ABSTRACT

Despite the large biomass potential, current management practices for roadside verges (ditch backslopes,foreslopes and bottoms, possible parking lots and other lateral land) consist of regularly cutting the vegetation manually with motorized brush saws or flail mowers and leaving it to rot in situ. Regular vegetation clearing is crucial for safety reasons and to maintain road functionality. This study considered the cost-efficiency of a mechanized harvesting system, using a harvester and a forwarder (as an alternative to current clearing practices), to maintain the verges of a forest road in northern Sweden. Cutting a 2.5-m wide swath on each verge removed between 32 and 112 dry t ha⁻¹ (16–56 dry t km⁻¹ of road) of biomass. Analyses showed that the use of forest machinery to cut and extract biomass from roadside verges can be cost-competitive compared with motor-manual clearing when the average tree height is above 7 m (~26-year-old trees), and profitable for average heights above 8 m (~29-year-old trees). As the overgrown biomass has to be cleared anyway, a mechanized harvest could partially or fully offset maintenance costs. When setting cutting intervals, a trade-off needs to be made between larger biomass production and maintaining a clear and safe road. Future research needs to investigate how size, density of vegetation and width of the cleared swath affects the long-term quality and safety of roads.

摘要

尽管具有巨大的生物质潜力，但目前对路边（沟后坡，前坡和谷底，可能的停车场和其他横向土地）的管理方法包括定期使用电动毛刷锯或fl草机手动切割植被并使其原地腐烂。出于安全原因和维护道路功能，定期清除植被至关重要。这项研究考虑了使用收割机和集运机（作为目前的清理作业的替代方案）来维持瑞典北部林道边缘的机械化收割系统的成本效益。在从32至112干燥t ha ^-1（16-56干燥t km ^-1道路）的生物量。分析表明，当平均树高超过7 m（〜26岁树龄）时，与使用人工清理相比，使用森林机械从路边砍伐和提取生物量可能具有成本优势，并且平均获利高度超过8 m（约29岁的树木）。由于无论如何都必须清除生长过度的生物质，因此机械收割可以部分或完全抵消维护成本。在设置切割间隔时，需要在更大的生物量生产与保持清晰安全的道路之间进行权衡。未来的研究需要调查植被的大小，密度和清理后的条幅如何影响道路的长期质量和安全性。