PROGRESS

When alien vegetation takes over, the problem just grows… and grows… and grows. Local plants are smothered, cut off from light and nutrients. This is why alien clearing is such an important element of our restoration work — like tackling the spreading bamboo in this video.

 

Documenting change in vegetation growth is a notoriously tricky visual problem. We use Google Earth, as well as ground level images, and drone pictures (when we can get them) to record our work. And we’ve joined a global movement that tracks restoration change, Restor, which helps us provide from-the-air visuals of our site. Check back to see how things change over time.

Where we’re working

LEFT: Our working sites. The initial pilot project sites are A: The Top Dam and Wetland; B: The Bamboo Forest and C: The Dell and Glade. Others have been added since. D is Twinstreams; E is the 2023 Arbour Month Event Area; F is Cussonia Place; G is the Waterfall Trail; H is the border of the primary forest; I is Holey Hill & Lower Twinstreams. RIGHT: A map from Plant-for-the-Planet, detailing most trees planted by December 2024. Each tree is a dot. More detailed examples will be added to the progress site areas as they are updated below.

The Dell

A beautiful stretch of indigenous forest along a stream that flows during the summer rainy season. There are mature trees to help form a canopy, but the understory has been decimated. Plants such as snake lilies and ferns have disappeared; and saplings are being crowded out too. Cestrum, an alien tree, grows skywards and then falls upon older trees, crushing and destroying them even as it send out new shoots. Almost every plant you see in this photograph is alien to South Africa. (2021 image: Vanessa Stephen)

Update 2023: The battle against Inkberry and Ginger continues, but both have been dramatically thinned. This has allowed more light for invasive groundcovers and creepers: the next challenge.

  • Area size: 11,280 square metres
  • Percentage alien vegetation: 40%
  • Top alien species present: Kahili ginger lily; Ink-berry; Lantana
  • Area size: 11,280 square metres
  • Percentage alien vegetation: 36%
  • Top alien species present: Kahili ginger lily; Ink-berry
  • There is far less Kahili Ginger Lily in many places, but Cestrum remains an issue. We are thinning this slowly.
  • Trees planted: Lemonwood, Real Yellowwood, Forest Natal-Mahogany, Black Stinkwood, Forest Cabbage Tree
  • Understorey species planted: Plectranthus, Club moss, Clivia, Large-leaved Dragon Tree
  • Area size: 11,280 square metres
  • Percentage alien vegetation: 25 - 30%
  • Top alien species present: Kahili ginger lily; Ink-berry; Tradescantia fluminensis (a groundcover), Jasmine; Cats Claw creeper; Indian Shot
  • The Kahili Ginger Lily is still present in places, and seedlings need continuous weeding. Groundcovers are the next problem now that the ginger is giving way. Cestrum has been thinned. Invasive Privets have also been ringbarked.
  • Trees planted: Lemonwood, Real Yellowwood, Forest Natal-Mahogany, Black Stinkwood, Forest Cabbage Tree, Crossberry
  • Understorey species planted: Various varieties of Plectranthus and ferns, Club moss, Clivia, Large-leaved Dragon Tree

Top dam

The Top Dam is an old municipal dam which was leased by Connor’s father many years ago. The watercourse has dried up a lot over the years, so it has become much shallower, and aliens extend around it and march up Corridor One. It is, however an important place for local wildlife, which visit the dam to drink. It is a key area for restoration as there are a number of mature trees here and some interesting understorey species. A key aim was to clear the Mauritius Thorn creeper kills trees, and start work on understorey invaders such as the ginger lilies. You can see the edge of the bamboo forest to the right, which is far more ragged in 2024.

On the left is an area that is a homogenous green: this was almost all Mauritius Thorn that is now being returned to a wetland, bisected by two streams (2022). See the change in the ‘texture’ of the landscape in the drone image taken in 2024.

