Author/Authors :
David R. Vann، نويسنده , , Arthur H. Johnson، نويسنده ,
Abstract :
In order to examine the effects of airborne chemicals and other atmospheric components on mature trees in natural ecosystems, branch-sized environmental chambers were developed. These were designed to withstand the rigors of season-long exposure in montane environments while effectively controlling the conditions within. Field testing of the chambers demonstrated a reasonable, although not exact semblance of ambient conditions. Solar heating effects were difficult to control, although a configuration was developed that allowed the chambers to operate within standard specifications for similar devices. Overall, performance was good, and it is felt that this technique is a valuable tool for the evaluation of the effects of atmospheric chemicals on trees, as long as attention is paid to the environmental alterations caused by the chambers, and comparisons are made against control chambers.