The Forest Effect : Biosphere 87sr/86sr Shifts Dues to Changing Land Use and the Implications for Migration Study Interpretations

This study documents a transect of 87 Sr/ 86 Sr values from a variety in plant, soil and rock samples from across the ancient woodland of the Sherwood Forest National Nature Reserve (SFNNR) and into adjoining farmland in Britain. All samples were collected from the Triassic Sherwood Sandstone Group. A shift of +0.0037 is observed between the average plant 87 Sr/ 86 Sr values from the biosphere of the ancient forest and that of the farmland. This shift is caused by the leaf litter accumulation in the forest, through time, leading to soil acidity which leaches out the carbonate component of the soil. This results in the forest floor soil reflecting only the silicate minerals from the original Triassic Sandstone rock formation. We have called this preferential leaching out of carbonate over time the forest effect. Rock samples from boreholes of the Sherwood Sandstone Group, as well as water samples from aquifers and mineral waters from previous studies, further indicate that the change in biosphere 87 Sr/ 86 Sr is a result of the wooded environment rather than the anthropological addition of lime to farmland