I would not rule out radio-chronology right away. Radiocarbon is your best candidate for that age range, and in modern AMS spectrometers you also get 13C measurementes that can be an indication of sample 'quality', i.e. if the carbon from the tree has been contaminated from other sources. I would recommend a thorough cleaning of the wood remains, and perhaps contact any AMS lab to request guidance, as they have lots of experience with these type of samples.

I doubt there much you can do with the tissues but assuming this is from a sedimentary sequence, are there any associated archaeological artifacts i.e. within the same stratigraphical layer, which might at least give you a minimum age estimate ( the remains could be reworked)? Apologies if I have misunderstood the context of your question.

Dear all thank you for your answers. There are still problems on many of the suggestions, as we plan to do measurements on different sites, with trees of more than 1000 years old (a rough estimation!!). The old tissue is not there any more, as also the roots. The artifacts may or may not be present as you may understand. The tree is still growing without the presence of pith, so the method described by the second suggestion of Martin I believe can not be done here. The first one though (the authors found a linear relationship between DBH and tree age (in years) (Age = 2.11 × diameter(cm) + 88.93, R2 = 0.80) has crossed our minds, for a relative estimation of the age of the tree. Someone determined the age of a tree in the island of Naxos Greece, to be around 1500 - 2000 years old by this method, which is a relatively large deviation.

Once again thank you for your suggestions. I believe this is a very interesting topic that merits attention from experts on dendrochronology, since olive trees differ from forest trees in terms of still growing even without the pith and surrounding tissues.

Cherubini (http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0054730)

says that due to intra- annual density fluctuations, age by counting tree rings is impossible in olive trees. May see the article on net; it's free access. If the rings are clearly identifiable, dendrochronology may help otherwise not.

AMS combined with delC13 may be tried as suggested by Leopoldo above.

We worked on the olive trees from the santorini eruption with AMS in our institut. You should contact my superior, Bernd Kromer. or send me an email. If you only have the surrounding sediment you could also work on the organic material in the sedmient. I know someone in Bern and someone in cologne who work on the radiocarbon dating of sediments. Anyway, I hope you find a proper solution :-)

Dear Chandra and dear Susanne thank you very much for your answers. I will contact the people who are interested in that and possibly send and e-mail to you Susanne if they are willing to go to that solution. My area of expertise is pomology so I am not familiar on the cost and labor the AMS requires. Anyway thank you very much!!!

I guess (I am not a dendrochronologist) one of the things you can do is applying dendro-counting according to Cherubini (Plos one) proceeding from the outer diameter towards the pit in order to accumulate a statistically robust number of points (i.e. radial increment vs year) till the presence of wood allows. If the counting is difficult, due to individual or specie characteristics, you can verify your chronology with some spot measurements of 14C (I do not thing that 13C tool is useful for chronology estimation being its abundances influenced by local climate conditions). Finally you can plot the available data as dendro years (x axis) vs cumulative basal area (a function of the radius on the y axis) and try to fit a growth function. This fitting procedure can, being left with a free parameter accounting for the birth radius, be used to infer the model fitted birth year (obviously affected by extrapolation uncertainties).

I hope I was quite clear with this explanation, anyway if you have further questions do not hesitate to contact me!

Ciao

Dear Fabio thank you for your answer. One thing we are thinking is to measure the radius of the trunk and compute the age according to a formula, taking into account that the annual growth rate of the radius is estimated to be between 0.7-3.0mm. This of course posses great deviation, but I think it would be nice to test it first on old trees which age is fairly known, construct a relationship and apply the formula to older trees, of the same area. As you may understand, the rainfall in each specific area will play a huge role among other factors. I am in contact with a dendrochronologist and hope we will be able to combine and test two different methodologies (if this is feasible with ancient olive trees). Once again thank you for your time. I wish you all the best.

wait, I guess it is well established that growth rate is affected by age. that is why it must be de-trended....

