Step 1: Understanding the Question:
This question tests knowledge of medicinal tree species.
Step 2: Detailed Explanation:
Terminalia belerica (bahera) is known for its medicinal bark.
It is used in Ayurveda and traditional medicine.
Casuarina equisetifolia (B): Not medicinal.
Melia dubea (C): Not a standard species.
Gmelina arborea (D): Timber species.
Thus, the correct answer is Terminalia belerica.
Step 3: Final Answer:
Thus, Terminalia belerica is known for its medicinal bark, which corresponds to option (A).
[0.5cm]