Land use capability classification of the Northland region: A report to accompany the second edition New Zealand Land Resource Inventory G. R. Harmsworth Manaaki Whenua - Landcare Research Private Bag 11-052, Palmerston North Landcare Research Science Series No. 9 Manaaki Whenua PRESS Lincoln, Canterbury, New Zealand 1996 © Landcare Research New Zealand Ltd 7 996 No part of this work covered by copyright may be reproduced or copied in any form or by any means (graphic, electronic or mechanical, including photocopying, recording, taping, information retrieval systems, or otherwise) without the written permission of the publisher. CATALOGUING IN PUBLICATION HARMSWORTH, GARTH. R., 1958- Land use capability classification of the Northland region : a report to accompany the second edition New Zealand Land Resource Inventory I Garth R. Harmsworth. - Lincoln, Canterbury, N.Z. : Manaaki Whenua Press, 1996. (Landcare Research science series; ISSN 1172-269X ; 9) ISBN 0-478-04531-X I. Title. II. Series UDC 631.474(931.268) Cover: View west across the Kaipara Harbour, towards the southern Kaipara sand barrier north of Helensville. The sand country is bounded by Rangtira beach on the seaward side, and by the Kaipara Harbour, Omokoiti Flats on the inner harbour side. The estuarine flats in the foreground are classified as land use capability (LUC) units lllw2 and 1Vw2 with gleyed Kaipara and gleyed slightly saline Takahiwai soils. In the background are LUC units Illes, 1Ve9, the steeper sand-country LUC units Vle6, Vlle9, and the more unstable VllelO on the horizon. Editing by Anne Austin. Design and desktop publishing by Tony Pritchard. Published by Manaaki Whenua Press, Landcare Research, PO Box 40, Lincoln 8152, New Zealand. CONTENTS 3 Contents ·summary 6 Introduction 7 Purpose 7 New Zealand Land Resource Inventory 7 Application of the NZLRI 7 Northland region 9 Second-edition (1993) Northland region worksheets 9 Physical resources factors of the Northland region 11 Physiography 11 Climate 18 Rock type 19 Soils 19 Slope 22 Erosion 23 Vegetation 24 Present land use 27 Exotic forestry 27 Horticulture 27 Pastoral farming 28 Undeveloped land 28 Future trends 29 Land Use Capability classification 30 LUC class 30 LUC subclass 30 LUC unit 31 LUC suite 32 Productivity data 33 Previous LUC surveys in the Northland region 33 NZLRI data in district and regional planning 33 Land Use Capability suites 36 Keys to recognition of land use capability units 36 LUC suite 1: Coastal sand country 36 LUC suite 2: Alluvial and estuarine plains and low terraces 45 LUC suite 3: Quaternary terraces with complex soils 54 LUC suite 4: Sedimentary rock terrain (excluding greywacke) 60 4 CONTENTS LUC suite 5: Greywacke terrain 74 LUC suite 6: Young basalt volcanic terrain 81 LUC suite 7: Old volcanic terrain 87 LUC suite 8: Cliffs and precipitous slopes 100 Land use capability unit descriptions 105 Acknowledgements 235 References 236 Appendices 1. Areas of LUC units, LUC subclasses and LUC classes 241-243 2. Areas of LUC units, LUC subsuites and LUC suites mapped 244-47 3. Correlation tables for 1 st edition and 2nd edition LUC classifications in the region 248 4a. Stock carrying capacity data and site index data (for Pinus radiata) for LUC units in the region 249-251 4b. Stock carrying capacity ranking 252 4c. Pinus radiata index ranking 252 5. Stock carrying capacity data and site index (for Pinus radiata) for LUC units grouped into LUC subsuites and LUC suites 253-255 6. Publication details of NZLRI data and NZLRI worksheets in the region 256-257 7. Bibliographic references for 2nd edition 1 :500 OOO NZLRI worksheets 258-259 8. Aerial photographs used in the 2nd edition NZLRI in the regions 260 9. Geological maps used in the NZLRI update of the region 261 10. Soil surveys used in the NZLRI update of the region 262 11. Vegetation maps used in the NZLRI update of the region 263 12. The NZLRI New Zealand rock type classification 264-265 13. The NZLRI slope classification 266 14. The NZLRI erosion classification 266 15. The NZLRI vegetation classification 267-269 CONTENTS 5 Tables 1. Relationships between lithology-terrain and erosion for the Northland region. 25 2. Area of LUC classes of the Northland region, compared with the North Island. 31 3. Areas of LUC subclass limitations mapped in the Northland region. 32 4. LUC suites, subsuites, and component LUC units in the Northland region. 34 5. Idealised cross-section showing relationship between LUC units within LUC suite 1, on 38 coastal sand country. 6. Idealised cross-section showing relationship between LUC units within LUC suite 2, on 46 alluvial and estuarine plains and low terraces. 7. Idealised cross-section showing relationship between LUC units within LUC suite 3, on 55 Quaternary terraces with complex soils. 8. Idealised cross-section showing relationship between LUC units within LUC suite 4, on 62-63 sedimentary rock terrain (excluding greywacke). 9. Idealised cross-section showing relationship between LUC units within LUC suite 5, on 76 greywacke terrain. 