countries lower greenhouse gas emissions enough to keep global warming in check. <a href="https://www.carbonpricingleadership.org/what" target="_blank" rel="noopener noreferrer">Carbon pricing</a> and <a href="https://www.csis.org/analysis/how-can-europe-get-carbon-border-adjustment-right" target="_blank" rel="noopener noreferrer">carbon border adjustment taxes</a>, which create incentive for companies to reduce emissions, may be part of it. A consistent and comprehensive set of national energy transition plans will also be needed.</p><p>The global shift to <a href="https://www.irena.org/publications/2019/Jan/A-New-World-The-Geopolitics-of-the-Energy-Transformation" target="_blank">clean energy will also have geopolitical implications for countries and regions</a>, and this will have a profound impact on wider international relations. Kerry, with his experience as secretary of state in the Obama administration, and Biden's plan to make the climate envoy position part of the National Security Council, may help mend these relations. In doing so, the U.S. may again join the wider community of countries willing to lead.</p>
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By Maria Caffrey
As we approach the holidays I, like most people, have been reflecting on everything 2020 has given us (or taken away) while starting to look ahead to 2021.
We Need More Than Listening<p>By now we have all become sadly accustomed to the current administration sidelining scientists, most prominently Dr. Anthony Fauci, because the facts they provide do not fit with the political rhetoric of the moment.</p><p>I have <a href="https://www.csldf.org/2019/08/22/csldf-helps-climate-scientist-maria-caffrey-fight-for-scientific-integrity/" target="_blank">my own history</a> of filing a scientific integrity complaint with the National Park Service (which falls under the Department of the Interior) after senior ranking employees attempted to censor one of my scientific reports. I know all too well the damage and pain that these actions cause, not just for the individual scientist, but also because these <a href="https://www.ucsusa.org/resources/attacks-on-science" target="_blank" rel="noopener noreferrer">attacks on science</a> over the last few years have undermined sound, evidence-based decision making.</p><p>President-elect Biden has repeatedly said that he will <a href="https://thehill.com/homenews/521638-trump-biden-will-listen-to-the-scientists-if-elected" target="_blank" rel="noopener noreferrer">listen to the scientists</a>. While this is certainly a welcome change, listening can only take us so far. This past week Lauren Kurtz from the <a href="https://www.csldf.org/" target="_blank" rel="noopener noreferrer">Climate Science Legal Defense Fund</a> and my colleague <a href="https://www.ucsusa.org/about/people/gretchen-goldman" target="_blank" rel="noopener noreferrer">Gretchen Goldman</a> published <a href="https://www.scientificamerican.com/article/ten-steps-that-can-restore-scientific-integrity-in-government/" target="_blank" rel="noopener noreferrer">an article</a> listing 10 actions the new administration should implement to show their commitment to strengthening government science:</p><ol><li>Clearly prohibit political interference and censorship.</li><li>Protect scientists' communication rights.</li><li>Acknowledge that attempts to violate scientific integrity, even if ultimately not fruitful, are still violations.</li><li>Protect federal scientists' right to provide information to Congress and other lawmakers.</li><li>Commit to incorporating the best science as part of agency decisions.</li><li>Elevate agency scientific integrity policies to have the full force of law.</li><li>Publicly release anonymized information about scientific integrity complaints and their resolutions at every agency.</li><li>Institute an intra-agency workforce, potentially under the White House <a href="https://www.ucsusa.org/sites/default/files/2020-09/strengthening-science-and-si-at-ostp.pdf" target="_blank" rel="noopener noreferrer">Office of Science and Technology Policy</a>, to coordinate scientific integrity efforts across agencies, foster discussion of policy improvements, and standardize criteria for policies across agencies.</li><li>Strengthen whistleblower protections.</li><li>Ensure that policies cover all actors who will be dealing with science.</li></ol>
Time for Action<p>I have spoken to many scientists, particularly federal scientists, who are eager to turn the page so they can hurry back to the work they had been doing before this administration, but I urge caution in assuming that things can be "normal" again.</p><p>Before Trump, I naively thought the scientific integrity policies established during the <a href="https://obamawhitehouse.archives.gov/blog/2016/12/19/scientific-integrity-policies-update" target="_blank">Obama administration</a> would be sufficient. I never imagined that any administration could so willfully ignore and attack expert advice and evidence that is intended to protect us and our public lands.</p><p>I have personally witnessed how hard our federal scientists work. They put in long hours with minimal pay (far less that what they could get if they worked in private industry) to pursue one simple goal: to make things better for the nation.</p><p>We need stronger scientific integrity policies to protect these people and their work. But more than that, we need stronger scientific integrity laws because they also benefit society.</p>
By Andrea Germanos
Environmental campaigners stressed the need for the incoming Biden White House to put in place permanent protections for Alaska's Bristol Bay after the Trump administration on Wednesday denied a permit for the proposed Pebble Mine that threatened "lasting harm to this phenomenally productive ecosystem" and death to the area's Indigenous culture.
<div id="da98c" class="rm-shortcode" data-rm-shortcode-id="478a197b7c59c92787c92bec92f1ac39"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1331662923710693376" data-partner="rebelmouse"><div style="margin:1em 0">Bristol Bay forever, Pebble mine never. #NoPebbleMine #SaveBristolBay https://t.co/CBQ9zuy8A5</div> — Save Bristol Bay (@Save Bristol Bay)<a href="https://twitter.com/SaveBristolBay/statuses/1331662923710693376">1606328156.0</a></blockquote></div>
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