Answer:
After 2009 the quality of the forests in this country improving.
Step-by-step explanation:
Consider the provided function.


Substitute f'(t)=0.



It is given that (0 ≤ t ≤ 10)
The test interval are (0,5) and (5,10)
For (0 < t < 5) the value of
For (5 < t < 10) the value of
Hence, the function is increasing from (5,10).
t = 0 corresponds to 2004.
Therefore, after 2009 the quality of the forests in this country improving.