ROADSIDE REVEGETATION—An Integrated Approach to Establishing Native Plants





Abundance (species) The quantity, dominance, or cover of a species in a given area. Often ranked on a scale of zero to 3, 0=never occurring, 1=rare, 2=common, and 3= abundant. Utilized to determine possible workhorse species. Technical Guide: see page 127
Amplitude (species) The occurrence of a species over a variety of ecological settings. For example, if a survey reveals the same species on hotter, drier environments and also on cool, shady areas that species has a high ecological amplitude. If the species only occurs in one special area, it has low amplitude. Utilized to determine possible workhorse species. Technical Guide: see page 127
Angle of repose The maximum slope gradient at which granular, non-cohesive material, such as loose rock or soil, remains stable. Technical Guide: see page 28
Animal repellent A product applied to the foliage of seedlings to make them less palatable to browsing animals such as deer and elk. May give off unpleasant smells (such as sulfur) or be irritating to the animal (garlic or chili pepper). Technical Guide: see page 347


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Beneficial soil microorganisms Naturally occurring bacteria, fungi, and other microbes that play crucial roles in plant productivity and health. Often added to disturbed sites via plant or soil inoculation. See also nitrogen-fixing bacteria and mycorrhizal fungi. Technical Guide: see pages 231, 232, 243
Best management practices Guidelines, practices, or procedures designed to best protect the environment while achieving desired road objectives. Technical Guide: see page 4
Biosolids Treated sewage sludge meeting EPA regulations. Sometimes used as a source of organic amendments. Technical Guide: see page 223
Biotechnological engineering Practices involving a combination of biological and engineering sciences, usually for soil stabilization.
Borrow pit (borrow site) An area where excavation takes place to produce materials for earthwork, such as a fill material for embankments. Typically a site used to mine sand, gravel, rock, or soil.
Broadcast (seed or fertilizer) Applying materials (usually seeds or fertilizer) over an area. Broadcasting may be done by hand, ATV, pickup, tractor and hydromulching equipment. Application rates are calibrated to ensure the correct rates are being applied. Technical Guide: see page 192
Bulk density The weight of a dry soil sample divided by the volume of that sample. If soil has a high porosity or is loose, the bulk density values will be low; if the soil is compacted, the bulk density will be high. Technical Guide: see figure 5.16 and page 57


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Carbon to nitrogen ratio (C:N) An indicator of the availability of soil nitrogen for plant growth. A low C:N ratio indicates that soil nitrogen will be available, whereas a high C:N ratio indicates that soil nitrogen could be limiting to plant growth. Technical Guide: see figures 5.30, 5.32 and pages 73-79, 226
Compaction (soil) The result of heavy machinery or other weight (such as livestock) pressing soil reducing soil pores and therefore reducing the soil's ability to hold water and air.
Compost The product of biological decomposition of organic matter under controlled aerobic conditions. An important soil amendment. Technical Guide: see page 222
Construction engineer Oversees road construction. Coordinates with contractors, oversight agencies, and revegetation specialists to install road. Key contact for the revegetation specialist during the implementation phase. See also "design engineer". Technical Guide: see page 19
Construction footprint The total area of land impacted by construction of the road. The goal is to minimize the footprint, thus minimizing the need for revegetation.
Cross-section view A drawing depicting the outline of the slope profile taken perpendicular to the direction of the road. Used with "plan views" to visualize road plans three-dimensionally. Key document in revegetation planning. Technical Guide: see figures 3.3 A, B and pages 21, 22
Culvert A drainage pipe set beneath the road surface to move water (streams, springs, and ditches) from the uphill to the downhill side of the road. Technical Guide: see page 27
Cut slope The landform created on the uphill side of the road during road construction. Typically cut slopes are steeper than the natural slope gradient. Technical Guide: see page 25
Cuttings Branches, roots or leaves that are separated from a host plant and used to create new plants. Technical Guide: see figure 10.109 p.327 and page 137


