Threatened plants of beech forest.

Three nationally threatened mistletoe species, a threatened small tree and three forest floor herbs could potentially be found within beech forest in the application area. All of these species could be adversely affected if the proposed logging regime markedly changes forest structure.

The threatened beech mistletoes Alepis flavida, Peraxilla colensoi, and Peraxilla tetrapetala have all been recorded in the upper Maruia catchment. Alepis and Peraxilla colensoi have been recorded in Timberlands forests within the Maruia working circle, and Peraxilla tetrapetala is also likely to be present. Information from the Department's mistletoe surveys also suggests that the upper Maruia catchment is one of the remaining strongholds for beech mistletoes in North Westland. However mistletoes are not at the high densities found in South Westland which has been more recently colonised by possums. The two Peraxilla species have also been recorded in the Grey and Buller catchments and are likely to occur in the Grey Valley and Inangahua working circles. Peraxilla colensoi is found almost exclusively on silver beech hosts. Alepis flavida and Peraxilla tetrapetala are most commonly found on mountain beech hosts, but have also been recorded on red, silver and hard beech.

Although there has been no specific data recorded within the beech working circles, research by Canterbury University in other beech forest has shown that mistletoe are more likely to be found growing on large diameter hosts. In South Westland beech-hardwood forest about 50% of Peraxilla colensoi are found on silver beech hosts between 65 and 90 cm diameter. This preference for large trees is probably due to a combination of factors including greater use by seed dispersing birds, more establishment sites on large trees, and a longer time period for mistletoe to establish on large trees. Beech mistletoes are dependent on their host trees and die when their host trees die. Therefore the finding that mistletoe prefer large trees provides further support to the evidence presented by Colin O'Donnell for a reduction in the upper size limit for harvest of red, hard and silver beech to 80 cm diameter at breast height (dbh).

TWCL have suggested they will survey the actual frequency of felling mistletoe host trees and research ways to mitigate the impacts of harvesting on mistletoe species through recognition and avoidance of felling host trees. In addition to this survey, a condition of any consents granted should state that trees to be logged be searched using binoculars by staff trained in the identification of mistletoe. The presence of mistletoe on a tree should be a criterion preventing selection of that tree for harvest.

Because mistletoe, particularly small individuals, can be difficult to spot high in the canopy of a large beech tree even when using binoculars, it is inevitable that if this consent is granted some mistletoe trees will be logged.

A number of reasons have been suggested for the decline in mistletoe distribution and abundance. These include possum browsing and loss of pollinating and dispersing birds. As is the case for forest birds (which are mistletoe dispersers), mistletoe require both habitat (including large trees) and low numbers of pests to survive. Therefore forest management to maintain large diameter trees in the forest and possum control in locations where mistletoe are found in high densities should ensure the survival of mistletoe in these forests. The greatest benefits from any possum (or other pest control) would be achieved by integration with the Department's work in adjoining forested areas.

Pittosporum patulum is a threatened small tree which grows in subalpine scrub and beech forest understorey. It is known to occur in upland beech forest in the Matakitaki catchment and could occur in similar habitat in the Maruia working circle at altitudes above 800m. As this species is found in gaps in beech forest it is possible it may respond favourably to forest disturbance caused by logging. However, because of the rarity of the species, if it is located in the Maruia working circle a precautionary approach should be taken. Specific conditions of any consent should ensure this species is added to TWCL's threatened species manual, and that no logging should occur within 50m of locations where this species is found.

The small, inconspicuous, and rare herbs Gratiola nana and Ourisia modesta are typically found in shaded, damp, flat sites usually under forest. Gratiola nana has been recorded at a number of sites in the Grey and Inangahua Valleys including Fletcher Creek terrace in TWCL's Perserverance Forest. It is likely to be found in beech forest in all three working circles. Ourisia modesta has not been definitely recorded on the West Coast but it is scattered throughout the upper Buller catchments. Therefore it may be present in the application area, particularly in the Maruia working circle. The uncommon orchid Townsonia deflexa grows on mossy forest floors and probably occurs within at least the Inangahua working circle. Provided TWCL's forest management system maintains a similar forest structure to unlogged forest, and does not result in greatly increased gap formation, these species should persist should any consents be granted.

