Mels Barton: Kauri dieback - what we must do to save our iconic New Zealand Kauri trees

GreenplanetFM Podcast

To have our venerable forest giant die before us is making us realise that even far from all other countries on our planet - that we too can be affected by something that is microscopic and beneath our feet that can destroy a living treasure that can live to 2,000 years of age.

It’s called Kauri dieback.

Kauri dieback is the deadly kauri disease caused by Phytophthora taxon Agathis. Following DNA studies, this fungus-like disease was formally identified in 2008 as a distinct and previously undescribed species of Phytophthora. Kauri dieback is specific to New Zealand kauri and can kill trees of all ages.

Microscopic spores in the soil infect kauri roots and damage the tissues that carry nutrients within the tree. Infected trees show a range of symptoms including yellowing of foliage, loss of leaves, canopy thinning, dead branches and lesions that bleed gum at the base of the trunk. Nearly all infected kauri die. In the past 10 years, kauri dieback has killed thousands of kauri in New Zealand.

Kauri is NZ’s canary in the coal mine with this organism and there are hundreds of different phytophthora around our planet.

The potato famine in Ireland was cause by a phytophthora and there is one in Australia called cinnamomi that is devastating forests in South West Australia.

Mels states that NZ authorities are not yet serious about this and our inaction is enabling this disease to spread

Because ecologists call kauri a key stone species - it is just not one species - as it changes the soil type underneath a kauri forest over the millennia to something called pod sol - which is a very leached soil type and they do this to support themselves and support other organisms that like to live with kauri (symbiosis) and kauri becomes surrounded by its friends.

Up to 17 different species that can survive alongside kauri. And this symbiotic relations is totally unique globally and if we loose our kauri, we will loose all these other organisms that depend on kauri as well. Thus she says it is not much to stretch this - that if no action is taken we could have extinction right throughout Northland. As this die off is doubling every 5 years.

Monitoring Report faults foot traffic for spreading it.

In August of 2017, the Auckland Council released a monitoring report showing that the places with the most foot traffic, particularly Piha and the Cascades and especially Piha have a risk of kauri going extinct in the next 5 years. Because the spread now is so large and has increased so much that if it doubles again - that in the next 5 years there will be no kauri in Piha.

The Auckland Council report - states quite clearly and in stark terms that if we do not change the management of our kauri forests in the Wairakere ranges - we risk losing all of the kauri.

The problem - These spores are carried by foot born human traffic and also mountain bikes that are then used in other areas of the forest. These tiny spores in the soil and mud, cling to our shoes or bike tires and the spread becomes easy.

It’s a bio security crisis affecting all of the kauri in New Zealand.

The range of Kauri in NZ is less than point 1% of what is was originally.

Before people settled in New Zealand, forest containing kauri covered much of the Coromandel Peninsula and northern areas throughout North Auckland. Today, the remaining 7,455 hectares of mature kauri forest is scattered in remnant patches.

Drastic Action Required

There are up to a million visitors walking the Waitakere Park annually.

Mels states the if we do not do something drastic as the management has been sporadic and patchy and wife we do nothing - we will lose our kauri.

Shoe cleaning stations are on many /most tracks to disinfect their shoes & boots, but unfortunately many people are not doing this small practice - the cleaning stations are quite rudimentary and people are spraying their muddy soles thinking it is a magical spray.

But as a somewhat benign spray it is not killing this organism. It needs to be a really, really good clean of your shoes and then a spray … and due to the condition of many of the tracks - mud is going to be moved around and deposited along these tracks and this is the crux of the problem.

The tracks in the Waitakere ranges Mels says are in an exceptionally poor state. For up to 20 years very little attention. She mentions that where stands of kauri are there are strategic scrub and spray stations - that the imperative is to use them every single time you came to one.

Not just once scrub and spray before going into the forest or one when you are leaving the forest. Because these ‘stations’ are strategically placed around all the different kauri and if you do not scrub and spray - you will just spread the contaminated mud to where the healthy kauri’s are - and there lies the problem - people are too unconscious to make a real effort, hence the rapid increase of this dieback.

Visitors are not using scrub and spray stations

Some of the Auckland council sites have been monitored for compliance - however it has been estimated that of the one million visitors year only 20% are scrubbing and spraying.

This translates to 800,000 people wandering around with this disease of their feet - causing this problem to rapidly spread.

Rats, possums birds and pigs are being blamed for moving this disease around but the monitoring has proved that it is always along the tracks that pass by kauri is where all the die off it happening.

Auckland Council has completed 2 major surveys of the Waitakere ranges in 2011 &2016 and clearly find that it is human foot traffic that is going up to trees, as these are the trees that are dying off. Trees that hide away from the tracks seem to be doing very well.

22,744 trees have been surveyed by helicopter and locked in by GPS and survey teams have checked each tree to do a health analysis.

Note it is not known how long it takes from infection until symptoms are expressed.

The Tree Council fb page - check the map - it’s like a cancer spreading along the tracks.

The Hillary Trail is badly infected …

The Cascades are bad too - over 20,000 people a day in summer - Piha has a lots people too. Very popular with runners too - hence this all adds to the infection along these tracks.

Pigs, rats, birds and possums are not to blame.

That she says it is not the pig, rats, birds and possums that are the cause as we would see are far more even distribution of across kauri and all over the ranges - but this is not so, as this contamination is happening all along the track network.

These animals do not exclusively use the track network like humans do. This makes it clear that it is a human problem.

The surveys show that 75% of trees infected lie within 50 metres of a track . Pigs are a problem, and need to be sorted but not the major cause by any stretch. But they are less than 25% of the problem and we humans are 75% of the problem and this is what we need to sort out.

