There are many beliefs concerning mechanized timber harvesting – and many of them are negative. In reality, however, things are mostly better than people usually think.
One of the most widespread myths about harvesters is that they are heavy. In actual fact, a harvester is light in weight. The pressure caused by the harvester’s wheels on the soil is about the same as that of your foot.
In contrast, a forwarder loaded by timber often weighs more, but this is fortunately something that harvesters can also help with.
Since the harvester operator is able to decide where to debranch the tree trunk, it can also be done on top of the route used by the forestry machines, called the strip road. Leaving the branches on the strip road protects the terrain from being deeply indented by the machinery.
Thus, the harvester protects the forest floor and, thanks to its lightness, it hardly damages the terrain.
Harvester protects nature values
Harvesters communicate continuously with information networks. Before the start of work, the machine receives a detailed instruction via the mobile phone network from the forest industry company that has purchased the trees in the logging site.
This instruction includes geographic information on both the boundaries of the logging site and the nature values to be spared within it. The operator can check this information on a map on the computer screen, and harvesting work and strip roads can be planned on this map as well.
The harvester is localized on this map by satellite navigation. The harvester takes account of the nature values by giving an alarm if the logging comes too close to features to be spared or to the site boundaries.
Compared to manual harvesting, it is much easier for the harvester operator to identify the nature values to be protected, especially during the winter season, when the snow cover is thick. On the other hand, in Finland the nature values must be taken into account even if they are not indicated on the map. Identifying them is the operator’s responsibility, and this is why all operators have been trained about the demands of nature management.
Harvesters bring mobile phone networks into forests
In Finland, mobile phone networks also cover uninhabited forest areas because they are needed in mechanized harvesting. Since the same networks are accessible by all, it is thanks to the harvesters that anyone spending time in forests, whether for recreation or work, can be reached by mobile phone.
The instruction sent to the harvester also includes information on the timber deals that the logging is linked to, the type of logging that should be carried out, whether the stumps need treatment to prevent root rot (a very common fungus attacking spruce stands in Finland), what safety guidelines must be observed on the site and the lengths to which the different grades are to be cut.
The preferred lengths given in the instruction depend on what kinds of sawn timber have been ordered by the sawmill, among other things. In this way, the requirements of individual customers can begin to be met before the timber leaves the logging site.
Together with cutting and debranching the trunks, the harvester also measures the volume of the harvested trunks. The information is transmitted to the forest industry company over the mobile phone network.
In fact, the company could receive real-time information on the harvested volumes by timber grade. However, this is normally not necessary, and the information is sent to the company once a day.
Harvester is packed with computer technology
The computer in the harvester’s cabin has a crucial role in its operation. For example, the points at which the trunks could be cut are suggested by the computer, although the final decisions are made by the operator. This is because the harvester does not recognise trunk curvature or decayed wood inside the trunk.
The harvester is packed full of computer technology – in addition to what is inside the cabin, there are usually several other systems. With the help of them and information networks, the harvesters owned by individual harvesting enterprises are linked to the information system of the forest industry company that has bought the trees.
These systems all work together. The harvester gathers information about how much timber of each grade is held in intermediate storages beside the forest roads. This makes it possible to plan optimal routes for the lorries taking the timber to the mill – they usually have to visit several storage sites to get a full load.
Harvesters are efficient. In terms of the actual logging alone, one operator and a harvester can carry out the work of 20 loggers.
Where needed, the harvester automatically sprays liquid pesticide on the stumps to combat root rot. The active substance in the liquid is either urea or a fungus which is a natural enemy of the Heterobasidion fungi.
By using a harvester in thinnings it is possible to minimize the damage to the trees left standing, because the operator can choose the direction in which the trees will fall.
And in contrast to manual logging, a harvester can also work after sundown.
Forestry work becomes inside work
For the operator, a harvester makes a nice workplace – at least when compared to what the alternative is. In former times, logging was heavy, physical work out in the open. Nowadays, thanks to harvesters, the operator sits in a warm and dry cabin, not worried by subzero temperatures or heavy rains and often listening to their favourite music or radio programme.
In addition to this, harvester is quiet, when compared to a chainsaw, for example.
Over the information networks the operators can have direct contact with employers, customers, colleagues or their family. Some harvesters even allow you to install a small kitchen in the cabin, with a microwave oven and coffee-maker.
On the other hand, a harvester operator is required to have diverse professionals skills. They must, for example, know how to carry out small reparations out in the forest, and be aware of the lifetime of wearing parts so as to order spares on time.
Mr. Simo Jaakkola, deputy executive director of the Trade Association of Finnish Forestry and Earth Moving Contractors, and Mr. Juha Kemppainen, Planning Manager at Ponsse plc have been interviewed for this article.
Correction (28.11.2016): “Skidder” replaced by “forwarder”.