Saturday, September 14, 2019

El Nino has faded to neutral, but those storms are still there

Although storm activity in the eastern and central Pacific is pretty active right now, itʻs not due to El Nino conditions, which have faded away.

The latest NOAA El Nino update  says the ocean continues to be in an ENSO-Neutral condition. (ENSO is for El Nino Southern Oscillation). The NOAA Climate Prediction Center says there is a better than even chance that neutral conditions will continue through the winter.

Thatʻs important to folks in the Islands, because El Nino is associated with a higher risk of major storms like hurricanes. Ocean surface water temperatures in the mid-Pacific tend to be higher in El Nino years and lower in La Nina periods.

But that said, itʻs a game of percentages. We can still get hurricanes in neutral or even La Nina conditions.

As this is written, there are four tropical disturbances and one tropical storm, Kiko, spinning in the waters from south of Hawai`i east to Mexico. Kiko is expected to die out, but still might bring us some rain in a week or so.

© Jan TenBruggencate 2019

Wednesday, September 11, 2019

You have a pile of yard waste. How best to deal with it?

Walking stick, coulda been a bonfire.
So, youʻve got a pile of yard waste or pruned tree limbs. What to do with it?

1. You could use it; 2. You could let it rot (compost); or 3. You could burn it.

This is an argument for the first and the second, but not the third.

Some yard waste, if it doesnʻt have a bunch of weed seeds in it, can be mulch to keep weeds down and retain soil moisture. Or parts of it can be used as planting material (stick a plumeria stalk or a trimmed hibiscus branch in the ground and theyʻll grow). Chunks of wood can be slabbed up for construction projects, or carved into art objects. Really, you donʻt need to buy a walking stick...itʻs called a stick for a reason.

Composting is magical. It turns waste into a valuable soil amendment. And you can get all scientific about it to get the best, fastest results that produce enough heat to kill weed seeds. Or you can just pile the stuff up and the natural world will break it down in its own time. The crawly bugs and fungi and bacteria, the mesophylic and thermophylic organisms, the worms and the larvae, theyʻll do all the work.

What about the burning option? It gets the volume down fast, and creates wood ash, which has a lot of potash and other micronutrients that you could use in your yard.

There are times when burning is appropriate, but the downsides to burning are compelling. The heat sterilizes the soil under the fire and kills anything living in the greenwaste. If composting is a technique that celebrates life, fire is the opposite. Fire can be a natural process, but weʻre not talking about lightning-lit fires in native forests or savannahs.

(We can concede that for some species fire is a friend—grasses in many cases thrive after fires, both because the competition is killed off and because the ash fertilizes the soil. And we note in passing that a dry compost pile can sometimes catch fire, but thatʻs another discussion.)

What else?

Smoke from fires can be irritating to human (and other species) breathing and to eyes. It can make allergies worse. Sometimes toxic compounds that were locked up in the biological matter can be released into the atmosphere.

Wood smoke contains particular matter as well as chemicals in gas form. Breathing that stuff can have both short-term and long-term health impacts.

Hereʻs a paper on hazards of wood burning. And hereʻs a warning from the Centers for Disease Control and Prevention.

And then, of course, thereʻs the elephant in the room—the whole climate thing. Every time you burn, youʻre dumping a pulse of greenhouse gas into the atmosphere. Itʻs why folks are so exercised about the burning of the Amazon forests.

A few boring statistics: For every pound of wood you burn, you create 1.5 to 1.9 pounds of carbon dioxide (depending on the carbon density of the wood). Carbon dioxide, of course, is a big greenhouse gas. You also produce other greenhouse gases, like nitrogen oxides.

So to go back to the start, weʻre all better off if you make something (compost, mulch, a carved elephant, a picture frame) than if you immediately convert your woody waste to greenhouse gas. Youʻre just locking up that carbon for longer.

It seems clear that keeping that carbon in the soil rather than in the atmosphere is a good thing. And itʻs a good thing for more than just the climate, according to a 2005 article by Canadian researcher Henry H.Janzen. 

