Oxfordshire Woodland Group

The following article was prepared for publication at the end of 2019 but because it demonstrated that it was not possible to determine whether or not climate change was having an effect on tree growth over a 20 year period the editor choose not to publish it.

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2021 Update

The growth results for 2021 were the best achieved to date.

If climate change is happening then this would appear to favour growing Douglas Fir in the home counties.

A DF growth study was undertaken by :-

REUKEMA, D. L., 1965. Seasonal Progress of Radial Growth of Douglas Fir, Western Red Cedar & Red Alder. U.S. Forest Service, Research Paper PNW-26.

Reukema used 20 comparable Douglas Firs in his sample measurement plot i.e. the same as OWG however conducted his study over a shorter 5 year period which is less than OWG's current and ongoing 22 year DF tree growth measurement programme.

Reukema concluded that rainfall amount and seasonal variations in same may cause many of the growth pattern variations observed however the combined relationship effect between rainfall, temperature and wind variables could not be established from the gathered measured data. Reukema's conclusions support OWG's own main inconclusive findings in respect of the annual measured growth of trees reflecting climate change.