Selwyns Wood is a small, mixed semi-natural woodland near the town of Heathfield, mainly Oak, Birch and Sweet Chestnut, with a few old big Beech trees. It is nestled in a south-facing valley with three streams running through it, one of which has developed into a typical Wealden ghyll stream. There is also a small open area dominated by heather, a characteristic feature of woodlands in this part of Sussex.
In spring, Bluebells and Wood Anemones can be seen carpeting the woodland floor, while wet areas along the stream have a distinctive flora with Cuckoo Flower, Wild Angelica and Marsh Thistle present. The ghyll stream itself supports a range of bryophytes, though no rarities are found in this particular stream.
While the majority of the Sweet Chestnut is not currently coppiced, the local volunteer group have opened up some of the paths and rides to provide structural diversity and nice sunny conditions with plenty of nectar sources for a range of invertebrates. Butterflies love these sheltered conditions and a good range can be seen utilising the paths, including Brimstone and Orange-tip in the spring and Silver-washed Fritillary and Speckled Wood later in the year. The woodland supports a good range of the common woodland birds, with breeding Willow Warbler, Chiffchaff, Nuthatch and Marsh Tit all singing to mark their territories during the spring.
The heather area is kept free of Bracken and Bramble which always want to take over, and the heather is cut in small patches to maintain a diversity of age ranges. Slow Worms can often be seen in this area. Also common is the day-flying moth, the Speckled Yellow whose foodplant, Wood Sage is found around this area.
In late summer look for numbers of Migrant Hawkers feeding around the edges of the open areas. The streams on site also make the reserve a good place to look for other dragonflies and damselflies.