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The Log - Issue four - West Australian machine evaluation studies

machine evaluation imageIt’s been exciting to get out in the bush and obtain some actual empirical machine productivity data for a range of known operating and stand variables.

The main aims of these applied research studies have been to:

  • amass the results to help populate a comprehensive database for the Australian logging productivity and costing appraisal (ALPACA) model that will contribute toward reduced operating costs
  • assist program partners in answering some immediate questions.

Since September 2008, detailed studies have been conducted for three of our partners.

A combination of measurement techniques including continuous time and motion study (T&MS), activity sampling and shift-level evaluation (SLE) have been applied to obtain the specific data required for analysis. Bulletins and presentations to all CRC partners have been published for two of these studies.

During February and March 2009 numerous activity sampling studies utilising time and production counts (T&PCs) and instantaneous observations (IOs) have been completed simultaneously on many different machines performing in different harvesting conditions.

These quick and easy studies provide a snapshot of machine performance while working in the specific set of operating conditions. These background conditions are also recorded at time of the study.  

To date, the data from all studies has been collected on 49 different situations (72 if truck studies are included) as tabulated below by machine type and general work activity. 

 Operation type Machinery type

 Single-grip harvesters
 Feller bunchers
 Forwarders extract & load trucks
 Skidders  Loading - other
 In-field chippers
 Trucks
 TOTAL  17  9  5 + 1
 8  2  7  23
 Harvest only
 0  9  -  -  -  -  -
 Harvest & process
 11  -  -  -  -  -  -
 Process only
 6  -  -  -  -  -  -
 Extract logs
 -  -  5  4  -  -  -
 Extract logs & clear debris
 -  -  -  4  -  -  -
 Loading only
 -  -  1  -  2  -  11
 Delivery  -  -  -  -  -  -  12


This dataset covers very few different stand and operating conditions representing only 13 different plantations with 20 different site types. It needs significant expansion in order to obtain reasonable comparisons and reliable averages for both different and similar situations in order to strengthen the algorithms in the model.

Even so, this small set provides some real figures and is indicating the range of productivity that exists across the diverse blue gum plantation estate that grows in south-west WA. For example, productivity for harvesting and processing into short logs at stump using single grip harvesters ranges from 14 to 40 tn/PMH with the main reason for the variance being individual piece size.

Fortunately, the CRC researchers have been ably assisted by industry staff for preparatory work. Special thanks go to Ernie Heidersdorf for his guidance in proper planning as well as his hands-on support in data collection, analysis and reporting. German forestry student worker Thilo Lange has assisted with data collection and analysis during all the activity sampling studies to date as well as with data collection during the comparative harvest system recovery study.


John Wiedemann

Tel: 08 9771 7400

john.wiedemann@wapres.com.au