Ecological – logging and sawing wood – Part III

Ecological – Part III (of VI)

Let us look at the different processes: Woodworking – Logging and sawing

The harvester cuts and debrances logs and the forwarder collects them according to thickness and lenght. Both have programmable computer programs.

The harvester, on the left. It cuts the tree, debranches it, sprays some urea on the stump, and paint-stripes on the end of the log.

The different colors on the ends of the logs, the paint-stripes, tell the forwarder-operator the length and sort of each tree.
The forwarder-operator can thus sort the logs by picking up one sort at a time.
The wagon of the forwarder can load about ten or more cbm [cubic meters] per time. The logs are taken to the nearest place where the log-trucks can be loaded.

In this video, the harvester cuts, debranches and debarks the logs:

The debarking of the log has many positive aspects when logging in the warm season; the log is not so easily attacked by insects and fungi, the bark that remains in the forest will stay there as nutrients, the mass of the load is reduced by 7 – 8 %, the weight even more as the log dries much faster without bark.

Here you can see how a forwarder works:

Both the harvester and the forwarder are computerized.

The univesity of Tampere (Finland) and a Finnish company developed a "Walking Harvester". The sawmill, the windmill, worked for 161 years, up to 1954, as a sawmill.

To the left is a “Walking Harvester

The university of Tampere (Finland) and a Finnish company developed a “Walking Harvester” before John Deere bought the company. This harvester is meant for steep hillsides, where safety is very essential when logging in such an environment, and also the environment itself needs to be taken care of. If the earth is very scarred at steep hillsides, the heavy rain and fast melting snow can endanger the soil before nature has taken care of the “scars”. If the soil that keeps the trees growing runs down together with the water, it takes thousands of years to recover the forest – if ever.

The best known example of this are the former dense cedar-forests of Lebanon. First the Foinikians logged the main forests and after that, the Romans logged the rest. After the hills where barred, there was nothing that kept the soil in place.

There are different methods to keep the forests growing for centuries to come. The methods of logging, depends on if the forest is at a big lake or on steep hill. As a rule, forest are logged in zig-zag-corridors, so that the wind can’t get too strong, but blow mainly above the forest.

A roman sawmill that has been found in Asia minor, got its power from a water-stream. The band-saw to the right has the advantage, as all bandsaws has, that the kerf is smallest possible.

On the left, a Roman saw-mill found in Asia Minor.
On the right, a commercially made band-saw, Serra. The kerf (the gap that becomes saw-dust) is about 2 mm when you saw with a bandsaw.
A typical kerf for circular log-saws and frame-saws is 5 – 6 mm. It might seem to be a small difference, but the fact is that from one medium-size log, you can get one extra board. That makes a big difference at the end of the day – especially if the logs are of the highest quality such as knotless logs. The knotless boards, for example which the carpenters make boats from, do not come cheap.
The downside with a band-saw is that it is slower, but one thing which compensates this fact is that it uses much less electrical power.

A framesaw is typically operated with 7 or 9 blades. A circular saw can saw al og which but-end can be up to 60 cm in diameter.

The framesaw, to the left, has a set of fixed saw-blades, 5 – 11 blades. The framesaw through-saws the whole log into unsquared boards simultaneously.
The circular logsaw, saws fast, but only one board at time.

Laser techniques are used in many different types of processing units in a modern saw-mill.

Laser technology is used in many different types of processing units in a modern saw-mill.
Usually the saw-mill needs a big yard in order to keep the logistics in good order.

To be continued…

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