|The Assessment of Environmental Effects for the Timberlands West Coast sustainable beech management proposals of 1998 - 1999, written by Kit Richards. Timberlands West Coast Limited (New Zealand) (TWC) applied to the Buller and Tasman District Councils for Resource Consent hearings under the Resource Management Act 1991, to carry out sustainable forest management in about 98,000 hectares of beech (Nothofagus) forest. TWC is a State Owned Enterprise, created following the dis-establishment of the NZ Forest Service by the 1984 - 1990 Labour Government. In 1999, a newly elected Labour government, acting on preservationist dogma, moved swiftly to stop the Resource Consent hearings. In consequence, the public of New Zealand, and the world, was enied the oppertunity to learn about the excellent and world-leading sustainable forest management developed and proposed by TWC. This document is published here to help make the information more publically accessible.|
Page two of this document.
Overview of Proposal
Timberlands West Coast Limited (TWCL) seeks 35 year resource consents to undertake sustainable management of Crown owned beech and beech/podocarp forests within the Buller and Tasman Districts. In short, sustainable management will involve the extraction of beech and a very small amount of rimu trees in a range of diameter classes. The extraction will be undertaken at a rate and in such a manner so as to ensure that extraction does not exceed the natural rate of replenishment of the forest. The forest ecosystem, and associated resources, are maintained in perpetuity and so that the activity is sustainable in the sense used in the Resource Management Act 1991.
The effects at issue are the effects of the activity during the 35 year consent period, and any resulting effects which might occur or endure beyond that period. The Councils should not assess the effects of the activity as if it were to be extended beyond 35 years. That is not the proposal which is the subject of these applications. The critical issue raised by the applications relate to the likely effects of 35 years of sustainable management on forest structure and ecology. Any renewal of consents after 35 years provides future generations with an important opportunity to evaluate their needs, those of future generations and the sum of any past or future adverse or beneficial effects as they consider any extensions beyond the term of the current application.
Extraction of beech, and rimu trees, will be selective and will almost exclusively use aerial extraction by helicopter, and will not involve clear felling or unsustainable partial felling. Instead, between 1 to 10 mature trees will be felled at each location and the canopy gap size will not exceed 0.05 ha. On average, for "old growth" unmodified forests, approximately 15 trees per hectare will be extracted from any given hectare once every 10 to 15 years. There are a number of other significant mitigation measures detailed in Section 8 of this report to ensure sustainability.
The activity requires consent as a restricted discretionary activity from the Buller District Council. That Council has limited its discretion to a list of particular matters. This assessment of effects focuses on those particular issues because the Council has no discretion to go beyond those. However, for completeness, other issues have been canvassed in the assessment of effects The conclusion is that any adverse effects on the environment will be minor and can be avoided or adequately mitigated.
So far as Tasman District is concerned, TWCL believes that the clearance part of the proposal is either a permitted or controlled activity (for which the Council has no discretion to decline consent). It has applied separately for certificates of compliance and controlled activity consents on that basis. Nevertheless, as a matter of precaution it also seeks consent for its proposal within Tasman District as a discretionary activity and will apply for that consent at the same time as the Buller consent so as to enable a joint hearing to be held.
Approximately 78% of the West Coast land area is managed by the Department of Conservation (DOC), with only 6% of the area available for sustainable indigenous
management by TWCL. The remaining land area is used for agriculture, urban areas and plantation forests. Therefore, the vast majority of indigenous forests on the West Coast are protected by mandate of the Conservation Act 1987 and will not be subject to any sustainable management proposals. Furthermore, approximately 50% of all lowland (under 600 m ASL) is formally protected. Similarly significant areas within Tasman District are protected. In addition, TWCL have identified many areas within its own management estate which have particularly high ecological or scenic values compared to the balance of the estate, and these areas will also be reserved from production.
The location of the forests subject to this application are shown on Map 1. Forests subject to the application have been divided into groups of forests known as "working circles". Each working circle consists of several forests of similar characteristics in terms of forest resources. The three working circles subject to this application are shown on Maps 2 - 4.
Sustainable Timber Yield and Growth Model
The regulation of timber yield is a complex process based on the modelling of the forest resources in terms of their patterns of growth and death. The sum of the forest increment and mortality represents the total turnover of biomass in the forest. The yield of trees that may be harvested from a forest, while maintaining a near-natural forest structure and ecological function under ideal conditions over the long term is called the 'sustainable yield', which is equivalent to net increment. The permissible harvest in this proposal is set significantly lower than the net increment (50%) to provide a wide safety margin.
The permissible harvest forecasts for individual tree species are derived using a deterministic growth model for uneven-aged forest similar to that developed by Usher (1966). Data is derived for each species across the entire working circle, which includes several forests and forest types. This provides an average representation of forest structure that provides a global permissible harvest for the working circle.