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Debris slide Shallow, fast-moving type of landslide most common on steep, non-cohesive soils, such as those derived from granitic bedrock. See also slump. Technical Guide: see figure 5.55 p.101 and page 101
Deep pot irrigation A method to deliver water directly to root systems using a pipe positioned in the ground next to the growing roots. Important for conserving water especially in arid environments. Technical Guide: see figure 10.136 p.352 and page 352
Design engineer Develops road construction plans. Coordinates with oversight agencies and revegetation specialists to integrate revegetation objectives and treatments into road plans. Key contact for the revegetation specialist during the planning phase. See also "construction engineer."
Desired future condition (DFC) Specific, measurable objectives for each revegetation unit, usually defined in terms of expected percentage of vegetative cover, ground cover, species composition at a defined point in time after the completion of the revegetation work. Determined based on project objectives, revegetation units, and data from the reference sites for each revegetation unit. Technical Guide: see table 4.1 and page 29, example p.41
Drip irrigation An irrigation method which delivers water slowly to roots of plants by dripping the water through emitters or tubes. Also known as microirrigation or low pressure irrigation. Used for establishing plants in arid and semi arid environments. Technical Guide: see page 354
Duff The dark, decomposed layer below the litter layer under tree and shrub plant communities, consisting of decomposed leaves, needles and other organic material. Can store significant amounts of nutrients. Can be salvaged separately or mixed when topsoils are salvaged. See also litter. Technical Guide: see pages 74, 214


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Ecoregions Defined areas of similar geographic, vegetative, hydraulic, and climatic characteristics, that are divided into different levels, each level representing increasing degrees of detail. Ecoregion maps identify areas with similar environmental characteristics; sometimes substituted for seed zones to guide the transfer of plant materials. Technical Guide: see page 133
Erosion The removal of soil and other particles by forces including water, wind, and gravity. Three types of surface erosion are 1) sheet erosion: the removal of soil in thin sheets, 2) the formation of numerous, closely spaced channels due to high runoff, 3) the formation of large channels due to high concentrated runoff.
Erosion mats Manufactured blankets or mats designed to increase surface stability and control erosion. Available in strips or rolls. Technical Guide: see figures 10.21, inset 10.3 and page 211
Evapotranspiration Combination of transpiration (loss of water through plant leaves/needles) and evaporation (loss of water from soil or other surfaces). The rate of evapotranspiration changes depending on weather systems, sunlight, and seasonal changes such as air temperature and humidity. Technical Guide: see page 64


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Fertilizer, fast-release Highly soluble fertilizers that dissolve rapidly and move quickly into the soil during rainstorms or snowmelt. Fertilizers include ammonium nitrate, ammonium sulfate, potassium nitrate and urea. Advantages - relatively inexpensive, easy to handle, and immediately available to the plants. Disadvantages - potential for fertilizers to move through the soil faster than can be absorbed by vegetation and is wasted, the potential to pollute surface and groundwater, and the possibility of damaging new foliage and roots through salt contact. Technical Guide: see pages 187, 188
Fertilizer, slow-release Slowly soluble fertilizers that release nutrients over a longer period of time than fast release fertilizers. They are available in organic or inorganic forms. Organic forms include manures, fish emulsion, and composted sewage sludge. Inorganic forms include ureoform, sulfur-coated urea, and nitroform. Organic slow-release forms are the most common for roadside revegetation projects as they release during active plant growth, have less potential to leach into ground water or cause salt injury to plants, and are reasonably priced. Technical Guide: see page 189
Fill slope The landform created from excavated material placed on the downhill side of the road. Technical Guide: see figure 3.8 and pages 26, 27
Forbs Flowering low-growing plants (not grasses or grass-like)
Forgiving roadside A roadside environment that reduces the threat of injury when a vehicle leaves the road surface. Technical Guide: see page 16
Freeze-thaw The process of ice formation and ice melting that occurs within the upper layer of soil. Freeze-thaw contributes to soil erosion and accounts for significant annual soil losses. Technical Guide: see figures 5.41, 5.42 and pages 89, 90


