Based on the provided statements, it appears that the tree population in the forest experienced different patterns:
- First option: The number of trees stayed the same for two years and then began to decrease.
- Second option: The number of trees stayed the same for two years and then began to increase.
- Third option: The number of trees decreased for two years and then stayed the same.
- Fourth option: The number of trees increased for two years and then stayed the same.
To summarize, the tree population in this forest either maintained stability (no change) for two years before either decreasing or increasing, or it experienced a decrease or an increase for the first two years before stabilizing. The specific scenario of what happened would depend on which option best fits the actual data you're referring to. If you have specific data or visuals (like a pictograph), that would help clarify the changes in the tree population.