The forest herb Brachyglottis traversii is restricted to shaded damp rocks close to rivers from the Buller River north through Kahurangi National Park. It is likely to be found near rivers in the Inangahua working circle and therefore should be protected by suitable riparian protection zones which preclude logging and roading should any consents be granted. As referred to in Phillippe's evidence.


Threatened plants of open or grey scrub filled- valley floors.

Four nationally threatened shrubs (Coprosma wallii, Coprosma obconica, Melicytus flexuosus, and Olearia polita), a rare leafless mistletoe (Korthasella clavata ) a rare unnamed herb (Hypericum "Howard") and a threatened sedge (Carex tenuiculmis) could potentially be found in open or grey scrub-filled valley floors in the Maruia working circle. These species are known from similar habitat in the upper Maruia, Howard, Hope, and Glenroy catchments. As this habitat is often subject to frosts it is sometimes referred to as 'frost flat'.

The conversion of much of this habitat to farmland throughout New Zealand has led to a number of these species becoming nationally threatened. Some of the proposed new roads in the Maruia working circle pass through open valley floor or shrubland.

Accordingly, any consents granted should include a condition that the routes of proposed roads or road upgrades in the Maruia working circle be surveyed for threatened plant species which could occur there by people who are familiar with them, prior to construction. If any of these species are found appropriate measures should be taken to avoid disturbing these sites.


Threatened plants of limestone substrates.

Limestone occurs within the Inangahua and Maruia working circles. Limestone outcrops or bluffs are habitat for important specialist plant communities and species. Threatened species likely to occur in such locations include the unnamed prostrate shrub Melicytus 'Matiri', the herb Myosotis brockei, the sedge Carex impexa and the grass Simplicia buchanannii. It is also possible that linestone bluff areas may provide habitat for new species, as endemism is very high within these communities.

The colluvial apron below these bluffs, which is comprised of eroded limestone material, may provide habitat for important open grassland communities or forest understory species such as Carex impexa, and habitat restricted Myosotis species. It is therefore desirable that trees are not felled on or around any limestone bluffs or the associated communities on limestone colluvium below.

TWCL have recognised the high landscape values of limestone outcrops and bluffs, and the difficulties of harvesting from these sites, and accordingly propose to exclude them from harvest. The high botanical values of these limestone outcrops and bluffs, and the colluvial apron beneath the bluffs should also be recognised. Therefore a condition of any consents granted should be that the limestone outcrops and bluffs identified as reserves from production in the TWC application, and a 50m buffer round the base of the bluffs, be given formal protection through consent conditions that exclude these areas from logging.


Significance of indigenous vegetation within the application area
The joint council staff report considers that the forest areas do not contain significant indigenous vegetation because the forest areas within the application area were excluded from reserve status in the West Coast Forest Accord process and were considered appropriate for forestry extraction purposes. John Craig's report reaches a different conclusion using the criteria from section 4..7.4 of the proposed Buller District Plan. He concludes that these forests could be considered significant.

Two further points support John Craig's conclusion. These are the evidence I have presented on threatened plants which are known or may occur within the application area, and the fact that much of the application area is lowland forest (below 500m above sea level) of which only about 15% remains.

Even if all of the application area was deemed to be significant indigenous vegetation in the context of the Resource Management Act 1991, harvesting could still proceed provided it sustained the species and ecosystem functioning that makes these areas significamt.

Recommendations to ensure protection of threatened plants.

The following conditions should be included in any consent gratnted.:
Any records of the plants listed in Table One of this evidence from within the application area be provided to the Department of Conservation for entry to the national threatened plants database.

The upper limit for harvest of red, silver and hard beech should be reduced to 80cm DBH to protect the best potential mistletoe host trees. Timberlands models need to demonstrate that their proposed logging regime will maintain natural levels of trees of this size in the forest see Dean's note.

Trees to be logged should be carefully searched using binoculars by staff trained in the identification of mistletoe. The presence of mistletoe on a tree should be a criterion preventing selection of that tree for harvest.

Logging should not occur within 50m of any locations where the threatened tree Pittosporum patulum is found..

The routes of proposed roads or road upgrades in the Maruia working circle should be surveyed for threatened plant species that could occur there by people who are familiar with them, prior to construction or upgrade. If any of these species are found appropriate measures, such as changing the roadline, should be taken to avoid disturbing these sites.

