Logging and Sawmilling Journal's Jim Stirling takes a first hand look at South American forestry, as practiced in Uruguay.
Harvesting heads that process wood at the stump have become an integral ingredient in the harvesting strategies of forest companies. This equipment's ability to perform a variety of functions quickly and efficiently to produce clean, measured logs has proven a boon. A variation on the harvester theme could take things even further-why not remove bark at the stump? It's a huge advantage when harvesting eucalyptus pulpwood. The longer bark stays on the log, the more difficult it becomes to remove effectively.
Debarking at harvesting requires a portable machine and three people or a hand debarking crew. The innovative debarking harvesting head Logging and Sawmilling Journal recently took a look at in South America was incorporated into a Timberjack 762C on the business end of a Timberjack 1270B. The pulling and cutting debarking blades work on a slightly tangential rotation so as not to be in the same footprint as it passes down the tree. Bark removal is typically between 95 and 98 per cent, depending on the species of eucalyptus, age, ambient humidity-even the time of day plays a role in how well bark is removed.
The five 1270s with debarking harvester heads were working with four Timberjack 1410 forwarders with Cummins engines and beefed up bogeys. Dealer Roman SA, Forestaly Servicios of Montevideo, Uruguay, supplied the Timberjack equipment to them. The well-run show was located in the department of Rio Negro, Uruguay and owned by Compania Forestal Oriental SA, a joint venture between the Dutch Shell Group (60 per cent) and UPM Kymmene of Finland (40 per cent).
Large, foreign forest companies are leading the way in Uruguay's surging forest industry. The goal of these partners is to plant and harvest 35,000 hectares in northwestern Uruguay. The plantation design includes a stocking rate of about 1600 stems per hectare to maximize wood volumes for pulp. Although described as a not particularly good site, the 10 year old eucalyptus grandis stems were around 20 metres tall and averaging between 0.18 and 0.20 solid cubic metres a stem. It was taking the operator of the Timberjack 1270/762C combo around 45 seconds to fall, debark, delimb, cut to length and pile an average stem in the stand.
It works out to about 20 cubic metres an hour stacked in 2.4 metre lengths for forwarding. Tops and branches were windrowed and walked on as the harvester worked the perimeter of the stand, leaving easy sites for replanting. The terrain was benignly level but there were a few lower, swampy spots which preclude the forwarders from working when wet-reducing environmental impact is an international prerogative, it seems.
The wood forwarded to roadside was loaded onto 30 tonne highway trucks for transport to tidewater and exported to Spain aboard ocean going freighters. Compania Forestal Oriental produces about eight million seedlings at its attractive riverside nursery near Paysandu. The operation focuses on two species and their clones, eucalyptus grandis and dunnii. Growth is remarkable by Canadian standards. Stock rotates through the system every 16 weeks, from sowing seeds to hardening outside to lessen stress prior to spring and fall planting seasons.
Optimum seedlings are 25 centimetres tall at planting, with six or eight leaves. "What we want is a wellbuilt, robust plant," says Jose P. Garcia De Leon, technical manager. Seeds are sown one for each container cavity with the objective of having the whole tray germinate at the same time, producing plants of similar size. You have to get the sowing right or there's a huge job in the nursery, he adds. Moisture and temperature are carefully regulated.
Compacted pine bark is used as substrate with fertilizer introduced through the closely monitored irrigation system. After germination, nets have to be hung to help protect the vulnerable plants from marauding birds. Clones are propagated from elite trees and while all trees react differently to propagation, most are producing cuttings within a month. "We want a fibre producing tree. Wood density is important because it correlates to many other features related to pulp making," explains De Leon.
Field trials help determine characteristics. The production target is three million clones a year. The large numbers of plants and their rapid maturity through the nursery emphasizes the necessity for sound planning. "We have to have and maintain a very strong data base to keep track of all the different characteristics of pure species and hybrids," he says. De Leon says eucalyptus dunnii is a very interesting species but is shy and reluctant to flower.
But under controlled orchard conditions using an eight year old scion and three year old graft, the nursery has nurtured plants full of flowers growing close to the ground and producing large numbers of seeds per tree. He believes that's been accomplished only once before in the world. Laboratory control process programs contribute highly valuable strategic work. In one section, a machine developed by Shell specifically for eucalyptus uses infrared rays to produce a spectrum of each wood sample and relates it to pulp properties. It can rapidly analyze large numbers of samples.
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