The data can be subdivided for individual forest types and reinforced by more localised inventory within operational units for determination of annual compartmental yields. Over the felling cycle additional inventory data will enable stratification of more specific forest type characteristics and stand specific yield calculations.
The Royal Forest and Bird Protection Society recently commissioned a Landcare Research critique of TWCL's modelling (Evaluation of model evidence for sustainability in Timberlands West Coast plans, Landcare Research Contract Report LC 9899, 1998). Their investigation involves reconstructing a similar growth model using TWCL input data. Their primary conclusion is that the TWCL model has a hidden bias and as a result "the proposed scheme is unlikely to be sustainable".
As explained later in this report, TWCL considers that Landcare's conclusions are wrong and are not soundly based.
TWCL has used adjusted the Landcare Model to reflect the prescribed management covered in this application. The outputs and more importantly additional sensitivity modelling confirm TWCL's original expectations that critical forest structural components and function can be maintained indefinitely within the bounds of variation that occur naturally.
TWCL's plans specifically note the need for regular review of both model systems and input data as it becomes available over the next 10 to 15 years. However, the current model and data limitations are being managed within a conservative set of starting assumptions, and integrated into an adaptive management framework. TWCL believes that the very low rates of timber removal in conjunction with all of the safety margins and mitigation measures incorporated into its proposal will more than adequately avoid, remedy or mitigate any adverse effects on the forests and forest ecosystems involved.
The sustainable beech management proposal has been designed to allow very low intensity harvesting of beech trees within the limits of natural variation of the forest. There will be only minor effects on the environment from the activity. The objective is to ensure the status quo is maintained in terms of natural processes and overall biodiversity within forest ecosystems. Predator & pest control and other mitigatory actions will not guarantee a reversal of the present nation-wide decline in numbers of some threatened species. Historically, these trends have been ongoing and in the absence of direct management intervention to reduce pests and predators would continue to occur irrespective of the proposed management regime. A brief summary of the potential environmental effects (based on the matters to which the Buller District Council has restricted its discretion) and how these are addressed in the proposal are as follows:
Effects on Water Bodies, Wetlands and Riparian Margins:
TWCL has identified stream side protection zones where timber extraction and roading activities will be strictly regulated. Design criteria for river crossings are also included to ensure fish passage is maintained and physical disturbance of water ways minimised. The method of timber extraction will minimise sediment mobilisation, while road construction and storm water control will be undertaken in a manner which protects water ways and any wetland areas.
Effects on Habitats of Any Threatened and Protected Species:
The low intensity of harvest, retention of large trees providing nesting habitat for birds and bats, protection of riparian margins and waterways, and reservation from production of areas with particular identified habitat values of special significance will ensure there are no significant adverse effects on the habitats of threatened or protected species.
Effects on Archaeological, Cultural or Historic Sites within the Extraction Area:
Known sites have been identified and mapped, while protocols have been put in place to ensure archaeological, cultural and historic sites which are inadvertently discovered during operations are adequately protected.
Protection of areas of Outstanding Natural Features and Landscapes:
Identifiable areas discovered through ground or aerial survey have been accorded protected status where appropriate and landscapes in general have been protected through the low-impact nature of the proposed operation.
Protection of areas of Significant Indigenous Vegetation and Significant Habitats of Indigenous Fauna:
The areas of West Coast indigenous forests with the most significant vegetation and habitat value have already been identified and included in the conservation estate through the West Coast Forest Accord process. TWCL has gone further to identify and reserve from production additional areas within its estate. These measures in association with the low intensity operations proposed will ensure protection of areas of significance, and will ensure that any effects on other areas are avoided or adequately mitigated to the extent that adverse effects will be minimal.
Effects on Ecological Functioning and the Life Supporting Capacity of Air, Water and Soil and Ecosystems:
The proposed low intensity nature of operations, harvesting of trees over a range of diameter classes (i.e. not just the large trees), deliberate retention of a proportion of felled trees and woody material on-site to retain sufficient nutrients from decomposition, and other management measures, will protect the ecological functioning of the forest ecosystem and the life supporting capacity of air, water and soil. In addition, proposed management of even-aged "recovery" forests which have been subject to previous natural disturbance or logging are likely to show improved ecological functioning as stands are returned to a more mixed age structure.
Effects on the Intrinsic Value of Ecosystems:
As well as protected identified areas of special value and reserving these from production, the management system by its very design and low intensity will protect the intrinsic value of ecosystems.