"Soil organic matter is far more than a potential tank for impounding excess CO2; it is a relentless flow of C atoms, through... myriad...streams—some fast, some slow—wending their way through the ecosystem, driving biotic processes along the way."

© Jan TenBruggencate 2019

Sunday, September 8, 2019

More on vaping deaths: black market vape fluid implicated, and the aerosol not the liquid has most caustic lung impacts

There is intriguing new evidence, but no hard conclusions yet, in the wave of hospitalizations and deaths associated with vaping.

Nearly 500 people have been hospitalized across the country with lung disease in the past few months, and five have died. All confirmed they had used e-cigarettes in the weeks or months before becoming ill.

Vaping has only been in the United States since 2006, but the sudden upsurge in hospital admissions starting early this summer is new. Researchers have recognized health issues with electronic cigarettes for some time, but now people are getting serious lung damage and some are dying.

It raises the question: It was always medically questionable, but what happened thatʻs new? What is making all these people so very sick, all of a sudden?

Early reports indicate that all the patients had used nicotine-based vaping fluids, but most of the sick had also used fluids containing a product from marijuana, THC (tetrahydrocannabinol) or CBD (cannabidiol). Some of the THC vape fluid came from black market sources, so itʻs hard to know how they were created.

New York State health officials reported they have found unapproved compounds in some of the black market THC vape fluids.

Researchers say the disease appears to be one associated with chemical attack on the lungs. That is relevant since much of the early concern about vaping impacts was about the impact of heat—the electrically heated smoke that could potentially "cook" mouth and lung tissues.

Many of the sick admitted acquiring cheap THC vaping oil from online sites or from "pop-up" retail vendors. Most of the victims admitted using both tobacco and marijuana compounds. It is possible that nearly all the victims used at least some THC fluid, but wonʻt admit it, one researcher said.

"Not everyone reported using THC oil, but we can't say if that was because they were scared to acknowledge it or because they never used it," Ngozi Ezike, MD, director of the Illinois Department of Public Health, said in a report in MedPage Today. 

The Centers for Disease Control said that some patients reported getting nausea, vomiting or diarrhea before they noticed lung problems like trouble breathing or chest pain. Several went for medical care several times before they were admitted to hospitals.

Many are being treated with supplemental oxygen, and some medical centers have had treatment success with heavy doses of steroids. In North Carolina, they used intravenous doses of methylprednisone. 

Some patients who have been released after treatement continue to have long-term lung damage.

There appears to be some suggestion that itʻs not (or not just) the nicotine or THC that is causing the problem, but some other compound in the vaping fluids. More than 100 such compounds are being tested, but as yet, the CDC says it doesnʻt have a prime culprit.

"To date, the investigation has not identified any single substance or e-cigarette product that has been consistently associated with illness," the CDC said in an August 30, 2019, report. 

That said, some health officials are focusing on a product called vitamin E acetate, which has been recovered from the vaping gear and in the lungs of many victims. The New York State Department of Health issued a statement last week, that indicated this compound is a target of its investigation.

"Laboratory test results showed very high levels of vitamin E acetate in nearly all cannabis-containing samples analyzed by the Wadsworth Center as part of this investigation. At least one vitamin E acetate containing vape product has been linked to each patient who submitted a product for testing. Vitamin E acetate is not an approved additive for New York State Medical Marijuana Program-authorized vape products and was not seen in the nicotine-based products that were tested."

While vitamin E products are not known to be harmful when eaten or applied to the skin, there is concern that when heated and taken into the lungs, they could cause disease. The New York State Department of Health "continues to investigate its health effects when inhaled because its oil-like properties could be associated with the observed symptoms."

But before we all go pointing fingers at specific compounds, there is at least some evidence that itʻs the vaping process itself that causes health effects.

A scientific paper released in the journal Thorax just a month ago tested live human lung tissue against vaping fluid in liquid form, and vaping smoke both with and without nicotine. (In this test, THC was not included.) 

It is a small but elegant study conducted by British and American institutions, and researchers found that human lungs react badly to vape aerosol, and worse to the smoke than to the raw fluid.

Here is Science Dailyʻs report on the study. And here is the paper itself.

