Unit 3 Site Preparation PDF

RESTORATION TECHNIQUES: SITE PREPARATION  What is site preparation Depends on prior Recontourin land use and g, structure functions forming, or Lays the...

RESTORATION TECHNIQUES: SITE PREPARATION  What is site preparation Depends on prior Recontourin land use and g, structure functions forming, or Lays the grading foundation for prior to successful application ecosystem of development vegetation Requires careful soil handling 2/1/20XX PRESENTATION TITLE 2 Landscape and surface expression Define the visible features of an area of land Goals: Recreate pre-disturbance landform Match local drainage and topography patterns Prepare for desired end land use Enhance restoration success 2010 Reclamation Criteria: Landscape criteria are assessed by looking at the site as a while from several vantage points and compared to adjacent land Drainage Operability (things left on site, does it fit on the landscape is it going to function) and Contour (does it fit with the landscape) 2/1/20XX PRESENTATION TITLE 3  Landscape and surface expression Reclamation criteria: Yes or no based Qualitative evaluation (Forested and Native grassland) Drainage- is it consistent with the original drainage patterns, direction and capacity or be compatible with current surroundings Erosion- No visible evidence of wind or water erosion Stability- No visible evidence of slope movement, subsidence (when a slope slid down or sinks in on the side of the slope) or tension cracks (very dry soil) Bare areas- Comparable to the surrounding communities Operability- Contour must conform and blend with adjacent contours or intended land use Debris- No industrial debris remaining  Landscape and surface expression Landform features that influence plant establishment and growth include: Slope Aspect Shape Stability Soil texture Natural site restoration is primarily concerned with modifying these at a small scale Most natural site will not feature large uniform area- most efficient landscape modifications create large uniform areas Traditional reclamation resulted in reduced surface feature diversity- smooth contours, destruction on mounds and walls, backfilling of pits. Landscape and surface expression Natural sites vary in soil characteristics resulting in greater species diversity within the plant community (Bowen et al. 2005) Modification of surface features Landform reconstruction, showing heterogeneity of materials and meso- topography (~10m), revegetation after oil sands mining in Alberta, Canada.  Landscape and surface expression Increasing surface structure improves wildlife habitat Escape terrain Nesting sites Burrowing sites Climatic extremes Places to get out of the hide Hiding cover Diversity in surface features leads to diversity of species (including plants)  Landscape and surface expression Compaction Alleviating compaction across disturbance Critical points for expected compaction? –roads, access points, storage areas Are grasslands the same as forests? –different roots, grassland we are worried about the top 10-15cm of soil, as a forest the depth of compaction is more important 1-1.5m No Grassland soils are not under the same influence of freeze thaw cycle as forest soils Deeper active rooting zone in forests requires deeper alleviation of compaction Problems from compaction? Impenetrable layers Lack of water and nutrient movement Lack of oxygen 12/11/2024 9 https://www.myfields.info/book/10-freeze-injury-and-other-environmental-stresses-13 Alleviating compaction- Shallow Focus on the microsite Enhancing topsoil to hold and promote germination of native plant propagules Chisel plows Curved shanks penetrate and “stir” the soil without inverting a soil layer Cause less residue disturbance than moldboard plows and are often used in conservation tillage systems. ~5-10cm depths Disk Plow Invert soil using concave steel disk blades Breaks clods and stubble Front blades move soil toward the outside of the disk while rear blades move soil back toward the center of the disk ~5-10cm depths Field Cultivator Both used for seedbed preparation and weed eradication 5-10cm depths Harrows Breaks up large aggregates and smooths soil surface 12/11/2024 10 Preparing seedbed after tillage Alleviating compaction- Deep Winged subsoilers, Rippers, Excavators Frozen or dry but not saturated Common on boreal sites with greater organic content 12/11/2024 11 Modification of surface features Modification of surface roughness – increasing site diversity at a small scale of the shape of the earths surface Manipulation of topsoil, overburden and debris Increases diversity of habitats Increases infiltration rates and reduces runoff Two options: Add above grade features Add below grade features Modification of surface features Above ground features Reduces flow of wind and water Increases retention of nutrients and organics Increase infiltration rates Enhances plant establishment Provides microhabitats Examples: Free dumping overburden (b/c horizons) Track packing* Mounding- intentional placement of mounds and pits Adding features (rocks, woody debris)  Modification of surface features Adding below grade features Depressions accumulate water, nutrients, organics Can be natural but man –made can have similar effect, one can use disturbance features Borrow and mine pits- Keep slopes and contours irregular, roads can become watercourses  Modification of surface features Excavation to create both above and below grade features- mounds and pits Mounding or “Rough and Loose” Common on peatland or forested sites  Topsoil replaceme nt The growing medium, living soil Best to use salvaged original soil a horizon, possibly some b hozion Thickness should match offsite and/or meet reclamation criteria Conduct at moisture content