Reference Soil Climate

Is there a reference timeframe for mapping soil climate? Is it the most recent 30 year normals, which shift forward every ten years? Is it a longer period? Is it a fixed period or a moving average? I ask because soil temperature and moisture regimes are subject to change over long periods.

I am responsible for developing provisional ecological site concepts for northern Lower Michigan where a mesic/frigid temperature regimes meet.

I could see a scenario in which we map landscape units that are fixed in space, but subject to changes in interpretations based on changes in climate through time. However, we will continue to refine the position of this boundary as our understanding of the how local elevation and snowfall affects soil temperature. The issue then is whether we should normalize the boundary to a fixed time frame to reflect the soil climate for which the original interpretations were written. In such a scenario, map units would remain where they are as climate changes.

But should the taxonomic classification of the soils shift from frigid to mesic if recent data suggests as much? Or should we include both a frigid and a mesic temperature regime as alternative states? Plant community composition would likely shift depending on local species climate relationships and range boundaries. Interpretations for forest productivity and site index would likely have to change if climate change persists beyond 50 years.