Vegetation management for fire safety during restoration of forest margin

Nature Talk
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Here in Kaipatiki, on the North Shore of Auckland, New Zealand, there are thousands of houses on forest and other reserve margins, with no fire breaks at all, and no vegetation management policy in relation to fire, I’ve been told in answer to queries to several departments of the city/regional land manager, Auckland Council.

In a volunteer manual weed control /restoration plot, since December 2018, I have been struck by the dryness of the (clay) soil as I try to dispose of dead plant material on the forest margin along an exposed and very sunny, windy ridge peak with a road and walkway along it. Anything brown or black on the ground becomes hot or at least warm to touch when the sun is out.

For a year I have been minutely considering and curtailing my manual weed control since finding that there is almost nowhere nearby that a significant amount of the resulting dry material will rot, in the dry soil conditions existing since Jan 2019.

There was a little rotting of the bottom layer of plant material at the soil surface during last winter, which was very short - there were only about 3 weeks in August when the ground was boggy, (usually its boggy for months), even further down the ridge, and only about 3 months (July-Aug?) when the ground wouldn’t be dry within a day or two of rain.

The soil is basically clay, acid from pre-homo sapiens kauri forests, of which fragments remain in some gullies.

In my restoration plot last summer (Jan-June 2019), the one place where I could put dry materials where they would conceivably rot was a patch of Tradescantia fluminensis under a dense stand of deciduous Erythrina x sykesii, creating shade during summer but invading the native canopy below and now scheduled for removal and/or poisoning.

In awe of the changed conditions and last year’s and the current wildfires in New Zealand, I would appreciate any thoughts, experiences or suggestions about any of this.

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In the Western Cape invasive aliens are felled. Gathered in heaps to dry out and shed seeds. Then on days very carefully chosen for the right weather conditions - stack burning to reduce fuel load, and make it possible for indigenous seeds to reclaim the space with the next rain.
We do also have firebreaks along the urban edge.
But still HUGE swathes, especially on private land, which need clearing before they cause or encourage the next awful fire.

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Thanks Diana. Interesting that you have fire breaks. I realised a year ago that according to Fire Service recommendations after the South Island fires which threatened outer suburbs of Christchurch, semi-rural areas ie outskirts of cities, should be treated as rural. I assume that recommendation has not yet been pursued.

I feel we should have them here, esp. as the roads are too congested and the housing too dense for rapid evacuation of the area. When it first occurred to me I was horrified at the idea of the valuable native trees, which would include some of our “iconic” and already threatened kauri.

Apart from that, trees and shrubs grow rapidly along the margins in most of the backyards, and are pruned or felled, and thrown into the Reserve or left at the bottom of the garden, which due to the in-fill housing of the last 20-30 years is right beside the houses.

This at least seems like something we could change. I myself am considering clearing out what is effectively the margin of the forest floor in our back yard, since we have trees right up to and overhanging the house.

But the downside of that is increased dessication of the ground, since I have for years placed dead wood to cover bare clay, in the expectation of contributing to humus to maintain moisture for the existing trees, some of which are wet-loving nikau, and to assist development of the locally native understorey plants.

I could pay to have such materials removed, as some people do, esp. for the tidiness of their front yards.

Up till now the feedback on my concerns has been that because this is a city, rural fire prevention advice does not apply. And with huge trees and years of accumulated pine litter both in our tiny backyard and the neighbours’, such efforts may be irrelevant.

How wide are your fire breaks? And how are they kept clear - ie are any plants allowed to grow there, or is it bare earth, or what?

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I would be, truly terrified to dump garden waste between my garden and forest! There is good advice about firescaping out of California.
You can see a little more about firebreaks here
https://www.inaturalist.org/observations/dianastuder?utf8=✓&q=banksia&search_on=&quality_grade=any&reviewed=&geoprivacy=&identifications=any&captive=&place_id=&swlat=&swlng=&nelat=&nelng=&taxon_name=&taxon_id=&day=&month=&year=&order_by=observations.id&order=desc&rank=&hrank=&lrank=&taxon_ids[]=&d1=&d2=&created_on=&site=&tdate=&list_id=&filters_open=true&view=map

Sorry for the ugly URL. On the firebreak between the houses and Table Mountain National Park four tall Banksia are intensely visible.