Effects on Recreational Values:
To a large extent the areas of highest recreational value are in the conservation estate and are not affected by this proposal. Recreational values within the Timberlands estate will be protected by reserving from production areas of particular identified value. Those areas not reserved from production will be subject to minimum disturbance due to the low intensity of helicopter extraction, large time period between extraction events in the same area (10 – 15 years) and relatively short periods when extraction operations are conducted in each area. There are also likely to be benefits for recreation with areas not undergoing operations being available for a wide range of recreational activities, some of which are not permitted in the conservation estate.
The Location, Extent and Methods Employed in Harvesting Operations:
The operational methods and management system to be employed have been designed to have minimum impact on the environment. This includes the use of aerial helicopter extraction, directional felling techniques, tree selection by suitably qualified professionals and canopy gap size and distribution modelled on natural occurrences.
Any effects on the environment can be adequately avoided, remedied or mitigated. In addition, management provides the opportunity for improvement in the forests, particularly with regard to improving the structure of recovery forests so as to achieve old growth forest structure more quickly, as well as providing at least equal commitment to predator and pest control in the sustainable management estate compared with the average which occurs in the adjacent areas of indigenous forest estate.
A range of mitigation measures are proposed to ensure any adverse effects can be avoided remedied or mitigated. These measures range from general forest management objectives and operational policies through to specific controls, some of which will be incorporated into consent conditions. Mitigation measures are included in full in Section 8 of this report:
Extensive monitoring programmes and audit processes are also proposed in conjunction with the opportunity for formal review of consent conditions if that is required. These processes are detailed in Section 9 of this report.
Timberlands West Coast Limited (TWCL) seeks resource consents to undertake sustainable management of Crown owned beech and beech/ podocarp forests within Buller and Tasman Districts during a 35 year term. Sustainable management will involve extraction of trees from a range of diameter classes at a rate and in such a sustainable manner so as to ensure that extraction does not exceed the natural rate of replenishment of the forest. It is designed so that the forest ecosystem processes and associated resources are maintained in perpetuity, and so as to ensure that the forests are managed sustainably in terms of the Resource Management Act 1991 (RMA).
Extraction of beech and small quantities of rimu trees will be selective and almost exclusively by aerial extraction by helicopter, and will not involve clear felling. The forest management approach proposed is designed to ensure timber harvesting has minimal impacts on forest areas. It is a passive rather than active management system, aiming to maintain a continuous forest cover by following closely the size and pattern of natural gaps.
The applications cover three groups of forests known as "Working Circles". Each working circle consists of several forests with relatively similar characteristics in terms of forest resources. The three working circles subject to this application are:
1.2 TWCL Forest Management Mandate
The forests covered by this application are owned by the Crown and are managed by TWCL which is a state owned enterprise. The basis for managing the forests is set out in the West Coast Forests Accord 1986 and the Deed of Appointment 1991 (by which TWCL was appointed by the Crown to manage the indigenous production forests).
The West Coast Forests Accord was an agreement put in place to address environmental concerns over the overcutting of indigenous forests, and facilitated a mutual agreement between conservation interests, industry and local and central government. The agreement provided for the establishment of a large new network of reserves and a National Park (Punakaiki), while at the same time providing for the supply of indigenous timbers in perpetuity through sustainable management of beech and rimu.
The Deed of Appointment from the Crown requires TWCL to manage the indigenous production forests so that the volume logged in any 15 year period will not exceed the growth increase of the managed forest in that period. The proposal which is the subject of this application is conservative in that it aims to ensure that no more than half the growth increment will be taken.
Approximately 78% of the West Coast land area is managed by the Department of Conservation (DOC), with only 6% of the area available for sustainable indigenous management by TWCL. The remaining land area is used for agriculture, urban areas and plantation forests. Therefore, the vast majority of indigenous forests on the West Coast are protected by mandate of the Conservation Act 1987and will not be subject to any sustainable management proposals. Similarly within the small areas of production forest within the Tasman District large surrounding tracts are protected. The production areas abut Nelson Lakes National Park to the north-east, Kahurangi National Park to the north-west and the Lewis Pass Scenic Reserve to the south. Within the West Coast region, approximately 50% of all lowland (under 600 m ASL) is formally protected. TWCL have also identified many areas throughout its own management estate which have particularly high ecological or scenic values compared to the balance of the estate, and these areas will also be reserved from production.