  • Area size: 5, 834 square metres
  • Percentage alien vegetation: 60%
  • Top alien species present: Bamboo; Ink-berry; Mauritius thorn; Bugweed
  • Area size: 5, 834 square metres
  • Percentage alien vegetation: 50%
  • Top alien species present: Bamboo; Ink-berry; Lantana (new seedlings); Bugweed (new seedlings)
  • Trees planted: Henkel's Yellowwood, Forest Elder, Pompon, Cape Fig, Waterberry, Real Yellowwood, Searsia Chirendensis, Quinine, White Ironwood, Tree Fuchsia, Forest Cabbage
  • Understorey species planted: Grasses, Plectranthus, Arum lily
  • Area size: 5, 834 square metres
  • Percentage alien vegetation: 45%
  • Top alien species present: Bamboo; Ink-berry; Bugweed (new seedlings), Kahili Ginger
  • Trees planted: Henkel's Yellowwood, Sneezewood, Forest Waterberry, Forest Elder, Pompon, Cape Fig, Waterberry, Real Yellowwood, Searsia Chirendensis, Quinine, White Ironwood, Tree Fuchsia, Forest Cabbage, White Pear, Wild Plum
  • Understorey species planted: Grasses, Plectranthus, Arum lily
  • Dramatic change is visible in the Wetland, left of the Top Dam. This area was blanketed with Mauritius Thorn, which has been 90% eradicated. The more shaggy look to the landscape is an indication of different species and ages of trees. The bamboo to the right and top of the Top Dam is much reduced: culms left for shade are obscuring some change. The trees planted here are doing well. The area above both the dam and wetland, along 'Kanji's Road', has seen Cestrum, Lantana and Mauritius Thorn drastically thinned and dozens of trees are becoming established.

The Bamboo Forest

Beautiful, ethereal bamboo is swallowing every inch of this area. Skeletons of forest bushwillow and a handful of giant survivors remain. It’s a complete monoculture and is growing all the time. Time to beat back the tide! In the image below, the Bamboo Forest can be seen extending up from the bottom of the drone shot. The crowns of just a couple of trees remain. (Drone images: David Southwood)

By 2023, we had cleared around 15% of the 3ha Bamboo Forest with the help of an independent company. The cleared area grew a little more in 2024, but regrowth remains voracious and uses up a lot of resources in the wet summer months. The borders have been contained, however, and trees are becoming established. We will continue to focus on ensuring the survival of the last mature indigenous trees, and the trees planted in the bamboo, as well as slowly clear water courses/riparian zones in this area.

  • Area size: 30,675 square metres
  • Percentage alien vegetation: 90%
  • Top alien species present: Bamboo (surprise!); Bugweed
  • Area size: 30,675 square metres
  • Percentage alien vegetation: 80%
  • Top alien species present: Bamboo (surprise!); Bugweed, Cat's Claw
  • Trees planted: Outeniqua Yellowwood, Real Yellowwood, Henkel's Yellowwood, Quinine, Cape Beech, Pigeonwood, Forest Elder, Pompon, Cape Fig, Lemonwood, Wild Plum, Horsewood, Forest Gardenia, Tree Fuchsia, White Ironwood, Forest Bushwillow, Forest Waterberry, Natal Forest-Mahogany, Forest Croton
  • Area size: 30,675 square metres
  • Percentage alien vegetation: 76%
  • Top alien species present: Bamboo; Bugweed, Cat's Claw
  • Trees planted: Red Currant, Forest Cabbage Tree, White Stinkwood, Outeniqua Yellowwood, Real Yellowwood, Henkel's Yellowwood, Quinine, Cape Beech, Pigeonwood, Forest Elder, Pompon, Cape Fig, Lemonwood, Wild Plum, Horsewood, Forest Gardenia, Tree Fuchsia, White Ironwood, Forest Bushwillow, Forest Waterberry, Natal Forest-Mahogany, Forest Croton, Crossberry
  • Progress is slow in that the bamboo regrowth must be continually cut in the wet summer months. But certain border areas are recovering and the plant is contained.
  • Area size: 30,675 square metres
  • Percentage alien vegetation: 72%
  • Top alien species present: Bamboo; Bugweed, Cat's Claw
  • Trees planted: Red Currant, Forest Cabbage Tree, White Stinkwood, Outeniqua Yellowwood, Real Yellowwood, Henkel's Yellowwood, Quinine, Cape Beech, Pigeonwood, Forest Elder, Pompon, Cape Fig, Lemonwood, Wild Plum, Horsewood, Forest Gardenia, Tree Fuchsia, White Ironwood, Forest Bushwillow, Forest Waterberry, Natal Forest-Mahogany, Forest Croton, Crossberry, Prunus africana, Kiggelaria africana, Cryptocarya woodii, Allophylus dregeanus
  • The hope that regrowth would slow was not realised this year. Again, large amounts of resources were required to contain regrowth over the wet season. That said, we made some additional inroads. Certain trees have grown dramatically, as has undergrowth. Thinning continues, although we did not focus on many new areas in the bamboo this year due to the effort required to maintain these. The company harvesting bamboo was less active.
  • Tree recruitment: Yes! Forest Croton, predominantly.