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Soil and Hydrology

Soil and Hydrology. Concerns Significance What are the Standards? How am I assessed? BMP’s. With support from Forest Research Partnership (Canadian Ecology Centre, Tembec, MNR, CFS) and MTCU Al Corlett, R.P.F., Forestry Consultant. Soil and Hydrology. Rutting. Erosion.

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Soil and Hydrology

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  1. Soil and Hydrology • Concerns • Significance • What are the Standards? • How am I assessed? • BMP’s • With support from Forest Research Partnership (Canadian Ecology Centre, Tembec, MNR, CFS) and MTCU • Al Corlett, R.P.F., Forestry Consultant Careful Logging – Partial Cuts

  2. Soil and Hydrology Rutting Erosion Careful Logging – Partial Cuts

  3. Soil and Hydrology Aquatic Values Soil Compaction Careful Logging – Partial Cuts

  4. Soil and Hydrology Careful Logging – Partial Cuts

  5. Soil and Hydrology Concerns –compaction • heavy equipment at wrong time or place, leading to— Careful Logging – Partial Cuts

  6. Soil and Hydrology Compaction • H2O & nutrients can’t move thru soil as easily • More surface run-off, especially if rutted • Increased moisture retention – longer to dry Careful Logging – Partial Cuts

  7. Soil and Hydrology Compaction • soil stays cool longer in the springtime, • shortened growing season and • delaying silviculture Careful Logging – Partial Cuts

  8. Soil and Hydrology Concerns – compaction • reduced growth - even for light traffic • increased dieback Careful Logging – Partial Cuts

  9. Soil and Hydrology Compaction – influenced by: • Texture, ground pressure / vibration, but most important – moisture content • Most severe, medium to fine textured soils, especially during wet periods • greatest at 60-100% of soils’ water holding capacity • Consequences – lowland sites Careful Logging – Partial Cuts

  10. Soil and Hydrology Compaction – influenced by: • # of passes – the first few count! • After average 2.5 trips, densities within 10% of the max Careful Logging – Partial Cuts

  11. Soil and Hydrology Concerns – effects can last a long time Careful Logging – Partial Cuts

  12. Soil and Hydrology Concerns: Erosion • movement of soil particles by wind, water, gravity Higher risk: • steep or long slopes, unstable road cut/fill • sands and silts, shallow soil over bedrock, water crossings Careful Logging – Partial Cuts

  13. Soil and Hydrology • Concerns: Erosion • soil movement • sedimentation into fish habitat Careful Logging – Partial Cuts

  14. Soil and Hydrology Concerns: Erosion • smothering of root systems, • reduced growth rate • mortality Careful Logging – Partial Cuts

  15. Soil and Hydrology Careful Logging – Partial Cuts

  16. Soil and Hydrology Concern: Rutting • wet soils –very prone to rutting/compaction • fine textured soils more susceptible than coarse textured mineral soils. • but very fine sands and fine sands may be susceptible when wet. • soils with lots of coarse fragments (e.g., stony tills or outwash) are less prone Careful Logging – Partial Cuts

  17. Concern: Ruttingespecially bad in the spring and fall when soils are saturatedmaking re-use of trails difficult – more trails needed next time Soil and Hydrology Careful Logging – Partial Cuts

  18. Soil and Hydrology Where are the issues? • steep slopes • rocky ridges • long slopes • complex terrain, water courses • treed lowlands Careful Logging – Partial Cuts

  19. Soil and Hydrology • Risk of damage: • reduced when soil frozen • Increased risk – spring snowmelt, above normal rainfall Careful Logging – Partial Cuts

  20. Soil and Hydrology Standards: Rutting • standards / BMP’s vary by district, but under development • evidence – 20cm leads to major, long-term, localized damage. • how much total coverage is acceptable? Careful Logging – Partial Cuts

  21. Soil and Hydrology Standards: Rutting • Caution: re-using severely rutted old trails – may put you out of compliance before you even start! • If productivity issue – re-use • If hydrological – re-locate Careful Logging – Partial Cuts

  22. Soil and Hydrology BMP’s: Planning – all stages • set clear objectives related to forest health • regulate the timing of harvest according to season / site condition (switch to winter harvest if a lot of wetland in the block) • good trail design and planning before the cut • have contingency areas Careful Logging – Partial Cuts

  23. Soil and Hydrology BMP’s: Landings • use maps, field information to locate landings • use existing landings (and trails) if appropriate • non-productive sites Careful Logging – Partial Cuts

  24. Soil and Hydrology BMP’s: Landings • don’t bulldoze (cut woody veg at ground level) • surface with chips / stone, aggregate if it will stabilize surface Careful Logging – Partial Cuts

  25. Soil and Hydrology BMP’s: Landings To reduce compacted area – • keep as small as possible • pile material as high as safety permits Careful Logging – Partial Cuts

