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Margaret S

Rapa Nui palm - life span?

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Margaret S

Hi

A bit of context - I'm a History teacher working on a unit of work on the collapse of the environment & society of Easter Island/ Rapa Nui. I'm hoping that the expert knowledge here can help me out.

I'm working on outlining the cases for & against the accepted view that the colonisers (the Rapa Nui, not European) were completely responsible for the destruction of their environment ('ecocide') between 1200 & 1650 AD through deliberate deforestation & overexploitation. This view is hotly contested in academia, with recent scientific & archaeological evidence undermining the traditional view of human responsibility.

One of the arguments for complete human responsibility is that the palms lived a long time, long enough to reproduce effectively despite seed eating rats, drought & climate change if they weren't chopped down.

I know the palm (Jubaea disperta, also known as Paschalococos disperta) is extinct (c. 1650), but it seems to have some relationship with Jubaea chilensis.  Is anything known of the life expectancy of the extinct palm & if not, what is it for the Jubaea chilensis & would that be a valid comparison ?

Also, John Dransfield, who assigned the species to to a new genus, suggested that the trees became extinct as they were cut down for the edible palm hearts as food supplies ran out for an island.  Do you think this is a valid claim? Can this be done with Jubaea chilensis?

I'd be grateful for help in this area, not exactly my area of expertise!

Margaret

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Darold Petty

Margaret, Welcome to Palmtalk !  :)

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Little Tex
8 hours ago, Margaret S said:

Thanks! 

For Jubaea chilensis They live a long long time, They are also extremley slow growing, 

Here is some information from another post.

On 10/11/2011 at 4:07 AM, Jane_Whitt said:

A palm is monoecious, ie a single tree can produce fruit and viable seeds, but will not bloom until it is about 50 - 60 years of age, when many short inflorescences seem rather hidden in the base leaves. They produce large clusters of fruit spherical, yellow 4 to 5 cm in diameter. They mature in the fall, with a soft pulp, and the interior is gray, stony, hard endocarp (seed), with three distinct germination pores and not as the 'eyes' of a coconut.

 

The endosperm (kernel) is edible and tastes like a coconut too. In Chile, where Jubaea is endemic, is called "coquito" which means "little coconut, and fruits are sold in the local market and also exports.

 

In areas of natural distribution, Jubaea is very rare today, due to excessive uptake before sugary sap, which involved killing the tree. It is the only palm native to mainland Chile, which occur in the dry forest overgrown on the slopes of the valleys and mountain ranges near the coast in the central part of the country, 31 to 35 degrees south latitude, just few hundred feet above, and not inside.

 

The climate of this area is very similar to the California coast, warm temperate, dry, extreme temperatures, in the summer to be quite similar to those of the warmer parts of northern Europe.

 

Today, Jubaea is widespread as an ornamental in parks and gardens, in many sub-tropical and temperate, but not common, probably due to its slow growth and the fact that, to the uninformed, is not very different from, for example, Phoenix canariensis, and the local authority, costs about 100 times more. However, it is grown in places as diverse as Florida and England, indicating their ability to climate adaptation.

 

However, it is essentially a palm Jubaea nontropical, preferring warm summers and cool winters for optimum growth. Its cold tolerance is surprisingly high, in fact, is probably the most tolerant to frost feather palm leaves. Mature trees can withstand a heavy frost to - 1 5c, undamaged, and several reports indicate that frost can withstand even if short-lived.

 

Even young plants are not damaged during long periods of frost and cold and stiff leather sheets can cope with the snow quite well. Seedlings are damaged to 7c-a-10C.

 

Furthermore, palm wine can tolerate severe drought. Many of the wonderful specimens in the Mediterranean region suffer even brown leaf tips during the extremely dry summer last year, when many of them had no water in every month. In his native country, Chile, Jubaea only receives little rainfall, below 500mm/year, but also see-is growing very well in high rainfall areas.

