Wildland Consultants Ltd NZ
About Dr Tim Martin
Tim Martin obtained First Class Honours in 2001, with a master’s degree dealing with the ecology of the rare tree species Ascarina lucida.
After this he joined a team in the School of Geography and Environmental Science, researching the history of New Zealand climate in the centuries before instrumental records.
Tim set out to document a chronology of severe storms, using the evidence left by them in tree-rings and forest structure. When forest areas are felled by wind, a new synchronous generation of ‘light demanding’ tree species commonly establishes. This new generation can be aged (and the storm thus dated) by counting the annual growth rings in a representative sample. Trees surviving such events may also experience abrupt changes in growth rates that can be dated; either experiencing ‘release’, a growth increase due to the death of competitors, or ‘suppression’, a growth decrease due to the survivor being storm damaged.
The temporal correlation of tree recruitment, release, and suppression was used to pinpoint the timing of storm events. Investigation of fallen logs provided supporting information as to the type of disturbance responsible, and measuring ring-width patterns allowed the use of dendrochronological techniques, which established the accuracy of the dates. The research tested the methods developed by investigating trees that survived known storm events, such as Cyclone Bernie, in 1982. The work was supervised by Assoc. Professors John Ogden and Anthony Fowler, and supported by The Foundation for Science and Technology and a University of Auckland Doctoral Scholarship.
In order to be confident that the storms recognised and dated were indeed major events, the research sampled stands of mountain beech and kaikawaka (New Zealand mountain cedar) in widespread locations: Tongariro National Park, Mount Taranaki, and the Ruahine, Kaimanawa and Tararua Ranges. Several individual severe and widespread storms were recognised the 1880’s, 1930’s, and 1980’s. More significantly, it became apparent that there were periods of increased storminess in the past (e.g. in the early 1600’s). These might be correlated with shifts in the major atmospheric circulation patterns in the south-west Pacific (‘ENSO’ related). Tim is currently employed by the New Zealand consultancy firm Wildland Consultants, where he is the Senior Ecologist for the Auckland and Northland regions.
FRIDAY 4th NOVEMBER
"A Blast from the Past: What can trees tell us about the history of extreme wind events in New Zealand?"
Click here for Tim's Abstract