A Meta‐analysis of the effects of ground‐based extraction technologies on fine roots in forest soils

Abstract

Fine roots are an important component of forest soil as they play a key role in fundamental processes like plant nutrition and water supply. As with all the features of forest soil, the compaction related to the forest operations and, in particular, to the wood extraction via ground‐based technologies could lead to a significant impact on the presence of fine roots in the soil affected by the passage of the machines. Considering the lack of a review, we used a meta‐analytic approach to synthesise effect sizes of ground‐based extraction technologies affecting the presence of fine roots in the soil, using a multivariate mixed‐effects meta‐analytic model. The obtained results revealed that the presence of fine roots in the soil affected by the passage of the machines was significantly reduced by both skidding (g = −1.23, 95%CI ‐1.87, −0.60) and forwarding (g = −1.37, 95%CI ‐2.01, −0.74). Due to the higher soil compaction caused by forwarding, this method had a marginally but statistically significant greater impact than skidding. We further confirmed the hypothesis that soil compaction and the presence of fine roots were strongly correlated, with the latter being greatly reduced in compacted soils characterised by higher bulk density. What is more, even more than 20 years after a harvesting intervention, the presence of fine roots was significantly lower in both strip roads (forwarding) and skid trails (skidding) as compared to areas which were not impacted by the machine passage. This shows that fine roots are particularly vulnerable to forest operations. On the other hand, the majority of the trails in the database used for the meta‐analysis were created in countries that favour the creation of a small number of widely used trails. Therefore, it would be scientifically valuable to do a comparative evaluation in various forestry contexts, such as in the Mediterranean area, where the development of the forest trails network is oriented on creating a large number of trails with low traffic volumes. Because machinery‐induced soil compaction is the major driver of the decrease in fine roots in skid trails and strip roads, both the application of best management practices as well as of a smarter planning of the trail network to limit soil compaction are strongly recommended. Both applications are highly recommended to be used in the planning phase and in the practical implementation of logging activities.

Severity of topsoil compaction controls the impact of skid trails on soil ecological processes

“…Due to the accelerated decomposition of litter on skid trails, there is an increased availability of nutrients in the soil, suggesting a possible positive effect on tree growth. However, it is important to consider the results of the meta-analysis by Latterini et al (2023), which showed that compacted soil on skid trails significantly hinders fine root growth. Consequently, improved nutrient availability may benefit tree growth only to a limited extent, as nutrients are less accessible to fine roots under compacted conditions.…”

Assessing the Extent and Severity of the Impact on Forest Soils of Two Different Fully Mechanized Timber Harvesting Operations

“…However, previous studies on the effect of lateral displacement and water infiltration along ground-based operating trails-forwarding or skidding-have not been sufficient [8,10,13]. These disturbances associated with forest operations can have a significant impact on biological processes such as litter decomposition rates and fine root abundance, as shown in previous studies [14,15]. Therefore, it may be necessary to investigate the impact of ground-based based technologies on forest soils.…”

The Effects of Soil Compaction on the Growth and Architecture of the Seedlings of Species Commonly Used for Afforestation in Iran

“…Logging operations are required to obtain wood for multiple purposes [5][6][7]. However, it is well known that logging operations can trigger substantial disturbance to the forest soil [3,[8][9][10][11][12][13]. Forest soils after logging are, indeed, in most cases, prone to compaction.…”