Temperate rainforest – also known as Atlantic woodland or Celtic rainforest – is the name given to rainforests which have high rainfall and humidity and a low annual variation in temperature.
A wide range of trees grow in them, including sessile oak, birch, rowan, holly, alder, willow and hazel.
The YWT said they can provide a home to red squirrels and pine martens, as well as threatened birds like wood warblers, redstarts and pied flycatchers.
Mr Leadley said: “Woodland is at a premium in this part of the Dales, and species such as black grouse which cling on in the area will also benefit from more berry-bearing bushes such as hawthorn in the landscape.
“This new reserve promises to be a vital oasis for wildlife in the Dales, and we cannot wait to see what wildlife it attracts as a result.
“We hope this beautiful site will be a haven for wildlife and a beautiful place for people to enjoy.”