Aldbury Nowers is a 19.7 hectares biological Site of Special Scientific Interest (SSSI) in the Chiltern Hills, north-east of Tring in Hertfordshire. The site was notified in 1990 under the Wildlife and Countryside Act 1981. It is managed by the Hertfordshire and Middlesex Wildlife Trust. The site, formerly known as "Duchie's Piece," comprises two areas of hillside, linked by The Ridgeway. The calcareous meadow element of the site hosts the flowers of chalk grassland and has butterfly habitats with thirty-four different species of butterfly recently recorded, including the Duke of Burgundy, hairstreaks and the Essex skipper. The site also includes a "beech hanger", a type of upland ancient woodland, and is considered one of the best examples of this feature in Hertfordshire.
Wormley-Hoddesdonpark Wood North is a 143.9-hectare (356-acre) woodland area in Hertfordshire which has been designated as a biological site of Special Scientific Interest. The site is listed as Grade 1 in A Nature Conservation Review, and is also designated a Special Area of Conservation. It is in Hoddesdon in the borough of Broxbourne, but part of the site is in East Hertfordshire.
Herts and Middlesex Wildlife Trust manages over 40 nature reserves covering nearly 810 hectares north of London, in Hertfordshire and the historic county of Middlesex, part of which is divided between the London boroughs of Barnet, Enfield, Harrow and Hillingdon. It has over 21,000 members, and is one of 46 Wildlife Trusts across the UK. It is a Registered Charity, with its Registered Office in St Albans, and had an income in the year to 31 March 2014 of over £1.5 million.
Old Park Wood is a 16.7-hectare (41-acre) Site of Special Scientific Interest in Harefield in the London Borough of Hillingdon. The south-east part is an 8-hectare (20-acre) nature reserve owned and managed by the Hertfordshire and Middlesex Wildlife Trust.
Waterford Heath is a 35.2 hectare Local Nature Reserve in Waterford in Hertfordshire, England. It is owned by Lafarge Tarmac and managed by the Herts and Middlesex Wildlife Trust together with East Hertfordshire District Council and Lafarge.
Balls Wood is a 58.5-hectare (145-acre) nature reserve managed by the Herts and Middlesex Wildlife Trust in Hertford Heath in East Hertfordshire. The wood was purchased by the Trust from the Forestry Commission.
Hertford Heath nature reserve is a 28 hectare biological Site of Special Scientific Interest in Hertford Heath in Hertfordshire. It is managed by the Herts and Middlesex Wildlife Trust and the local planning authority is East Hertfordshire District Council.
Stanborough Reedmarsh is a 3.3 hectare Local Nature Reserve in Welwyn Garden City in Hertfordshire. It is owned by Welwyn Hatfield Borough Council and managed by the Herts and Middlesex Wildlife Trust.
Tewinbury is a 7.5-hectare (19-acre) biological Site of Special Scientific Interest near Tewin in Hertfordshire. The local planning authority is East Hertfordshire District Council, and the site is managed by the Herts and Middlesex Wildlife Trust
Uxbridge Alderglade is a 2.9-hectare (7.2-acre) nature reserve in Uxbridge in the London Borough of Hillingdon. It is managed by the Herts and Middlesex Wildlife Trust.
Pryor's Wood is an 8.7-hectare (21-acre) nature reserve in Great Ashby, near Stevenage in Hertfordshire. It was formerly managed by the Herts and Middlesex Wildlife Trust (HMWT). In February 2016 HMWT announced that three sites, Barkway Chalk Pit, Hill End Pit and Pryor's Wood, which HMWT managed on behalf of their owner, North Hertfordshire District Council, were to return to Council management as the Trust was no longer able to meet the cost.
Hill End Pit is a 0.7-hectare (1.7-acre) nature reserve on the site of a former chalk pit, in St Paul's Walden in North Hertfordshire. It was formerly managed by the Herts and Middlesex Wildlife Trust (HMWT). In February 2016 HMWT announced that three sites, Barkway Chalk Pit, Hill End Pit and Pryor's Wood, which HMWT managed on behalf of their owner, North Hertfordshire District Council, were to return to Council management as the Trust was no longer able to meet the cost. It has the largest colony of Azeca goodalli snails in Hertfordshire. Plants include viper's bugloss, cowslip and marjoram, there are butterflies such as common blue and gatekeeper, and many birds including woodpeckers.
Fir and Pond Woods is a 29 hectare nature reserve in Potters Bar in Hertfordshire. It is managed by the Herts and Middlesex Wildlife Trust. It is two separate woods, with Fir Wood connected by a short footpath to the large Pond Wood to the south.
Willowmead is a 1.5-hectare (3.7-acre) nature reserve in north Hertford. It is managed by the Herts and Middlesex Wildlife Trust.
Tewin Orchard and Hopkyns Wood is a 4.3-hectare (11-acre) nature reserve in Tewin in Hertfordshire. It is managed by the Herts and Middlesex Wildlife Trust.
Gobions Wood is a 36 hectare nature reserve managed by the Herts and Middlesex Wildlife Trust in Brookmans Park in Hertfordshire. The site was formerly owned by the Gobions Woodland Trust, a registered charity which was closed down in 2013 because it had ceased to exist.
Lemsford Springs is a 4 hectare nature reserve in Lemsford, Hertfordshire, England. It is managed by the Herts and Middlesex Wildlife Trust, which purchased the site in 1970. Notable for its lagoons, the site is in the Lea valley and its other habitats are meadow, hedgerows, marsh and willow woodland.
Longspring Wood is a 1.2-hectare (3.0-acre) nature reserve managed by the Herts and Middlesex Wildlife Trust in Kings Langley in Hertfordshire.
Danemead is a 5.6-hectare nature reserve west of Hoddesdon in Hertfordshire, managed by the Herts and Middlesex Wildlife Trust. It is part of the Wormley-Hoddesdonpark Wood North Site of Special Scientific Interest.
