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Comment by jimnotgym | Hacker News Reader

On several UK rivers, most notably the River Wye on the Welsh/English border, there exists a powerful river trust that has raised millions to remove 'barriers to salmon migration'. They took down and bypassed weirs on tributaries. They pulled out dead trees.

Then other bodies started felling trees into their river to create habitat for juvenile fish.

As an angler you might forgive me for thinking one of those bodies was in the wrong. Either way their conservation efforts have not mitigated the collapsing stocks of salmon over the two decades of their management.

I for one am happy for the beavers to have a go instead

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To be clear, they pulled out isolated dead trees, that weren't part of a weir? It's hard to imagine how those could act as a migration barrier.

Yes they did. They would deforest the banks, fence it off and clear the stream. Then they tried to convince other trusts to do the same. Now they are planting trees etc.

I believe that the group pulling out the dead trees was wrong. A good search term for this topic, btw, is "large woody debris".

Depending on the tree and local conditions it can take tens or hundreds of years for them to decay. That’s why old growth forests take so long to restore, they require several generations of dead trees in different states of decay. This allows everything to fungi and insects get established.

They definitely shouldn’t have removed dead trees. Worst case scenario if they were ugly and someone politically powerful wanted them gone they should have been broken up or ground into large mulch.

They also removed a lot of living trees to 'let in more light'. I always felt that let in more heat too. Other river trusts were planting more trees at the same time!

I always felt that varied habitat was better.

I was once at a conservation event with the Wye and Usk foundation and the Wild trout Trust. WUF presented first on removing obstructions, then WTT presented on large woody debris! WUF, however, was rich and could push out other people and groups and push their vision. Another group were working on a novel way to stock salmon (semi natural rearing, pioneered successfuly on the Tyne) and WUF campaigned successfully to have it banned! It was a lesson to me as a young man that not all conservation groups were net good. The rod salmon catch on the Wye was 188 last year, down from 6,000 in the 1960s.

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