Unvaped fluid increased inflammation of lung tissue, but exposure to vaped fluid was far worse, causing more inflammation and also lung cell death. There was evidence vaped fluid also reduced the lungʻs ability to deal with bacteria—possibly setting people up for more severe infections.

"We show a significant increase in cytotoxicity caused by the vaping process itself," the authors write. Cytotoxicity is the quality of being poisonous to cells.

While the study was small and has limitations, its conclusions are consistent with other medical advice.

"While further research is needed to fully understand the effects of e-cigarette exposure in humans in vivo, we suggest continued caution against the widely held opinion that e-cigarettes are safe," the authors write.

For more on the vaping issue, see our previous post:

© Jan TenBruggencate

Saturday, September 7, 2019

Hundreds hospitalized, five dead: Alarming new disease threat from vaping

There is increasing evidence that vaping can be even more dangerous, and dangerous faster, than smoking.

And within the past week, researchers identified a strange new lung disease associated with vaping, but itʻs just the start. Very little is known about it. Hundreds of vapers are being admitted to hospitals with lung disease.

(Image: Lipid-laden macrophages found in patients with vaping-related respiratory illness. Oily lipids are stained red. Credit, Andrew Hansen, Jordan Valley Medical Center)

The U.S. Centers for Disease Control yesterday issued a report recommending Americans stop using vaping technologies. They said health departments in 25 states have reported more than 200 new cases of lung disease linked directly to vaping.

The Washington Post says that since that report, the count has risen to 450 cases in 33 states and one territory, with five deaths. 

Ironically, vaping was hailed as the great middle ground. Get the nicotine without all the other dangerous chemicals in cigarettes. A safer alternative. Instead, itʻs getting people sicker with lung disease even faster than cigarettes.

And it is potentially an epidemic. Vaping is huge, with a quarter of Hawai`i high school students using the e-cigarettes and a sixth of middle school students using.

There are fewer chemical compounds in vape fluids than in cigarettes, but increasingly, itʻs clear that there are other issues. Johns Hopkins produced an older balanced look at vaping here

It cites both the increased nicotine addiction hazard, and the direct health impacts of huge hits of nicotine, far stronger than you can get from a cigarette. But the new reports within the past week up the ante: the danger is from far more than nicotine.

There are other chemicals in vape fluids, and researchers do not yet know which one or which ones are causing the lung diseases theyʻre seeing. A New England Journal of Health report has just identified a new vaping lung disease that has sickened hundreds and has killed. Lung scans show damage that looks like severe pneumonia, but is not.

Ailing patientsʻ lungs have large white blood cells filled with globs of fat, and itʻs not yet clear whatʻs going on with them. Whether they are a symptom or a cause of the disease is not clear.

"While it is too soon to be sure, these lipid-laden macrophages may turn out to be useful to confirm or rule out this disease," said co-author Scott Aberegg, a critical care pulmonologist at the University of Utah.

Researchers across the country are seeing hospital admissions of vapers with breathing problems. A paper by doctors from Wisconsin and Illinois reported that of 53 reported cases, most of the patients are male, with an average age of 19, and that a majority (but not all) was taking both nicotine and tetrahydrocannabinol (THC) products via e-cigarettes. Almost all required hospitalization and one died.

The Utah doctors reported: "A previously healthy 21-year-old man who had been vaping nicotine and tetrahydrocannabinol (THC) daily presented with 1 week of dyspnea, cough, abdominal pain, nausea, and vomiting." (Dyspnea is shortness of breath.)

The U.S. Centers for Disease Control issued a paper this week citing hundreds of cases of severe lung disease associated with vaping. In its Morbidity and Mortality Weekly Report, the CDC said itʻs too early to know what the chemical cause is, but that thereʻs enough information to recommend against using e-cigarettes.

"Based on available information, the disease is likely caused by an unknown chemical exposure; no single product or substance is conclusively linked to the disease.

"Until a definitive cause is known, persons should consider not using e-cigarettes. Those who use e-cigarettes should seek medical attention for any health concerns. Clinicians should report possible cases to their local or state health department," the CDC said.

