027 550 0611The location of Northlands Tangihua Ranges
Tangihua Range is a prominent range situated in the centre of the Northland peninsula midway between Whangarei and Dargaville.
The Tangihua Complex a unique formation
For hundreds of millions of years Northlands peninsular has changed in shape and size and is continuing to do so, although so slowly that humans do not notice it happening. These changes are caused by sea levels rising and falling, tectonic plate movement and erosion. Tectonic plate movement causes great chunks of land to be lifted, lowered and twisted and it is this movement that created the unusual formations in Northland referred to as the Tangihua Complex.
The Tangihua Complex forms a series of ranges that extend down the eastern and central portion of Northland and includes the Tangihua, Tutamoe, and Maungaru ranges.
The Tangihua Complex began forming around 100 million years ago beneath the sea. Underwater volcanoes spewed out lava that turned to basalt rock on the sea floor. As time went on, further layers formed on top of this basalt. These layers included:
- Sandstone, which is formed by grains of sand being cemented together by time and the weight of the water and other layers above.
- Mudstone, formed by very fine-grained clay particles being deposited into water and settling to the bottom where they are buried and compacted by more sediment above.
- Limestone, an organic sedimentary rock that forms from the accumulation of shell, coral, algal, and faecal debris in shallow marine waters.
Tectonic plate movement creating the Tangihua Ranges
About 30 million years ago the movement of one tectonic plate overriding another created a widespread overthrusting of rock from the north-east. This movement can be compared to a giant bulldozer pushing dirt into a mound. Everything is scraped up and slowly rolled over and over, resulting in a complex mixture of sedimentary and volcanic rock. This is why different rocks and soil types are found mixed together in the Tangihua Ranges and areas around the ranges. An example of this is the patches of limestone in Waikeke, Omana Road and Maungakaramea that can be found surrounded by other soil types.
After being scraped and rolled, this rock was then forced upwards off the sea floor, eventually forming the Tangihua Ranges and other ranges in Northland. This process is referred to as the emplacement of the Northland Allochthon. During the formation of Northland and New Zealand into the land we know, hundreds, if not thousands, of volcanic eruptions occurred, spreading lava and ash across the land and leaving volcanic cones sticking up out of the landscape. From Horokaka some of these cones can be seen stretching in a line to the north-east. Some of the lava and ash from these volcanoes ended up on the Tangihua Ranges.
Since then, erosion has reduced the size of the ranges and changed the shape to what we see today. This erosion is also what has created the alluvial soils in the valleys.
Tangihua Ranges Topography
The landscape is nationally unique, but typical of many of Northland’s steeper ranges, which is why conservation agencies consider it so important.
The Tangihua Ranges are made up of 3,177 hectares of forest on steep, rugged terrain. The ruggedness of this area is why the forest still remains as it was too steep to be developed into farmland.
The main jagged ridge runs along the centre of the range, creating an impressive skyline. The range consists of 6 main peaks:
The peaks of the Tangihua Ranges
- A Whangai Mokopuna, the highest at 627m, is where the trig station is
- B Te Tohungia
- C Ruaroa, the northern end of the range
- D Horokaka, where the transmitter tower is visible at the top
- E Huarua, 421m high at far eastern end of the range, not visible in the picture
- F Notch or ‘the gun sight’ on the side of Whangai Mokopuna
The Tangihua Ranges vary in altitude from 46m to the 627m. The lowest point is at the Pikiwahine Stream on the southern side of the ranges near the entrance to the Tangihua Lions Lodge. The highest point is at the trig station near the north-western edge of the ranges. There are no higher points to the east or west of the ranges, very few to the north and none to the south until well past Auckland. That is why the view from the Horokaka mast, at 552m, is well worth the climb.
The Pikiwahine Stream starts deep in the Tangihua Ranges at an elevation of about 400m. From the edge of the forest, the water travels for 48km before entering the Northern Wairoa River that travels another 97km before entering the Tasman Sea on the west coast of Northland. This route was travelled by many Kauri logs during the years of Kauri Logging in the Tangihua Range.
Tangihua Ranges Climate
Northland has a subtropical/temperate climate that generally means warm, humid summers and winters that are wet but not too cold. There are always exceptions and one rather notable exception occurred in 2012 when snow fell on the Tangihua Ranges.
The prevailing wind in Northland is from the south-west so the Tangihua Ranges is often the first high points that weather systems hit as they come in from the Tasman Sea. The drastic increase in height from the surrounding land causes the air to be lifted up and cooled. This cooling process causes moisture in the air to condense and turn to rain. This effect means the Tangihua Ranges receives an average of between 1,200 and 1,600mm of rain annually, a higher amount than the surrounding flatter areas.
The highest point of the range at the trig is 627m. The lowest part of the forested range is 46m above sea level at the Pikiwahine stream by the entrance to the lodge. The Horokaka mast is 552m. There are no higher points to the east or west, very few to the north and none to the south until well past Auckland. This is why the view is so worthwhile.
Where the Pikiwahine stream meets the bush line is 48km (by stream and river) from the Northern Wairoa river and 145km from the sea. There are no real natural obstructions until the first waterfalls in the bush. The stream then climbs to about 400m before petering out.
The Forest on the Tangihua Ranges
For more information visit The Tangihua forest.
References
It is very apparent that specific information has been shared online between many organisations. Attributing to the initial source is impossible. As much as possible we use our own photos but this will take time and for extinct birds that is not possible. We have used the following websites as sources for our information:
- Department of Conservation
- Northland Regional Council
- Wikipedia
- T.E.R:R.I.A.N Taranaki Education Resource: Research and Information Network
- Te Ara The Encyclopaedia of New Zealand
- New Zealand Plant Conservation Network
- Landcare Research
