Clarken Coombe is a shallow valley on the west side of the Ashton Court Estate southwest of Bristol, filled with many ancient trees, principally beech across the upper reaches (Pill Grove, formerly Church Wood), with oak lower down (Clarken Coombe Wood), these latter trees particularly gnarled and characterful.
All the coombe is sheltered and moist, resulting in a wide range of fungi plus the usual range of woodland wildflowers and at least one much rarer species, the green-flowered helleborine. A busy road, the B3128, runs through the coombe just south of the valley floor; most of the trees are on the northern slopes, extending across the flatter ground beyond.
The bedrock is a mix of mudstone and conglomerate from the Mercia Mudstone Group at the lower elevations, with limestone higher up, from the Oxwich Head Formation and the underlying Clifton Down Formation, and rocks are exposed in a few places including an old quarry near the road, towards the west edge of the coombe.
The coombe can be approached via a long walk through the Ashton Court Estate, though while there are no official car parking places close by, a few vehicles can be left either along Longwood Lane beside the west edge, at the entrance to a working quarry, or on a verge on the north side of the B3128. A wide track starts from the former location, running eastwards through the trees above the coombe, and two other routes branch off, descending the slopes and linking with another track along the valley floor that continues towards the main part of the estate and may be reached from the B3128 verge by climbing over a low stone wall. Several lesser paths also criss-cross the woodland, and the undergrowth is generally light making it easy to walk anywhere in the valley.
The green-flowered helleborine grows right next to the road near the verge parking area, while the fungi and other wildflowers are evenly distributed across the whole site. Some of the largest, oldest and most photogenic oak trees are within a fenced-off section of Clarken Coombe Wood, part of a fallow deer enclosure, but it seems reasonable to climb the fence if the deer are not in residence. Many of the oaks are healthy and undamaged, some are alive but split or hollow, while others have fallen, yet their huge trunks endure for centuries.