TRUNK CALL

Technology is positioning the much-maligned pine as a sustainable alternative to endangered hardwoods and other construction materials

TRUNK CALL

Forestry and commercial plantation workers can tell them apart at sight, but for the layperson, one pine tree looks pretty much like another. There’s a simple trick they teach you if you spend enough time outamong the pine planta­tions. If the needles droop, it’s Pinus patula (also known as the Jelecote or Mexican weeping pine); if the needles don’t droop, but the cone is sharp when you hold it and squeeze it, it’s probably a Pinus taeda (or loblolly pine); if that cone doesn’t hurt too much when you squeeze it, it’s probably a Pinus elliottii (slash pine).

Then you also get the Pinus pinaster (cluster pine or Trosden if you’re Afrikaans-speaking), Pinus pinea (stone pine) and Pinus radiata (Monterey pine), and just as the names sound similar and the trees look a lot like each other, the products you get from these trees are virtually indistin­guishable. Looking at a wooden roof truss, a window frame or a finely crafted piece of pine furniture, you wouldn’t know whether it was patula or pinaster.

Those needles and cones on the plantation floor will tell you a lot – but what they won’t tell you is how difficult it is in the SA pine industry right now. In 2014, Sappi – the world’s biggest producer of dissolving wood pulp – confirmed that it was selling off R640 million worth of the country’s pine forests.

CEO Steve Binnie told the media that Sappi was ‘going through a process to dispose’ of 30 000 ha of forests in Mpumalanga, as more focus on higher-margin products reduced the need for trees. ‘In South Africa we do have excess softwood plantations, so we will continue to look for opportunities to sell those,’ he said.

Things have only become more difficult since then. Last November, as Cape Town started to realise the full extent of its drought, the City of Cape Town began a drive to remove alien vegetation near the Wemmershoek dam catchment area in an attempt to save water. ‘Over the last year, a City of Cape Town-appointed contractor has cut down over 50 ha of pine trees from a city plantation used for commercial and industrial purposes. The remaining 110 ha will be cleared over the next year. Removing these remaining plantations will improve stream flow into the dam and could secure an extra week or month worth of water supply for the city,’ said mayor Patricia de Lille.

Pine trees, ultimately, are thirsty. By some estimates, an average pine will consume at least 50l of water per day. That’s admittedly far less than a eucalyptus (which uses as much as 600l a day), but it’s thirsty nonetheless. It’s also invasive. Pinus patula, Pinus elliottii and Pinus pinaster all appear alongside cousins such as Pinus halepensis, Pinus roxburghii, Pinus radiata and Pinus pinea on the SA Green Industries Council’s naughty list of invasive species. SA National Parks notes pine and other alien species (including Port Jackson‚ rooi­krans‚ wattle‚ hakea and blue gum) as ‘one of the biggest threats to the biodiversity of the Table Mountain National Park’.

Yet many of those pine species are planted commercially in SA as a timber resource, and the forestry industry is – in the words of the Department of Agriculture, Forestry and Fisheries – ‘of considerable importance to the national economy and to large numbers of poor people living in remote rural areas’.

As stated by the department: ‘The forest products industry ranks among the top exporting industries in the country, contributing some 9% to the overall export of manufactured goods and earning net foreign exchange of approximately R8.8 billion in 2015. In the same year, the com­mercial forest products’ GDP was R31.1 billion and [the industry] employed an estimated 158 400 permanent, contract and informal workers. This amounted to 1% of national GDP and 1.4% of total formal employment.’

The department added that plantation forestry provides the raw material for downstream activities such as pulp milling, paper manufacturing, saw milling, wood chip exports, timber board, mining timber and treated poles. ‘Taking into account the multiplier effect of plantation forestry through its downstream value-adding activities and the effect it has on local – mostly rural – economies, between 534 000 and 692 000 people are dependent on plantation forestry for their livelihoods.’

