The Fleming blockchain faced a critical scalability issue: storing the full state in every block created massive redundancy, with 1,000,000 accounts requiring over 50 MB per block. This approach is unsustainable for any real-world application.

Merkle Trees offer a solution by creating a cryptographic fingerprint of the entire state. Instead of storing all account data, each block now contains just a single 32-byte Merkle Root. This root hash uniquely represents the complete state, enabling compact storage and efficient verification.

The implementation uses a Sparse Merkle Trie, a specialized data structure where the path through the tree is determined by the account's hexadecimal address. This allows incremental updates and generates Merkle Proofs—small cryptographic proofs that verify an account's balance without revealing the entire state, making light clients viable.