© 1968 by Institute of Chartered Foresters
Studies of Airborne Salt Deposition in some North Wales Forests
Department of Agriculture, University College of Wales Aberystwyth
Forestry Commission
Severe damage to trees has been observed in the seaward-facing sections of Newborough Forest, Anglesey. Salt deposition by marine winds was strongly suspected as the causative agent. This investigation used collectors, which are briefly described, to measure the deposition of NaCl both horizontally and vertically within the damaged zone of the forest. Quantity of salt deposited decreased rapidly with distance from the sea and increased with height above the ground, both these trends being exaggerated by increases in wind speed and much influenced by local shelter, e.g. adjacent sand dunes or trees. Highly significant negative correlation was found between salt measured at a site and the height of trees growing at that site. NaCl deposition on trees at three sites in North Wales was measured for comparison with NaCl levels found on the same sites using collectors. Significant correlations between these data were stablished at two sites and there were highly significant differences in salt deposition between sites. It is concluded that a causal relationship could reasonably be inferred between salt deposition and tree damage at Newborough, and that the levels of salt found in forests more remote from the sea, though they clearly responded to increases in wind speed, were so much lower than at Newborough that winds of quite exceptional violence would be needed to raise salt there to damaging levels.