Ciao

I did measure 14C age of several old olive trunk cavities. and used the procedure of Andersen for Acacia tortilis in desert ( with Krzywinski BMC ecology 2007). Like them but on olive, my eldest in mediterranean were about 800 y BCE with an SD of 350 y (apparent radii at BH about 1.3 to1.5m). Wood is diffuse porous and olive makes several rings per year; rings convolute in 50+ y-old wood; the terminal of a Gompertz equation for trunk mass gives the same mass for different ages (I do not have enough space here to give details) . Pruning fires and caries makes hard to hold a radius rate, A very good trick is usnig peak bomb to calibrate growth but this requires several samples per tree and represents the last 50years. One major obstacle to go on is the desperate belief of some local politician in fabolous ages and the wide spread use of seedling grafting. True olive archeology resides in soil carbons, a matter for antracologist. We have a comprehensive collection of olive stones and can reduce them to charcoal for shape analysis; further in some alluvional deposition on on ship wrecks old olive stones can be preserved on them is possible to play back for indefinite times; JF Terral did so in Montpellier. Charcoal does not degrate at a measurable rate, but living wood does Any positive link would be welcome, I do not have any firther fund on this and to date an SD of 350y is not enough for a good journal. A (1) AMS date is worth about 350eu

Dear all, as we all can see, the estimation of ancient olive age is quite difficult. It would be interesting though to check various methods for that. As I already mentioned I am not a dendrochronologist, so the methods proposed will be discussed with the expert. Of course the simple method i described above has many defaults. AMS and other methods rely on the fact that we will be able to find ancient wood - tissue, don't they?

Yes, that is why I would classify AMS as an option to increase ring counting accuracy while, in order to go back on time if you do not (physically) have data the preciser way to establish the year of birth is modeling

Yes Fabio, this is my opinion too. Thanks again for your time and interest.

Well about 800 years for a trunk having a radius of about 1.3 to 1.5 m at 1.3 m heigth from base is a point of start. You may take a ribbon and measure circumference compensating for gaps with poles. You may record GIS, pictures and dna collection from bark and leaves. The inner part of trunk can be taken with a chisel, dried and maintained on silica gel; the amount required is about 50g. Use clean tools without any petrol or oil and remove all brown fungi from surfaces. A number of laboratories can then date. Science must admit nothing else but evidence and models require calibration. For rings you may take 3 year wood (easy to recognise because is the first shoot without leaves in the branch, cut and polish with a sand paper, fill surface with white chalk and stain with the ordinary walnut dye used by furniture makers. Very primitive but gives an idea about how many and how thick rings are. Unfortunately growth in aging trunk is an epicormic bundle of fused and partial shoots without ring symmetry

Thank you Guido for the helpful comments. I will have it in mind.

Olive tree is not a resinous. So the technique of dendro counting is not available. In the i*other hand the use of Carbon didn't give a good result. We too are looking for a method.

There is a strong similarity between aging ancient yews and olives. The key problem is the lack of early wood because of hollowing, as you say. Having (I think) explored all avenues I have decided to triangulate four forms of data: (1) ring counting complete cut yew stumps

Dear Toby thank you for your suggestions. I am thinking on doing the three last things you have suggested. We do know that this would be a rough estimation, but based on all the suggestions and remarks by the kind researchers who answered to my question so far, I feel that this is the only way. As Monji wrote, dendro chronology is out of question, while the use of sediments seems quite the only real scientific approach, but I must contact an archaeologist to see how we can select sediments and use them to calculate tree's age. This method also has drawbacks (from what I can think) since we will not be sure on the real nature of sediment deposition. But at the end, the archaeologist should be able to answer this, I suppose. Once again thank you for your time, both you and Monji as well as all the other researchers.

Dear Roger thank you for your answer. Unfortunately in ancient olive trees there is a hollow and the oldest tissue one can find (as far as i am told by a dendrochronologist) is about 100 years old. So the method you propose can not be done with ancient olive trees. Thank you though for your valuable time and suggestion.