One of the issues is not knowing just what youʻre taking into your lungs: "Aerosols produced by e-cigarettes can contain harmful or potentially harmful substances, including heavy metals such as lead, volatile organic compounds, ultrafine particles, cancer-causing chemicals, or other agents such as chemicals used for cleaning the device," the CDC report said.

Symptoms may start with an unproductive cough, and as it progresses, many patients require oxygen to help them breathe.

© Jan TenBruggencate 2019

Thursday, July 11, 2019

El Nino fading out--good news for hurricane-phobic islanders

The mild El Nino that has been in place this spring and early summer appears to be on the way out.

Statistically speaking, thatʻs good news in terms of hurricanes. The Hawaiian Islands tend to have a couple fewer hurricanes per year in periods when El Nino is not in play. 

Here is a rundown on whatʻs been going on, from NOAAʻS Climate Prediction Center. 

And here is the latest news—todayʻs assessment that the current El Nino will dissipate in the next month or so. 

This is the synopsis from todayʻs report: "A transition from El Niño to ENSO-neutral is expected in the next month or two, with ENSO-neutral most likely to continue through Northern Hemisphere fall and winter."

That doesnʻt mean weʻre out of the woods. Itʻs still hurricane season, but this suggests weʻll move statistically back to normal conditions, which is about 3.5 named storms per season in the Central Pacific.

© Jan TenBruggencate 2019

Tuesday, July 2, 2019

Pele slipping upslope to Mauna Loa, pumping magma, USGS raises caution level yellow

Peleʻs Kilauea home Halema`uma`u. Credit: USGS

Is Madame Pele shifting residences, slipping upslope from her Kīlauea playground to her mountain palace at Mauna Loa?

It seems that way because thatʻs where sheʻs rumbling now.

After last yearʻs dramatic destruction on Kīlaueaʻs East Rift Zone, destroying homes by the hundreds and forests by the thousands of acres, Kīlauea has been quiet. That quietness, according to the USGS Volcano Hazards Program, has now continued for some months.

What of the other Hawaiian active volcanoes?

Haleakala remains quiet, as well. Hualalai too. Mauna Kea, which hasnʻt erupted in 4,600 years, shudders now and then, but mainly remains serenely calm. Lo`ihi, the undersea volcano building off the Hawai`i Island coast, shakes occasionally, but doesnʻt appear ready to erupt.

But seismic observations indicate thereʻs new activity now under massive Mauna Loa—the biggest active volcano on the planet. Not that itʻs ready to release raw lava in the short term. But right now, it is the most active of the Hawaiian volcanoes.

Magma—the term for molten rock underground—is moving. The volcano stores magma in different places, and one of them is a fairly shallow reservoir beneath the summit. Earthquake activity around that reservoir indicates that thereʻs movement in that region.

The Hawaiian Volcano Observatory uses a range of equipment to take, as it were, Peleʻs pulse. There are seismic monitors, and tilt meters, and even satellite measurements. You can see the observatoryʻs reporting on Mauna Loa here.

So far, the geologists are using very careful language, clearly intending to inform but not alarm.

"For the past several months, earthquake and ground deformation rates at Mauna Loa Volcano have exceeded long term background levels. An eruption is not imminent and current rates are not cause for alarm. However, they do indicate changes in the shallow magma storage system at Mauna Loa," the observatory reports.

It has upped Mauna Loaʻs alert level from placid green to cautious yellow. That means thereʻs stuff going on but the experts donʻt think an eruption is imminent. For perspective, the next two levels would be orange (eruption possible in as little as two weeks) and red (eruption likely within 24 hours.)

Weʻre nowhere near those more fiery color levels, but again, thereʻs something going on. It started with a significant earthquake "swarm" in October 2018. Since then, quake level and the actual swelling and shrinking of the mountain have been above background levels.

Theyʻre not yet a big deal, but this is the kind of activity that has led to eruptions in the past.

"Seismic stations have recorded an average of at least 50 shallow, small-magnitude earthquakes per week beneath Mauna Loa's summit, upper Southwest Rift Zone, and upper west flank. This compares to a rate of fewer than 20 per week in the first half of 2018. 

