Post Fire Rehabilitation

What we did - and what we’re doing - to restore the natural habitat at Featherbed after the Knysna Fires of 2017. And what we’re doing to prevent that horror from happening again.

Extent of the damage

The fires that swept through the Garden Route, and that raged for about ten days from the 7th of June, 2017, destroyed almost 20,000 hectares of the region, and, at Featherbed, reduced most of the vegetation to ashes.

Aerial photos of the reserve taken in the days after the smoke cleared reveal a largely charred landscape with only a few small portions of indigenous forest left standing - the forest on the mountainside above Needles Point and Coffin Bay, and the forest above the site where our restaurant had stood. (This came as no surprise: multi-species, evergreen, indigenous forests are always the most fire-resistant of habitats in the regions where they occur.)

Easily 95% of the reserve had been burned - and this included most of our visitor facilities. We were therefore forced to close for business while we took stock, and during the long eighteen months it took to rebuild what we’d lost.

We determined to build back, and to do it better than we’d ever done before.

New shoots

Despite the fact that almost everything had burned to the ground, we started to notice that new seedlings began sprouting within weeks of the inferno - and to us, they looked magnificent.

But it wasn’t all good news: in large areas of the reserve, the greatest number of seedlings that were germinating were those of the rooikrans or red-eye wattle (Acacia cyclops), which is an invasive alien that’s a particular threat to the fynbos of the Western Cape Province.

Rooikrans was brought from Australia to Cape Town back in the 1830s to stabilise the sand dunes of the Cape Flats, but, with no natural enemies in this country, every one of the many seeds they produced became viable, and the species began colonising large areas that had previously been covered by fynbos (Cape heathland or Cape macchia).

The rooikrans had spread to the Garden Route by the middle of the 20th Century, and by the ‘70s and ‘80s, even places as remote and protected as Featherbed had been colonised.

Although we began following a programme of cutting down as many rooikrans as we could in the early 80s, the invasion proved almost too much of a challenge - so the fires came as something of a mixed blessing: while they killed almost all the old rooikrans, they also burned the fynbos that had survived despite the onslaught of the invasive aliens.

Professional team

Good rains after the fires encouraged germination of all kinds of plants - indigenous as well as exotic - but the speed with which the rooikrans were sprouting was alarming. So, despite the fact that we have always taken advice from qualified and locally-knowledgeable environmental consultants, we decided that we needed to employ a full-time team on site to help us get Featherbed back on its feet.

This team included a qualified horticulturist with many years experience of the reserve and the Garden Route, as well as 14 labourers, who came to us with no knowledge or experience of the work they’d need to do.

Our hort and his ‘Aliens Team’ began their work about six months after the fires. (Yes, hort. It’s the nickname horticulturists around the world have adopted for themselves). In hindsight, we realised that six months after the burn was in fact just the right time for the team to begin its work - because by now (mid-summer) the seedlings had reached a workable size, and they were thus both easy to identify, even from a distance, and easy to grip and remove.

Weeding

In essence, the team’s job - at first - was to go over every inch of the reserve that they could get to, and to pull the rooikrans saplings out of the ground, roots and all. By hand. (Later on, when some of the plants got too big to pull by hand, they used a tool invented in South Africa for the purpose: the Tree Popper).

The team worked in blocks of 900 square metres - blocks which they marked for themselves and pegged out using 30x30 metre pre-cut lines - and rested after each plot was completed. Resting was necessary because most of the land at Featherbed is steeply sloped, and the team often had to climb considerable heights to get to their work.

When they got into the rhythm, though, the members of the team were usually able to finish each block in a reasonable period of time (varying depending on the degree of difficulty of the slope) - but one day our hort realised that they’d taken more than twice as long to cover less than a third of the usual area. So, curious, he marked out a square metre test plot, and personally pulled out and counted every one of the seedlings he found there.

There were 217 of them.

217 seedlings x 900 square metres = 195,300 future rooikrans trees.

Fourteen people pulled 195,300 invasive rooikrans seedlings out of one, steeply-sloping, 900 square metre block of land in less than one single morning!

Now THAT’S rehabilitation for ya.

Motivation

So how did the team stay motivated to keep going, to keep doing the same thing over and over again through those endless hours out there in the sun and the rain?

“Two or three days into the project, I asked them if they knew why we were doing this boring stuff,” said our hort. “And they didn’t. So I explained that invasive alien plants threaten the biodiversity of the habitats they infest - which threatens the local ecology as much as it threatens local economies, specially in tourism destinations like Knysna.

“But aliens also deplete our water resources and increase fuel loads, which causes wildfires to become far more damaging and destructive than the regular, lower-temperature veld fires that form part of the fynbos’s natural cycle.

