During Dr. Sanborn's years with the Ministry of Forests research program (1991-2002), he worked on forest fertilization research with silviculturist Rob Brockley (retired; formerly at Kalamalka Research Station, Vernon, BC). Brockley’s work in the 1980s and early 1990s had documented the widespread pattern of sulphur deficiencies across the BC interior, and the superior response of managed stands to fertilization treatments involving sulphur (S) and nitrogen (N) rather than nitrogen alone.
To progress farther, different methods for understanding the fate of sulphur fertilizers in forests and soils were needed. Sanborn contacted the stable isotope group at the University of Calgary which had done important work on the fate of pollutant sulphur emitted by oil and gas extraction and processing in Alberta, using natural abundances of sulphur stable isotopes as a tracer. This was the beginning of a collaboration with Dr. Bernhard Mayer of the University of Calgary, and also with his German soil scientist colleague, Dr. Joerg Prietzel (Munich Technical University).
The research team engaged in the Cluculz retrospective study (E.P. 886.10) for the BC Ministry of Forests.
An ancillary project involved resampling (2002 - foliage, 2003 - soil) of a previously fertilized (1990) installation (E.P. 886.10) south of Cluculz Lake in order to compare the longer-term effects of different fertilizer sulphur forms on soil and foliage chemical properties. Results were published as a journal article and a Ministry of Forests Extension Note:
Sanborn, P.T., J. Prietzel, R.P. Brockley. 2005. Soil and lodgepole pine foliar responses to two fertilizer sulphur forms in the Sub-Boreal Spruce zone, central interior British Columbia. Can. J. For. Res. 35 (10): 2316-2322. https://cdnsciencepub.com/doi/abs/10.1139/x05-138
Sanborn, P. and R. Brockley. 2005. Sulphur deficiencies in lodgepole pine: occurrence, diagnosis, and treatment. Ext. Note 71. B.C. Min. For., Res. Br., Victoria, B.C.