corresponds to NCS
Leakage are negative external effects. This means here that a reduction in use in the forest at one location must not be compensated by an increase in use at another location. Internal leakage concerns the forest owner himself. External leakage, usually referred to as market leakage, can also occur at geographically further distances.
Internal leakage: Leakage in the narrow sense is avoided by a forest owner having to consider his entire forest in the project in the case of managed forest. The exclusion of areas must be justified and must be conservative with respect to the C-balance. For example: non-inventoried yield boundary areas, areas up for sale, large damaged areas according to chap. 5.1.3
External leakage: It is fundamentally not excluded that more timber may be felled elsewhere due to the sink project. However, the timber market is often interconnected both globally and nationally. The project results in an underutilisation of the sustainable use potential at project level. As long as national use remains below what is sustainably possible, no leakage can be attributed to the individual project. Only when this utilisation potential is exceeded does a possible causal connection begin.
It must be demonstrated that the national utilisation amount of the country where the project is located is lower than the utilisation potential in the accounting year (calamity years are excluded). In this case, leakage is assumed to be zero. Otherwise, a 10% leakage must be deducted. If the utilisation quantity for the accounting year is not yet known, the following applies: If the difference between the national utilisation volume and the utilisation potential did not fall below 10% the previous year, this value can be used as a proxy
The non-consideration of soil carbon means an underestimation of the sink performance. This underestimation contains an additional buffer for potential external leakage effects.