Shallow earthquakes are occurring in locations similar to those that preceded Mauna Loa's most recent eruptions in 1975 and 1984," the observatory wrote.

The near-surface magma storage area seems to be inflating, filling with molten rock, they say. That said, the volcano has had similar activity twice since 2000, without an this is not a countdown.

"As has happened before, it is possible that current low-level unrest will continue and vary in intensity for many months, or even years without an eruption. It is also possible that the current unrest is an early precursor to an eventual eruption. At this time, we cannot determine which of these possibilities is more likely," the observatory reported.

If an eruption nears, there should be plenty of warning signs: "These signs could include further increases in rates of earthquakes and ground deformation, increases in the sizes of earthquakes, an increase in surface temperatures, or an increase in visible steam plumes or sulfur dioxide emissions."

Mauna Loa erupted 33 times since 1843. That works out to once every five years, although some of those were quite small. Among larger eruptions—ones whose lava covered 10 square kilometers or more, there were 16—one every 11 years.

The last eruption was in 1984, meaning itʻs been 35 years without a Mauna Loa eruption.
Kīlauea was erupting during much of Mauna Loaʻs recent quiet period. For many years, some scientists argued that a connection between the volcanoes prevented one from erupting while another was spewing lava. You can still see this information on websites, but the 1984 double eruption proved this wrong. Hereʻs a New York Times storyon that

© Jan TenBruggencate 2019

Monday, July 1, 2019

Hawaiian tradewinds shifting NE to East, and that means warmer weather for us

It feels warmer in the Islands, and it is—in part because there are significant changes in our tradewind flow.

It is not that the trades have stopped blowing, but that theyʻre blowing from warmer water, which makes the breeze warmer.

State Climatologist  Pao-Shin Chu said wind data over the past 40 years show a definite shift in the flow of tradewinds. Theyʻre blowing more from the warmer waters east of us, and less from the cooler waters northeast of us.

Chu, a meteorologist at the University of Hawai`i, compared two sets of decades-long data for winds at Honolulu Airport. And while the two sets are not precisedly comparable, they both tell the same story—a shift from northeast trades to easterly trades.

What does that mean to the person on the street, or sitting in front of a fan at home, or selecting restaurants for the efficiency of their air conditioning?

"The wind from the northeast is cooler than with the easterly component," Chu said.

Chu first noted the change in a paper published in 2012 in the Journal of Geophysical Research. He has since reviewed updated numbers and said the trend continues.

That paper, by Jessica A. Garza, Chu, Chase W. Norton and Thomas A. Schroeder, is entitled "Changes of the prevailing trade winds over the islands of Hawaii and the North Pacific."  

The researchers looked at wind data from eight stations on land and from ocean buoys around the Islands. The data runs from 1973 to 2009. Here is a press release on that paper.

"The northeast trade frequency is found to decrease for all eight stations while the east trade winds are found to increase in frequency," the authors wrote.

Hawai`i gets its reputation for having a comfortable climate in part from the remarkable consistency of the trade wind flow. It is the most consistent wind field on the planet, the authors said.

When Chu recently reviewed a newer set of wind numbers, from 1980 to 2014, he found a compable result: The frequency of northeast trades drops while the frequency of easterly trades rises.

He said that at the beginning of the data set, there were 170 days of northeast trades, and they dropped to 150 by the end of the period.

Meanwhile, east trades increased from 95 to 120 days.
And there is other news in trade winds. Chinese researchers report that during the past century, trade wind speeds have increased in the western Pacific, but decreased in the eastern Pacific. (Hawai`i is kind of in the middle.)
That study "Long-term trend of the tropical Pacific trade winds under global warming and its causes," is by a team lead by Yang Li, an atmospheric scientist at Chinaʻs Chengdu University. 
University of Hawai`iʻs Chu said he has seen a slight weakening in Hawaiian tradewinds, but not enough to be statistically significant.

©Jan TenBruggencate 2019

Sunday, June 23, 2019

Ancient botanical ink between far-flung Polynesian cultures, and why does Pitcairn keep showing up?

Polynesian voyagers visited nearly every island in the tropical and subtropical Pacific, and they colonized and remained on most of them.

