[Pars]

Pars asked the Naked Scientists:
   
Dear Sir / Mam,
 
I am Shiyal Parsotam from India ( Gujarat ). I am grate thankful to you if you can give me any scientific/authentic way to know the age of Tree.
 
Kindly note that there is hundred of  threes in my farm which is more then 100 years old but some fraudulent people want to cut it. So I need to submit this report urgently to the police dept.  Can you help me that how I got such a authenticated certificate which prove the age of trees..
 
With the hope of your prompt reply..
 
THANKS & REGARDS,
PARS.

What do you think?

[Don_1]

Measure the girth of the tree about 150cms form ground level. Then read this lot.... http://www.forestry.gov.uk/website/PDF.nsf/pdf/fcin12.pdf/$FILE/fcin12.pdf

Or you could take a core sample, but this could cause harm to your trees.

[blakestyger]

A core sample shouldn't really harm a tree, should it? It only makes a small hole in the bark so only a minute amount of cambium is destroyed and the heartwood doesn't conduct anything anyway and it won't reduce the trees strength significantly either. The biggest danger is from infection, so the hole needs covering until healed - or so I understand.

[Don_1]

Provided the tools are clean and sharp, and the hole well protected from infection, then a core sample shouldn't cause any real harm. But if applying this method, do make sure you get it right.

[dentstudent]

The FC information is obviously a good starting point, but only relates to UK tree species. There are exotics (to the UK) whose circumference / age ratio is rather different.

If you do do a core sample, then the main problem as far as age is concerned is making sure that you go through the centre of the stem and therefore capture all of the rings. It is a perennial problem in age estimation that because the tree didn't grow uniformly around the centre, some of the rings are missed. It is possible to make x-rays of the stem, though this is rather more expensive. Another method would be to use old maps - the age of some trees can be verified through their appearance on historical documents such as planning documents or photographs. Then there is carbon dating which has been used to verify the age of the very oldest trees (Spruce trees in Sweden) but this may not be too useful in trees that are "only" 100 years old or so.

But, it should be noted that although the trees are 100 years old, this is in general not all that old for a tree. In the production of timber in the UK, the lowest age for felling is around 70 as it takes this long for them to grow enough. In oak species in France, the "rotation age" (the age at which the crop of trees is felled) is 140 years. There are many rotation ages that are around 120 years, especially in deciduous species. In Germany, often there is no rotation age, and it is a question of girth or "target diameter" and so many trees are much older than 100 years when they are felled. In addition, in many cases of natural regeneration under a heavy canopy, species such as spruce and fir can remain in a relatively static growth situation for decades. I have seen many "trees" that were only 2 or 3 metres tall and which were 70 or 80 years old.

If you want to preserve the trees, it perhaps needs to be irrespective of their age, and more to do with amenity, in that they are aesthetically pleasing for example. If there is something similar to the UKs Tree Preservation Order where you are, this may be the better option.

[dentstudent]

Measure the girth of the tree about 150cms form ground level.

Just for info, this is "Diameter at Breast Height" (dbh) and is at 1.3m.

[dentstudent]

A core sample shouldn't really harm a tree, should it? It only makes a small hole in the bark so only a minute amount of cambium is destroyed and the heartwood doesn't conduct anything anyway and it won't reduce the trees strength significantly either. The biggest danger is from infection, so the hole needs covering until healed - or so I understand.

Quite right Blakestyger - the core itself will not harm the tree through the removal of cambial tissue. A tree can survive very well with virtually a complete ring of cambium missing, something that is very clear when you look at historic oak trees that are missing an entire side. Of course, the tree's vitality is somewhat compromised.....