Forestry

Industrial Round-Wood Damage and Operational Efficiency

Losses Associated with the Maintenance of a Single-Grip

Harvester Head Model: A Case Study in Russia

Yuri Gerasimov 1,*, Alexander Seliverstov 2 and Vladimir Syunev 2

1 Joensuu Research Unit, Finnish Forest Research Institute, Yliopistokatu 6, Box 68,

Joensuu 80101, Finland

2 Forest Engineering Faculty, Petrozavodsk State University, A. Nevskogo av. 58, Petrozavodsk

185030, Russia; E-Mails: alexander@psu.karelia.ru (A.S.); siounev@psu.karelia.ru (V.S.)

* Author to whom correspondence should be addressed; E-Mail: yuri.gerasimov@metla.fi;

Tel.: +358-408-015-162; Fax: +358-102-113-251.

Received: 5 July 2012; in revised form: 26 August 2012 / Accepted: 20 September 2012 /

Published: 27 September 2012

Abstract: A field-based study was performed to broaden our knowledge of operational

efficiency losses associated with the neglect of the proper maintenance of the delimbing

and feeding mechanisms of a harvester. The post-harvest assessments of industrial

round-wood (IRW) processing damage, fuel consumption and productivity were examined

in clearcutting operations. Observations were made of seven combinations of wear levels

of feed rollers (A—heavy, B—medium, C and C’—without wear) and sharpening states of

delimbing knives (1—incorrect, 2—correct), depending on the degree of feed roller wear

and matching of angles of knife blades to the technical requirements. The processing

defects of IRW were broken down into unprocessed branches, bark stripping, and damage

caused by feed roller spikes. The results were then compared with the effective quality

requirements, and the IRW losses in terms of the reject rates (RR) were determined in the

context of the technical condition. The most frequent damage was by unprocessed branches.

The harvester with correctly sharpened knives produced the minimum RR

(4% of pine, 6% of spruce and 6% birch logs). The quality of IRW harvested under B1 and

C1 resulted in 6%, 6% and 8%. A1 turned out to be the lowest (12%, 10% and 8%).

Improvement in the maintenance of delimbing knives can reduce the RR of IRW by 5%.

Timely restoration of worn-out rollers can increase productivity by 2% and reduce fuel

consumption by 5%.

OPEN ACCESS

Forests 2012, 3

865

Keywords: cut-to-length; wood damage; fuel consumption; productivity; harvester head

1. Introduction

The fully mechanized cut-to-length (CTL) wood harvesting system based on a single-grip harvester

is now widely used by the logging industry in temperate and boreal forests, particularly in the

Nordic countries. Today almost 100% of logging in Sweden and Finland is carried out by the

harvester-forwarder system [1]. In Russia, particularly its northern European part, there has also been a

movement towards mechanized CTL [2]. A remarkable growth in Russian forest machine markets is

anticipated in the long term, mainly because of the need for renewal of current wood harvesting

machines and because of the huge harvest potential of Russian forests [3]. CTL harvesting was

introduced in the Russian regions along the Finnish border in the 1990s, mainly because Finnish

entrepreneurs and forest machines from Finland operated in this cross-border area. The CTL method

has become even more common in the 2000s, along with an increase in the import of harvesters and

forwarders. The proportion of harvesting carried out using CTL systems has increased, especially in

Northwest Russia, where more than 50% of harvested wood is already logged with the CTL method [4].

The domestic production of harvesters is quite low in Russia, and most of the machines in use (over

300 harvesters per year) are exported to Russia from Finland, Sweden, Canada and the USA [2].

Over 20 years of experience with the operation of CTL harvesting machines has demonstrated their

effectiveness for logging companies in Russia; i.e., better labor conditions

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