But a remarkable few were abandoned, despite apparently having the resources to maintain a population. Pitcairn is one of those.

This remote high island in the eastern South Pacific is best known as the refuge that the Bounty mutineers and their Tahitian friends went to, to hide from the British navy. Pitcairn was uninhabited at the time. But it had been inhabited.

Canoe-sailing Polynesians had moved there a millenium ago, apparently thrived for 400 years, and then vanished. Like a sailing ship found drifting with no one aboard, its story is a mystery. Even today, as a British Overseas Territory, it has difficulty attracting people. An immigration site for Pitcairn is here

There is something eerie about Pitcairnʻs Polynesian history. Where did these islanders go? Did they abandon their island. Were they killed off by disease? Did war play a role? Or starvation?

One thing they may not have been is alone. 

In a major study of the Pacific-wide connections between island samples of paper mulberry (wauke, or Broussonetia papyrifera), which this blog covered in an earlier post, the plants collected on Pitcairn display deep genetic connections to Polynesiaʻs ancient past.

Wauke was a canoe plant—one of the critically important plants that all Polynesian voyaging canoes carried on their missions of colonization. It was important because it was the key plant for making fabric.

In studying the genetic differences and similiarities of wauke collected on different islands, the researchers found that Pitcairnʻs plants had strong genetic roots elsewhere in Polynesia.

For example, they found that "New Guinea is directly connected to Remote Oceania through Pitcairn."

There are distinct cultural differences between portions of Polynesia that were occupied at different times. For example, Fiji, Tonga and Futuna are an older Polynesian culture, which the authors call Western Remote Oceania (WRO). Islands like Niue, the Cook Islands, the Marquesas, the Austral Islands and Rapa Nui are understood to have been populated later. They are called Eastern Remote Oceania (ERO). New Guinea, in Near Oceania is outside that range and is considered even older in Polynesian history.

Yet, then there is Pitcairn.

"We found Pitcairn plants in a pivotal position between WRO and ERO. In addition, Pitcairn accessions linked with genotypes from New Guinea in Near Oceania," they write.

How to explain that? Pitcairn is physically in the newer area of Eastern Remote Oceania. Yet its wauke tells a different story, a story of ancient connections: "The link between these... groups was Pitcairn," the researchers write.

But the authors suggest that this does not suggest that Pitcairn was an ancient voyaging crossroads that maintained voyaging connections across thousands of miles of open sea. "We do not propose a direct migration route from New Guinea to Pitcairn," the authors write.

The explanation, they suggest, is simpler.

Pitcairn was occupied so long ago, and also abandoned so long ago, that it retained the ancient genetics of the wauke that the earliest voyagers carried with them.

"This relationship between samples from New Guinea and Pitcairn represents the survival of old genotypes on Pitcairn Island due to centuries of isolation after initial colonization by Austronesian speaking peoples. We suggest that these genotypes were probably lost on other islands that represent the intermediate steps of dispersal and migration," they write.

Hawaiʻi, the Marquesas, Rapa Nui (Easter Island) and Pitcairn are also linked genetically through wauke.

"The connections observed in our study through the genetic analysis of paper mulberry plants... show ties between Rapa Nui and Marquesas and between the Marquesas and Hawaii," the write.

Ultimately, the work confirms the conclusion that all Polynesia is connected, and that a thousand years ago, this stone age culture was tightly connected.

©Jan TenBruggencate 2019

Friday, June 21, 2019

Wauke tracks Polynesian voyaging routes: New genetic studies

Fiji kapa making. 
Credit: Andrea Seelenfreund
Genetic studies of one of the key canoe plants, wauke, appear to confirm Polynesian voyaging from west to east across the Pacific, but also identify key regions of voyaging.

Wauke, also known as paper mulberry or Broussonetia papyrifera, is the raw material for some of the best Hawaiian and Polynesian kapa or bark cloth. It also produces edible fruit. And interestingly, most of Polynesia only has female plants, while the Hawaiian Islands have both males and females.

How does that happen? The Hawaiian males apparently were brought to these islands after European contact. That will be reviewed later.  On all other Polynesian islands, all plants found today are female, but the research did find a couple of examples of male plants in samples from the early 20th century from the Marquesas and Rapa. 

