Scaling Up Physiological Responses of Loblolly Pine to Ambient Ozone Exposure Under Natural Weather Variations

The challenge of scaling up (i.e., of incorporating such small-scale information as leaf physiology into larger-scale processes of the canopy, stand, or ecosystem) has been the subject of considerable discussion in recent years (e.g., Ehleringer and Field, 1993; King 1993; Luxmoore et al., 1991; Rastetter et al., 1991; Reynolds et al., 1992). Two particular concerns in scaling up from physiological to landscape scales are 1) accounting for relevant processes that express the behavior of the soil-plant-atmosphere system at particular scales, and 2) the integration and transfer of relevant information from one scale to the next. One approach for scaling up involves simulation with models of differing scales and the transfer of information from the smaller-scale to larger-scale simulators. This linked modeling approach addresses scaling concerns by 1) explicitly modeling processes at the scale of their operation using available mechanistic understanding and appropriate data, and 2) by explicitly transferring integrated information from one scale to the next through a hierarchy of linked models.