I wonder if I can link a photo here? Fire on one of our mountains.
https://2.bp.blogspot.com/-kC6st2TLtiI/VqjOtkOoEHI/AAAAAAAASw4/srOhdJOTJt0/s1600/C%2BGlencairn%2Bto%2BFish%2BHoek%2Bfire%2BJanuary%2B2016.jpg

I have many blog posts about fire. It is a fact of life here.
https://eefalsebay.blogspot.com/search?q=fire

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perhaps a bit unrelated, but some small farmers here are starting to recommend rotating multiple species of livestock with their crops as a means to improve soil health. the ideal livestock seem to be a grazing animal (cattle, sheep, goats) first, followed by chickens, the grazers clear the old vegetation and turn it into fertilizer, insects help break it down more, and then the chickens come through and clear out the insects and aerate the soil as they peck. after that, new crops are planted and are supposed to do really well. it’s supposed to really improve the soil over time and also reduces the need for pesticides.

i wonder if this kind of practice could be applied to small restoration areas? the crops here would be be whatever your native plants are. the grazers essentially mow your land to help with fire management, and you can add chickens if your local bird population isn’t sufficient. together, the animals improve the soil for healthier plants.

you’d probably have to manually clear out certain toxic plants like Erythrina (without herbicides) before you send the animals in though. a tree puller often makes quick work of pulling out small woody plants.

EDIT: this just came on the radio after i fnished this post:
https://ww.npr.org/2020/01/05/792458505/california-cities-turn-to-hired-hooves-to-help-prevent-massive-wildfires

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Thanks Diana. I have already read the NZFS advice re landscaping, and that’s the issue - there is no vegetation management for fire prevention by the largest local land manager, the council, who “manage” the forest and roadsides and many other public spaces here. My restoration plot is on Council land, and I have asked for advice from Council, and found that out.

Last year I rang the local Fire Service asking if it was Fire Watch season, and what guidance they had, and the person who responded was mystified. He said there is no fire watch season in the city.

In the last week there has been a lot of publicity about fire threats to semi-urban areas in Australia, and yesterday an article saying that all NZ currently has dry soil conditions hence increased fire risk. So hopefully the wheels of government both national and local are creaking into action.

My own response has been to cease weed control to avoid creating more dead vegetation, while trying to maintain existing soil moisture, encouraging the growth of live vegetation esp. the less flammable species for shade reducing surface heat on the ridge along the roadside, while avoiding having more dry material on the ground.

The conundrum seems to echo the large-scale issues:

  • weeds tend to produce dead material, so removing them has to be timed so they rot rather than dry, and the current extended dry season makes that problematic.

  • On a dry ridge, the native plants that grow spontaneously will tend to be the highly flammable manuka and kanuka

  • removing dry dead material, either in the bare areas outside canopy or in the forest itself where canopy is thin, exposes the ground to more sun and evaporation, stressing the existing small trees and halting growth of seedlings.

Even dead material placed in the forest under shade of tall trees showed little sign of rotting over the last year.

If the council were to undertake fire-preventive vegetation management, they would take some time to learn the current situation, eg the years of dead weed vine around dead or dying trees hidden by live weed vine, and to plan and co-ordinate its removal and disposal.

Hopefully this will start before NZ is much drier.

Much of what I have read so far echoes what I learnt as a child as campfire safety, so I will look at your links, thanks, at a later time when I am less emtionally reactive.

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What you describe sounds like the ordinary “mixed farming” of England 60 years ago, and common-sense to me.

Some NZ “lifestyle block” and small farmers with an interest in sustainability are now doing this sort of thing, thankfully.