This is confusing. The authors of one study on the subject said it could be that wauke males were included in early voyaging, and have since disappeared, leaving the plants to be reproduced only by human involvement. But there is an odd alternative possibility. The Broussonetia clan is known to occasionally undergo sex reversion, in which female plants may rarely produce male flowers, or males may change to females. 

Credit: USDA, J.S. Peterson
Hawai`i is different from the rest of Polynesia because it still has male wauke. But those do not appear to be from early Polynesian introductions. Rather, the males apparently descend from a separate, non-Polynesian introduction to the Islands by 19th century Asian immigrants. The male wauke do not appear to have come through Polynesia, like the females. You can read more about the sexual distribution of the paper mulberry here

"Most paper mulberry plants now present in the Pacific appear to be descended from female clones introduced prehistorically," the authors of that paper write.

The dominant wauke stock in the Pacific appears to have originated in Taiwan, where, as in China and Indochina, it is native. But as a valued canoe plant, it was carried by Polynesian voyagers virtually everywhere they went. The plants are found not only in Hawai`i but at New Caledonia, Fiji, Samoa, Wallis and Tonga, in the Marquesas, the Society Islands, the Austral islands (Rapa), Pitcairn and Rapa Nui or Easter Island.

Wauke is a dioecious plant, meaning that male and female flowers occur on different plants. Because the existing plants are all female, the Polynesian wauke can't reproduce itself, and needs human help being transported and being kept alive.

"In the absence of breeding populations, the spread (i.e. movement) of paper mulberry depends entirely on a continuous human cultural tradition of preserving, propagating and transporting the plant," wrote the authors of the paper cited above.

In a new paper, many of the same authors, add to the story of the wauke. The latest paper, published this year in the journal PLOS One, is entitled "Human mediated translocation of Pacific paper mulberry [Broussonetia papyrifera (L.) L’He ´r. ex Vent. (Moraceae)]: Genetic evidence of dispersal routes in Remote Oceania."

The authors are from Chile, New Zealand and Taiwan. They include Gabriela Olivares, Barbara Peña-Ahumada, Johany Peñailillo, Claudia Payacan, Ximena Moncada, Monica Saldarriaga-Cordoba, Elizabeth Matisoo-Smith, KuoFang Chung, Daniela Seelenfreund and Andrea Seelenfreund. 
A Eurekalert press release on the study, which is simpler reading. 

The researchers conducted genetic studies on samples of wauke from 380 modern and museum samples from 33 islands across the Pacific.

They found that while all those female wauke are presumably clones of an original import, there is still some genetic diversity, and it can help understand migration patterns within the remote islands of Oceania.

"Our data detect a complex structure of three central dispersal hubs linking West Remote Oceania with East Remote Oceania. despite its vegetative propagation and short timespan since its introduction into the region by prehistoric Austronesian speaking colonists," wrote co-author Andrea Seelenfreund.

The three clusters where the wauke are most closely related to each other are: 1. Tonga and Fiji; 2. The islands of Samoa, Wallis and New Caledonia; 3. and then all of eastern Polynesia, including Hawai`i, Tahiti, the Marquesas Islands, Austral Islands and Rapa Nui.
There is evidence that Hawai`i had a more complex wauke heritage than other islands. Not counting the modern importation of male plants, it appears that traditional Polynesian strains of wauke came from both eastern Polynesia and Tonga in separate importation voyages. That adds an odd wrinkle to migration theory.

There seems to be a suggestion in the data that the wauke traveled between Taiwan and New Guinea, and from there into the rest of Polynesia. There are also suggestions that the wauke traveled on all voyaging canoes that were in the process of colonizing new areas, but after that were likely not on subsequent back-and-forth voyages.

"Crops important for survival and cultural reproduction were probably aboard all colonizing canoes, although probably not part of later inter-archipelago commercial networks or part of ritual exchanges of high valued objects, such as textiles, adzes, whale teeth, shells and other items between established settlements," the authors wrote.

© Jan TenBruggencate 2019