Planting Rate – the number of trees that are planted
Young Trees – the number of young trees, result of planted trees
Maturity Rate – the number of years before a young tree becomes mature
Mature Trees – young trees that mature through time
Forest Area – area of the forest in hectares
Deforestation Due to Logging – rate of the depletion of forest area with regards to the number of mature trees cut down.
3.2Causal Loop Diagram
After defining the variables, the proponents now make a development of the model. The model is shown in Figure 3-1. The causal loop shown below summarizes the relation ship that each contribute with each other. The causal loop will be discussed further to see the feed back loops in the whole model.
Figure 3‑1: Causal Loop Diagram
The first feedback loop is between the trees planted and forest area. It has a negative feedback loop as shown in Figure 3-2. The more trees planted the more the forest area recovers. But if the forest area is high, then there would be a limit to the trees that could be planted.
Figure 3‑2: Trees Planted and Forest Area The next feedback loop is for the variables trees planted, young trees, and forest area as shown in Figure 3-3. They are connected since when trees are planted, the young trees are also included in the forest area recovered. The feedback loop generated is a negative feedback loop.
Figure 3‑3: Trees Planted - Young Trees - Forest Area
The next feedback loop is for the variables trees planted, young trees, mature trees, and forest area. The loop generated is a negative feedback loop. With regards to the young and mature trees, there is also a negative feedback loop between them since when young trees mature, they are not considered young and won’t mature any longer to be cut down. Figure 3-4 below shows the feedback loops stated above. Figure 3-5 shows the relationship of all the variables in the causal loop diagram. It shows a positive feedback loop. Also seen in the figure is that there is a negative feedback loop regarding the mature trees and the deforestation due to logging. Since deforestation due to logging decreases the mature trees in the forest, while if there are mature trees, the loggers will have more supply of wood to be cut.
Figure 3‑4: Trees Planted - Young Trees - Mature Trees - Forest Area
Figure 3‑5: Trees Planted – Young Trees – Mature Trees – Deforestation – Forest Area 3.3Stock Flow Diagram After discussing the causal loop diagram, the proponents now design the stock flow diagram to be used as guide to making the simulation model. The stock flow diagram is shown in Figure 3-6. The same variables are used in the stock flow diagram and additional rate variables which is the planting rate and maturity rate.
Chapter 3 : Model Formulation
3.1 Definition of Variables- Trees Planted – number of trees planted
- Planting Rate – the number of trees that are planted
- Young Trees – the number of young trees, result of planted trees
- Maturity Rate – the number of years before a young tree becomes mature
- Mature Trees – young trees that mature through time
- Forest Area – area of the forest in hectares
- Deforestation Due to Logging – rate of the depletion of forest area with regards to the number of mature trees cut down.
3.2 Causal Loop DiagramAfter defining the variables, the proponents now make a development of the model. The model is shown in Figure 3-1. The causal loop shown below summarizes the relation ship that each contribute with each other. The causal loop will be discussed further to see the feed back loops in the whole model.
Figure 3‑1: Causal Loop Diagram
The first feedback loop is between the trees planted and forest area. It has a negative feedback loop as shown in Figure 3-2. The more trees planted the more the forest area recovers. But if the forest area is high, then there would be a limit to the trees that could be planted.
Figure 3‑2: Trees Planted and Forest Area
The next feedback loop is for the variables trees planted, young trees, and forest area as shown in Figure 3-3. They are connected since when trees are planted, the young trees are also included in the forest area recovered. The feedback loop generated is a negative feedback loop.
The next feedback loop is for the variables trees planted, young trees, mature trees, and forest area. The loop generated is a negative feedback loop. With regards to the young and mature trees, there is also a negative feedback loop between them since when young trees mature, they are not considered young and won’t mature any longer to be cut down. Figure 3-4 below shows the feedback loops stated above.
Figure 3-5 shows the relationship of all the variables in the causal loop diagram. It shows a positive feedback loop. Also seen in the figure is that there is a negative feedback loop regarding the mature trees and the deforestation due to logging. Since deforestation due to logging decreases the mature trees in the forest, while if there are mature trees, the loggers will have more supply of wood to be cut.
Figure 3‑4: Trees Planted - Young Trees - Mature Trees - Forest Area
3.3 Stock Flow Diagram
After discussing the causal loop diagram, the proponents now design the stock flow diagram to be used as guide to making the simulation model. The stock flow diagram is shown in Figure 3-6. The same variables are used in the stock flow diagram and additional rate variables which is the planting rate and maturity rate.