Solving the mysteries of our landscape through time travel

One of the steepest sections of the gully

First published on http://www.catherineknight.nz

Last weekend, we entered a time machine, which took us back in time about 18,000 years to a much colder version of the Manawatu – the last glaciation period. And we did this by walking just metres from our house. We were fortunate to have as our time-machine guide Professor of fluvial geomorphology Ian Fuller.

This bit of time travel solved a number of mysteries that had drawn on my curiosity for some time.

As I have described in previous posts, to access our gully stream, we walk down a spur from our paddocks (on a river terrace), with sheer drops on either side. The top of the spur is made up of a loose mix of soil and stones, the sort of material you would expect to see on a river flood plain. But the spur is 20 metres higher than the current streambed – could the stream at one time been a surging torrent so voluminous it had scattered river gravel across the spur?

With an expert at our disposal (not literally obviously – we are nice to our guests!), we discovered the more likely explanation. Our river terrace, now tens of metres above the Pohangina River, was once the flood plain of a braided river, bringing huge quantities of greywacke rock down from the ranges in its wandering currents. This braided river flowed during the glacial maximum – 18,000 to 20,000 years ago, when glaciers was last at their maximum extent, and otherwise known as the last glaciation. Aotearoa New Zealand was quite a bit bigger then, and joined up as one island (see this map) – which would have been handy if there had been any people around to enjoy the convenience!

As well as being a lot colder, the landscape was quite different then – instead of the dense forest that greeted our island’s first settlers 700 or so years ago, the landscape was a mosaic of grassland and shrubby plants, with patches of beech and a few scattered conifers. See vegetation map from Newnham, Wilmhurst and McGlone (2013).

From Newnham et al. (2013). ‘The vegetation cover of New Zealand at the Last Glacial Maximum’, Quaternary Science Reviews

The second mystery that this bit of time travel solved was how a relatively small stream that can go dry in the summer months could have carved out such a cavernous gully of 20 metres depth. Well the answer, in very simple terms is this. As our islands started to warm after this last ‘cold snap’, the Pohangina River, which our stream is a tributary to, started to cut down into the soft mudstone land. As it did so, the stream also needed to cut down to keep up (or more accurately, down) with the river, probably through the gradual shifting of a waterfall into the river upstream, or, in fluvial geomorphologist language: ‘the mechanism was probably the headward retreat of a waterfall, initiated by incision of the main river’. … What I said.

Here, the stream has carved out pools in the mudstone.

The exciting thing is, we still have that waterfall, though it now comes out of a concrete culvert rather than a natural channel. It is likely that it cut back to this place, an area of particularly hard and stable rock, and because of its relative stability, engineers chose this place to build the road over the stream a century or so ago, piping it through a culvert. Thus, the waterfall has been ‘frozen’ in time, unable to cut back any more.

The waterfall, now unceremoniously piped through a concrete culvert, thanks to roading engineers of a century ago

“Nature and Wellbeing” is launched into the World!

Totara Press launched “Nature and Wellbeing in Aotearoa New Zealand” on 12 November in Wellington, with attendees coming from far and wide: Auckland, Hamilton, Bay of Plenty, Hawke’s Bay and even Christchurch. Thank you all for coming and for making the event such a success! We were so fortunate to have Professor Bruce Clarkson as our launch speaker, ably supported by Caitlyn Madge. Here are some photographs of the evening, taken by Bob Zuur. (Click right arrow to progress through slideshow.)

New book urges for more nature in our cities

The author’s daughter at a grove of kohekohe trees on the Kapiti Coast. Catherine Knight

In her new book examining the link between nature and wellbeing, environmental historian Dr Catherine Knight explores the benefits of nature experienced by everyday New Zealanders, and argues for more nature in the places where most New Zealanders live – our towns and cities. 

In New Zealand, we think of ourselves as a country rich with nature, but the fact is that most of our surviving forest and pristine waterways are concentrated in the most mountainous parts of the country. They’re preserved not as a result of careful stewardship, but rather an accident of history: it was just too hard to develop and economically exploit these rugged, inaccessible places. Our lowland landscapes are largely bereft of any forests, wetlands or any nature in its original form.

Read more of this article on The Spinoff.

New book exploring nature and wellbeing in New Zealand

I am very excited to announce the emergence into the world of my latest book Nature and Wellbeing in Aotearoa New Zealand: Exploring the connection (Totara Press).

This comes as the culmination of three years of research, interviews and writing, but in many ways, could not be more timely. The experience of many New Zealanders during this year’s Covid lockdown has only served to underscore how important access to natural spaces are – for both body and mind.

To find out more about the book, visit the Totara Press webpage.

Details on launch coming soon!

Christchurch’s “Garden of Tranquility”

rocks in the Recovery Garden
“Tomorrow is a new day”: A rock in the Recovery Garden

Christchurch, and especially its Red Zone, it a veritable hotbed of nature and wellbeing projects – the topic of my latest book. A vast area in the eastern parts of Christchurch as well as a number of inner city sites were deemed too risky to reoccupy following the February 2011 earthquake. While this has had tragic consequences for those many people who had to say goodbye to their homes, gardens and neighbourhoods forever, it has created a unique opportunity – unique not only within the context of New Zealand and its history, but also a rare opportunity anywhere in the world. I explored this in my 2016 book New Zealand’s Rivers. Continue reading

‘New Zealand’s Rivers’ is impressive for its scope, clarity, poignancy and power

Rivers coverIt is a daunting to have your work reviewed by someone as well respected in the field of environmental history as Graeme Wynn, Professor Emeritus in Geography, University of British Columbia. A relief to find it is a positive review, and an very nice indeed to read his assessment that “Catherine Knight is set fair to take her place among the country’s leading environmental historians”. Continue reading

‘Komorebi’ – sunlight filtering through leaves

skyward-view-of-kohekohe-grove
Light through the leaves of a kohekohe grove in Waikanae, Kapiti Coast. C. Knight

As part of my literature review for my book exploring the connection between nature and wellbeing in New Zealand, I have been reading Shinrin-yoku: The art and science of forest-bathing, by Dr Qing Li, who has researched the subject extensively in Japan.

Shinrinyoku LiIn describing the Japanese experience of spending time in a forested environment, he draws the reader’s attention to the Japanese word ‘komorebi’, 木漏れ日 in Japanese characters, meaning ‘sunlight filtering through leaves’ (木 = tree, 漏れ = leak through, 日 = sun). Continue reading

“Beyond Manapouri is an important, highly readable and hard-hitting book”

Beyond Manapouri cover webI am thrilled with Shaun Barnett’s review of “Beyond Manapouri: 50 years of environmental politics” in this month’s Backcountry Magazine, particularly given that Shaun himself is such a talented and well-respected writer of NZ non-fiction.

His review concludes:

“Knight writes succinctly, clearly and convincingly. Continue reading

Nature & wellbeing in NZ – case study ideas please

nature_and_wellbeingAs you may have seen from an earlier post Can you help? The connection between nature & wellbeing  I am interested in exploring the connection between nature and wellbeing as the subject of my next book. In that earlier post, I asked for help finding existing literature on the topic, particularly in the New Zealand context. And I got some super-helpful responses, so thank you so much to everyone who responded! Continue reading