Harvesting wattle bark the UCL way

October 31, 2009

Every year in early spring the familiar sight of trucks loaded with wattle bark can be seen winding their way through the green hills of KwaZulu-Natal and southern Mpumalanga. The wattle bark processing business, which plays a holding game through the winter months, comes alive after the first rains as the moisture taken up by the trees makes it possible to strip the valuable bark easily off the stem.

UCL team UCL bark
L-R forestry manager Edward Naidoo, agriculture manager Friedel Eggers, bark stripper Yedwaphi Buthelezi, and harvesting supervisor Thulani Khanyile. Felling and crosscutting is done by chainsaw (right). Testing the wattle for bark stripability (left). Bark bundles are weighed infield. One stripper will make 14 x 30 kg bundles per shift (right).


The bark harvesting season, which stretches from October through to March, is therefore a very busy time for the wattle farmers, including hundreds of small growers with small, scattered woodlots in tribal lands. For many of them, the wattle tree provides an economic lifeline that no other crop can match.

One of the pioneers of the bark processing business in South Africa is UCL (UCL Company Ltd) which operates a bark processing factory and sugar mill in Dalton in the KZN Midlands. (Two other bark processing factories are located at Hermannsberg and Iswepe, operated by NTE.)

UCL was established in the 1920s as a co-op – the marketing of bark harvested by its members was the sole source of income until the 1960s when a sugar mill was built alongside the bark processing factory. Five years ago, UCL was re-constituted as a company and its members are now shareholders.

UCL is also involved in the sawmilling business, having acquired the Seven Oaks Sawmill in 1988. With the recent acquisition of a 70% share of the Kusel sawmill in Glenside, lumber production capacity has been significantly increased.

UCL's shareholders collectively operate around 30 000 ha of wattle, stretching from Harding in the South to Melmoth in the north. This includes a company-owned farm outside Dalton with 1 100 ha of wattle, 500 ha of gum (which will be converted to wattle), 500 ha of pine and 1 300 ha of cane. The wattle is grown on a 10-year rotation with 10% harvested each year and average production of 18 tons bark per hectare. Roughly three tons of bark processed produces one ton of saleable product.

UCL has 360 small woodlot growers on their books who supply around 1 800 tons of bark per season.

The market for the products processed from wattle bark at the factory include several grades of tanning material (powdered and solid) which is used in the leather industry, and adhesives used in construction. Over the past few years, the market for the bark products has been good and UCL processed 60 000 tons in both 2007 and 2008. This coincided with weak demand and low prices in the sugar industry, so the bark business provided a useful counter-balance for sugar. This year, they plan to harvest 55 308 tons, and expect the market to start picking up in 2010.

"The market for bark products hit a low point in February this year, but now it's on the up and performing better than expected," said Friedel. The main markets are in China, India and Italy.

The harvesting season lasts just 27 weeks, and in that time UCL must process enough product to fill the warehouse at Dalton so that they can supply the market all year round.

This brings us to the main purpose of our visit to UCL: what is it about harvesting wattle bark that sets it apart from normal timber harvesting?

Friedel Eggers, who is responsible for farming operations and the supply of raw materials (sugar and bark) to the UCL factory, gets straight to the point:

the bark must be fresh, ideally it should be harvested and delivered to the mill on the same day;the bundles must be clean, ie. free of soil, leaves, sticks, stones and branches, etc.

"Fresh bark is important because we can make top quality product from it, which fetches a premium price," explained Friedel. "Even after one day you can see the bark changing colour and getting darker. Our customers ideally want a light product which can only be made from same-day bark. Older bark makes a darker tannin which is not as useful or valuable.

"We also want to receive clean bundles at the factory, free of soil, harvest residue and stones," said Friedel. The farmers are paid according to the weight of the bark coming over the weighbridge, and UCL doesn't want to be paying for all the rubbish that they can't use. Besides it damages the knives in the chipper, thus increasing maintenance costs unnecessarily.

