OPERATIONS PROTOCOL FOR ECO-EFFICIENT WOOD HARVESTING ON SENSITIVE SITES

Transcription

1 OPERATIONS PROTOCOL FOR ECO-EFFICIENT WOOD HARVESTING ON SENSITIVE SITES Quick Reference Card ECOWOOD Project (

2 Step Classify the Soil as Strong, Average, Soft or Very Soft Soil Strength Score ( to 4) Strong Average Soft 4 Very Soft Cone Index (kpa)* E Shear Strength (kpa) > 500 > 60 > < 00 < 0 < 0 <<00 <<0 <<0 Classification of soil strength based on three soil strength indices. The classification is based on the lowest index i.e. the parameter value that falls into the lowest soil strength category. If none of these three measurements are available, estimate the soil strength category based on visual observations and local knowledge. Step Match the Soil Strength to the Ground Bearing Capacity (kpa) Soil Classification Relating Soil Strength to Ground Bearing Capacity (GBC) Soil Strength Score General Description of the Soil Types* Ground Bearing Capacity (GBC) ( to 4) Strong Dry sands and gravels; Firm mineral soils High GBC > 80 kpa Average Soft mineral or iron-pan soils Medium GBC kpa Wet gleys and peaty Low GBC Soft 4 Very Soft soils Wet peats * These descriptions will vary with soil wetness kpa Very Low GBC < 40 kpa

3 Step Classify the Terrain Soil Strength Score ( to 4) Strong Average Soft 4 Very Soft (not suitable for Terrain classification* Ground Roughness Ground Slope Score ( to ) Score ( to ) Even Gentle (< 8 o or 4 %) Uneven Intermediate (8 o 4 o or 4-5 %) Rough Steep (> 4 o or > 5 %) machine traffic) * Combine Soil Strength with Ground Roughness and Slope to classify the terrain. For example, a soft soil with an uneven surface on a steep slope has a Terrain Classification of,, Matching Terrain Classification to Harvesting System Tracked Forwarder, Forwarder, Tracked Forwarder, Step 4 Match Terrain Classification to Harvesting System Tracked Forwarder, Forwarder, Horse Forwarder, Tracked Forwarder Tracked Forwarder, Chained Forwarder, Forwarder, Tracked Forwarder, Forwarder, Forwarder, Tracked Forwarder, Harvesting System Selection

4 Step 5 Select a Harvester with NGP less than GBC Nominal Ground Pressures (NGP) for typical harvester configurations > 80 kpa * axle harvester, tyre widths range from mm kpa * axle harvester, tyre widths range from mm kpa * Harvester Selection 4 axle harvester, typical tyre width = 600 mm < 0 kpa * Tracked harvester * NGP is dependent on tyre / track size and general machine configuration. Further details can be obtained from the machine manufacturers.

5 Step 6 Select a Forwarder with NGP less than GBC kpa* kpa * kpa * kpa * Forwarder Selection With Band Tracks fitted: kpa * These NGP values refer to fully loaded forwarders and are dependent on tyre / track size and general vehicle configuration. Band tracks significantly reduce the NGP. Further details can be obtained from the machine manufacturers.

6 GENERAL CONSIDERATIONS FOR ECO-EFFICIENT MANAGEMENT OF WOOD HARVESTING ON SENSITIVE SITES IT IS MOST IMPORTANT TO HAVE AN EFFECTIVE HARVEST SITE PLAN IN PLACE THAT COMPLIES WITH ALL LOCAL AND NATIONAL GUIDELINES ON FORESTRY, FISHERIES, ARCHAEOLOGY AND LANDSCAPE. OPERATIONS MUST BE CARRIED OUT UNDER THE GUIDING PRINCIPLES OF SUSTAINABLE FOREST MANAGEMENT. Categories of site damage and degradation due to machinery operations are listed, and the potential remedial measures. Soil damage (rutting and compaction) Repeated passes of heavy machinery on the same track may lead to the development of ruts. Rutting can be particularly severe on soft soils, such as wet peats or gleys, and is exacerbated with each vehicle pass. The internationally acceptable maximum tolerable rut depth is 00 mm. The soil beneath the ruts becomes compacted, with the zone of maximum compaction extending to a depth equal to approximately half the rut width (most severe in upper 50 mm but extends to ca. 00 mm depth). Compaction decreases soil pore space and prevents water and nutrients from entering the soil. It also reduces the water infiltration capability of the soil, hence making the rut an excellent channel for surface water flow. Use existing knowledge base and measurements (e.g. cone penetrometer, shear cane) to assess ground conditions; Select the appropriate machines for the site (i.e. Steps to 6, outlined earlier); Minimise dynamic effects by ensuring proper load balance and driving techniques; Use brash mat if possible; Minimise the number of machine passes; If an operation must be executed under wet conditions, avoid waterlogged areas; Consider reduced but economically viable forwarder payloads. Schedule the work appropriately, wintertime (when frozen) or summertime (when dry) Soil erosion and sedimentation Input of soil to the watercourses (increased suspended solids and sedimentation on the stream bed) is potentially one of the most significant changes in the environment surrounding the forests. Harvesting can increase soil input to watercourses by a variety of processes, including: surface run off from landings, skid trails and compacted areas; slope failure caused by the removal of vegetation; increased surface runoff; physical damage to the stream banks, such as slippage and bank collapse, and; impedance of natural water flow when watercourse crossing structures are not provided, are damaged, or poorly maintained. Select the appropriate machines for the site (i.e. Steps to 6, outlined earlier); Use brash mat if possible; Access roads should be surfaced with weather resistant material such as gravel, and maintained in good condition during harvesting operations; Smaller ditch drains emanating from the forest should not discharge directly into streams or watercourses, but should be routed through areas of natural vegetation such as forest edge areas, scrub land or filter media such as straw or brash; Temporary stream crossings should be provided, either built with logs on site or comprising portable equipment; Erosion control and soil stabilisation structures such as terraces should be developed as necessary alongside the access routes; Regular road inspection to identify and repair damaged areas after harvest operations.