“Simply understanding why we were doing what we were doing, and knowing that the job was bigger than any one of us, made all the difference, and the team remained motivated for the rest of the period of our contract,” he said.

Stabilising the slopes: Mats and why we removed them

Our first concern on seeing the exposed soil after the fire was that slippage might happen. It’s easy to understand why: the soil at Featherbed looks and feels very much like loose beach sand, and without plants to bind it, we were worried that it might wash right down into the lagoon. So, on received advice, we covered the slopes that we thought were most vulnerable with roll-on mats made of biodegradable netting filled with poplar-wood shavings, and we pegged them down to hold them in place.

But when our hort-friend looked carefully at what was happening beneath those mats, he found that:
(a) the germination rate for all seeds left in the soil after the fires (indigenous as well as invasives) was far lower under the mats than it was on the exposed slopes - which slowed down the entire rehabilitation project;
(b) the mats trapped the heat of the sun, which raised soil temperatures considerably (seeds don’t like that);
(c) the leaves of seedlings that did manage to germinate beneath the mats quickly became yellowed and unhealthy (chlorotic, or starved of chlorophyll), which caused those plants to grow only very slowly; and
(a) (d), the soil actually (in most places) held itself in place quite effectively on its own, thank you very much.

So we removed the mats, and, in those few places where we still felt we needed to protect the slopes against erosion, replaced the mats with lines of 30-cm diameter ‘sausages’ made of the same materials. We pegged these sausages down along the contours at intervals of between two- and four metres, and we worked the soil above each line into shallow, almost horizontal basins (‘swales’ in the jargon) to trap and hold any water that might seep down from above.

New planting

Although we quickly learned that our policy of minimum intervention worked best, we did find it prudent to speed up coverage of the ground in various places where the soil had been disturbed by construction.

We planted the swales above our ‘sausages,’ for example, and also planted the exposed ground along the cut-lines of our roads. For this, we chose the bitou bush (Osteospermum moniliferum - whose seedlings we harvested from the veld, and then grew on in our on-site nursery), and also a succulent groundcover called sour fig (Carpobrotus edulis), which we collected in the veld, but which didn’t need any special preparation: we simply cut ‘em and stuck ‘em in the ground, no irrigation required.

Biological control

It’s probably no exaggeration to say that South Africa is a world-leader in the science of biological control of invasive alien plants - and biological control agents are certainly helping us at Featherbed, especially where the rooikrans is concerned.

At around the turn of the millennium, the Biocontrol Research Programme of the University of Cape Town’s Plant Conservation Unit identified and released a gall midge (Dasineura dielsii) onto the invasive rooikrans trees of the Western Cape.

We were excited to find that a viable colony of these midges had survived the 2017 fires because we knew that the midge lays its eggs in the rooikrans’ flowers, and that, by feeding on the flowers, the larvae cause them to form galls rather than set seeds - which prevents reproduction.

The Plant Conservation Unit’s Prof. John Hoffman and two of his research associates visited Featherbed in April 2018, and then again in April 2019. After examining more than forty samples from each of two different sites on the reserve on each visit, they reported a dramatic decline in the number of viable seeds in the soil.

Reasons for this include:
(a) Predation - mostly by field mice and other small mammals that began to re-establish themselves at Featherbed within months of the fires;
(b) Removal - by 2019, we’d pulled out the seedlings that had emerged from seeds that had been resting in the soil before, during, and after the fires; and
(c) The rooikrans on the reserve had been prevented from forming new seeds during almost two decades before the fires - so the stock of seeds in the soil had become (at last!) a finite resource.

As our hort still likes to say - “Hearing Prof. Hoffman tell us that we were basically on top of our rooikrans problem was one of the most satisfying moments of my time at Featherbed.”

Bless.


Into the future

Although our hort and his aliens team left us after about 18 months of intense work, we’re acutely aware that the environment at Featherbed will need ongoing vigilance - and we’ve committed ourselves to keeping up their work for the sake of all the generations to come.

Biochar Seedballs Project

  • You can help us with our rehabilitation project when next you visit Featherbed Nature Reserve. Please click here for more information.

Our catalogue of life at Featherbed

  • Please visit Featherbed on iNaturalist.com to see images and our latest observations of the plants, birds, insects, and other life-forms at Featherbed.

Featherbed Co.

Remembrance Drive
off Waterfront Drive
Knysna

Postal Address:
PO Box 753
Knysna
6570

Tel: +27 (0)44 382-1693
Fax: +27 (0)44 382-2373
E-mail: bookings@featherbed.co.za