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ACID FOG EFFECTS ON CONIFER SEEDLINGS
Citation:
Turner, D., D. Tingey, AND W. Hogsett. ACID FOG EFFECTS ON CONIFER SEEDLINGS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/D-89/196 (NTIS PB90132697), 1989.
Description:
Experiments were performed to assess the effects of acid fog on foliar injury, biomass production, and nutrient leaching in selected conifers. ne-year old seedlings of Pseudotsuga menzieii, Pinus ponderosa, Tsuga heterophylla and Thuja plicata were exposed episodically to fog events of variable duration (22 events over a 60 day period for a total of 93 hr). Exposures occurred in open top chambers with fog acidified to pHs of 2.1, 3.1 or 5.6. oliar injury was observed only in T. heterophylla (pH 2.1 and 3.1) and T. plicata (pH 2.1). he low pH fog treatments significantly reduced root biomass in T. heterophylla and across species there was a trend towards a reduced proportion of total dry weight as roots with decreasing fog pH. oncurrent experiment examined foliar leaching in P. menziesii. Seedlings were grown in solution culture at two levels of nutrient availability and exposed to pH 5.6 or pH 3.1 fog (24 events over an 84 day period for a total of 96 hrs). or seedlings at the higher level of nutrient availability, foliar leaching rates were determined by analyses of throughfall solutions and compared to root uptake rates (based on depletion from the nutrient solutions). og pH did not affect total biomass production or foliar nutrient contents. owever, plant growth and foliar nutrient levels were higher in plants grown at the higher nutrient level. oliar leaching (K >Ca >Mg) was greater with a pH 3.1 fog than a pH 5.6 fog but the amounts leached (by a 4 hour pH 3.1 fog) were small compared to the daily uptake rates for these seedlings.