Mels says that we humans need to own this and get it sorted. Accept responsibility for it and stop making excuses and take action.

She says that we would not see the doubling of the disease if it was only animals doing it.

The Hunua’s are another Auckland Council area forest that has no kauri dieback - so the imperative is to make sure that this dieback does not happen there - It has been surveyed exactly like the Waiitakere ranges - and the Tree Council is confident that there is no infection in the Hunua’s.

The Coromandel has a tiny number of infection sites - Northland has some infection but has not been surveyed like Auckland council have done, thus we do not know the scale of it, but it’s in Waipoua Forest and Trounson Park and on Great Barrier island too.

Infection of other forests - Mels says is a matter of time, not if …

Maori have said enough!

This is what Te Kawerau e Maki the local iwi (tribe) - the mana whena for the Waitakere’s have said - Enough!

Saying we need to get humans out of the forest and let it heal and for us to take action.

This is the forest they are kaitiaki of - that they are the guardians - to lose the kauri the Te Kawerau e maki - lose who they are …

They want a ‘rahui’ placed on the whole Waitakere area

Rahui is a closure and an exclusion of people from their normal activities - to let natural systems heal and regenerate - wanting us to respect the forest for this process to take place. They will be doing this very soon. Having asked the Auckland Council to do this under the sanction of a controlled area notice under the BioSecurity Act. Anyone found inside this exclusion zone woods be in breach of the BioSecurity Act.

Thus is backed by the Tree Council, Forest & Bird Society and the Friends of Regional Parks and the Waitakere Protection Society. They have all said this is what Auckland Council needs to do.

Mels say that Auckland Council must get in and move this whole initiative forward and if not the NZ Government may see fit to come in over the top of the Council - and force it to implement the closure, and then Auckland Council will lose all control over this process. Listen

Stating this is a national crisis for this toanga - treasure this keynote species that is unique that grows for up to 2,000 years - it is estimated .

She says it is not about spoiling every ones fun or a killjoy or exaggerating the scale of the problem - this is a critical time - it’s about the survival of a giant mega flora species.

She wants the tracks to be brought online again once the tracks have been upgraded so as to not facilitate the spread of the disease - this way we can get people back into the Waitakere to once again to bathe in the magnificence of the cool shade and beauty that the Waitakere forest harbour.

We must remember that is was only in 2007 that Kauri dieback was first noticed

Education

Education of New Zealanders is important. Because she does not want people to.be closed out forever it’s just a necessity now .. a temporary closure. To then rebuild the tracks and make them safe bio security wise.

Myrtle Rust another very recent problem in NZ.

Myrtle rust is mentioned too as an airborne disease and this now has been found in various areas of NZ - A great danger to NZ Christmas tree the pohutukawa. If seen - don’t touch, just photo and call the appropriate bio security authorities or Auckland Council.

There is another fungal disease in Hawaii discovered in 2014 - called the Ohi which lives in the soil, causing leaves to turn black and fall off killing a tree in s matter of weeks. They find that human movement is the cause of spreading this disease. They say that NZ pohutukawa tree could be at risk. It has affected about 75,000 acres of forest on the big Island of Hawaii and has now spread to Tahiti.

Mels says we have to future proof our forests - infrastructure that has to last another 50 years has to be planned for and put in place.

Call to Future Proof our Forests

This disease in some ways is an opportunity for humans to step up and wisely future proof our forests, our infrastructure and tracks, our biodiversity and get on top of biosecurity at every entry point in NZ.

She says one of the reasons she came to live NZ was to walk and hang out in NZ bush and forests and show them to friends and overseas visitors

Mels say that this disease may find other hosts other than kauri and we are finding that tanekaha is being affected - so this is why the urgency for NZers, Councils and the National Government to get in and educates the masses to support a major action to save what we cherish.

Kauri root system is shallow, sensitive and close to the surface making it vulnerable - listen

Mels then tells of the biological story of the roots and how a forest giant of a kauri succumbs to these tiny microorganisms cause starvation to the colossus above.

That Kauri cannot evolve fast enough due to the rapid appearance of this disease to build up its own immunity once again

Germination of seeds that then grow around the base of the Kauri as in a nursery - that may stay very small for 30 years or more - when a nearby tree dies and falls then the seedling take off and grow in the space provided to fill that gap.

Kauri does not keep its seeds for long - it instead has a ‘live’ nursery that stays within the umbrella of the above foliage - but with this disease the seedlings cannot withstand it and they die - so there is no generation alive to take off and grow when the parent kauri dies.

She wants urgent Council action - before summer of December 2017-18 as there will be 100’s of thousands of people tramping more disease around

Get behind the rahui.

Auckland Council is to spend $51.48 million on kauri die back over the next 10 years

Waitakere Forests are in many ways the ‘Jewel in the Crown of Auckland.’

She says that after the rahui - this process of opening new tracks etc can happen in stages - this is not a bad news story.

Incrementally open tracks once the fundamentals are in place.

Mels spell sit out - the strategy the mindfulness to get it right - with the education and championed by the Auckland Council in symphony with Maori.

Mels states we need all the firepower of NZ’s science - as we do not know what else this disease infects and how to actually destroy and eliminate it.

These 2 fundamental questions have not even been started in the last 9 years - Mels socks it to the scientific ineptitude in dismissing the urgency of what is attacking our venerated kauri - under the NZ Government’s MPI - the Ministry of Primary Industries.

Investment is needed into our future.

She lets it rip in the end.

www.KauriRescue.org.nz