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Gabion walls Stacked metal baskets filled with rock or soil used in retaining walls. Technical Guide: see inset 10.3 p.211 and pages 28, 211
Geotextiles Permeable woven or nonwoven fabrics used to reinforce foundations. Technical Guide: see figures 3.4B, 10.15
Growing contract (nurseries) The agreement made with the nursery for plant propagation. Contracts usually specify seed source, age, and size of the plant materials to be delivered, dates for delivery, price and payment schedule. Technical Guide: see pages 174-175, 296


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Hydraulic mulch Material composed of fine wood or paper applied through hydroseeding equipment to the soil surface for surface stabilization. Technical Guide: see figure 10.103 p.318 and pages 316-319
Hydroseeding The hydraulic application of seed through hydroseeding equipment. Seeds are placed in a slurry with hydromulch, tackifiers, and soil amendments and sprayed thinning over the soil surface. Technical Guide: see figures 10.95 p.306, 10.102 p.317 and page 306


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Infiltration rates (water) The ability of the surface of the soil to absorb water from rainfall, snowmelt, irrigation, or other sources. The infiltration rate of a soil is the time it takes for a known quantity of water to be absorbed. When infiltration rates are slower than the amount of water received, runoff and soil erosion occur. Technical Guide: see page 48
Introduced species Plants that are not native or locally adapted to the area where they are being installed. Technical Guide: see page 135
Invasive species See "weeds"


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Lime amendments Used when soil pH of a disturbed site needs to be raised to improve plant survival and establishment. Liming materials include agricultural limestones, pure limestone, pure dolomite, slag, marl, or other forms of lime
Limiting factors Site conditions that affect plant establishment and growth. They include water input; water storage and accessibility; water loss; nutrient cycling; surface stability; slope stability; weeds; pests; and human impacts. Defining limiting factors is important in revegetation planning because it identifies from a multitude of site factors only those that are roadblocks to successful vegetation. Technical Guide: see figures 5.1, 5.2 and page 43
Litter The layer of fresh and partially decomposed needles and leaves that cover the surface of most soil under trees and shrubs. Provides soil protection and nutrients, and can contain viable seeds. May be salvaged and applied to revegetation sites. See also duff. Technical Guide: see page 214
Live brush layers Cuttings from dormant willow species that are spread on excavated benches and covered with soil. Used to increase slope stability and reduce erosion by breaking slope length, trapping sediments, increasing infiltration, and increasing soil strength as cutting's develop root systems. See also "cuttings." Technical Guide: see figure 10.113 p.330, inset 10.22 p.331 and page 330
Live pole drains A system of interconnecting willow bundles placed in ditches to intercept water from seeps or unstable areas and redirect it to more stable areas, such as draws or ditches. Technical Guide: see page 105
Live stakes Large, individual cuttings that are inserted into the ground for establishing plants (typically willow and cottonwood species) and physically stabilizing the soil. Technical Guide: see figures 5.8, 10.109 and page 326
Locally-adapted native plants Plant materials collected near the project site (or sites with similar ecological attributes to the project site), and best suited to the local conditions of the project area; generally requiring less maintenance and persisting longer than non-local species. When properly established, they form self-sustaining plant communities. Technical Guide: see figure 5.4 and page 132