1.3 TWCL Sustainable Management Plans
TWCL has prepared a sustainable management overview plan for all of the indigenous beech production forest estate on the West Coast, and has developed specific sustainable management plans for each of the working circles subject to these resource consent applications. These documents have been prepared to meet the requirements of the Forests Act 1949 as amended in 1993. They also provide additional supporting background information for this application, but do not form part of the applications. The resource consent applications have been framed within the context of the RMA rather than the Forests Act though they must comply with both. They necessarily include both additional controls and some changes to the prescriptions included within the TWCL plans particularly with respect to responses TWCL have made to the Crown run submission process of October 1998. Therefore, it is not appropriate that the TWCL plans actually form part of the applications. The TWCL documents referred to and cross referenced from time to time in this application are:
Part IIIA of the Forests Act 1949 (inserted by the Forests Amendment Act 1993) requires any indigenous forests on private land to be managed in accordance with a sustainable management plan approved by the Director General of the Ministry of Agriculture and Forestry (MAF). However, TWCL managed land is excluded from Part IIIA, and as such the Minister of Agriculture and Forestry cannot grant a formal Part IIIA approval to TWCL operations. Notwithstanding this, TWCL has submitted its overview and sustainable management plans to MAF, and obtained formal written notification that the plans as written are compliant with the intent of part IIIA of the Forests Act.
Sustainable forest management is defined in the Forests Act as:
"the management of an area of indigenous forest in a way that maintains the ability of the forest growing on that land to continue to provide a full range of products and amenities in perpetuity while retaining the forest's natural values".
The sustainable management plans include statements of how the forests will actually be managed. These statements are called "prescriptions", and are included throughout the plans in various subject areas. The prescriptions form the basis of TWCL's management objectives, operational policies and specific controls for sustainable management for the beech forests subject to these resource consent applications. The specific proposed mitigation measures based on these are included in this application.
1.4 Audit Requirements
The role of internationally recognised certification of forest management has gained prominance in recent years as a way of establishing global performance standards or criteria for the management of forests. Two current processes are ISO 14001 and the Forest Stewardship Council.
1.4.1 ISO 1400l Environmental Management System
In recent years there has been a strong thrust to develop internationally recognised, credible forest management and product certification systems. TWCL has recently achieved certification for its Environmental Management Systems under ISO14001. This certification confirms the ability of the company to demonstrate that the targets and actions prescribed in its management systems are being met. Retention of this certification requires regular external auditing and public disclosure of outcomes.
1.4.2 The Forest Stewardship Council (FSC)
A second vehicle for accreditation developed from the work of international non-governmental organisations (NGOs) and businesses has been the Forest Stewardship Council (FSC). This process is widely promoted by many of the international NGOs including World Wide Fund for Nature (WWF) and Greenpeace. The core of the FSC system is a series of nine Principles of Forest Management (see p. 10 of TWCL Sustainable Management Overview Plan) against which natural forest management operations should be audited and certified.
TWCL, mindful of these criteria, have sought to develop a management system that could be accredited under the FSC system. Part of the FSC process requires active participation with environmental NGOs, and some of the New Zealand NGOs have indicated a willingness to work constructively with forestry companies to assist the certification process. Organisations such as Forest and Bird would be included in this process if they wished to continue to have a say in the process after consents have been issued. TWCL will also be mindful of maintaining compatibility with and certification under other potentially relevant systems such as the "Pan European" system currently being developed.
1.5 Objectives of Management
TWCL has defined the following objectives for the sustainable management estate:
2. APPLICATION AREA
2.1 The Physical Resource
2.1.1 Land Description
The legal descriptions of the land subject to this application are included in a schedule in Appendix 3, Volume 2, and are also included in Section 1.3 of each working circle sustainable management plan.
2.1.2 Working Circles
The total beech resource allocated to TWCL for sustainable management comprises approximately 98,500 hectares. The estate is inclusive of 31 distinct and discontinuous land areas located from near Karamea in the north to the Arnold River (north of Greymouth) in the south, and from the coast eastward to the Maruia Valley near the Lewis Pass. Areas of relatively uniform forest composition, landform, geographic location and operational cost structure have been amalgamated into five forest groupings, each of which will be managed as an independent sustainable working circle. Three of these five working circles are the subject of this application.
The sustainable management working circles covered by this resource consent application are:
The Grey Valley Working Circle forests, which straddle both sides of the Grey River valley. They are geographically centred on the township of Ahaura and are located on dissected infertile hill country. The forests are dominated by mixed hard beech / hardwood / podocarp forests with smaller quantities of red beech on more fertile valley bottoms and terraces, and silver beech on cold or drainage impeded sites. Parts of this working circle are located in Grey District, and are not subject to this application, with the balance being located within Buller District.
The Inangahua Working Circle forests are geographically centred on Inangahua township and straddle both sides of the valley. These areas are more diverse, being a mixture of dissected hill country, glacial outwash terraces, alluvial terraces and heavily broken limestone country. Reflecting this diversity, the forests have a more or less equal balance of the main beech species. All forests in this working circle are located within Buller District.
