Trees release water through its leaves.
all the water they suck up, they release. Its called transpiration.
I absolutely agree that tree planting needs to be strictly controlled and regulated - which the programme made a point of.
the planting of non native conifers would be no help at all.
the problem we have here is that many folks either don't understand basic science or they are just opposed to it on principle.
its no coincidence that the programme featured national and local scientists, fishery owners and managers, and ghillies.
I wonder if you actually understand basic science? Because if you do, you should know that transpiration is when trees release water vapour through their leaves back into the atmosphere. That will not help or counter the loss of water that has been taken up by the trees that would have previously ended up in the river. Yes, it will end up falling as rain somewhere but unlikely back into the river that was deprived of the water in the first place.
I have actually discussed this film with a fishery scientist who is of the same opinion as myself on this subject.