Reduced Impact Logging in the Tropical Rain Forest of Guyana: Ecological, Economic and Silvicutural Consequences (Tropenbos Guyana series)
Language: English
Pages: 0
ISBN: 903932185X
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the linear model, yields the following linear model that applies to both logging methods: (pre-skidding time) = –2.32* + 2.22*** ⋅ (logs), R2 = 0.34. By applying this model to an average load of 9.7 m3 - as in the conventional operation - and hence an average load of 3.1 logs, a pre-skidding time of 4.5 minutes was computed, which stands against 4.9 minutes in the conventional operation. The time required to move the logs from the stump area to the assembly point was, as anticipated, strongly
lower rivers. Strenuous manual overland extraction was undertaken within a narrow strip of land about 1 km deep inland along the banks of the rivers. A system of rollers was adopted to reduce the resistance of logs being dragged over the ground. As the log advanced, the last roller, freed at the rear end, was taken forward and used again at the front end. Movements of logs in this way was carried out by workers pushing from the rear of the log by means of levers of suitably sized poles (locally
each damage category. Sums of Squares are Type IV; degrees of freedom are 13, 1, 2 and 1 for Error, Method, Intensity and Interaction respectively. In case of conventional logging, significantly more trees are found in the moderately and severely damaged tree categories. Damage category Killed Severe injury Moderate injury Minor injury Total damaged Error Effect of Method Sum of Sum of F Squares Squares 531.0 38.0 0.93 ns 244.7 251.1 13.34 ** 134.2 528.9 51.23 *** 640.0 9.1 0.19 ns 1793.5
respectively, while this amounted to 64% and 76% respectively in the conventional operation. Skid trail Skid trail Figure 4.24 Hypothetical felling patterns in a conventional (left) and reduced impact logging operation (right) at similar high logging intensity. Note that the chance that very large gaps are formed is higher in case of linked gaps with reduced impact logging than with conglomerate gaps formed by piling up of felled trees with conventional logging. The difference is created by
interfering factors influenced the results, for which further corrections will be made in the following sections. In order to find and eliminate noise factors and to pinpoint the time elements leading to the difference in performance stated above, the times spent on 156 Chapter 5: Logging efficiency the individual work elements are compared. The uncorrected average time of work elements involved in the felling of a single tree for both systems is shown in Table 5.2. Table 5.2 Felling