The Maruia Working Circle is entirely located in the Maruia Valley. Comprising Glengarry, Pea Soup, Shenandoah and Station Creek Forests, they are centred around the settlement of Maruia. This working circle is dominated by pure red and silver beech forest on a range of sites, with generally more fertile soils. The area has a drier, cooler more continental climate. Approximately 40% of this working circle is located within Tasman District, with the remaining part of Station Creek Forest being located within Buller District.
The locations of the forests within these working circles are shown in Maps 2, 3 and 4 within this document, as well as Map 4 in the TWCL Sustainable Management Overview Plan, and Map 1 of each TWCL Sustainable Management Plan.
2.1.3 Geology and Geomorphology
Although many rocks from which the West Coast is formed are extremely old, the region itself is geologically "young". The land has been uplifted, and the landscape developed from it, quite late in geological time. The development of the landscape has proceeded, and is proceeding, in two ways: partly by actual movement and deformation of the land longitudinally and vertically (particularly along the Alpine Fault), and partly by the sculpturing of its surface by erosion.
The movements of deformation have taken place very slowly, but they have been sufficient (in the course of hundreds of thousands of years) to raise the Southern Alps and to rough out the shape of the other main relief features. The movements have taken place by displacement of blocks of the earth's crust at faults and by warping and folding of the land surface. As deformation has proceeded, streams, rivers and glaciers in the Pleistocene ice age have carved the pattern of hills and valleys from the growing land. Today the most powerful erosive agents are streams and rivers (Ministry of Works, 1959).
The forests of North Westland can be found on a range of geomorphic forms, from steep mountainsides, to dissected and rolling hill country, to flat glacial and river terraces. The diverse underlying geology reflects the complex geological history of the area.
Further details relevant to each working circle are contained in section 3.1.3 of each relevant TWCL Sustainable Management Plan.
Generally speaking, the soils are moderately to strongly acidic. The high rainfall, open-textured and mainly shallow soils, and scrub or forest vegetation, which produces a rather sour litter, combine to produce soils of marked acidity. This is general throughout, though the more recent soils of the river flats are less acid than those on the older deposits (Ministry of Works, 1959).
Forest composition varies with soil conditions. Drainage determines forest composition on glacial outwash terraces. Red, silver and hard beech can all be present on freely drained sites. However, on poorly drained sites, red beech disappears, silver beech becomes progressively less important, and mountain beech and podocarps dominate.
The soils are capable of supporting a beech forest association of moderate productivity. Protection of the thin soil mantle and limiting nutrient losses will be important to the long-term capability of these soils to support forest ecosystems.
Further details on soils relevant to each working circle are contained in section 3.1.4 of each relevant TWCL Sustainable Management Plan.
Soil maps for each working circle are included in Maps 5, 6 and 7 of the TWCL Sustainable Management Overview Plan for the Grey Valley, Inangahua and Maruia Working Circles respectively.
Whilst parts of the West Coast receive an annual rainfall over 10,000 mm, the highest rainfall in the North Westland area is in the Paparoas, where the rainfall lies between 3,750 and 5,000 mm per annum. Not far away, in the Inangahua and Maruia River Valleys, the annual rainfall is 1,500 - 2,000 mm.
The temperatures and number of rain days are similar to western parts of the North Island, and this is reflected in the presence of some plant species, such as the nikau palm, which reaches its southern-most limit in Westland.
The West Coast has comparatively high sunshine hours, moderate temperatures with very few frosts, a rainfall well distributed throughout the year, and an absence of persistent strong winds (MOW, 1959). These conditions are ideal for temperate rainforest growth.
Further details on climate relevant to each working circle are contained in section 3.1.2 of each relevant TWCL Sustainable Management Plan.
2.2 The Biotic Resource
Three major broad forest types are recognised in these forests:
The forests of North Westland exhibit two generalised trends. From north to south, rimu becomes increasingly dominant until beech is totally absent south of the Arnold River near Greymouth. From west to east, podocarp/ hard beech gradually gives way to pure beech, with red beech and silver beech becoming dominant. Mountain beech assumes dominance at higher altitudes in most localities.
