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Queen’s University Belfast holds an extensive database on tree rings, particularly Irish oaks; information that may be used in the reconstruction of past climate conditions.  A request for this information from Doug Keenan under the United Kingdom’s Freedom of Information Legislation was disputed on the basis of intellectual property rights, compliance costs and usefulness of the information as a proxy for temperature. 

John Abbot and I review the saga and its implications in a new paper:

Accessing environmental information relating to climate change: the case of Irish oaks tree rings. Environmental Law and Management 2010 Volume 22, Issue 4, 172-181.

Quoting from the paper,

“The QUB case suggests a degree of misunderstanding with respect to some of the legal issues, which is not entirely surprising. The case also reveals confusion amongst the dendroclimatology community as to exactly which trees are useful to reconstruct past temperatures, arguably a more significant finding given the reliance on these interpretations in formulating public policy…

“Much of the tree ring data requested by Mr Keenan specifically related to Irish oaks. According to Mr Keenan, this data is extremely valuable for global warming studies for reconstructing temperatures over past millennia.  Professor Mike Baillie [a recognized expert in dendrochronology who became the public voice for QUB], however, disputes this, claiming that the oak data is not relevant to temperature reconstruction records. 

‘Although ancient oaks could give an indication of oneoff dramatic climatic events, such as droughts, they were not useful as a temperature proxy because they were highly sensitive to water availability as well as past temperatures. In my view it would be dangerous to try and make interpretations about the temperature from this data. It’s been dressed up as though we are suppressing climate data, but we have never produced climate records from our tree rings.’

Dr Rob Wilson from the University of St Andrews tree ring laboratory has concurred, stating that ‘oaks were virtually useless as a temperature proxy’.

In 1982 Professor Baillie and co-workers did in fact publish a study using oaks from 13 sites in Britain including some from Ireland, reporting temperature and rainfall reconstructions. In more recent technical publications Baillie and co-workers, however, explain that 20 years
ago dendroclimatic studies using Irish oaks were discontinued because trees growing in the British Isles are less sensitive to temperature than trees in Scandinavia and Siberia…

In light of these reservations that the temperature signal from oak trees may be difficult to determine, it is relevant to note that a multi-proxy study incorporating 47 data series, of which 37 were based on tree ring widths, with 7 from oaks, including 1 from Northern Ireland
spanning the period 1001–1970, was cited in the 2007 IPCC report.

More recently, Professor Michael Mann and co-workers have incorporated tree ring data from oaks, including Irish oak data from QUB, in multi-proxy temperature reconstructions of the last millennium in support of their famous ‘hockey stick’ temperature proxies which featured prominently in the 2001 IPCC reports, which later came under intense scrutiny for its statistical validity. In this technical paper more than 110 datasets from oaks were included in a primary set of 926 tree rings from the International Tree Ring Data Bank. For some multi-proxy reconstructions this primary dataset was reduced to 484 by statistical screening, but it is unclear to what extent the oak data was retained.