Early forestry: science v wisdom

A Marlborough Sounds man is offering a cash reward for proof of forestry in his area 80 years ago, in a last-ditch effort to verify claims in a scientific study.

Dallas Hemphill got curious after reading a study about how sediment affects the seabed of Pelorus Sound/te Hoiere, published two years ago by Niwa (National Institute for Water & Atmospheric Research).

Scientists said they found sediment from forestry runoff as early as 1901 but Hemphill says none of his neighbours – some in their 90s – know of any forestry operations pre-1940.

Hemphill said he would give $1000 to the first person who could provide ‘‘incontrovertible evidence’’ of industrial-scale pine logging, on land draining into the Sound downstream of Havelock, before 1940.

The report said sediment sources analysed using the compound specific stable isotope (CSSI) method showed ‘‘profound changes to sedimentation rates and shellfish composition since European settlement’’.

Sediment was accumulating on the seabed at a rate of up to 4.6 millimetres a year, posteuropean settlement, compared with a maximum of 1.2mm a year before that, in Kenepuru Sound, the study said.

The main contaminant was ‘‘pine-derived sediment’’.

‘‘They claim to be able to date the sediment in the Sound, and state what land use it comes from, they say they can distinguish forestry from farming,’’ Hemphill said. ‘‘And they’re saying there was massive amounts of sediment from pine forestry starting