If you use a magnifying glass to examine the needle of a Picea abies,
you will see the needles have four sides and are slightly flattened.
You will need a magnifier of at least eight power to see this. Now, the
two acute angled edges are dentate. That is, they have tiny, sharp
protrusions along the ridge that, under a microscope, look like the
teeth on a saw.
The teeth are all in a row and, with a suitable instrument, their number
can be counted. This number is genetically determined and is linked to
the provenance of the seed from which the tree grew.
Why is this this so? It is because, during the last Ice Age, the range
of Picea abies was reduced to a number of very small geographical areas
or "retreats" (havens, pockets whatever). In these areas the trees
interbred over the thousands of years the glaciers lasted, until the
trees in each retreat had virtually NO natural genetic variation between
the individuals in a given retreat (but they had differences between
retreats). When the Glaciers left, the trees spread out, carrying with
them the peculiar genetic characteristics that had developed while the
spp had survived in its retreat, of which, by the way, there were a
number. This work was done before the 1960's and the expert at that
time was Dr Chris. Morgenstern who taught at the University of New
Brunswick in Fredericton, Canada.
Hope that helps!
Tom Roach
Waterloo, Ontario
519 746 5324
519 503 3806
On 2017-03-13 8:54 AM, Mustafa Umut Sarac wrote:
> Tom,
>
> What do you mean with tiny teeth number and needle ? This is first time I
> faced with these terms . Can you bit explain and can others help me to find
> references and tables ?
>
> May be you meaned the foliage of the wood - pine needle - but I really dont
> know.
>
> Thanks,
>
> Umut
> Istanbul
>
> On Mon, Mar 13, 2017 at 3:16 PM, Tom Roach <[log in to unmask]> wrote:
>
>> Interesting choice of terms! Both trees are spruce and Picea abies is, of
>> course, common Norway Spruce. It should be readily available in the US and
>> certainly is in this area of Ontario where it was introduced by German
>> settler/farmers. Picea excelsa is the same tree, just from a different
>> area of Europe. See: http://www.lutherie.net/eurospruce.html for a
>> discussion.
>>
>> If, IF, you have a microscope with a measuring scale in it. You can count
>> the number of tiny teeth per cm on a needle of P. abies and, using a
>> published table,find out the provenance of the tree. I am sorry, but I do
>> not have a reference for this activity.
>>
>> Tom Roach
>> Waterloo, Ontario
>> 519 746 5324
>> 519 503 3806
>>
>> On 2017-03-13 4:54 AM, Chris Vandekerkhove wrote:
>>
>>> Thanks to all for answering me. I've checked a couple of websites.
>>>
>>>
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