Thank you for the opportunity to contribute to this exiting effort and the great work already accomplished. Following are my insights after reading the paper.
What exactly is FAO trying to measure under their definition of Primary Forests? The definition of primary forests is an attempt to envision how forests look like and evolve in the absence of humans or in the presence of human population levels that are perceived as not having an impact on the environment (as a read the exception for indigenous communities). However, we all know that this far from reality. Humans, indigenous or not, have an impact in forests, even in those cases where their presence is remote. Climate change is a good example, as the paper addresses. Another example of indirect impact is when human action pushes species to move to areas less influenced by humans, becoming habitat competitors to other species. This is the cases of the Northern Spotted Owl (Strix occidentalis caurina) and the Barred Owl (Strix varia) in the U.S. The Northern Spotted Owl was listed as “threatened” species in 1990, which lead to changes in land management throughout the U.S. Pacific Northwest and northern California, primarily by curtailing logging of old forests, the owl’s preferred habitat. The assumption was that by reducing habitat loss, primarily on federal lands, population numbers will recover. However, after nearly two and a half decades of protection under the Endangered Species Act, the spotted owl is not showing signs of recovery and, in fact, its situation has worsened. This is due to the arrival of the barred owl, a historical resident of the U.S. eastern forests. At some point less than 100 years ago, barred owls began dispersing towards west. It’s believed that this was due, at least partially, to changes in habitat caused by a cessation of Native American burning in the plains after Europeans and other foreigners arrived. Lack of fire allowed trees to grow creating habitat “bridges” across the plains that facilitated barred owl movement. Barred owls were first reported in northern British Columbia in 1949; today they overlap the entire range of the northern spotted owl. As a result of the barred owl migration to the west and their biological advantages over the spotted owl, populations of spotted owl are rapidly declining in many areas.
The extend of human footprint on the environment is broad and complex both in space (scale, direct and indirect impacts) and time. Given the latest adopted definition states: "Naturally regenerated forest of native tree species, where there are no clearly visible indications of human activities and the ecological processes are not significantly disturbed." The definition is confined to human visibility/perception. Does the definition focus on forest appearance to the human eye or on ecological resilience/health (significantly disturbed)?
Philosophically, Primary Forest attempts to capture those forest tracks that remain “pristine”, “virgin”, “not exploited/modified by humans”. The definition embraces the underlying assumption that human impact is negative (or at least not as good as nature), but in some cases human action is ecologically beneficial. What is the ecological difference between a natural disturbance and a silvicultural prescription that mimics nature? For example, is there any difference between a natural low intensity fire and a prescribed fire? If human intervention through silvicultural practices can accelerate forest successional stages, why this is not capture in the given definition.
Recommendation. Reporting on measurable characteristics (or metrics) attributed to primary forests conditions rather than on a broad definition left to country interpretation would improve the comparability of reported data at the global level and its use for decision making. Intact Forests Landscapes (IFLs) represent a good practical attempt to measure some of the related characteristics (lack of fragmentation in large tracks of forests) that exist in many primary forests. Although IFL mapping criteria excludes all burned areas regardless of their origin, human or natural, and their 500 km2 threshold was a subjective mapping criteria decision based on the best knowledge at the time, it provides an estimation of where large areas of unfragmented core habitat free of visual human impact exist, a forest characteristic that exists within primary forests as defined by FAO.
Because of the different nature and characteristics of the many biomes on Earth and the forest ecosystems within them, criteria to measure some primary forest’s characteristics might need to be adjusted to biome or appropriate scales.
Resources. Any reporting mechanism must acknowledge the differences among the countries’ financial resources to conduct forests estimations and inventories. Reporting on agreed primary forests characteristics could adopt a “tier approach”, where the accuracy of the data increases as we go down in the defined tiers. This would allow countries with fewer financial resources to report comparable numbers to countries with more financial resources.
Tiers could be defined for as many primary forest characteristics as are agreed. In the case of estimating unfragmented forest area, the following tier approach could be modeled:
- Tier one – gross estimations as defined by IFLs or other mapping criteria identified for remote sensing analysis and using imaginary that is currently readily available and free.
- Tier two – estimations of unfragmented forest area based on remote sensing analysis (tier one) and ground inventory data.
- Tier three – precise estimations that combine inventory information with high-resolution remote sensing data and/or airborne data (lidar, hyperspectral, camera, etc.) that might not be freely available and might require more advanced processing and computing technology.
In conclusion, countries could report on acres of forest presenting each of the quantifiable and measurable characteristics associated to primary forests (unfragmented forests, undisturbed forests, etc), perhaps tailored to a biome scale, rather than total acres of primary forests using a general definition subject to country interpretation and political drivers.
Dr. Mila Alvarez Ibanez