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PROJECT REPORT May 2014

Productivity assessment for a Lamtrac LTR6125T: a case study at the Slave Lake Mulch Research Area Steven Hvenegaard, Rex Hsieh

INTRODUCTION

The Slave Lake Mulch Research Area was designed for ongoing research on mulch fuel treatments and the productivity of mulching equipment. In February 2014, we attached a MultiDAT1 to a Lamtrac LTR6125T mulcher to capture real-time data from the machine while it completed a 6 ha mulch fuel treatment. We then calculated its productivity rate and machine utilization rate.

METHODS

Machine Description The Lamtrac LTR6125T (Figure 1) is a 93 kW (125 hp), low ground-pressure (25.86 kPa or 3.75 psi) machine on steel tracks. The attached FAE 175 horizontal drum mulcher head (Figure 2) has fixed teeth and a working width of 1.75 m.

Figure. 1. The Lamtrac LTR6125T.

1 MulitDAT is a system for recording and reporting information about the activities of forestry machines.

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Figure 2. The FAE mulcher head on the Lamtrac LTR6125T.

Fuel Treatment Site The Slave Lake Mulch Research Area (Appendix A) is 4 km southeast of the town of Slave Lake, Alberta. For this study, we established four study plots of about 1.5 ha each. The plots were flat and predominantly Black Spruce (Picea mariana). At the time of mulching, the ground was frozen and covered with 50 cm of snow.

Fuel Treatment Activities The LTR6125T worked in strips as it pushed over trees and mulched the felled stems and other woody debris. This is called strip mulching, and it is a common forest fuel treatment in high density, small diameter Black Spruce stands. The operator made two passes to create a mulch strip 3.5 m wide. He left 3.5 m of standing trees between each mulch strip. During this phase of the operation, it was common for felled stems to become lodged within the remaining standing timber. In the second phase of the operation, the cleaning phase, we had a Volvo skid-steer2 fitted with a grapple pull the felled stems from the standing timber and lay them in the mulch strip. The LTR6125T then returned to re-mulch the strip (a final mulch).

In Plot 6A and 6B, the mulch strips were not cleaned (Figure 3); in Plot 7A and 7B (Figure 4) the mulch strips were cleaned and re-mulched (Figure 4).

2 The productivity assessment for the Volvo skid-steer is in a separate report.

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Figure 3. A 3.5 m mulch strip in Plot 6A, with no cleaning.

Figure 4. A 3.5 m mulch strip with cleaning and a final mulch in Plot 7A.

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RESULTS

We collected data over four days from February 24 to 27, 2014. The productivity rates of the LTR6125T in the four study plots are summarized in Table 2. The rates are based on productive machine hours (PMH), which includes mulching time, manoeuvring time, and delays shorter than 15 minutes. It does not include the time of the skid-steer. The table also includes the stand characteristics we measured that could have had an effect on productivity.

Table 1. Productivity rates of LTR6125T at the Slave Lake fuel treatment plots.

Study Plot

Pre-Treatment Stand Density (stems/ha)

Average Tree

Height (m)

Treatment Activity Productivity (ha/PMH)

>9 cm DBH <9 cm DBH Total

6A 1375 5000 6375 7.8 two passes 0.26

6B 400 4750 5150 6.0 two passes 0.20

7A 663 7000 7663 5.9 two passes + final mulch 0.12

7B 550 6000 6550 6.0 two passes + final mulch 0.18

The machine utilization rate is productive machine hours divided by total scheduled machine hours multiplied by 100:

(PMH/SMH x 100)

The overall utilization rate for the LTR6125T in this study was 92%. Delays were minimal and included refuelling, replacing cutter teeth, and cleaning debris from the mulcher head.

DISCUSSION

The utilization rate of 92% suggests that this was a very efficient operation. The LTR6125T seemed well suited for mulching Black Spruce stands of this density and stem size. The final mulch in the cleaning phase predictably reduced productivity from an average of 0.23 ha/PMH (Plot 6A and 6B) to 0.15 ha/PMH (Plot 7A and 7B). The width of the mulch strips (3.5 m) provided plenty of room for the skid-steer to manoeuvre during the cleaning phase in Plot 7A and 7B.

This assessment provides a snapshot of the potential productivity of the Lamtrac LTR6125T for two types of mulch treatments in spruce-dominated stands. We caution readers against relying on these results to estimate the cost of their fuel treatment project, or to expect a certain production rate from their equipment. Generally, productivity assessments are conducted over much longer periods, but because forest fuel treatments are small and variable this is difficult to achieve. We continue to look for opportunities to conduct these assessments for different machines and in different types of fuel treatments.

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APPENDIX A

Slave Lake Mulch Research Area

Map courtesy of Mistik Environmental Services Ltd.