Please have a look at enclosed PDF...

Thanks Dr. Srivastava.

I saw a cubic wooden sample of Egger Company. They had used wood laser engraving method to show clear difference between early and late wood in the cross section of tree stem. They set up the laser so that only the softer parts can be removed (Laser has three parameters for adjusting).

Thanks to Dr Anoop Kumar Srivastava.

Does anyone know if there is any chemical product that can highlight the growth rings?

Sir, I also wish to know the chemical product, if any, which can be used to highlight the growth rings in eucalyptus.

However, I think, you need to specify your species so that researchers will find it easier to answer, as there is great diversity in this genus.

Thanks Dr. Huse. The specie that I'm work is a clone of Eucalyptus urophylla.

Hi Paulo,

There are several techniques to increase the contrast of the tree rings.

There is an old method which provides good results - the cores are coated in zinc oxide and then submerged in 10 percent acetic acid (Parker, M. L., Barton, G. M., & Smith, J. H. G. (1976). Annual ring contrast enhancement without affecting X-ray densitometry studies. Tree-Ring Bulletin.)

Another old reference: Yang, K. C. (1987). Growth ring contrast enhancement and the differentiation of sapwood and heartwood zones. Wood and fiber science, 19(4), 339-342.

Also good results are obtained smoothing the cores with a finer sand paper (progressive) to expose the cross-sectional surface.

I know there is a paper The use of dendrochronology to determine eucalypt ring annuality (https://eprints.utas.edu.au/7812/4/02ch_3JvP.pdf) which seems to be more specific.

You should also check

A Technical Perspective in Modern Tree-ring Research - How to Overcome Dendroecological and Wood Anatomical Challenges (Article A Technical Perspective in Modern Tree-ring Research -How to...

Good luck!

Hi Ciprian,

Thanks for his informations.

I forgot to add this excellent book of Speer.

Book Fundamentals of Tree Ring Research

Chapter 5 describes in detail the field and laboratory methods

You should check Preparing Core Samples (page 142).

It doesn't offer details on Eucalyptus cores preparation, but it has specific details regarding preparation methods.

Hi Ciprian,

I thank you for sending the articles.

Thanks a lot Dr. Chiprian for sharing valuable information and book.

Dear Paulo and Santoshkumar,

I have searched for an old Romanian book which presented a method (Osterman) that we used for a long time to increase the contrast for beech rings (Fagus sylvatica). Unfortunately there is no digital copy of it ( Estimarea calităţii lemnului prin metoda carotelor de sondaj / Estimation of wood quality by sampling cores method - Dumitriu-Tataranu et al, 1983).

In short, the cores were pre-treated with nitric acid (6 parts of nitric acid and 4 parts of water), because the beech rings are too faint.

Another old paper recommended the immersion in different concentrations of ethanol for soft-wood (poplar) and use of safranin dye as the counterstain in order to increase contrast.Article Thin section preparation of poplar tree-rings for computer-a...

For Santoshkumar - Another good paper on preparing dendrochronological samples: Article Trimming and Planing Rough-Cut Wood For Efficient Dendrochro...

Thanks a lot Ciprian. I'm going to do tests with these procedures.

I am highly obliged to you for the information. One another problem I am facing that the logs, which are collected from the felled trees and stored for further wood study including ring observations, have developed so many cracks (Shakes). The logs are of 45 cm length. Can anyone suggest me the procedure or treatment that can protect the logs from developing cracks/shakes, especially in Eucalyptus -camaldulensis, tereticornis, grandis , urogradis and urophylla.

Dear Dr. Hue,

These cracks occur because growth strains are high in these species of Eucalyptus.

Dear Santoshkumar,

To add to Paulo's comment, the cracking (if present) generally increases up to 72 hours after felling, after which it stabilises (although it can increase still but not as fast as in the first 72 hrs). It's also connected to moisture loss, so coating the ends with a wax can delay moisture loss and therefore cracking. We use wax on board ends when kiln drying Eucalyptus boards.

Regards