A long-term vision of a desirable future terrestrial monitoring system, realizing that it is not clear yet what key variables should be measured, will increase the chances that decisions on current designs will ultimately lead to better systems in the future. The designs must not only address simple status and trends estimation, but also give emphasis to identifying interesting changes occurring in the sampled populations thus facilitating identification and establishment of possible cause-effect relationships. FHM, FIA, and NRI should collect a subset of variables in common. Complementarity of data collected would make it more likely to identify promising cause-effect relationships for a wider range of resource variables. At this stage we recommend focusing on the mortality of trees, shrubs, forbs, and grasses as the key indicator of forest and range health.
Mortality is objectively measurable and can often be detected by remote sensing.
This may not be possible if unrepresentative populations result because of this. If studies are designed properly, we could achieve our objectives yet tie such studies to current natural resource inventory systems.