"Foreign matter coming in with the bark has a detrimental effect on the process," said Friedel. "Normally we change the knives every four hours, but when there is soil and rubbish in with the bark we may have to change the knives every two hours."

He revealed that .68% of bark delivered last season was actually soil. That translates into around 275 tons of soil over the whole season.

UCL has a three-tier payment system, based on the freshness and presentation of the bark:

  • Same-day clean bark – R825/ton.
  • Two-day-old clean bark – R775/ton.
  • Older than two days and badly-presented bark – R675/ton.
  • So-called stick bark, which is old and dry, can only be used to make the bondtite product.

I accompanied Friedel and UCL's forestry manager Edward Naidoo to the UCL plantation where they had just started harvesting, to pick up some harvesting tips.

Selective harvesting

As soon as the first rains come, they start testing the trees for strippability by making a small cut through the bark with an axe. If all the trees in a compartment have taken up sufficient moisture to facilitate stripping, then you can clear-fell. But more often than not, especially early in the season, some trees in a compartment have enough moisture while others don't. In this case, the trees that are ready are marked and selectively harvested, while the rest will be harvested later when the moisture content in the trees is sufficient for stripping.

This seems like a lot of extra PT, but is unavoidable if they need to start getting bark into the factory early.

The harvesting teams create a windrow after every fifth row of trees in the wattle compartments. An innovative practice adopted by the UCL team is that, at the end of a harvesting season, they will fell the centre row (in between the windrows) of the blocks they plan to harvest next spring.

This will be used as an extraction route for the harvesting operation, and helps the trees on either side to take up available moisture for early harvesting and stripping.

If they see a drought coming, they will also fell the trees on either side of the windrows to give the remaining trees better access to light and moisture.
When the season is in full swing, UCL fields four harvesting teams. Each team comprises a chainsaw operator with eight bark strippers producing 30 kg bundles. Each stripper's task is to produce 14 bundles per day. In addition, there are two stackers per team who stack the timber after it has been cross-cut to 2,4 metre lengths.

The bark bundles are taken to roadside by hand and then loaded onto a tractor equipped with a grapple crane, which transports them to the factory. The timber is collected later by the same tractor/trailer combo. The timber is sold to Durban Woodchips or Bay Fibre in Richards Bay.

Bark bundles

The bark is stacked with the white underside of the bark strips facing inwards to reduce exposure to the sun (which causes it to discolour rapidly). The bundle is then tied up tightly by means of three evenly-spaced bark strips and weighed in-field. Bark bundles awaiting collection and loading are stacked on pallets or logs to avoid soil and slash contamination.

The speed and timing of this bark harvesting operation is crucial, because the bundles must be delivered to the factory by 10 pm on the same day that the trees are felled.

It's no secret that stripping bark off trees is one of the most physically demanding jobs in forestry. So why don't they mechanise that operation?

Several mechanical debarkers have been tried over the years, but a major problem is that the bark often gets damaged in the process, causing discolouration which means it can't be used to produce the premium tanning product.

The Hypro tractor-mounted debarking processors were introduced into South Africa some three years ago, and some farmers are using them quite successfully. These heads debark and cross-cut, speeding up the harvesting operation considerably, but bark damage is still a problem.

UCL has bought a Demuth debarker which is undergoing extensive trials at the moment.

In the meantime, the tried and tested manual operations are still the favoured harvesting system for most wattle farmers.

Published in September/October 2009

Notify of
Newest Most Voted
Inline Feedbacks
View all comments
Warren Buchanan
Warren Buchanan
2 years ago

I have a garm with over 600 heactars of whattle and would like to enquire whether it is worth us using the bark of simply felling it for timber and fire wood . Your input would be greatly appreciated

Samora Chapman
2 years ago

Hi Warren... get in touch with UCL: info@ucl.co.za / 033 501 1600.

Charles Mnisi
Charles Mnisi
2 years ago


linkedin facebook pinterest youtube rss twitter instagram facebook-blank rss-blank linkedin-blank pinterest youtube twitter instagram