Best hash size for hash trees I want to know if having a 8-byte hash value is better than 16-byte hash value for use within hash trees.

My mind tells me that the shorter the hash value, the better. But doesn't a smaller hash value make it easier to invert? More strings would lead to the same hash value.

I guess this is very opinion-based, but I'd like to hear different reasoning for your answers.
The shorter the hash value the less effort for the attacker to brute force it. If the output is 16bytes then the attacker must spend $2^{128/2}$ "time" to find a collision. If it was 8bytes it would need $2^{64/2}$