10. Idealised cross-section showing relationship between LUC units within LUC suite 6, on 82 young basalt volcanic terrain. 11. Idealised cross-section showing relationship between LUC units within LUC suite 7, on 89 old volcanic terrain. 12. Idealised cross-section showing relationship between LUC units within LUC suite 8, on 100 cliffs and precipitous slopes. Figures 1. North Island NZLRI regions. 8 2. Location of the North land region (NZLRI region 1), showing position of NZMS 260 map 1 0 series. 3. Main locations and physical features of the Northland region. Auckland City marks the 12 southern boundary of the region. 4. Major rivers and lakes of the Northland region. 1 3 5. Major physiographic units (generalised) in the Northland region of New Zealand. 15 6. Components of LUC classification. 30 7. Location of LUC suite 1. Coastal sand country. 37 8. Location of LUC suite 2. Alluvial and estuarine plains and low terraces. 47 9. Location of LUC suite 3. Quaternary terraces with complex soils. 56 10. Location of LUC suite 4. Sedimentary rock terrain (excluding greywacke). 61 11. Location of LUC suites. Greywacke terrain. 75 12. Location of LUC suite 6. Young basalt volcanic terrain. 81 13. Location of LUC suite 7. Old volcanic terrain. 88 14. Location of LUC suite 8. Cliffs and precipitous slopes. 101 6 SUMMARY Summary The report describes the second-edition Land Use Capability (LUC) classification 2 of the Northland region, an area of 1 582 698 ha (15 827 km ) in the north of the North Island, New Zealand. This region is one of 11 in the New Zealand Land Resource Inventory (NZLRI). The NZLRI provides a physical-resource inventory for land-resource and land-use planning, particularly for evaluating the potential of land for sustained production, using the Land Use Capability system of land classification. Fieldwork for the second-edition worksheets at 1 :SO OOO scale began in 1985 and was completed in 1990. A total of 11 718 inventory map units were delineated in the Northland region. These map units were grouped into 91 LUC units on the basis of their management requirements, soil conservation needs and land-use potential. The LUC units have been arranged into eight LUC suites - groupings of LUC units which, although differing in capability, share a definitive physical characteristic that unites them in the landscape. Within LUC suites, LUC units are further grouped into LUC subsuites according to features such as micro-topography, rock­ type characteristics (e.g. composition, age) soil type, erosion potential, wetness, and management. A description of Northland region's physical land resources is provided, as well as a key to the recognition of LUC units in LUC suites, and descriptions of each LUC unit. Introduction Purpose isation (NWASCO), later the National Water and Soil Conservation Authority (NWASCA), by the The purpose of this report is to explain the basis Water and Soil Division, Ministry of Works and of the second edition New Zealand Land Resource Development, and later by DSIR Land Resources, Inventory (NZLRI) Land Use Capability (LUC) Palmerston North and Christchurch. Present­ classification of the Northland Region, and to dayupgradingis carried out by Landcare Research describe the land use capability units delineated. under contract to the Foundation for Research, The report accompanies 26 worksheets (maps) of Science and Technology. the Northland region at 1 :SO OOO scale. This report is not intended to be an exhaustive description of the land resources of the region; New Zealand Land Resource Inventory rather it describes the region's physical resources (NZLRI) in terms of land use capability. A number of The NZLRI is a national database of physical earlier publications have fully documented the land-resource information. All NZLRI data are physical and social resources of the region, for stored on a computer in a geographic information example the Northland Regional Development system managed by Landcare Research. This Resources Survey (Northland Regional Develop­ provides the versatility to produce worksheets ment Council and Northland Regional Planning (maps) of various scales and tables in response to Authority 1978a,b). specific requests from users. NZLRI information was first published as a Two sets of data are on the Land Resource series of first-edition Land Resource Inventory Inventory Worksheets: worksheets at a scale of 1 : 63 360 (1 inch to 1 mile) (NWASCO 197S-79), together with support­ of the five physical factors (rock, 1. An inventory ing documents. soil, slope, erosion and vegetation) that are basic Many first-edition NZLRI worksheets have to the assessment of land resources. The physical been updated or remapped as second-edition factors are represented by symbols, in a standard worksheets at 1: SO OOO scale, which correspond layout: with New Zealand Mapping Series (NZMS) 260 Rock type - Soil unit- Slope group series topographic maps.