Deposition of air-borne salt on Pinus radiata and the underlying soil.
Sea-salt deposition was measured under the windward and leeward side of trees of Pinus radiata D. Don growing near the coast of west Wales. Deposition was compared with that in adjacent open areas. Annual deposition rates equivalent to 29.1 g Na, 2.6 g K, 5.5 g Mg and 7.0 g Ca m-1 occurred under the windward side compared with 9.8, 1.7, 1.9 and 3.7 g m-1 respectively under the leeward side and 3.6, 0.5, 0.4 and 1.8 g m-1 in the open. The deposition rates of cations were closely correlated with the onshore run-of-wind. Deposition of cations (Na, K, Ca and Mg) was greater on leaves on the windward side, than on the leeward side; deposition was also greater on yellow, salt-damaged leaves than on healthy leaves. Leaves on the windward side contained more Na, and to a lesser extent Ca and Mg, than those on the leeward side. Leaves on the windward side contained less K. The soil beneath the windward side of the trees contained more Na and Mg and less Ca than soil beneath the leeward side. Soils in the open contained less Na and Mg than either of the other two soils.