Gentle Forrest Machines

Background

Cut-to-length logging (CTL) is a mechanized harvesting process where trees are delimbed and cut to length directly at the stump. CTL is the primary logging method in the European countries while full tree logging and tree-length logging are more popular in, e.g., North America, where tree sizes can exceed the capacity of the harvester's felling head, i.e., tree stems with a butt diameter of over 70 centimeters.

CTL lends itself to timber harvesting in plantation forestry where stems are often harvested before they reach large dimensions. CTL is typically a two-man, two-machine operation with a harvester felling, delimbing, and bucking trees and a forwarder transporting the cut logs from the felling area to a landing area close to a road accessible by trucks, or trains.

The challenge

Due to global competition, tightened regulations and a general concern for sustainable havesting of forest resources, the following technical challenges have been identified:

1 - Reduce fuel consumption, exhaust emissions (e.g., CO2, NOX, and particles).

2 - Reduce the impact from the worjing machines on soil, especially sensitive soils often referred to as Eco-soil, i.e., reduce the normal shear pressure during operation on soft soil.

3 - Reduce the daily vibration exposure for the machine operators by 50%.

4 - Increase the productivity by 2-3% anually.

Objectives

The main objective for the project is to research and develop new knowledge and new technology that enable development of new sustainable (with respect to climate, soil, operators, and economy) forest machine technology, with a significant aid from model-based design.

The means are Post-doc and PhD research, MSc degree projects, student projects, and participation in extensive field tests.

Project members

Ulf Sellgren, Assoc. professor

Kjell Andersson, Assoc professor

Abdurasul Umataliyevich Pirnazarov, PhD candidate

Abbos Ismoilov, PhD candidate

The partners

The project is a joint initiative by KTH Machine Design, the Swedish Forestry Research Institute (Skogforsk), and the major Nordic forest machine manufacturers.