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Microcatchments Structures that capture runoff from outsloped road surfaces and compacted shoulders into terraces and berms where the water can be used for plant growth. Technical Guide: see figure 10.45
Mitigating measures Site treatments that reduce or eliminate the conditions limiting revegetation (see "limiting factors"). There are usually several ways to mitigate each limiting factor. For example, a limiting factor of insufficient nutrients may be overcome with fertilizers, topsoil, compost, nitrogen-fixing species, or a combination of these. Technical Guide: see figure 7.2 p.151
Monitoring protocol A specific set of directions that details how monitoring will be conducted. For roadside revegetation projects, monitoring protocols have been developed for soil cover, species cover, species presence, plant density, and plant attributes. Each protocol outlines how transects and quadrants (or plots) are located, methods for collecting data at each plot, and how data is summarized for statistical analysis. Technical Guide: see Chapter 12
Monitoring report Summary of monitoring findings submitted after monitoring plan has been fully implemented. Report assess whether the revegetation project met standards and commitments made during the planning stages, particularly in regard to stated desired future conditions (DFCs), have been achieved. The report may also share lessons learned (successes and failures) for the benefit of future projects. See also monitoring; monitoring protocol; desired future conditions.
Monitoring plan (strategy) The written details for monitoring a revegetation project. Usually consists of monitoring protocols, schedule, location, and expertise. Technical Guide: see tables 11.1, 11.2
Mulch Protective material placed on the soil surface. Mulch materials may include wood fibers or chips, hay, straw, erosion mats, duff, and litter. Mulch effects included reducing evaporation, moderating surface temperatures, preventing weed establishment, enriching the soil, or reducing erosion. See also duff; litter; and organic matter. Technical Guide: see pages 201-215
Mycorrhizal fungi Beneficial fungi that forms a fine web or netting on the roots of host plants, acting as an extension of the plant root system. Mycorrhizal fungi forms a symbiotic relationship with the host plant, increasing water and nutrient uptake, and protecting plants from stress and diseases. Technical Guide: see figures 10.31, 10.32, 10.33, 10.34


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Native plants See "locally adapted native plants". Technical Guide: see pages 7,8 etc.
Nitrogen-fixing bacteria Beneficial microorganisms that live in nodules on plant roots and accumulate ("fix") nitrogen from the air and share it with their host plants. Only certain plant species (e.g. lupine) can form symbiotic partnerships with nitrogen-fixing bacteria. On degraded land, re-introducing plant species that form a symbiotic relationship with nitrogen-fix bacteria can improve nutrient cycling. Technical Guide: see figures 10.38 a and b, 10.39, table 10.11 and page 239
Noxious species See "weeds"
Nutrient cycling The process by which vegetation, soils, and other components store and release essential elements for plant survival and growth. Technical Guide: see page 70
Nutrient threshold A minimum level of a nutrient that must be achieved to meet the revegetation objectives of a project. Threshold values are determined by comparing soil test results from disturbed and undisturbed reference sites. Technical Guide: see figure 10.1 and section 5.5 p.77


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Organic matter amendments (organic amendments, organic matter) Materials from plant sources, including yard waste (lawn clippings, leaves), wood residues (bark, sawdust, needles, roots), manures, agricultural waste products (fruits and vegetables) and biosolids (treated sewage sludge) or a combination of these. Organic matter amendments can improve soils, rooting depth, infiltration and drainage, and water-holding capacity, as well as encourage quicker release and availability of nutrients. Technical Guide: see figure 10.6
Outplanting window The optimum time of year to install plant materials for achieving the highest possible plant survival. Technical Guide: see figures 6.8, 6.9, 6.10 and pages 139-145


