A threat to our mighty atmospheric guardians

For my generation, Climate change is a deep and consistent fear of an unavoidable doom. Every day we hear reports of melting icecaps, critters going extinct and magical sea creatures washing up on shore with plastic in their stomachs.

For a fledgling female scientist like myself, climate change means more storms, higher global temperatures, water shortages and potential famines in the near future.

I feel people are hugely reliant on technology and that we are all hoping and waiting for a ‘quick fix’ from technology to help against Climate change. Some sort of contraption that pulls carbon out of the atmosphere for us without any fuss.

However, instead (or while we wait) I call attention to the forests.

“The clearest way into the Universe is through forest wilderness. ” 

– John Muir in “John of the Mountains, 1939 Page 313”

Forests are a part of the nutrient cycle of nutrients, creating weather patterns, pumping out oxygen, filtering and storing precious water. Forests are absolute carbon hoarders – helping mitigate the planet’s temperatures.

70-80% of terrestrial carbon is said to be stored in forests, in the form of vegetation, soil and organic matter, such as leaves and twigs. So forests infected by diseases or forests undergoing deforestation, are a huge cause of carbon dioxide emissions into the atmosphere.

Upon learning this I wondered, do all plants suck up the same amount of carbon? Do certain forests matter more than others when it comes to carbon in New Zealand? Are there some trees that need more protection and attention?

In my investigation, I found a group of scientists that show that different trees store different amounts of carbon and at different ages throughout their lifespans. Some get a small muffin-to-go and others get a full-on-feast. This is where one of my new favorite trees comes in! Enter the mighty kauri! (Species Latin name: Agathis australis). They take the carbon cake!
If you’re not familiar with New Zealand’s North Island kauri trees, then let me quickly introduce you to their glory.

Tāne Mahuta, Photo taken by itravelNZ (CC By 2.0)

Kauri are New Zealand’s largest tree species and the third largest trees of the world and can live up to 2000 years! They hold vast cultural and spiritual significance to communities connected with the tree, Māori, Pākehā (NZ European) and beyond. They are known as a ‘keystone species’ as they alter the environment around them, with many plants and animals which have evolved to live on and around them.

The old-growth kauri forests are considered to be one of the most dense carbon ecosystems in the world! A scientific paper by Cate Macinnis‑Ng, Sarah Wyse (a postdoc here at Lincoln), Tristan Webb, Daniel Taylor and Luitgard in New Zealand worked in Haupai forest in 2011 to 2013, to find out the age and season in which kauri store the most carbon.

They found that a kauri stand in 2013 stored up to 4.21 tonnes of carbon per hectare per year… but how much is this really?!

After many equations, I found that this equates to a kauri stand the size of a rugby field, storing the same amount of CO2 that a 1990’s Toyota Corolla would emit by travelling around the South Island three times! Or for those more of a picture sort of thinker, this is worth around 150 bags of 20 kg bags of coal from The Warehouse per rugby field stand, per year!

A kauri stand the size of rugby field accumulates enough CO2 to cover a round trip of the South Island 3 times!

This research also found that 100 year old trees (young-adults of the kauri forest world) grow the fastest and suck up more carbon than the little bubba seedlings and the ancient oldies – to fill their boots, so to speak. They also found that kauri trees of all ages sucked up more carbon in the spring (Oct – Dec) and went dormant (a trees equivalent to sleep) through the harsher winter months (July – Aug). Although, still even with their 2 months off, this is still a hefty amount of carbon to bring in annually!

So keeping a good cycling of young-adults trees around is important in keeping carbon slurpers in the mix!

Unfortunately, Kauri have a mortal enemy causing widespread mortality to these trees, especially for the seedlings in the forest, you may have heard of it – ‘Kauri dieback’, this is a fungi-like pathogen found in the soil called Phytophthora agathicidia, which is killing these glorious trees off at alarming rates. Potentially facing extinction within our lifetime.

A warning sign in the Waitakere Ranges. Photo by Sonia (CC By-SA 3.0).

But wait! Its not all doom and a heating planet, there are many scientists researching, testing and working hard on awareness to protect these trees and find a solution to this disease spreading.

Scientists working on the kauri dieback Wikipedia page. Photo by Adventureforscience (CC By 4.0).

For instance, an article recently posted in stuff, writes of Dr Volker Nock and Dr Ashley Garrill from University of Canterbury, who are researching the penetrative force of diseases very similar to the kauri dieback species. This will help us understand how the pathogen works its way into the trees.

People like Monica Girth, who is running a team at the University of Wellington, looking for biochemical solutions against the disease.

Or Dr Ian Horner, a plant pathologist at Plant & Food Research, who is looking if phosphite injected into diseased kauri trees can halt the spread of the disease.

There are also awesome volunteer groups out there like The Kauri 2000 Trust, who are focused on restoration. They work hard to plant out already grown seedlings with a head start in life. This restoration of forests with planting kauri is a vital step in ensuring rehabilitation of this ecosystem and is movement against the widespread death of kauri.

And you can help too, with your new knowledge and awareness about kauri, you are now a kauri-carer, cause you now know just some of their vast importance and awesomeness!

If your now hoping to see these magnificent trees, all you have to do see these trees in botanical gardens so to keep the wild ones safe, or if you really, really want to see one in the wild make sure you are a tidy kiwi and clean your boots at the stations at the start of the tracks and end of the tracks and say “thanks kauri for helping keep the planet cool!”

Cleaning station for footwear to minimise spread of kauri dieback. Photo by Kathrin & Stefan Marks (CC By-NC-ND 2.0)

Jacque Bennett is a postgraduate student in the Master of Science. She wrote this article as part of her assessment for ECOL 608 Research Methods in Ecology.

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