SA pine is a versatile, low-cost wood, so naturally it’s widely used in the construction industry. The question then becomes, how can pine move to becoming a sustainable choice? Perhaps the answer lies somewhere along the line from seed to wooden window frame.

Pine cones are gathered from seed orchards, where the seeds are extracted, treated and sown into plastic tubes. The seedlings are then grown in tree nurseries until they are ready to be planted in the plantation. This is done by hand, usually at a spacing of 2.7m x 2.7m (which, according to the Southern African Institute of Forestry, is optimal to yield an initial stocking of 1 370 trees per ha). No fertilisers are used for pine trees, but the tree species is matched to the environment and the soil type.

The pine trees are thinned out – typically at five-year intervals – to allow the stronger trees to develop faster. Lower branches are also pruned regularly to avoid knotted timber. ‘South Africa is considered a leader in commer­cial tree farming and therefore our saw timber plantations associated with our members are managed to world-class standards,’ says Sawmilling SA. ‘These South African struc­t­ural pine plantations […] would have undergone acute silvicultural management in terms of on-time pruning and thinning. The main aim would be to produce high-quality logs that yield structural grade lumber.’

Once the plantation has reached a density of about 300 trees per ha, the trees grow undisturbed until they are ready to be felled. From there, logs are cut and transported to sawmills, where they are sawn into boards, kiln-dried and graded to SA Bureau of Standards specifications. The age of the tree at when it is felled is key to reducing the environmental impact of the process. Usually, pine trees are felled at 25 years, which is consistent with recommendations stemming from research published last year in the SA Journal of Botany.

That research found that pine plantations should be cleared preferably before 30 years‚ and certainly before 40 to 50 years. ‘The longer you wait‚ the less likely the chances that any fynbos seeds will be left in the soil to sprout successfully,’ says lead researcher Alistair Galloway of Stellenbosch University’s Department of Conservation Ecology and Entomology.

‘Pine plantations and pine invasions have numerous impacts on native ecosystems in the fynbos biome of South Africa. The severity of these impacts greatly determines the extent of potential ecosystem recovery after the pines are felled,’ he adds.

Ironically, a new treatment technology is transforming pinewood into a sustainable alternative to building materials such as plastics, steel, concrete and – crucially – hardwood. Hardwood timbers used in commercial and industrial applications are most commonly sourced from tropical rain forests in Asia, Africa and South America – often to a dangerously unsustainable degree.

Scott Sargent and Stuart Prior, co-founders of SA company Rhino Wood, developed a wood treatment process that turns SA pine into a sustainable alternative to those tropical hardwoods. Their innovation saw them become one of the first SA companies to receive the WWF Climate Solvers Award, in late 2014. ‘We need to slow down deforestation,’ Prior said at the time. ‘The WWF has set a target of net zero deforestation and forest degradation by 2020, and we need a totally new approach if we are to achieve this.’

Rhino Wood’s treatment technique sees a patented wax compound being injected deep into heat-treated pine. That heat treatment collapses the cells, burning out the sugars and resins that make the wood susceptible to rot, and the non-toxic compound pushes out any remaining moisture and fills the voids. This alters the wood’s chemical structure, transforming the softwood into a hardwood with increased strength and load bearing capabilities – suitable for decking, cladding, beams, posts, joists and spokes. (Builders and homeowners will also note that the treated wood is not recognised as a food source by termites or woodborers.)

‘It is ingrained in consumers’ perceptions that SA pine is simply inferior and cannot be subject to exposed conditions for long,’ Prior adds. ‘This preconception is often associated with a lack of education regarding timber products and their sourcing. It is our duty to show people that our product can outperform other forest hardwood products while being truly sustainable.’

This technology makes the pinewood unrecognisable as pine… Not that most home-owners would know the difference between one plank of pinewood and another. Yet it’s at the leading edge of technology that could position it as a sustainable alternative to other plantation timbers, and potentially save SA’s most popular commercially grown softwood from its continued barrage of bad press.

By Mark van Dijk
Images: iStock, Unsplash, Alamy

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