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Parent material (soil) The mineral or rock material from which a soil is formed. Parent material influences the soil texture, rock fragment content, nutrients, rooting depth and other soil properties. Technical Guide: see page 124
Permeability The rate at which a volume of water moves through a soil profile or portions of a soil profile (technically referred to as hydraulic conductivity).
Pests An organism that is considered problematic. Includes mammals (e.g. gophers, deer), insects, and diseases. Technical Guide: see figure 5.67
Photo point monitoring A method of displaying landscape changes in vegetation over time by taking photographs at the same location at different times. Technical Guide: see figure 11.2 and pages 363-464
Pine straw Needles from pine trees collected for use as a soil cover or mulch. The interlocking feature of the long needles reduce surface erosion and increase surface strength. Technical Guide: see figure 10.18 F
Plan view A drawing depicting a section of the road from a bird's eye view. Technical Guide: see figure 3.1 p.21 and page 20
Plant attributes (monitoring) Measurements used in monitoring to determine how fast planted grasses, forbs, shrubs or trees are growing. Attributes measured include total height, last season's leader length, stem diameter, crown cover, and weight (for grasses and forbs). Technical Guide: see figure 12.1 and page 366
Plant communities An assembly of different species of plants growing together in a particular habitat or site.
Plant density (monitoring) Measurements used in monitoring to determine how many seedlings or cuttings survived after planting; used to assess whether stocking is adequate or if the site needs replanting. Technical Guide: see page 366
Plant propagation The reproduction of plants usually in a nursery. Plants may be propagated from seeds, cuttings, or transplants.
Planting islands Used where deep-rooted tree and shrub species are desired, but topsoil, soil amendments, and/or soil depth are limiting; designed so that good growing environments may be established in limited areas. Technical Guide: see figures 10.47, 10.48
Planting pockets Terraces or other structures filled with growing media (usually topsoil or amended subsoil) and planted. Technical Guide: see figure 10.44 and page 245
Profile view A drawing depicting the elevational rise of a road. Technical Guide: see figure 3.2 p.21 and page 20
Project log A diary with regular entries documenting the progress of the revegetation efforts.
Pure live seed (percent) The percent of the bulk seed weight that is composed of viable seed.


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Rainfall interception The capture of rainfall through a series of layers, beginning with the tree and shrub canopy, 2) grass and forb cover and 3) litter and duff layer. Technical Guide: see figure 5.6
Reclamation A type of revegetation objective that calls for the recreation of a site that is designed to be habitable for the same or similar species that existed prior to disturbance. Reclamation differs from restoration in that species diversity is lower and projects do not recreate identical structure and function to that before disturbance. However, a goal of long term stability with minimum input is implied. See also revegetation, rehabilitation, restoration. Technical Guide: see table 4.2 and page 30
Reference sites (disturbed or undisturbed) Disturbed and undisturbed sites that serve as models for desirable recovery of native plant communities. One or more reference sites are identified for each revegetation unit in the project area. Technical Guide: see figure 4.2 p.29 and pages 34-37
Rehabilitation A type of revegetation objective that calls for creating alternative ecosystems that have a different structure and function from the pre-disturbance community, such as park, pasture, or silvicultural planting. See also revegetation, reclamation, restoration. Technical Guide: see table 4.2
Restoration A type of revegetation objective that calls for the recreation of the structure and function of the plant community identical to that which existed before disturbance. Restoration's goal is conservation, with the intention of maximizing biodiversity and function. See also revegetation, reclamation, rehabilitation. Technical Guide: see table 4.2
Restrictive layer Any soil horizon or stratum (including unfractured bedrock) that has very low permeability. Technical Guide: see figures 5.57, 5.58 and page 104
Revegetation A general term that may refer to restoration, reclamation, rehabilitation or other goals to reestablish vegetation on a disturbed site. Technical Guide: see table 4.2
Revegetation objectives The stated goals for establishing vegetation on a roadside project. These may include erosion control, wildlife protection, weed control, and visual enhancement. Technical Guide: see page 30
Revegetation plan An integrated strategy developed by the revegetation specialist to establish vegetation on a roadside project. The plan includes the revegetation objectives; a description and location of each revegetation unit; the desired future conditions (DFCs); an analysis of the site attributes and vegetation; a description of mitigating measures; list of plant materials/stocktypes and application methods; key contacts; budget and timelines; and monitoring protocols. Technical Guide: see Chapter 8 (example revegetation plan) and page 148
Revegetation specialist Resource person tasked with overseeing the initiation, planning, implementation, and monitoring phases of the roadside revegetation project. Usually has a background in natural sciences and an ability to generate context-appropriate solutions, cooperate with other disciplines (engineering, hydrology etc.) and meet timelines. Technical Guide: see pages 6, Manager's Guide p.9
Revegetation unit Areas within the project that are relatively similar in terms of soil, aspect, slope gradient, microclimate, and type of vegetation. Technical Guide: see figure 4.2 (especially 4.2 E) and page 31
Revegetation zones (zones, revegetation) Roadside zones parallel to the road travelway each with specific sets of road objectives including road safety, maintenance, and revegetation. Technical Guide: see figure 3.5B and pages 23, 24
Right-of-way (ROW) The strip of land over which facilities such as roads, railroads, or power lines are built. Legally, it is an easement that grants the right to pass over the land of another. Technical Guide: see page 26
Riprap Large rock placed to resist scour or soil erosion caused by concentrated water flow. Technical Guide: see page 27
Road construction plans A set of engineering drawings and specifications (contract descriptions) which act as "blueprints" for road building. They may include a plan view, profile view, cross-section view, typical view, summary of quantities table, and other specifications and details.
Road decommissioning Permanently closing a road through techniques that include blocking the entrance, scattering limbs and brush on the roadbed, replanting vegetation, adding water bars, removing fills and culverts, or reestablishing natural drainage patterns. The basic road shape, or template, is still in place. The end result is to terminate the function of the road and mitigate the adverse environmental impacts of the road. See road obliteration. Technical Guide: see page 28
Road maintenance (maintenance) Human activities that maintain the road and/or roadside. May include salting, plowing, or other winter safety measures; weed control; clearance for visibility and safety, fire hazard reduction, erosion control and/or utilities maintenance. Technical Guide: see figure 5.69
Road obliteration A form of road closure that restores the site to the natural contours by removing fill slopes and filling cut slopes. Objective is to restore soil function and establish native plant communities. See road decommissioning. Technical Guide: see page 28
Roadside The area extending from the road shoulder to the limits of the road right-of-way. Technical Guide: see figure 1.7 and page 7
Rock fragment Particles that range in size from fine gravel to large stones; rock fragments affect the amount of water and nutrients a soil can hold. Technical Guide: see figures 5.12, 5.13
Rooting depth The distance from the surface of the soil to the lower reaches that plant roots can penetrate. It encompasses any strata that can be accessed by roots (topsoil, subsoil, parent material). The deeper the rooting depth of a disturbed site, the greater total available water storage and the higher the productivity of the site. Technical Guide: see page 59
Runoff Portion of precipitation that moves over the soil surface and enters ditches, streams, or other water courses. Runoff occurs when precipitation rate exceeds infiltration rate.