I had to smile at the idea of introducing animals to my restoration plots though …it is on urban Council land with formal Reserve status, and our native forest evolved without mammals except two species of bat, and is not adapted to any grazers at all. The local forest types are dry kauri ridge and lowland streamside forest, both of which develop slowly and densely, often with many plants per sq metre from ground to canopy. And chickens scratch up every bit of it! I used to keep them on a large suburban property next to the forest, some of which was in our garden", and they are veritable forest-destroying engines if they escape into it.

An interesting thought in the long-term though. We certainly need to maximise food-production as well as native conservation, and how best to arrange that is an interesting subject.

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Oh, and I think the first people to inhabit NZ, about 1000 years ago, found very little to eat among the native plants. They brought with them a root vegetable, “kumara”, and planted that, ate bracken roots and shoots and berries of some smaller tree species, but I don’t believe any native species was ever cropped by the first settlers or the subsequent European settlers… Would be interested to know of any …@kiwifergus Do you know?

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I’m not aware of exactly what they did eat when they first arrived, but there would have been no shortage of birds, eel, kai moana (sea food), and given that a substantial part of their diet would have been from the sea back in the islands, I imagine that they would have found similar to eat here. Initial settlements would have been coastal… and it would only have been when travelling across the interior or during times of hardship that they would have turned to fernroot etc. Plants like puha (Sonchus oleraceus) and scurvy grass (Lepidium oleraceum) would have been known to them from their homeland.

You’ve peaked my curiosity, I am going to have to research into this now!

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We have the Gantouw Project, using eland to browse shrubs and make space for smaller plants (bulbs, orchids, annuals)

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and apologies for asking for exactly this, then refusing to look at it at the moment! The right time will come.

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yup… i was thinking fences would keep animals from getting in the forest, but i guess no fence is guaranteed to keep 100% of things in (ex. https://www.inaturalist.org/observations/36424174).

i was also thinking that the grazers and chickens could create/maintain a fire break for you in the near term and possibly improve the soil for new growth in the long run. but if all the native vegetation in the area is slow-growth, then the animals might just turn the grazed area into a barren wasteland primed for invasives. so that might not be great.

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You don’t need courage … my view is mostly from later … Look fire lilies and fresh green and hoofprints!!

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Thanks Diana, I had alook - very pretty place! So the photo was taken from a town, or city? How far from the fire, and do fire restrictions and/or landscaping precautions apply there? Is that where you live?

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Thanks Diana, that is a link to four of your Banksia observations - is that what you intended? Is the area with scattered small trees or shrubs and lots of dry ground cover the fire break?

I couldn’t log into iNat there for some reason - I use the .NZ portal usually - but I was going to comment on one that they are a very common street, garden and park tree in my neighbourhood. (Maybe not the same species but look just the same, including the cones).

Are the Banksia invading your fire break?

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Nice website! I wpondered what fynbos looked like. Before you had mentioned it in the other current thread re wildfire, I had thought “fynbos” was an IT term, a bit of code or something! I must have seen the word a lot on iNat and didn’t understand the context.

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It is a suburb of Cape Town. We live further up the valley, a few houses from the urban edge, which is Table Mountain National Park.

We are not obliged, but encouraged, to be prepared for fire. We have lived here for 5 years, and in that time we have had fires burning on each side in turn.

Since the appalling fires in 2000 we have well trained teams of volunteer firefighters, who work with the various paid teams. Also Working on Fire teams who clear alien vegetation. Including high altitude teams to work on the cliff faces.

We try.

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Banksias are invasive aliens, escaped from gardens and horticulture.

On the satellite view you can see the firebreak as grey versus the greener vegetation.

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interesting, I don’t think banksia is invasive here - yet, anyway. I must look it up.

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Thanks for the explanation of the view, and the Working with fire teams. Our local coastal cliffs are particularly infested with exotic pine, Black Wattle/Acacia mearnsii and brush wattle, whose Latin name i always forget - and more recently Tree privet; and they have no control at all as there are no contracts for abseiling for weed control (unless the tree is a threat to people who walk underneath it - which is rarely the case on the coastal cliffs).

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