  26. Soil and Hydrology BMP’s: Landings • gently sloping (less than 8%, but not flat) • outside AOC’s Careful Logging – Partial Cuts

  27. Soil and Hydrology BMP’s: Landings • locate so skidding traffic doesn’t cross natural drainage • locate so water won’t flow in or out where roads or trails enter Careful Logging – Partial Cuts

  28. Soil and Hydrology BMP’s: Landings • locate to promote skidding & forwarding down-hill Careful Logging – Partial Cuts

  29. Soil and Hydrology BMP’s: Trail Management • Minimize sections where water may be difficult to drain or divert. • grades >10%, • long unbroken grades, • long flat stretches, • stretches that are straight up or downhill that still require ditches Careful Logging – Partial Cuts

  30. Soil and Hydrology BMP’s: Trail Management • stay out of AOCs, wet areas, floodplains, outcrops, gullies,sensitive areas (watercourses, seasonal ponds, seeps, poorly drained areas) Careful Logging – Partial Cuts

  31. Soil and Hydrology BMP’s: Trail Management • stick to coarser soils (sandy or higher coarse fragments / gravelly), avoid silts and clays • run trails parallel to contours, run upslope trails along ridge crest Careful Logging – Partial Cuts

  32. Soil and Hydrology BMP’s: Trail Management • avoid locating skid trails on moderate to steep slopes (it is the gradient of the trail that is critical, not the hillside slope) • winch wood off areas with slopes >30% • reach onto slopes with feller/buncher, place piles at top or bottom of slope Careful Logging – Partial Cuts

  33. Soil and Hydrology BMP’s: Trail Management • forwarding downhill is preferred (downhill = favourable grade, uphill = adverse grade • recommended grades for primary trails: • <10% adverse (up to 20% OK for short adverse pitches. E.G. 100-200 feet uphill, if straight and level before pitch) – use a clinometer Careful Logging – Partial Cuts

  34. Soil and Hydrology BMP’s: Trail Management • pre-plan (walk the block 1st to locate wetlands & other sensitive sites) • orient trails away from wetlands, toward dry ground • place tops in wet areas Careful Logging – Partial Cuts

  35. Soil and Hydrology BMP’s: Trail Management • during dry periods, operate on low-lying areas with sufficient ground strength first • move to better drained sites when it gets wet Careful Logging – Partial Cuts

  36. Soil and Hydrology BMP’s: Trail Management • when possible, reach into wet areas to fell, and • pile bunches on dry ground for easy access by forwarder Careful Logging – Partial Cuts

  37. Soil and Hydrology BMP’s: Trail Management • in winter, prepare roads and trails ahead of time so that they are frozen • work wetter areas early in the day while still cold Note: 7.5 cm. soil frost to support small equipment, 15 cm. for large Careful Logging – Partial Cuts

  38. Soil and Hydrology BMP’s: Trail Management Risk of unfrozen soils – • little frost before snowfall • soils are dry • temperatures above freezing • lower slopes, wetter sites Careful Logging – Partial Cuts

  39. Soil and Hydrology BMP’s: Trail Management • Postpone logging if soil at 30cm depth will hold a cast • too late if water can be squeezed from a handful of soil, if ruts deep, or if water seeps into ruts Careful Logging – Partial Cuts

  40. Soil and Hydrology BMP’s: Trail Management • where roads / trails must be located across contours, use runoff ditches to reduce velocity and magnitude of runoff Careful Logging – Partial Cuts

  41. Soil and Hydrology BMP’s: Trail Management • drop load, winch across trouble spots • reduce weight of forwarder • forwarders – back-up trail on short runs rather than having to turn around in the bush Careful Logging – Partial Cuts

  42. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • wood chips, waste wood, bark mulch • lasts several seasons, 2-6” depth, slopes less than 4:1 (not in areas of concentrated water flow) • gravel • low slope, little concentrated flow Careful Logging – Partial Cuts

  43. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • hay or straw mulch • one or two seasons, 2 bales for 30’X30’ area • on steep slopes, anchor with netting or twine Careful Logging – Partial Cuts

  44. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • hay or straw mulch • trench 10cm deep, width of bale, Careful Logging – Partial Cuts

  45. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • single row – no gaps, • backfill on uphill side Careful Logging – Partial Cuts

  46. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • vegetation • permanently stabilize disturbed areas Careful Logging – Partial Cuts

  47. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • vegetation • best on slopes less than 4:1 Careful Logging – Partial Cuts

  48. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • vegetation • rake, grade, remove debris, smooth site Careful Logging – Partial Cuts

  49. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • vegetation • apply seed spring, fall or after rain Careful Logging – Partial Cuts

  50. Soil and Hydrology BMP’s: Trail Management • stabilizing exposed soil • vegetation • mulch on dry or erodible soils or if seeded in summer Careful Logging – Partial Cuts

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