management requires maintaining biodiversity in order to continue supporting life on earth. As indicated, the term biodiversity includes the diversity of ecosystems,
communities, species and genetic structures. Areas which are identified as functionally sensitive to any disturbance
must be protected to ensure the continuity of ecosystem functions. These areas also function as reserved forests - any uniqueness should be as representative
as possible to the FMU. This became the second criterion. The ecosystem integrity principle includes maintaining hydrological functions to avoid water
erosion and floods, soil quality and food chains - and it became the third criterion. Table 4.1 shows the ecological criteria for SFM. All these criteria are outcome
parameters derived from the principle: ecosystem integrity is maintained. This means these criteria are used to judge the impacts of forest management at FMU
level.
Table 4.1. The generic knowledge of ecological criteria for SFM Category
Text Principle 1
Ecosystem integrity is maintained Criterion 1.1
Biodiversity is maintained Criterion 1.2
Maintenance of ecologically sensitive areas Criterion 1.3
Ecosystem function is maintained
4.1.2.3. Economic Criteria
A forest management unit is a commercial unit of managed forest aimed at producing products and services from which economic benefits are derived.
The principle of economic sustainability of forests was determined by the sustainability of forest products and services. It is close to the concept of
sustained yield principle, which is the central term of traditional forest management. This principle is defined as the regular and continuous supply of
desired products according to the full capacity of the forest. Under this principle, two criteria were derived. These criteria stated the importance of the concept of
a ‘normal’ forest. Helms 1998 p. 125 defined a normal forest as a forest composed of normal stands that have reached a conceptual ideal in stocking and
age- and size-class distribution. The first criterion was the forest has a normal series of diameter size-
gradation, a normal volume and a normal increment. Each of those diameter size-gradations differs by one diameter class. The normal state of size-gradation,
volume and increment can be found through extensive work in the area, guided by knowledge of similar forests used as benchmarks. An inverted J curve for the
number of stems and diameter class relationships is usually found in the normal forest, as shown in Figure 4.6.
Figure 4.6. Number of stems and diameter class relationship. The idea of normality should also relate to non-timber forest products
NTFP and services - in the sense of those products and services being produced by the forest in a sustainable manner and according to the forest’s full
capacity. That became the second criterion. Table 4.2 lists the economic
Number of stems
Diameter class
criteria for SFM. All these criteria become outcome parameters of the principle: forest products and services are sustained.
Table 4.2. The generic knowledge of economical criteria for SFM Category
Text Principle 2
Forest products and services are sustained Criterion 2.1
Forest has a normal series of diameter size-gradation, a normal volume and a normal increment.
Criterion 2.2 Normality in non-timber forest products and services
4.1.2.4. Social Criteria
