[imagesource: Haakdoorn Nursery]

All hail the humble spekboom, which is mightier than the Amazon when it comes to ‘sucking carbon’ out of the atmosphere.

Except, of course, for the fact that the statistic above comes with some caveats which need to be unpacked.

The Spekboom Challenge blew up in late 2019 and early 2020 (a simpler time), with people encouraged to plant 10 spekbooms (or Portulacaria afra, to get technical) over the course of the year.

There were many reasons for this, such as the plant’s water-wise requirements and resilience to harsh conditions, but it was the carbon dioxide capabilities that grabbed headlines.

Consider this from Getaway, back in 2019:

This carbon sponge can sequester more than 4 tonnes of carbon dioxide per year per hectare planted, making it more effective than the Amazon rainforest at sucking carbon dioxide out of the atmosphere. The unassuming-looking bush with its round, succulent leaves is especially good at photosynthesis (making plant food from sunlight), which produces a byproduct we desperately need: oxygen.

We also reported on the Spekboom Challenge, and the hype around the plant, in early 2020.

First of all, there is good reason to plant spekboom, so there’s no need to head to your garden to start uprooting things just yet.

The Daily Maverick’s Karel van der Vyver has spoken with some experts in the field, starting with Dr Donovan Kirkwood, the curator of the Stellenbosch University Botanical Garden:

 “Spekboom is … a fantastic, tough, easy to grow, attractive waterwise plant for the garden, available horticulturally in a range of forms from ground cover to tall shrubs – it’s a great choice for gardens anywhere.”

“In its natural… habitat, spekboom is an important element in maintaining huge natural carbon stores.”

Dr Anthony Mills, the CEO of C4 EcoSolutions, was also full of praise for the hardy shrub:

“Spekboom cuttings, unlike cuttings of most other thicket species, have a high rate of survival in the dry, hot soils of degraded thicket… Spekboom is also unusual in being able to grow rapidly in both wet and dry conditions,” says Mills…

“Planted in the correct area, spekboom is indeed a miracle plant.”

Both of those quoted above stress the “natural habitat” and the “correct area”, and that’s where the caveat comes in.

The talk of it being more effective than the Amazon rainforest at sequestering carbon is highly dependent on spekboom being planted in its natural environment.

As was pointed out in a Facebook post by then PhD candidate Elzanne Singels, titled ‘Spekboom Mayhem’, the plant is “not indigenous to Cape Flats Sand Fynbos”, and “can still be a threat to biodiversity due to genetic pollution”.

Singels also appeared on CapeTalk to further discuss the matter.

Back to the Amazon claims, which Africa Check summarised in an article last year:

The claim that spekboom “can sequester more than 4 tonnes of carbon dioxide per year per hectare planted” is misleading.

According to research from 2014, spekboom can capture and store between 2.9 and 8.6 tonnes of carbon dioxide per hectare per year in its aboveground biomass. When the plant is considered in its entirety, this number can increase to 15.4 tonnes of carbon dioxide per hectare per year.

But this is only under very specific circumstances. The available research shows that these rates were achieved where spekboom was being used in the restoration of a subtropical thicket in its natural habitat with other plants.

Spekboom occurs indigenously in subtropical thickets ranging from the eastern parts of the Western Cape to beyond East London in the Eastern Cape.

Planting it in your garden outside of those areas is fine, but it’s not going to work its full carbon wonders.

Here’s Kirkwood again:

 “If you are planning on planting spekboom outside of the thicket biome it is unlikely that spekboom will be more effective at sequestering carbon than vegetation indigenous to your area.”

I’m a big fan of planting species in the garden, and in pot plants on the balcony, that don’t require a great deal of love and attention, so the spekboom is perfect on that front.

If you’re hoping it’s going to outshine the Amazon rainforest, though, you’re a little off course.

Read the rest of van der Vyver’s article here.

[sources:getaway&dailymav&africacheck]