Impacts of forest harvesting related soil disturbance on end-of-rotation wood quality and quantity in a New Zealand radiata pine forest

Abstract

The long-term effect of soil disturbance (litter removal, topsoil removal and compaction) from forest harvesting on wood quality and quantity of second-rotation Pinus radiata growing on a clay loam soil, was assessed at the end the rotation, 26 years after planting. Relative to Control plots, average tree and stand total volume at rotation end was not significantly affected by litter removal and nil or light compaction, but was significantly reduced by 28% by litter and topsoil removal and moderate subsoil compaction, and further reduced by 38% by heavy compaction. Wood density at breast height in the inner rings of trees in the most disturbed treatments was elevated by up to 30 kg m-3. This occurred because these treatments were more N deficient as reflected by foliar N levels during the first 11 years of growth relative to the Control. However, no treatment differences in wood density were evident in outer rings, and by rotation age overall mean density did not differ significantly between treatments. Neither acoustic velocity of standing trees, nor acoustic velocity of logs, was significantly affected by soil disturbance, indicating that stiffness of lumber cut from trees in the trial was likely to be similar for all treatments. Economic impacts of soil disturbance and compaction on this soil type will therefore result largely from the considerable negative impacts on final tree size, with little or no compensation from improved wood properties.

Post-Harvest Evaluation of Soil Physical Properties and Natural Regeneration Growth in Steep-Slope Terrains

“…These findings are consistent with Zenner et al [16], Ezzati et al [11] and Picchio et al [32]. The higher value of BD in high traffic intensities rather than low traffic intensities could be explained by the high soil moisture content of soil during harvesting operations, more timber from these locations [33], the thickness of litter layer, the mixing of organic matter with the soil and, ultimately, the low activity of soil organisms. BD has a significant difference in the traffic densities of high, medium and low compared with the control area; it was 14%, 11.6% and 8.6% higher than the control area and, in all traffic intensities, was less than the threshold of 15% [34].…”

Modelling soil moisture – soil strength relationship of fine-grained upland forest soils

“…Recently, compaction has been receiving increasing attention also in forestry. Compaction results in reduced porosity, which implies limitations in oxygen and water supply with negative consequences for soil productivity (Murphy et al 2009;Ampoorter et al 2010;Goutal et al 2013;Cambi et al 2015). Forest soils have been shown to recover more slowly than presumed previously (Labelle et al 2011).…”

Short-term effects of firebreaks on seedling growth, nutrient concentrations and soil strength in southern Australian wet eucalypt forests

“…Increased acidity and reduced moisture content on both the firebreak track and the disturbed firebreak may also affect nutrient uptake, contributing to lower foliar N concentrations on these treatments (Taiz and Zeiger, 2010). The decrease in soil nutrients on the firebreak treatments is likely due to both the removal of organic matter including fine and large fuels and humus and to displacement or mixing of the topsoil during firebreak construction (Williamson and Neilsen, 2003;Rab, 2004;Murphy et al, 2009).…”

“…In eucalypt forests, volumes were reduced by 52-79% on snig tracks 17-23 years after harvest (Pennington et al, 2004). Pinus radiata volumes were reduced by 28-38% at 28 years (Murphy et al, 2009), and Pseudotsuga menziesii (Douglas-fir) volumes were reduced by 75% at 32 years (Wert and Thomas, 1981). Although these losses are considerable, increased growth on transitional areas adjacent to snig tracks can compensate for reduced growth on the snig tracks themselves, leading to much smaller effects on overall site productivity (estimates of losses range from 0% to 12%) (Wert and Thomas, 1981;Dykstra and Curran, 2000;Whitford et al, 2001b;Pennington et al, 2004).…”