Background
Stumps are residues which remain after the harvesting of a forest stand. In plantation forestry, stump heights may vary depending on the harvesting system used to fell the trees. When re-establishing or repurposing a forest stand, stumps can pose a challenge because:
• They can impede and restrict machine movement if semi or fully mechanised planting equipment is used
• Overtime they can decompose and post a risk in terms of concealed holes in the stand
• When extinguishing fires in a stand, stumps can burn and smoulder for extended periods which may increase the likelihood of flareups
• If organisations want to change tree spacing, existing stumps can interfere with the new spacing alignment
One of the effective ways of dealing with residual stumps in a plantation forestry context is to use a stump puller. Savannah has two trailing stump puller attachments (Models 1710 and 1720) which have been designed to fulfil this purpose. The designs are patented and comprise of Model 1710 designed to pull smaller stumps in the 8 – 20cm range whilst the 1720 can pull larger stumps ranging between 10-58cm diameter.
How the stump pullers work
The stump pullers use lifting wheels mounted at an optimum geometry to grab and lift the stump and main root structure high enough to release from the soil for efficient raking. To achieve this, the stump pullers are towed behind an adequately powered Tractor or Bull dozer. The optimum pulling speed for Model 1710 and 1720 is 6.4km/hr and 4.8 – 7.2km/hr respectively. In terms of work output, the Model 1710 can destump an area at a rate of 1.2 – 1.6 ha/hour whilst the Model 1720 can produce 1-1.6ha/hr. The productivity can be affected by stand conditions such as average stump diameter, stump height, root structure, stump weight, row spacing, soil conditions, debris over stumps and towing machine traction and speed.
Conclusion
Savannah stump pullers can be combined with the Savannah Rotary Rake. The rake can be used to remove heavy debris prior to the stump puller operating. Thereafter, the rake can also be used move and gather the lifted stumps to a required location. Over and above having a stump free site to re-establish, the stump material removed from the site can be processed for other uses e.g. energy generation
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