تعیین فاصلۀ بهینۀ زهکش‌های عرضی در مسیرهای چوبکشی به‌منظور انحراف رواناب (مطالعۀ موردی: جنگل خیرود)

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ‌ارشد مهندسی جنگل، دانشکدۀ منابع طبیعی، دانشگاه تهران

2 استاد گروه جنگلداری و اقتصاد جنگل، دانشکدۀ منابع طبیعی، دانشگاه تهران

3 دانشیار گروه احیای مناطق خشک و کوهستانی، دانشکدۀ منابع طبیعی، دانشگاه تهران

چکیده

استفاده از ماشین‌آلات چوبکشی در مناطق پرشیب جنگل‌های شمال برای خروج چوب موجب افزایش وزن مخصوص ظاهری و کوبیدگی خاک و کاهش نفوذ آب در خاک مسیر چوبکشی، افزایش رواناب و هدررفت خاک می‌شود. این پژوهش با هدف تعیین فاصلۀ بهینۀ بین زهکش‌های عرضی در مسیرهای چوبکشی به‌منظور کاهش رواناب در پارسل‌های 315 و 316 بخش گرازبن جنگل خیرود انجام گرفت. در این پژوهش، نه پلات با طول‌های 20، 30 و 40 متر در شیب‌های طولی 15، 25 و 35 درصد مسیرهای چوبکشی نصب شدند. در خروجی هر پلات، یک مخزن برای جمع‌آوری رواناب مستقر شد. در هر پلات، متغیرهای جرم مخصوص ظاهری خشک، درصد رطوبت وزنی، درصد مادۀ آلی و بافت خاک و نیز در هر واقعۀ بارندگی، مقدار بارندگی روزانه و رواناب جمع‌شده در مخزن اندازه‌گیری شد. نتایج نشان داد که فاصلۀ بهینۀ زهکش‌های عرضی در مسیرهای چوبکشی برای کاهش رواناب 30 متر است و مناسب‌ترین شیب مسیر چوبکشی به‌منظور کاهش رواناب، شیب تا 25 درصد است. براساس نتایج، مقدار رواناب با طول پلات دارای رابطۀ معنی‌دار است. نتایج تحلیل رگرسیون نشان داد که مقدار بارندگی با رواناب در طول‌ها و شیب‌های مختلف پلات‌ها رابطۀ معنی‌دار دارد. از این‌رو برای کاهش رواناب در مسیرهای چوبکشی بهتر است تا حد امکان از ساخت این مسیرها در شیب‌های تند خودداری شود و بعد از عملیات چوبکشی، اقداماتی مانند ساخت زهکش‌های عرضی (با طول 30 متر و زاویۀ شیب 25-20 درصد) برای کاهش رواناب انجام گیرد.

کلیدواژه‌ها


عنوان مقاله [English]

Optimal distance among water diversion structures for mitigating runoff on the skid trails (case study: Kheyrud forest)

نویسندگان [English]

  • K. Fathi 1
  • M Jourgholami 2
  • S.A. Hosseini 2
  • Sh. Khalighi Sigaroodi 3
1 MSc Student of Forest Engineering, Faculty of Natural Resources, University of Tehran, I. R. Iran
2 Prof., Dept. of Forestry and Forest Economics, Faculty of Natural Resources, University of Tehran, I. R. Iran
3 3Associate Prof., Dept. of Reclamation of Arid and Mountainous Regions, Faculty of Natural Resources, University of Tehran, I. R. Iran
چکیده [English]