Thanks for understanding. We were stopped against the evidence of trees much younger than believed, even if any care including AMS was applied. A basic effort is then required avoiding the false thought that value is connected to age. A monumental tree can build up his shape in 300 y if the radius growth is about 3mm/ year. Diffuse porous evergreens make more than a ring per year (3-7). Andersen in BMC for Acacia tortilis, cavity and AMS and Cherubini in PLOSone on olive rings published the basic procedures. The real history sits in DNA taken from sunk oil jars pores (Foley Hanssonn JarcS) or in the morphometry of partially burnt stones in excavations in many of Terral studies in biogeography. Still now no one was successfull in getting varietal id, but the presence of many local cvs led me to think about the time scale of selection just about when the varietal spread by commerce records took place. At end archeologists do not require cv but they do not share samples, agronomists look for typical products possibly from classic age, and genetists (also in Nature reports claiming the persistence of primitive genotypes on the basis 'as everybody knows olives can last more than 1000Y') play with a very large heterozygosity without clear evidences of useful fruit markers. Then we need a policy for in situ big tree maintenance and the removal of fakes. In the Hopes, Bye

Please contact

He wrote a paper about it.

http://www.citab.utad.pt/researcher.php?ID=34

Dear DR Montanha

I did fail in finding the one you meant. In most of applications there are evidences not tested by 14C, or attempts in counting rings in olea, (no rings, diffuse porous, marginal continous growth) but please sent more details, we left this topic 7 years ago...

Dear Dr. Guido Bongi,

I am so sorry for my delay.

I contact the person I referred but all he told me that the patent did not allow they explain how to do!!!!

It is like a black box a firm use to certify the age of the olive tress they sell .

Denderochronolgy methods help u the most!

Gear Dr. Roussos

You asked a good question and valuable comments were presented. A Portuguese researcher, José Luis Penetra Cerveira Lousada, who works at the University of Tras-os-Montes e Alto Douro (Vila Real, Portugal), has patented a formula that ensures the age of olive trees. Please see his interview and I'm sure you will get good information by contacting him.

http://en.mercacei.com/mvc/amp/noticia/1115/

Dear Dr Peter Roussos, the methodolgy I suggested four years ago (see above) is now bearing fruit and the first of a series of papers on ageing monumental specimens of yew will soon be forthcoming. It is with Fellows of Brunel and Harvard Forest for revision right now. There are a few surprises, and the current methodology which yields a parabolic age/girth curve based on constant annual increment derived from John White's Forestry Commission note 250 (e.g. Tabbush and White 2006) is overturned. I believe that the method may be transferrable to monumental olives. Key is measure/re-measure data in order to inform and verify theoretical work. This ageing conundrum cannot be solved using mathematics and theory only. I will alert you when publication is complete. Keep measuring and re-measuring to the highest accuracy possible.

Dear colleagues, does anyone know in which part of the ancient olive tree can we find the oldest plant tissue? for example, bottom inside or bottom outside? surface or underneath? elsewhere?

Dear Toby thank you for the notice. I will be waiting for further news!!

Dear Georgios I think you will find the oldest part bottom inside and at subsurface level if this still exists.

https://www.frontiersin.org/articles/10.3389/fpls.2017.01918/full

very useful study

Nice paper, indeed, thanks to both for your feedback!

Thank you for your patience Peter! The ageing publication we have been working on is out at last in the Quarterly Journal of Forestry. I have uploaded it, although because of copyright it is not yet public on RG. But a non-peer reviewed commentary and expansion in informal article style is freely available. This is a new way of thinking about ancient trees which have fragmented. The circumference is discarded as a measure and estimated radius and diameter measured directly are used. Briefly: this cuts out the variability generated by irregularities and gaps in the stem. A general measure of expansion rate of the vigorous parts of the tree is found using cores, and then the ring width applied to the radius. There may be applications in ageing olives.

Dear Toby thenak you for the information. I will look up for the publication and hopefully we could use the same methodology in ancient olive trees (although these are mainly hollow in the center, so there is not any part left of the original pith). Best regards, Peter