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Safety plan Usually part of a quality assurance plan by an agency or contractor working on the project, the safety plan details how workers and the public will be kept safe while tasks are being preformed. Technical Guide: see page 175
Sediment Sand, clay, silt, and organic material eroded and deposited by water and wind.
Seed mix A combination of species used in a seeding project that meet the environmental requirements of the site and project objectives. Technical Guide: see figures 10.86, 10.91
Seed source The identity of a batch of seed which includes the seed collection location (seed zone and elevation), number of parents, date collected and ownership. Technical Guide: see figure 10.53
Seed zones A defined geographic area within which plant materials of one species can be transferred with minimal risk of being poorly adapted. Used by resource managers to identify appropriate sources of locally-adapted native plant materials to use on projects. Seed zones are mapped by state. See also transfer guidelines, ecoregions, locally-adapted native plant materials. Technical Guide: see figure 6.4 and page 132
Self-sustaining plant communities The ability to develop and perpetuate into a healthy community of native plants without input from humans.
Shade cards Structures that protect seedlings from heat damage caused by high solar radiation. Technical Guide: see figure 10.131
Site resources assets on the project site that can aid the conservation or re-establishment of vegetation, including topsoil, duff, litter, plant materials (seeds, seedlings for salvage, cuttings) woody materials (for mulch), and water. Technical Guide: see figure 5.72 and page 122
Site treatments See "mitigating measures"
Slash material Woody materials (brush, trees, etc) created during activities such as tree thinning operations, fuels reduction projects, and road right-of-way clearing. Technical Guide: see figure 5.72
Slope aspect The direction a slope is facing; measured by facing the fall line (the direction a ball would roll) and taking a compass bearing downslope. Technical Guide: see figures 4.3, 5.24
Slope gradient The angle of a slope. For road engineering, it is defined as the rise (vertical distance) over run (horizontal distance). Technical Guide: see figure 5.5
Slope length The linear distance of a defined segment of slope.
Slope stability The resistance of a natural or artificial slope to failure by mass movement. Technical Guide: see figure 5.60
Slump A rotational failure, a slow moving landslide occurring in cohesive soils. See also debris slide. Technical Guide: see figure 5.55 p.101 and page 101
Soil cover (monitoring) A revegetation parameter that is monitored to determine the amount and type of soil cover (such as bare soil, gravel, mulch and plants). Technical Guide: see page 366
Soil imprinting A form of surface tillage that leaves the soil with a pattern of ridges and valleys. Equipment to carry out imprinting applies a downward compressive force to a metal mold, leaving an impression on the soil surface. Technical Guide: see figure 10.12 and page 200
Soil shattering Loosening compacted soils without mixing horizons. Technical Guide: see figure 10.8 and page 195
Soil strength The capacity of soil to resist forces without failing (rupturing, flowing, fragmenting). Soil strength consists of both physical factors (particle sizes, porosity, etc) and biological factors (roots and stems that anchor or add support to the soil). Technical Guide: see pages 107-108
Soil structure The arrangement of soil pores (or voids) determined by how individual soil granules aggregate together. Soil structure is responsible for water movement, water storage, air flow, and root penetration. Soil structure is compromised by the use of heavy equipment and resulting compaction. Technical Guide: see figures 5.14, 5.15
Soil testing The analysis of a soil sample to determine chemical properties such as pH, soluble salts, macronutrients, micronutrients, and organic matter as well as physical properties that may include density, water-holding capacity, and texture. Technical Guide: see pages 81-82 (how to do a soil test)
Soil texture The relative proportion of sand, silt and clay particles in a soil; controls how soils store water, release nutrients, erodibility, and type of sediments that will result. Technical Guide: see figure 5.9 and page 52
Sowing window The optimum time of year to seed in order to facilitate the highest possible plant establishment. See also "outplanting window" and "planting window." Technical Guide: see pages 144-145
Special contract requirements (SCRs) Modifications of existing road specifications (the standards, provisions, and requirements given by the constructing agency to employees or contractors carrying out the road construction plan) based on the specific objectives of the project. Technical Guide: see page 18
Specialist species Species with narrow ecological amplitude but high ecological importance. Used to fill in niches that workhorse species do not adequately cover. Technical Guide: see figure 6.2 and page 130
Species cover (monitoring) A revegetation parameter that is monitored to determine the aerial cover of plant species. Technical Guide: see figure 12.7 and page 366
Species presence (monitoring) A revegetation parameter that is monitored to determine the presence of a plant species. Technical Guide: see figure 12.8 and page 366
Spot-fertilizer A method of applying fertilizer to trees or shrubs by concentrating fertilizer on the surface or in the soil near the plant. Technical Guide: see inset 10.1 and page 194
Stocktypes Types of plants that nurseries can provide, including bareroot seedlings, container seedlings, rooted cuttings, transplants, and plugs. The stocktype also refers to the age of the plant, size and container shape of the container. Technical Guide: see figure 6.5
Stooling beds Stands of large willows or cottonwoods plants (or other species that propagate well from cuttings) propagated in nurseries for the purpose of providing a ready source of cuttings; usually started from wild collections. Technical Guide: see figure 10.71, table 10.15
Subsoil The soil horizon between the topsoil and the parent material. The subsoil is usually lighter in color than topsoil and contains less organic matter and nutrients. Technical Guide: see page 124
Succession (successional processes, ecological succession) The natural changes and development in the composition and structure of a plant community over time following disturbance. For example, the succession of a grassy area into a forested area over a period of fifty years. Technical Guide: see figure 4.3
Surface roughness The micro-relief of the soil surface. High surface roughness is exhibited by many micro-basins that capture and store soil particles and seeds that have become detached in the erosional processes. Technical Guide: see figure 5.52
Surface stability The tendency of soil to remain in place under the erosive forces of raindrop impact, runoff, wind, freeze thaw and gravity. Good surface stability is essential for establishing plants, reducing erosion, and maintaining high water quality. Technical Guide: see page 88


