Step 1: Understanding the Question:
This question tests knowledge of forest sampling methods and the Bitterlich method.
Step 2: Detailed Explanation:
The concept described is the Bitterlich method (also called angle-count sampling).
It was developed by Walter Bitterlich in 1948.
It uses a critical angle to count trees and estimate basal area per hectare.
Gingrich (A): Not related.
Zobel (C): Not related.
Metzler (D): Not related.
Thus, Bitterlich is the correct answer.
Step 3: Final Answer:
Thus, the concept was proved by Bitterlich, which corresponds to option (B).
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