PERSPECTIVES ON LARGE-SCALE NATURAL-RESOURCE SURVEYS WHEN CAUSE-EFFECT IS A POTENTIAL ISSUE

Our objective is to present a perspective on large-scale natural resou rce monitoring when cause-effect is a potential issue. We believe that the approach of designing a survey to meet traditional commodity prod uction and resource state descriptive objectives is too restrictive an d unnecessarily limits the ability to investigate cause-effect issues. We only consider terrestrial natural resources, focusing on forests a nd rangeland. A large institutionalized programme is required to estab lish cause-effect relationships when monitoring terrestrial resources. This is justified based on the growing concerns about our natural res ources. A long-term Vision of a desirable future terrestrial monitorin g system, realizing that it is not clear yet what key variables should be measured, will increase the chances that decisions on current desi gns will ultimately lead to better systems in the future. We propose a pronounced shift in the designs applied to forest and range, specific ally, the National Resources Inventory (NRI), the Forest Inventory and Analysis (FIA), and the Forest Health Monitoring (FHM) programmes. Th e designs must not only address simple status and trends estimation bu t also give emphasis to identifying interesting changes occurring in t he sampled populations thus facilitating identification and establishm ent of possible cause-effect relationships. We propose an integrated d esign consisting of a large-scale, long-term ongoing survey as the cor e design accompanied by supplemental experimental design studies or an alytic survey. Continuous inventory involving annual measurement of a subset of the sample from selected populations should be implemented: inventorying a population every five years (as with NRI) or every ten years (as with FIA) is insufficient. FHM, FIA, and NRI should collect a subset of variables in common. Complementarity of data collected wou ld make it more likely to identify promising cause-effect relationship s for a wider range of resource variables. At this stage we recommend focusing an the mortality of trees, shrubs, forbs, and grasses as the key indicator of forest and range health. Mortality is objectively mea surable and can often be detected by remote sensing. When possible, fo llow-up observational studies to document cause-effect relationships s hould be limited to public lands because of concern of infringing on t he personal rights of landowners. This may not be possible if unrepres entative populations result because of this. If studies are designed p roperly, we could achieve our objectives yet tie such studies to curre nt natural resource inventory systems.