Using machinery wood extraction in steep slope in the Hyrcanian forests can increase the soil bulk density and soil compaction, decrease the infiltration water into soil of skid trail, which results in an increase runoff and soil loss and has detrimental effects on soil nutrients loss and sedimentation into the downstream infrastructure. The aim of this study was to investigate the optimal distance of water diversion in skid trails to mitigate sthe ediment and runoff in compartments 315 and 316 of Gorazbon district in Kheyrud forest. In this study, 9 plots with length of 20, 30 and 40 m and slope gradient of 15, 25 and 35% were established along the longitudinal slope of the skid trails. A tank was installed to collect runoff at the outlet of each plot. Also, runoff in each rain event as well as soil bulk density, moisture content, organic matter, and soil texture of the plots were measured. The results revealed that the optimal distance among water diversions in the skid trails to suppress the runoff was 30 m and the most appropriate slope for mitigating runoff on the skid trails was up to 25% slope gradient. Runoff had a significant relationship with plot length. The results showed that the amount of rainfall was significantly correlated with runoff at different lengths and slopes. Therefore, it should be avoided to plan the skid trails on steep slopes for mitigating runoff, and some engineering measures such as the installing water diversion structures (by length of 30 m and slope gradient of 20-25%) to decrease the runoff should be done.

کلیدواژه‌ها [English]

