Spotlight : The year rings of growth
By Izak Smit , PPS CEO
My youngest son and I love to climb mountains together . Despite having grown up in Cape Town , I have never climbed some of Cape Town ’ s mountains , though . It is the old story – when you live in a place , you often do not do the things that tourists come to do in your neck of the woods . So , the other day when we were in the Mother City , I told my boy : “ I have never climbed Simonsberg or Devil ’ s Peak , let ’ s do them ”. One of my PPS colleagues told me : “ Izak , if you want to do Devil ’ s Peak , there are easier ways , you just order one – a lager – from a pub in Cape Town !”. However , we decided to do it the harder way and tackled this peak one morning from the University of Cape Town ( UCT ) side of the mountain .
Not far from UCT , we came across workers who were busy felling and cutting trees that were damaged by the fires that raged on Table Mountain a year ago . It was those giant pine trees that have become such a part of the Table Mountain scenery . Although pine is not indigenous , it was still sad to see these giants go . We stopped at some of those toppled goliaths to inspect the year rings in the stumps . The number of rings was the same for almost all of them , a little more than 120 . The rings in a tree , of course , result from the fact that a tree grows faster in some seasons than in others , so counting the number of rings gives one an accurate estimate of the age of a tree . These trees were planted at the turn of the previous century , around the time when Cecil John Rhodes lived down the slope at Groote Schuur .
On closer inspection , we saw that the pattern of these year rings was more or less the same for the different trees . This is not surprising , as trees grow more in a good year than in a bad one . Hence , a sequence of years has a fingerprint pattern of wide and narrow rings , and this pattern will be the same for trees that were planted at the same time in an area that experienced the same weather conditions .
We successfully conquered Devil ’ s Peak ( and a few lagers afterwards ), but those trees triggered an interest in dendrochronology , the study of tree year ring patterns . Dendrochronologists compile catalogues of labelled tree signature patterns . In tree rings , the outer ring represents the present . The past can be reckoned with by counting inwards . Patterns from different periods can be chain-linked together . A fragment of wood can then be dated by matching its ring pattern against previously collected libraries of signatures . In Europe , for example , people use the technique to
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