Berwick Forest consists of three blocks; the Main block, Maungatua and Waitahuna. The forest lies approximately 45 kilometres southwest of Dunedin. Berwick has a gross area of 13,141 hectares, of which 11,100 hectares is stocked or awaiting replanting. The forest covers a diverse tract of land between the coastal plains and the Otago uplands. Topography varies from flat through rolling to steep.
Berwick is managed under a Forestry Right between Otago Land Company who own the land and Wenita who own the trees.
The main block extends westwards up to and over a broad flat ridge, with the western side dropping towards the Waitahuna River. Altitude ranges from 10 to 684 metres above sea level (asl), with the highest parts in the northwestern portion of the block.
Maungatua block lies on the southwestern flank of the Maungatua Range. Altitude rises steadily from the southwest, with the northeast part of the block reaching 644 metres asl.
The Waitahuna block lies in rolling hill country north of Waitahuna township, reaching 360 metres asl.
Climate varies from a maritime to an inland type, with rainfall ranging between 700 and 1000 millimetres per annum. Rainfall is highest on the major ridge system running through the main block.
Berwick Forest soil types range from lowland yellow brown earths to upland and high country yellow brown earths belonging to the Warepa, Kaitangata, Waitahuna, Tuapeka and Waipori series. Soil drainage and fertility are adequate for good forest growth without application of fertiliser. Radiata pine site index ranges from 16 to 28 metres at age 20. The wide variation is a result of the altitudinal range of the forest.
Prevailing winds come from the southwest. They can be strong to gale force and can carry "wet snow" during the winter. Consequently windthrow and wind damage occurs predominantly across broad ridge tops where soils are shallow and maximum exposure occurs. Snow accumulates in north and northeast top slopes and can cause damage in some years. Areas of such damage are typically small (1 to 5 hectares). Management in high altitude areas needs to recognise the combined effect of wind and snow.
Rare Threatened and Endangered Species
A number of rare species are known to exist within Berwick Forest. These include the New Zealand Falcon and the indigenous fish, Dusky galaxias.
A Biodiversity Survey has been carried out to identify areas of significant indigenous habitat. These have been given protection under the Wenita Environmental Management System. Further surveys are being carried out to identify additional rare, threatened or endangered species and to monitor the known species.
Areas protected by way of Department of Conservation (DOC) covenants include - a small area within the main block to ensure protection of the Table Hill ecological area; Browns Cottage, also within the main block and which was built in about 1888 for a pastoral run holder; and Hawkers dam, in the Waitahuna block, which was built for gold mining in 1887.
Other protected areas include riparian margins, areas of significant indigenous habitat identified during the Biodiversity Survey and historic or cultural sites.
The Clutha District Councilís, Bruce District Rural Water Scheme draws water from a stream within the main block.
The Otago Youth Adventure Trust Inc. facilities are sited within the main block. High-tension powerlines cross the eastern and northeastern corners of the forest. There is a popular walking track from the Berwick picnic area through to the Waipori Scenic Reserve.
Tramping, mountain biking, horse trekking, motorcycle riding, fishing and hunting are popular recreational activities in the forest. All access requires an Access Permit.
Some forest grazing by neighbours is carried out where environmental outcomes are acceptable.
Long term estate planning is carried out to ensure the forest is managed within an overall sustainable cut and to identify any potential environmental or social impacts at the landscape level. Management Plans are developed for rare, threatened and endangered species, protected areas and non-forest resources to ensure that these are identified and protected through the planning and management process. Medium-term plans identify the order in which stands are to be harvested. As Berwick Forest is a mixed-age forest, harvesting is an ongoing activity, with the centres of activity moving through the forest in the sequence that the forest was planted. The projected harvesting areas for the next two years are shown on the maps.
The predominant forest crop is Radiata pine, which grows well on most sites. Other minor species include Douglas fir and Corsican Pine. Higher altitude areas with environmental limitations currently growing Radiata pine will be replanted in Douglas fir, a species more suited to these conditions.
Harvesting is carried out using a mix of Cable and Ground-based systems, depending on the topography. Harvest areas are clearfelled as whole stands to minimise losses from windthrow. Internal roads are upgraded prior to harvesting allowing sufficient time for them to consolidate before use.
Following harvesting areas are replanted within one year. Approximately 70% of the areas replanted in Radiata pine undergo an intensive silvicultural regime including pruning and thinning. The remaining areas, including other species, are thinned.
All operations that can have a significant environmental impact are controlled by Best Management Practices.