The beech forests of North Westland are contained within four subregions of the northwestern South Island region, as described by Wardle (1984). These are:
1. northwest Nelson;
2. south of the Karamea River only;
3. Buller; Paparoa-Inangahua; and, 4. Grey-Taramakau.
Wardle describes twelve general beech forest types. Only some are represented in the forests of North Westland. Those that are represented in the TWCL sustainable management estate are:
1. Mountain beech forests of the upper slopes;
2. Silver beech forests of the upper slopes;
3. Mid-slope silver beech-red beech forest;
4. Mid-slope beech-Metrosideros Weinmannia forest;
5. Pure red beech forest;
6. Hard beech-podocarp forest (NB. the black beech component of this type rarely occurs in these forests); and
7. Stunted beech-podocarp forest and shrubland.
In general, it is the natural preferences of the beech species that dictates their distribution. On dissected, well-drained but infertile hill country the forests are mainly dominated by hard beech. On glacial outwash terraces, drainage determines vegetation composition. Forest on the most freely drained sites is dominated by red and silver beech. On poorly drained sites, red beech disappears, silver beech becomes progressively less important, and mountain beech (which otherwise does not appear at low altitudes) increases (Coker, 1988).
The close interaction of the various species of beech with podocarps and associated hardwood understorey species is essentially a representation of broad trends in climate, aspect and topography operating at the 'macro' scale. A 'micro' scale of influence due to soil moisture, fertility, depth and structure underlies these patterns.
The forests of North Westland support an interesting and diverse wildlife in the wide range of habitat provided from the coast to the mountains and from wetlands to deep forest. As has occurred in the rest of mainland New Zealand, most native wildlife in North Westland has suffered as a direct result of colonisation. The single largest cause of the demise of most species in this region, particularly in the last decade, has been the cumulative effects from past introductions of predators.
Unlike many other parts of New Zealand, land clearance has not been as significant a factor in the lowering of faunal values in North Westland, with less than 15% being cleared for agriculture or exotic forestry compared with a national average of around 70%.
Nevertheless, within the indigenous forest matrix, extensive modification of parts of the estate due to past unsustainable logging and mining has led to fragmentation of habitat and a partial modification of forest structure. In particular the loss of large old trees thought to be critical to the habitat requirements of some specific bird species such as kaka and parakeet will likely have contributed to their localised decline. This process would have been most prevalent in the lower Grey Valley.
Introduced animals have had a major impact on native wildlife and, in some cases, on the forests themselves. Predators such as stoats, possums, cats, rats, dogs and even wasps have all been identified as contributing to an ongoing and serious decline in our native wildlife. Probable adverse effects from mice are also recognised but not yet measured.
Apart from birds and bats, other native wildlife includes fish, frogs, lizards, snails and insects, of which some species are rare. As part of the development of the TWCL proposal, single purpose inventories have been undertaken to benchmark avifauna, bats, and reptiles while existing databases have been used for fisheries and new research undertaken with respect to insects.
Specific research work undertaken on native fauna is summarised in Table 1 below.
Table 1: Fauna Survey Work
A number of New Zealand’s native bird species are now declining in population at a rapid rate and several species are at risk. Morse (1981) suggested that mammalian predators were the prime cause of the decline in wildlife (native birds) which began in the early 1860s. This trend is continuing, with some species now approaching rare and endangered status even in the short time since Morse wrote her report.
Morse (1981) lists the species known to have occurred in Westland at the time of European settlement which is shown in Table 2 below. This summary of earlier survey data has been confirmed by the more recent surveys.
Table 2: Inventory of Bird and Bat Species Known to Have Been Present in Westland (at the time of European settlement – Morse, 1981)
** Declined in 1860s but have made a good recovery and are now relatively common.
The avifauna/ bat surveys undertaken between 1995 and 1999 (Buckingham et al, 1994-99) have been the most comprehensive undertaken over large areas of West Coast forests. They cover the forests of Paparoa and Granville in the Grey Valley working circle, all of the Maruia working circle and the forests of the Inangahua working circle.
The surveys have provided important data on the distribution, numbers of species and relative abundance of species and are reported separately. Overall, these surveys confirmed the existence of a number of nationally important bird species at various but generally low densities in the forests surveyed. The exception was in parts of Maruia where parakeet numbers in some locations reached high levels.
Further details relevant to each working circle are contained in section 3.2.2 of each relevant TWCL Sustainable Management Plan.
The sustainable management estate is within the catchments of the Grey, Maruia and Buller Rivers. All three are major freshwater fisheries for both native and introduced fish species. A review of fisheries resources and management impacts upon them (Ryan, 1997) was undertaken utilising records from the West Coast Fish & Game Council and the National Institute of Water and Atmospheric Research (NIWA) database. The databases showed that the general densities of native fish species in or around the beech forest working circles were low. However, of the ten species present, the Department of Conservation considered four to be threatened in some way. Table 3 below summaries the status of the species found (i.e. level of endangerment).
Table 3: Fish Species Present in or Adjacent to Beech Working Circles
The sample is from 146 electric fishing machine samples.
Status refers to the Department of Conservation’s classification of endangered species.
