Dear colleagues,
We, Prof. Zeng Weisheng, Prof. Gao Xianlian and I, have carefully read the background paper on primary forest and the contributions on-line. Combining with the properties of forest resources in China and the situations of forest resources assessment for FRA2020, some opinions are presented for reference as follows:
On the background paper. The background paper is a review document with rich information, which not only clarified the background of improving the primary forest reporting in the 2020 global forest resources assessment, but also outlined the current situation of primary forests reporting and the international efforts related to measuring and mapping primary forests, and finally presented some options for improving operational methods and guidance for data collection and reporting on primary forests. Therefore, we should thank Professor Patrick Norman and his colleagues at first for their efforts on drafting the background paper. Of cause, just as some experts have stated, the background paper needs to be improved further.
On the definition of primary forests. As stated in the background paper, the FRA 2015 definition of primary forest is a reasonable statement and consistent with how the term is used in the scientific literature, but we still think the definition remains vague and abstract. In the FRA 2020 terms and definitions, supplementary explanations of what is included and what is not included have been added to make the definition of primary forest clearer. The definition is a little bit more specific, but the argument is also appeared. For example, are traditional activities by indigenous people not human disturbance, and can the forest still be considered as primary forest after fire? Generally, the more abstract, simpler definitions are easier to agree on, while the more complex, concrete definitions are more likely to be controversial. Since the definition of primary forest cannot be expressed by specific inventory variables, countries will inevitably have inconsistent understanding and practices in the reporting process. The percentage tree canopy cover and height thresholds use to delineate forest from non-forest vegetation. How to set the thresholds for primary forest is a challenge. It would be very difficult for countries to undertake forest assessments on an eco-regional basis, to specify the forest canopy cover and height thresholds for each forest type, and to then establish baseline characteristic values for primary, secondary and degraded forests in a short period. Furthermore, besides the two factors of canopy cover and height, the attributes of anthropogenic influence, ecological characteristics and vegetation structure should also be taken into account in the definition of primary forest. In addition, further consideration is also needed regarding questions of spatial scale or minimum area and other controversial issues in assessing primary forests, such as, whether or not human disturbance should be treated differently between indigenous people and other people, whether the effects of fire are natural or human disturbance?
On the purpose of primary forest reporting. As Ms. Sonja Oswalt from USDA Forest Service stated, firstly we should be informed “why we want this”, or the purpose of primary forest reporting. It is because the definition of primary forest and the method of obtaining primary forest data are highly relevant to our goal. For example, do we care about anthropogenic influence or ecological characteristics of primary forest? If it is the former, we can focus on the "undisturbed forests", and obtain the relevant data by using remote sensing techniques; and if it is the latter, the situation is much more complicated because different forest types have different ecological characteristics. Some experts have suggested conduct forest resources assessment on a bio-regional or eco-regional basis, which would be difficult to implement only based on remotely sensed data. Viewing from forest inventory and global scale, we think we should prefer the former. For the assessment of clearly visible human activities on forests during the near period or the last 20 years, we can use the full Landsat archive data to conduct monitoring, just as stated by Christelle Vancutsem and Frederic Achard from Joint Research Centre, European Commission. Considering the differences among the countries’ financial resources, the “tier approach” suggested by Dr. Mila Alvarez Ibanez from USDA Forest Service, could be referenced to reporting on primary forests characteristics, which defined 3 tiers with different accuracy of the data.
On primary forest data of China. The data of primary forests in the country report of China submitted to FAO were from the National Forest Inventories, which were obtained from experts’ assessment based on the variable “degree of naturalness”. The “degree of naturalness” is an index that reflects the degree of forest naturalness by considering the attributes of anthropogenic influence, ecological characteristics and vegetation structure. From primary forests to plantations, there are 5 grades of “degree of naturalness”. In our original sense, primary forests are those with grade I of “degree of naturalness”. However, due to the vagueness and abstraction of the criteria of naturalness and the lack of clear quantitative indicators, inconsistent understandings and practices had appeared in the field work, resulting in unsatisfactory inventory results. That is, some of the grade I forests classified by the field teams are obviously not primary forests, and some of the grade II forests are probably better to classified into primary forests. Finally, after expert analysis and evaluation, 85% of grade I forests and 20% of grade II forests were identified as primary forest area.
On primary forest mapping. The national data of many countries, including China, used for FRA 2020 are derived from NFIs’ data, which are hard to be drawn upon map. Even for total forest area, the NFI data are hardly consistent with the sum of data from forest management inventories. Unless the definition of primary forest is based on a small number of measurable characteristic variables (such as area, height and canopy cover), and the primary forest reporting is carried out by means of mapping based on remote sensing, the consistency between statistical data and map area is difficult to be achieved.
In summary, it is a challenging task to improve the definition of primary forest and its reporting methods. Although we can’t attend the workshop to be held in March in Canada, we will continue to pay attention to the progress of the expert consultation on Improved Reporting on Primary Forests. I wish this workshop every success.
Jing Yang
FRA National Correspondent from China
Jing Yang