Heavy Logging Machinery Impacts Soil Physical Properties More than Nematode Communities

Abstract

Mechanized logging equipment causes considerable soil disturbance, but little information is available regarding thresholds for impacts on soil nematodes—critical members of soil foodwebs which perform important ecological functions. We examined responses of nematode communities and soil physical characteristics to the increasing number of passes (one, three, or nine) by a tracked feller buncher during thinning of a xeric mixed conifer forest in New Mexico, USA. Within and between the harvester tracks, we measured soil surface penetration resistance and shear strength, quantified bulk density at four depth increments up to a maximum depth of 27 cm, and characterized nematode assemblages in the upper 10 cm. Eight months after treatment, nematode communities were less impacted than soil physical properties by harvester passes. Total nematode abundance was unaffected by any level of feller buncher disturbance, and sensitive K-selected nematode groups were reduced only at nine passes. Conversely, soil compaction occurred with a single pass and extended deep into the soil profile to at least 23–27 cm. The first pass also decreased surface penetration resistance and shear strength, indicating disruption of soil surface structural integrity. Additional passes did not further increase bulk density or decrease surface structural integrity. Our results indicate that low levels of logging machinery traffic may have negligible effects on nematode communities, but nevertheless emphasize the importance of minimizing areas subjected to disturbance because of impacts on soil physical properties.

Relationships among Soil Properties, Nematode Densities, and Soybean Yield in a Long-Term, Double-Crop System in Eastern Arkansas

“…The current study showed a negative correlation between BD and the total genera counts, where soil BD averaged 1.3 g•cm −3 across the study site (Table 1). However, Gibson et al [56] reported that total nematodes did not correlate with soil BD between 2 -6 cm and 9 -13 cm intervals after logging machinery traffic in a mixed conifer forest in New Mexico.…”

Considering Soil Biota and Symbioses in Forest Management and Ecosystem Restoration

“…Additionally, while heavy machinery may be required for some management, restoration, and multiple-use activities, including the above recommendation, the heavier the machines and the greater the number of passes required, the greater the negative effects on both the soil and the soil biota become [42][43][44][45]. Dr. Kara Gibson presented at the symposium about her research regarding how machinery of varying weights negatively affects soil quality and the communities of microbes in those soils [46]. Rutting and soil compaction from machinery cause reduced soil porosity, nutrient recycling, drainage, and oxygen supply, and these harms can be both difficult to correct and long-lasting [42,[47][48][49].…”