  • Skidding operation
  • Soil compaction
  • Water diversion structure
  • Soil physical properties
  • Kheyrud Forest
Ahmadi, M., Jourgholami, M., Majnounian, B., & Khalighi, S. (2019). The effect of sawdust mulch application on amount of runoff in the skid trails (Case study: Kheyrud Forest). Iranian Journal of Forest, 11(3), 297-307.
Akbarimehr, M., & Naghdi, R. (2012). Reducing erosion from forest roads and skid trails by management practices. Journal of Forest Science, 58(4), 165-169.
Arnaez, J., Larrea, V., & Ortigosa, L. (2004). Surface runoff and soil erosion on unpaved forest roads from rainfall simulation tests in northeastern Spain. Catena, 57(1), 1-14.
Assouline, S., & Ben-Hur, M. (2006). Effects of rainfall intensity and slope gradient on the dynamics of interrill erosion during soil surface sealing. Catena, 66(3), 211-220.
Cambi, M., Certini, G., Neri, F., & Marchi, E. (2015). The impact of heavy traffic on forest soils: a review. Forest Ecology and Management, 338, 124-138.
Ekwue, E.I., & Harrilal, A. (2010). Effect of soil type, peat, slope, compaction effort and their interactions on infiltration, runoff and raindrop erosion of some Trinidadian soils. Biosystems Engineering, 105(1), 112-118.
Ekwue, E.I., Bharat, C., & Samaroo, K. (2009). Effect of soil type, peat and farmyard manure addition, slope and their interactions on wash erosion by overland flow of some Trinidadian soils. Biosystems engineering, 102(2), 236-243.
Etehadi Abari, M., Majnounian, B., Malekian, A., & Jourgholami, M. (2017). Effects of forest harvesting on runoff and sediment characteristics in the Hyrcanian forests, northern Iran. European Journal of Forest Research, 136(2), 375-386.
Etehadi Abari, M., Majnounian, B., Malekian, A., & Jourgholami, M. (2018). Does forest harvesting change the runoff quality?. Iranian Journal of Forest, 10(1), 13-2.
Fu, X., Zhang, L., & Wang, X. (2016). The effect of slope length on sediment yield by rainfall impact under different land use types. Water Resources, 43, 478-485.
Hartanto, H., Prabhu, R., Widayat, A.S.E., & Asdak, C. (2003). Factors affecting runoff and soil erosion: plot-level soil loss monitoring for assessing sustainability of forest management. Forest Ecology and Management, 180, 361-374.
Hashemi, M., Nikooy, M., Salehi, A., & Naghdi, R. (2020). Short-term effects of water bar construction on soil physical properties of skid trail after logging operation. Forest and Wood Products, 73(2), 213-224.
Ide, J., Finér, L., Laurén, A., Piirainen, S., & Launiainen, S. (2013). Effects of clear-cutting on annual and seasonal runoff from a boreal forest catchment in eastern Finland. Forest Ecology and Management, 304, 482-491.
Jaafari, A., Najafi, A., & Zenner, E.K. (2014). Ground-based skidder traffic changes chemical soil properties in a mountainous Oriental beech (Fagus orientalis Lipsky) forest in Iran. Journal of Terramechanics, 55, 39-46.
Jourgholami, M., & Majnounian, B. (2011). Soil compaction and disturbance from logging with a wheeled skidder (Case study: in Kheyrud Forest). Iranian Journal of Forest, 2(4), 287-298.
Jourgholami, M., Fathi, K., & Labelle, E.R. (2018). Effects of foliage and traffic intensity on runoff and sediment in skid trails after trafficking in a deciduous forest. European Journal of Forest Research, 137, 223-235.
Jourgholami, M., Labelle, E.R., & Feghhi, J. (2019). Efficacy of leaf litter mulch to mitigate runoff and sediment yield following mechanized operations in the Hyrcanian mixed forests. Journal of Soils and Sediments, 19(4), 2076-2088.
Makineci, E., Demir, M., & Yilmaz, E. (2007). Long-term harvesting effects on skid road in a fir (Abies bornmulleriana Mattf.) plantation forest. Building and Environment, 42(3), 1538-1543.
Malvar, M.C., Silva, F.C., Prats, S.A., Vieira, D.C.S., Coelho, C.O.A., & Keizer, J.J. (2017). Short-term effects of post-fire salvage logging on runoff and soil erosion. Forest Ecology and Management, 400, 555-567.
Masumian, A., Naghdi, R., & Zenner, E.K. (2017). Effectiveness of water diversion and erosion control structures on skid trails following timber harvesting. Ecological Engineering, 105, 370-378.
Moreno‐de las Heras, M., Nicolau, J.M., Merino‐Martín, L., & Wilcox, B.P. (2010). Plot‐scale effects on runoff and erosion along a slope degradation gradient. Water Resources Research, 46(4), 1-12.
Palviainen, M., Finér, L., Laurén, A., Mattsson, T., & Högbom, L. (2015). A method to estimate the impact of clear-cutting on nutrient concentrations in boreal headwater streams. Ambio, 44, 521-531.
Robichaud, P.R., Wagenbrenner, J.W., Brown, R.E., Wohlgemuth, P.M., & Beyers, J.L. (2008). Evaluating the effectiveness of contour-felled log erosion barriers as a post-fire runoff and erosion mitigation treatment in the western United States. International Journal of Wildland Fire, 17, 255-273.
Sadeghi, S., Attarod, P., Van Stan, J.T., & Pypker, T.G. (2016). The importance of considering rainfall partitioning in afforestation initiatives in semiarid climates: A comparison of common planted tree species in Tehran, Iran. Science of the Total Environment, 568, 845-855.
Sobhani, H., & Naeijnoori, S.A. (2006). Guide direction for placing of decking and skid trial, Iranian Forest and Range Lands Organization. 45p.
Sohrabi, H., Jourgholami, M., Majnounian, B., & Zahedi Amiri, G. (2016). Soil moisture recovery after timber harvest cessation on abandoned skid trails after 20 years. Iranian Journal of Forest, 8(2), 179-194.
Wagenbrenner, J.W., MacDonald, L.H., & Roug, D. (2006). Effectiveness of three post-fire rehabilitation treatments in the Colorado Front Range. Hydrological Processes, 20, 2989-3006.
Yanosek, K.A., Foltz, R.B., & Dooley, J.H. (2006). Performance assessment of wood strand erosion control materials among varying slopes, soil textures, and cover amounts. Journal of Soil and Water Conservation, 61(2), 45-51.
Zhang, X., Hu, M., Guo, X., Yang, H., Zhang, Z., & Zhang, K. (2018). Effects of topographic factors on runoff and soil loss in Southwest China. Catena, 160, 394-402.
Zhang, X.J., & Wang, Z.L. (2017). Interrill soil erosion processes on steep slopes. Journal of hydrology, 548, 652-664.