Forest hydrology research in New Zealand

https://www.scionresearch.com/about-us/about-scion/corporate-publications/scion-connections/scion-connections-2/scion-connections-issue-34,-december-2019/solving-the-mysteries-of-forest-hydrology

Just heard the start of a radio interview with a rural fire research team, and had a carfull of groceries to unload so missed hearing it, but googled Scion as the name was mentioned. That led me to their blog and this extremely pertinent study seeking to ascertain the optimum species and spatial arrangements of forest planting as “passive” water storage.

It sounds really really important, as New Zealand’s largely-nationwide drought continues and is impacting water supplies for both city and rural populations as well as agriculture.

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Was that a National Radio interview? I’ll have to see if I can find it.

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I’m not sure. I had only just figured out how to use the car radio, and have given up trying to figure out the one at home :). I guessed so.

Yes, Scion and NIWA are working together on that project. Unfortunately they make it sound like there has been little work done on forest hydrology in New Zealand since the 1970s, which is is simply not true. See this paper for example.

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Thanks, and is any of it being disseminated and/or acted on? I dont know where to turn to learn how to best manage weed control and moisture retention in “my” volunteer patch of urban forest Reserve, or who to talk to, and had come to the conclusion that while my uneducated impressions and practices are largely correct, there is no authority to seek advice from. Auckland Council have not responded to my requests for advice, and only lately through the News subsequent to current events have I become fairly sure I am not imagining the dire state of the local environment here on North Shore Auckland.

EDIT: The practical issues that concern me are on a microscale from the sort of research I referred to in the original post, but I am hoping studies have, or will, shed light on how to stage weed removal so that minimal moisture is lost from the soil through disturbing or exposing it to sun and wind, tree canopy extends as fast as possible to shade the ground and slow rainfall’s descent, and ground is covered with vegetation (alive or dead) that will slow the runoff, allowing as much as possible to be absorbed, and minimising erosion and pollution…without creating a lot of dry material that can actually prevent water reaching the ground, I think?

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So, basically that study found that planting radiata pine forest dries up the stream?

EDITED after more thought: And that is the sort of thing that is requiring more study as their is a perception that planting will reduce water available for agriculture (downstream?), whereas the shade of the trees retains soil moisture in the catchment, and the vegetative filtration reduces pollution of the water supply - so it is not known what the best practice is - is that right?

Is the radiata pine a New Zealand plant?

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Californian, introduced in 1859. In it’s home range it is a fairly slow growing tree, but here in New Zealand and under cultivation practises, it grows extremely quickly. circa 10 year cycles, from memory

from booklet FRI#124-12 Pinus Radiata:

Radiata pine is a North American species, belonging with P. murtcata and P. attenuata to a group of closely related pines known as the Californian closed-cone pines. Though in its natural range it occupies only about 7000 ha and is of little commercial significance, it has, as an exotic, become one of the world’s major commercial forest trees. Its fast growth, ease of raising in the nursexy and transplanting, and the versatility of its wood, make it the utility softwood of choice wherever it can be grown satisfactorily. It now occupies around 3.5 million hectares of plantation. including nearly 1.2 million ha in New Zealand, slightly more in Chile, nearly 700,000 ha in Australia, around 220,000 ha in Northern Spain, and nearly 55,000 ha in South Africa. Lesser areas have also been planted in several European countries, in Argentina, and at high altitudes near the Equator. In total, this represents about 500 times its natural extent. In New Zealand it has become by far the most important commercial forest species, currently occupying about 90% of the total exotic plantation forest area.

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A plague we have in common then.

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