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Tackifier Sticking agents applied to the soil surface (through hydroseeding equipment) to bind soil particles, fine mulches, seed and other surface-applied materials together for protection from wind and water erosion. Technical Guide: see figure 10.105 and page 319
Target plant concept (target plant materials) A tool for selecting plant materials best suited to the project. It consists of six requirements for establishing native plants: 1) objectives of outplanting project 2) type of plant material 3) genetic considerations 4) limiting factors on outplanting site 5) timing of outplanting window and 6) outplanting tools and techniques. The concept is based on the premise that there is no such thing as an "ideal" all-purpose seed mix or stocktype for every situation. Instead, the fitness of the plant material is determined by its appropriateness for the conditions of the project. Technical Guide: see figure 6.3
Target seedling density The number of plants per unit area that is desired after a defined interval of time. Technical Guide: see page 274
Tillage Any mechanical action applied to the soil for the purposes of improving soil productivity, reestablishing plants, and controlling soil erosion. Used to shatter compacted soils, incorporate soil amendments, and/or to roughen soil surfaces. Technical Guide: see figure 10.10
Topographic enhancements Alterations to the landscape designed to improve the growing environment for plants. Often used to concentrate resources such as topsoil, organic matter, and water to key areas of the project. Examples including planting pockets, microcatchments, planting islands, and biotechnical engineering structures. Technical Guide: see figure 10.46
Topsoil The uppermost soil horizon; high in organic matter, roots, and biological activity.
Topsoiling The salvage, storage, and application of topsoil material to provide a suitable growing medium for vegetation and to enhance soil infiltration rates. Technical Guide: see figure 10.24 and page 216
Total available water-holding capacity The sum of all water that a soil profile can store when fully charged and which is accessible to roots. Technical Guide: see inset 5.1 p.54 and pages 50-54
Transfer guidelines Recommendations of how far plant materials can be moved from their point of origin and still be adapted to the local conditions. To date transfer guidelines have only been developed for a small number of native plants; however work is underway to define these guidelines for more species. See also seed zones, ecoregions, locally-adapted native plants. Technical Guide: see pages 132
Typical view A representative drawing depicting features of a particular design, installation, construction or methodology. Technical Guide: see figure 3.4 A, B p.23 and page 20