Not Considered Endangered = NCE
Conservation status = A, B, C
The vulnerability of fish species in timber production forests almost universally relates to matters of water quality, sedimentation and temperature. In intensively managed and harvested production forests, changes in “instream” and adjacent riparian fauna abundance and productivity can also lead to significant adverse effects upon instream fauna. Under the low intensity management system proposed only water quality, sedimentation, and temperature factors are considered relevant risks. The primary objectives of management that will apply across all working circles will be to avoid or minimise any alteration to the status quo of current stream habitat conditions.
The locations of sampling sites where native fish species have been identified are shown in the TWCL Sustainable Management Overview Plan in Tables 10A - 10D (pp.42,43), and Map 8 of the same Plan. As well as the actual presence of fish, rivers important either directly for fisheries breeding habitat or indirectly as important feeders of such streams, have been documented as shown on Maps 8 and 9 of the TWCL Sustainable Management Overview Plan.
Further details relevant to each working circle are contained in section 3.2.3 of each relevant TWCL Sustainable Management Plan.
A survey of the habitats of the Grey Valley and Maruia working circles (Whitaker, 1997) and Inangahua (Whitaker, 1999) in relation to the presence (particularly) of rare lizards was completed. Data from other sources was also compiled to give an overview of the species likely to be present in the production estate and their vulnerability to management systems to be utilised in the harvest of wood.
No rare or endangered species were found, though expected lizard species were found generally throughout the forest areas and in both modified and virgin forest habitats. The primary objective of management will be to avoid the creation of any situation that could increase the use of the forest habitat by competing predators.
Two lizard species of conservation concern are known to occur within the indigenous forests of North Westland. These rarer species were not located during the surveys which only found forest geckos and green geckos in DOC conservation estate land adjacent to production forests. The results of the 1997 survey are summarised in Table 4 below. Data from the recent Inangahua survey followed the same pattern as before with numbers being extremely low. Data from this survey is available on request.
Table 4: Reptiles Present in the Geographic Region
There have been neither comprehensive nor systematic studies of native invertebrate fauna in New Zealand’s indigenous forests, let alone the West Coast. The reason relates mainly to the sheer magnitude of effort required for systematic survey, the lack of an appropriate standardised method to objectively assess large areas and the fact that basic taxonomic descriptions are very incomplete. There are species not yet even properly described. Their status is unknown in relation to population stability or viability. A few localised studies have been undertaken in various locations on the West Coast. Some rare invertebrates have been found. Referral to DOC databases show no rare or endangered species were known within the sustainable management estate.
TWCL commissioned Lincoln University (Evans, Keesing & Frampton, 1996) to conduct a series of tests of forest sites disturbed by past conventional or coupe logging operations ranging from those felled recently to over 40 years ago. The results of that study and a subsequent more recent comparative study are discussed in the assessment of environmental effects section of this document.
2.3 The Commercial Resource
2.3.1 Previous Inventory
At least three ‘global’ forest inventories have been carried out to assess the merchantable (recoverable) volume from these forests. The first was the National Forest Inventory of 1923. This was superseded by a much more controlled and methodical survey, the National Forest Survey (NFS), of 1946-55. The third was the Beech Survey, carried out in the 1970s and
updated at various times throughout the last 20 years (Coker, 1988). None of these surveys was intensive enough to provide a detailed and reliable estimate of the structure, composition and recoverable volume of the forests covered by the TWCL Sustainable Management Overview Plan; neither was the data they produced suitable for interpretation for current or future potential markets. This problem was highlighted during the course of the 1986 West Coast Forest Accord deliberations when a lack of appropriate inventory data resulted in only rough and much down graded estimates of recoverable volume being made for these forests. New comprehensive inventories were completed throughout the Grey, Maruia, and Inangahua working circles during the period 1993-1996. The inventory system incorporated both full MARVL plots (Method of Assessment of Recoverable Volumes by Log Grades) and associated temporary RECCE vegetation plots (Floristic Reconnaissance Plots), over a total of 784 random sampling points. Analyses of inventory records are the basis for describing forest volume and composition.
The total volume from new inventory studies represents a substantial increase on 1986 inventory volumes because it includes the total growing stock across all tree sizes and all grades of logs irrespective of utilisation and marketing factors.
2.3.2 Previous Logging and Catastrophic Disturbance
Many parts of the estate have been subject to the combined effects of severe natural disturbance (Murchison earthquake 1928, Inangahua earthquake 1967) and/ or human disturbance over the past 150 years. Mining, past logging and fires have today significantly affected approximately 58% of the sustainable management estate (TWCL managed indigenous forests).
