A recent investigation at Plas Tan Y Bwlch, Gwynedd, by Tree Register of the British Isles (TROBI) representative Owen Johnson confirmed that the four are "Champion Trees". They are:
- Japanese cedar (Cryptomeria japonica)
- Sawara cypress (Chamaecyparis pisifera)
- Golden-leaved Lawson cypress (Chamaecyparis lawsoniana 'Stewartii')
- Variegated holly olive (Osmanthus heterophyllus 'Variegatus')
The visit also identified a further nine Welsh champions and 16 county champions.
"There is also an attractive range of trees in the main garden, including a Davidia (Dove Tree) unsurpassed for its crown size and beauty," Johnson added.
Plas Tan y Bwlch is a Victorian Gothic mansion and grounds lying in the mountains of Snowdonia National Park, and is run by the park authority as an environmental studies centre.
Its director Andrew Oughton said: "We have long been aware of the magnificence of the trees at Plas, but had no idea so many of them were the biggest of their kind."
Garden consultant Tony Russell is preparing a book on the estate's trees, due to be published shortly.