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Weed-resistant plant communities A mix of species that occupy multiple ecological niches in order to prevent the invasion of weed species. Technical Guide: see page 111
Weeds Any non-native species that occupies a revegetation site and limits successful revegetation. The exact list of weed species will generally be determined on a project-by-project basis. Categories of weeds include invasive, noxious, competing, introduced, and exotic. Weeds may be listed on federal, state, or local lists as noxious weeds or invasive species. Technical Guide: see page 109
Wildings (wild plants) Plants that are excavated from their point of origin and transplanted directly on to a restoration site or into a nursery. Sometimes wildlings are salvaged from an area that will be disturbed by construction activities. Technical Guide: see figure 10.58 and page 265
Wood strands Long, thin pieces of wood, produced from wood waste veneer, developed as an effective erosion control alternative to straw and hay. Technical Guide: see figure 10.13
Woody material Consists of live and dead plant materials (tree boles, root wads, bark, and branches) used as surface mulches, biotechnical engineering structures, obstacles for erosion control, or as material to enhance site productivity. Technical Guide: see figure 10.18 (B and C) and page 124
Workhorse species A locally-adapted native plant that has the following characteristics: 1) broad ecological amplitude; 2) high abundance, and 3) easy to propage.
Working group A mix of workhorse species developed for a specific ecological function or management objective. Functions may include weed control (to form a weed-resistant plant community), conservation goals, soil stabilization goals, wildlife habitat goals, or visual enhancement goals. Technical Guide: see figure 6.1 p.129 and page 129

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