In limitations it states: >While there is no hard limit on the size of the Tree, in most practical implementations it will need to be read entirely into main me

In limitations it states: >While there is no hard limit on the size of the Tree, in most practical implementations it will need to be read entirely into main memory in order to interpret it, particularly to support forward references. This imposes a practical limit on its size relative to the system memory on the machine. It is not recommended to store large data sets in the tree directly, instead it should reference blocks. I would guess that HDF5 would be the better choice for large datasets. However I quite do not understand the capital 'Tree' in this sentence and what that means for practical data sets.