 

From Jubaea supports cold and wet winters, frost and drought as well, and grow very well even in cool summers, probably the best - if not only - feather palm leaves to grow in northwest Europe. What a pity it is so rarely seen there. For example, the huge sample in Torquay, England, seems to be the only outdoor Jubaea across the country. If only the forward-looking gardener who planted 100 years ago, had planted another 499!

 

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Margaret S

Thanks Little Text for that.

I have read some further articles on the issue of the extinct Rapa Nui palm.

One in particular by Terry Hunt & Carl Lipo (2007) looks at the archaeological/ historical scholarship on the lifespan of the Rapa Nui palm & it seems a rather mixed bunch. https://www.researchgate.net/publication/237410037_Chronology_deforestation_and_collapse_Evidence_vs_faith_in_Rapa_Nui_prehistory#pf8


They note:

  • Flenley & Bahn (2007) assert the Jubaea chilensis palms of Chile live 2,000 years! Is there any basis for this????
  • Chilean palm expert Juan Grau (2004) refers to the possibility of a few palms greater than 700 years on the mainland.
  • The Jubea chilensis at Kew gardens was planted in 1846 & only recently cut down in 2014, at 168 years.  It is suggested its natural life span is 200 years?
  • However, with its reclassification as Paschalococos dispersa can you compare an extinct different species to a living one?

So is 200  years realistic for a related palm?  What about 700 years?  Is there a possibility of beyond 200 years?

 

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Darold Petty

I believe that the Kew palm was cut down because its greenhouse building needed to be demolished and rebuilt, not for any senescence of the palm.

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PalmatierMeg
1 hour ago, Darold Petty said:

I believe that the Kew palm was cut down because its greenhouse building needed to be demolished and rebuilt, not for any senescence of the palm.

True.

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Kim

While I am by no means a scientist, botanist or archaeologist, it does seem unusual for palms on islands to go extinct on their own. Considering what we know today of palm populations on remote islands, it is indeed very often the hand of man that reduces or eliminates the native flora, whether directly for food, or to repurpose land for agriculture, cattle grazing, or urbanization. Can anyone make a case for Rapa Nui being an outlier in that respect? Perhaps yes, perhaps no. I know Lord Howe Island palm populations were seriously threatened by rats. Something to look into for comparison? Madagascar is burning natural areas for agriculture; some estimates say up to 80% or more of the orginal forest has been lost. Humans have a very poor track record when it comes to respecting forests. That is an interesting subject you are studying.

For further reading: https://scifundchallenge.org/firesidescience/2016/08/22/the-loneliest-plant-of-the-world/

https://www.abc.net.au/news/2021-02-02/lord-howe-island-recovers-from-rat-infestation/13111770

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0265224

https://www.frontiersin.org/articles/10.3389/fevo.2021.719566/full

https://www.atlasobscura.com/places/wax-palms-of-cocora-valley

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Margaret S

Yes the traditional view is that the Polynesian settlers (1200 AD) introduced rats & deforested the island by 1650AD (pollen evidence) through slash & burn agriculture.  This led to the leaching of the soils, erosion & agricultural failure. A growing population's needs put additional pressures on increasing agriculture & slash & burn. Also, some argue that palms were cut down as rollers to move the giant moai (statues, there were about 1000, although only 1/3 were only moved into place, the furthest journey 18km across the island) adding to deforestation (although alternative means of moving them without rollers contest this cause of deforestation). Rats that journeyed with the settlers have also been blamed for the palms not reproducing (ate nuts & seedlings), however the evidence for this  & extent of impact is also hotly contested. Much of the research is moving away from this traditional model & man-made ecocide. Many are attributing deforestation to other factors - eg rats, climate change, etc.

One of the arguments against rats is that many of the trees would have lived down to the time of European contacts (1st 1722) if they had super long longevity of 100s of years.  As per my previous post,  could they have lived 200 to 700 years? Is there any evidence for this beyond the Kew palms premature demise? 

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