In 2005-06, we continued efforts to improve our ability to predict the effects of machine traffic on soils and forest productivity.
? Tree growth measurements at Okanagan Falls showed that early trends were not indicative of the eight year results, illustrating the need for long term measurements for evaluating soil productivity.
? Investigations of thresholds for growth limiting factors in a silt loam soil were initiated through installation of an experiment in raised soil boxes at Kalamalka Forestry Centre.
? Field investigations of the relationship between soil bulk density, mechanical resistance and water content continued in 2005-06 with measurements taken at the LTSP plots near Kamloops. These investigations have confirmed the ability of our methods to evaluate soil physical conditions in soils with approximately 25 percent coarse fragments, but have also revealed that measurements are much more difficult in soils with higher coarse fragment contents.
? More detailed investigations have also confirmed the usefulness of an air pycnometer for evaluating air filled porosity and soil particle density.
? Water retention prediction using two models has continued, and is showing promise for estimating the water retention curve from soil properties
? Investigations have continued on the relationship between maximum bulk density and other soil properties such as particle size distribution, organic carbon, and Atterburg limits.
Blouin, Vikki M., Schmidt, Margaret G.; Bulmer, Charles E.; Krzic, Maja; Simpson, David G.; Curran, Mike P.. 2006. Soil conditions and tree growth on rehabilitated and degraded sites: stewardship of British Columbia?s forest soils. Forest Investment Account (FIA) - Forest Science Program. Forest Investment Account Report. FIA2006MR166