The limestone outcrops and bluffs identified as reserves from production in the formal TWCL application, and a 50m buffer around the base of the bluffs, should be given formal protection that exclude these areas from logging.


Modelling

There has been considerable debate over Timberland's forest model, and an alternative put forward by Landcare Research. Because the Department does not have expertise in this area Associate Proffesor Bruce Manley, School of Forestry, University of Canterbury was contracted to review these two models.

His review, based on red beech in the Maruia Working Circle, is attached as an appendix to this evidence. In brief the review confirmed the Department's initial analysis that the major difference between the models is whether the natural tree mortality is subsumed into harvest or whether harvest is largely additional to natural mortality. This question cannot be answered without trialling the proposed harvest system, including testing whether Timberlands staff can accurately predict which trees are going to die during each 15 year felling cycle.

This conclusion is also reached in John Craig's report, and he suggests a more clearly defined experimental or adaptive management approach, including variable takes of 30%, 50% and 70% of net annual increment. I agree that such an approach would provide better information on the long term effects of logging. However, because this application is effectively an experiment, questions remain over whether the experimental treatment should be applied to the whole application area.

The Landcare model allows for compensatory growth and mortality of trees in response to logging. Varying these functions in the model can have a major impact on model outputs. Some information on compensatory growth and mortality can be obtained by using cores taken from trees. Rings from such cores can be counted and measured to observe responses to trees to natural canopy gap formation. Timberlands need to include this information in their yield models, or if necessary obtain further information from existing gaps in the different forest types proposed for harvest.

The debate over models, the apparent lack of information to feed into the models, and the fact that the application is effectively a large experiment, supports the Department's assessment that a precuationary approach needs to be taken in setting harvest regimes and to the term of the consent should and consents be granted.

References

de Lange, P.J.; Norton, D.A. 1997. New Zealand's loranthaceous mistletoes. Proceedings of a workshop hosted by Threatened Species Unit, DOC, Cass, 17 - 20 July, 1995.

de Lange, P.J.; Norton, D.A 1998. Revising rarity: a botanical perspective on the meanings of rarity and the classification of New Zealand's uncommon plants. Pp 145-160 in Ecosystems, entomology and plants. The Royal Society of New Zealand Miscellaneous Series 48.

de Lange, P.J.; Heenan. P.B.; Given, D.R.; Ogle, C.C.; Johnson, P.N.; Cameron, E.K.; Norton, D.A. 1999. Threatened and uncommon plants of New Zealand. New Zealand Journal of Botany 37: 603-628.

Dopson, S.R.; de Lange, P.J.; Ogle, C.C.; Rance, B.D.; Courtney, S.P.; Molloy, J. 1999. The Conservation requirements of New Zealand's nationally threatened vascular plants. threatened species occasional publication no. 13. Department of Conservation, Wellington. 194pp.

Ladley, J.J.;Kelly, D. 1996. Dispersal, germination and survival of New Zealand mistletoes (Loranthaceae): dependence on birds. New Zealand Journal of Ecology 20: 69-79.

Norton, D.A. 1997. Field guide to the threatened vascular plants of the Department of Conservation's West Coast Conservancy. Prepared for Department of Conservation, Hokitika. 79p.

Norton, D.A.;Ladley, J.J.; Owen, H.J. 1997. Distribution and population structure of the loranthaceous mistletoes Alepis flavida, Peraxilla colensoi and Peraxilla tetrapetala within two New Zealand Nothofagus forests. New Zealand Journal of Botany 35: 323-336.

Runkle, J.R.; Stewart, G.H.; McClenahen, J.R. 1997. Temporal changes in height and diameter growth for two Nothofagus species in New Zealand. Journal of Vegetation Science 8: 437-446.

Townsend, A.J. 1999. Pittosporum patulum recovery plan 1999-2009. Threatened species recovery plan 28. Department of Conservation, Wellington. 12 p.

Van Uden, S.; Lamoureaux, S. 1994. North Westland mistletoe presence / abundance survey 1993 / 1994. Unpublished report, Department of Conservation, Hokitika.

Williams, P.A.; Courtney, S.P. 1995. Site characteristics and population structures of the endangered shrub Olearia polita (Wilson et Garnock-Jones), Nelson, New Zealand. New Zealand Journal of Botany 33: 237-241.