Much of the most severely modified areas are designated ‘recovery forests’ and will require many years or even decades of recovery before a tall forest reclaims the site. A different management regime is proposed for these forests, which, if harvesting occurs, should assist these forests in attaining a more stable and multi aged structure more quickly than would occur if management did not occur. In the interim, a recoverable yield based on a low intermittent harvest is calculated for such areas. It is calculated independently from the growth related yield applied to the “old growth” forests. Once the recovery forests have attained a more mixed-age structure and full biomass, eligible forest areas will be incorporated into the old growth forests and the management regime for those forests.
Some forests logged many years ago for mining timber have recovered to a full forest structure. These forests are included for sustainable management but the silvicultural approach takes cognisance of their youthful character. Over the next 150 years they will progress towards a structure approaching that of mature beech forest.
Logging under the New Zealand Forest Service administration has taken place in various forests, particularly in the podocarp-dominated forests, and also in beech forests at trial sites logged during the late 1970s by the Experimental Utilisation and Management Unit. These sites are in various stages of regeneration.
Some research harvesting trials of beech forests have occurred in the Paparoa, Maruia and Granville forests. This harvesting has involved helicopter extraction except in the Maruia where both helicopters and low ground pressure tracked vehicles were used. Mining operations are having an impact on the valley floor forests, especially in those of the Grey Working Circle. Sites cleared are often not regenerating well and many have become choked with gorse. Difficulty has been experienced in ensuring site restoration to beech species once mining operations are complete.
Details and locations of forests in each working circle subject to past modification are included in Section 3.3.1 of each TWCL Sustainable Management Plan, and are shown on the Maps in Appendix 8 (Recovery Forests).
2.3.3 Forest Descriptions The forests within each working circle are subdivided into forest ‘types’, utilising ecological forest descriptions, volumetric data and visible characteristics from aerial photos.
At the time of the forest inventory, survey methods were applied to gather information about the nature and composition of the vegetative components of the forest ecosystems. Using computer analysis that sought to differentiate forests by the associations of plants that occurred and various site parameters, it was possible to determine a number of ‘vegetation associations’ within each working circle.
The analysis was undertaken with the intention of providing:
Further details of forest types relevant to each working circle are contained in section 3.3.5 of the relevant TWCL Sustainable Management Plans.
2.3.4 Forest Volume Composition
Inventory data has been applied to describe the forest in terms of volume and tree numbers by species to provide a basis for biological resource description independent from the commercial volumetric description.
The total volume and stocking of the estate as derived by recent inventories is collated in Section 3.3.3 of each TWCL Sustainable Management Plan. These figures are not reproduced in this document, as actual stem numbers and standing volume recorded while relevant for detailed operations planning, are not considered particularly relevant to describing the sustainable management concept, describing the proposal and formulating appropriate mitigation measures. The inventory system utilised the MARVL methodology adapted from exotic plantation methods to cope with multi species forests. Taper and volume table equations specific to the species were created from direct measurements.
The inventory can be presented in terms of tree numbers and volume. The former has been adopted specifically as a simple measure that provides a biologically correct means of yield regulation. This methodology provides resource data that is independent of commercial log grade definitions of the day and is thus timeless for audit purposes. The extensive database enabled a detailed analysis to be made of the relevant dominance of the numerous species making up the forests’ structure and their merchantable characteristics.
For forest volumes, computer algorithms can be used to calculate the proportions of log grades that can be expected from any defined requirement of forest managers and their market constraints. If market conditions or utilisation technologies change, log grade definitions can be redefined and the resource data run without any requirement to conduct new inventory. Limits of error range between 5% and 10% for major species components and higher for minor species. These variations are accounted for in precautionary margins and practices applied during the determination of the actual sustainable yield described later in this document.
Further details relevant to each working circle are contained in section 3.3 of each TWCL Sustainable Management Plan.
2.4 The Historical and Cultural Resource
The West Coast has a colourful history of saw milling and gold and coal mining dating back to the 1860’s. During those times many parts of the West Coast were subject to the activities of the early pioneers who used a wealth of ingenious technology to earn a living in many inhospitable sites, some of which occur within the boundaries of this production forest estate. Full records of all known registered historical sites are retained in a computer database. The locations of such sites are shown on Map 5.
While Maori undoubtedly used parts of the forests for food and possibly travelled near or through some of them, there have been no sites of significance officially identified to TWCL. During the Crown asset sales process in the late 1980’s, attempts were made to contact Maori representatives regarding waahi-tapu and no confirmations were received. Recent approaches have been made to Ngai Tahu, Te Runaka o Katiwaewae and Te Runanga o Makawhio, and again no specific sites of significance have been identified to TWCL. It is hoped that further liaison with iwi will assist in identifying any matters not currently anticipated.
2.4.1 Forest Recreation
Present and potential recreation and tourism use of the sustainable management estate includes: