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THINNING AND HARVESTING

Thinning is required to select plants with the best stem in the stand, ensuring the highest possible diametric gain.

First thinning: a first thinning should be carried out in plots of plants younger than two years, leaving 600 plants/ha. In this thinning, one can exclude 25% of the planted plot, without productivity loss. The selective thinning, recommended in the second year, aims at circumventing problems caused by external factors such as strong winds, hailstorms, and others which by their nature, are beyond the farmer’s control.

Thinnig at 4 years old plantation – clone BV 1120.

Thinnig at 4 years old plantation – clone BV 1321.

Second thinning: one should hold a second thinning when the trees reach the age of 8 years, or a diameter of 30 cm, so that they can be harnessed to the saw-mill. At this stage, 300 trees are systematically removed. The remaining 300 are saved for clearcutting at 15 years of age, or when the plants reach a diameter of 50 cm or more.

This second thinning timber can be used in different ways, such as the manufacture of furniture, window frames and wainscoting. The remaining trees, more spaced, will have a stronger diameter growth.

9 years old plantation after second thinning.

9 years old logs at the sawmill.

Manual harvesting: In this process, the felling of trees is performed with a chain saw, a simple, affordable and cost-effective equipment that has good performance. One must take into account all safety aspects of the work, training and correct use of PPE, as this is the forestry operation that carries the most risk to the worker. Following, the short logs are loaded on boards, pulled by tractors and taken out of the plots, from where they are loaded onto trucks or boards. This procedure is suitable for mechanized areas. In non-mechanized areas, this process can be done by animal traction or cable systems.

In our experience, the best way to harvest, considering the size of the forest and the operating cost was by using chainsaws, the logs are dragged with mini skidders and the trucks are loaded by a forest crane. This equipment is fitted to tractors and thus it is more affordable.

Felled with a chainsaw.

Manual loading.

Pulling with a mini skidder (eucalyptus).

Loading 4 years old logs with a forestry crane.

Mechanized harvesting: Mechanized harvesting usually requires a number of machines for different types of operation. These sets typically operate with harvester + auto loader (or forwarder) or feller buncher + skidder + tracing claw. Due to the high cost of the equipment and its high performance, these models can only be justified for large forestry operations, with yields exceeding 500 hectares of crop per year. Smaller size equipment, of lower cost have been developed for midsize operations. This is the case with the TMO feller head, which can be fit to a tire loader.

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