1992. Sist et al. in prep. noted that logging in Inhutani II is done using high felling intensity 9 trees per ha or about 80 , that results in high damage to
residual trees. The percentage of dead trees due to felling was estimated for the different diameter classes as follows: 50 for 1 to 5 cm, 40 for 20-30 cm, 30
for 30-40 cm, 20 for 40-50 cm 20 for 50-60 cm, and 10 for higher than 60 cm. In contrast, expected mortality in traditional logging done under low-felling
intensity manual harvesting system is only about 1-2 trees per hectare or about 10 . Therefore, it created low damage to the residual stands. Logging L and
its damage LD changes the previous model into:
N
j,t+1
= N
j,t
+ R
j
+ O
j
- M
j
– L
j
- LD
j
The length of a forest concession is 20 years, which may be renewed pending satisfactory compliance of government rules and regulations. During that
period, the company logs the area systematically according to approved harvest plans. The concession area is divided into 35 annual cutting blocks consistent
with the length of the cutting cycle. Harvesting moves from one block to another every year using the TPTI rule. At the same time, the local communities move
alongside, and may open a part of the forest if the current rice field area is not sufficient due to population growth and their goal achievement. For a new rice
field area, they generally seek an area closest to the existing rice field area or their villages if possible.
4.5.4.2. SMALLTALK Programming
The simulation was written in SMALLTALK computer language that runs over open code software CORMAS Common Pool Resources and Multi-Agent
System. By using these CORMAS routines, the simulation was developed and
executed. Figure 4.16 illustrates the main menu of the multi-agent system simulation which is CORMAS-ForestActors. There are 14 entities specified,
comprising three types: spatial, social and passive. The first two entities have been explained previously. The other entity is passive”, consisting of
ActorsMessage, CandI and LongTermPlan.
Figure 4.16. Main menu of ‘Forest Actors’ ActorsMessage is a media of communication between agents,
consisting of: symbol, object, sender, receiver, status and amount. These components represent media to deliver messages. Meanwhile CandI Criteria
and Indicators is criteria and indicators for determining the score of forest sustainability under different scenarios. LongTermPlan consists of components
of forest management plans such as Rencana Karya Pengusahaan Hutan
RKPH, a long-term plan. On the Visualization part, three icons represent spatial, communication and diagram of the simulation.
Icon Spatial shows map inputs and outputs of simulation. Figure 4.17 shows the map of five-year cutting blocks and rice fields surrounding the villages.
This is the situation map of the study area. This map and maps of road areas and networks, annual cutting blocks, forest function and vegetation maps are
inputs in the simulation. The five-year cutting blocks were obtained from the company’s forest utilization long-term plan, which is one of the government’s
requirements. The geographic location of the rice field area is depicted on the vegetation map. Using geographic information systems GIS, the areas are
presented spatially as pixels, including rivers, roads, vegetation, logging plans and elevation. Each pixel represents an area of approximately 35.27 hectares.
Figure 4.17. The situation map of study area in 1991 Long
Loreh
Langap
Long Seturan Inhutani II
log pond
Five-year cutting blocks
1
st
dark gray –7
th
light gray Logged by
Inhutani I, before
allocated to Inhutani II
Icon “Communication” shows communication links among agents as illustrated in Figure 4.18. The agents are represented with symbols, and the
communications are represented with lines between agents. Icon “Diagram” shows the diagram outputs of the simulation. Figure 4.19 shows an example of
diagram output.
Figure 4.18. The communication observer
Figure 4.19. The example of simulation output diagrams
4.5.4.3. Baseline Simulation Outputs