7 Residual stand damage (stems and roots) Traffic induced stand damage is important in thinning operations. The process of soil compaction impedes root proliferation, particularly in the maximum compaction zone (viz. down to ca. 00 mm). Rutting may make the surrounding residual trees prone to windthrow (falling over in heavy winds). Exposed roots are subject to direct scuffing action by the wheels (or tracks), and this may increase the potential for fungal infections. The extent of such scuffing damage depends on the degree of rutting and the severity of the machine s action e.g. the use of band and full metal tracks exacerbates the effect. On soft soil, rut depths can extend 500 mm on poorly maintained main extraction routes, hence root damage may not be confined to surface roots and can have a substantial impact on the trees. Example of severe (Class 5) root damage Select the appropriate machines for the site (i.e. Steps to 6, outlined earlier); Use brash mat if possible, and employ only trained operators; Limit the movement of tracked machines around residual trees in partial cutting; Use appropriate band tracks for the inherent ground conditions. Surface disturbance Forestry machines rely on soil shear resistance at the wheels/track and the soil interface to generate the required drawbar pull. The magnitude of the drawbar pull depends on several factors such as soil condition, vehicle weight, tyre (or track) type, load resistance and is invariably accompanied by a degree of wheel/track slip. Damage due to slip includes: scuffing of the soil surface; mixing (and dislodgment) of the upper soil layer (top mm); root damage and, in extreme cases, a breakdown in the structure of the top layer of soil (puddling); surface disturbance which may also lead to significant erosion problems in dry climates. Example of severe surface disturbance caused by excessive wheel slip (wet soil) Select the appropriate machines for the site (i.e. Steps to 6, outlined previously); Use brash mat if possible; Access roads should be surfaced and maintained with weather resistant material such as gravel; Schedule harvesting operations to coincide with best soil conditions. Water pollution and waste management Most minor oil or chemical spills can be dealt with by means of a pollution control kit. This comprises a small (< 0 m long) portable floating boom (white in photo) that can be placed across a stream to stop the surface flow of the pollutant slick. Floating absorbent pads (light blue in photo) are placed on the upstream side of the boom to absorb the slick. Such kits are available commercially and are contained in a small sack suitable for carriage on the machine. It is recommended practice that all forestry machines carry such a pollution control kit. In contrast, major pollution incidents require a concerted action that may involve local authorities such as emergency services, environment agencies, etc. Harvest managers and machine operators must comply with rules for transportation, storage, handling and disposal of hazardous substances; Product data sheets and spillage control procedures should be in place where chemicals are in use; Temporary fuel and chemical storage facilities should be located away (approximately 00 m) from watercourses; Machines should carry spillage control kits to contain small oil and chemical leaks, while there should be guidelines for handling of major spillage incidences; Waste oil and empty oil containers, grease cartridges, paper towels, broken cables and hydraulic hoses should be temporarily retained on site in disposal bins for disposal later. In all of the above, bearing in mind the Health and Safety regulations, it is of the utmost importance that;. Proper planning is carried out resulting in a documented harvest plan, available on site. This involves consultation with relevant bodies, both statutory and local, choice of machine and method, timing of operation and adequate monitoring of on-site activities.. Only competent operators are used. This implies trained, skilled, possibly certified operators that have the experience and knowledge to handle operations on sensitive sites, bearing in mind the constraints that these impose.. Responsibility lies with clearly defined personnel to ensure an adequate quality of work.