The horse called Nathan took part in the efforts to prevent flooding in the Calder Valley, West Yorkshire.
A team of volunteers worked at Hardcastle Crags to use the timber to slow the flow of water down into the valley.
The work is to reduce the risk of flooding in Hebden Bridge, Mytholmroyd and Brighouse.
Adrian Horton, of environmental charity Slow the Flow, said: "This is what Nathan does for a living, he is huge and by moving very large tree trunks he reduces the need to use concrete to slow the water down."
The timber is placed into the brooks and gullies on the crags to slow the progress of rainwater heading into the valley bottom.
Hardcastle Crags is north of Hebden Bridge and the work is part of the Calder Valley Catchment Plan.
In December 2015 the Calder Valley suffered the most significant floods in recent times.
More than 2,700 homes and 4,400 businesses were flooded all along the valley.
Floods had also hit the valley in 2012, 2013, 2104 and earlier in 2015
The earliest flood on record - in 1615 - destroyed Elland Bridge.
A working horse has been used to move tree trunks to be used for natural flood management.