| Potential negative impacts | Mitigating measures | ||
|---|---|---|---|
| Direct: Logging | |||
| 1. | Soils | 1. | |
| • | Erosion: disturbance of the forest understory and soil, increasing susceptibility to water erosion. | • | Avoid logging in the rainy season and establish criteria for logging on slopes and near water,; and clearly mark areas that should not be harvested. |
| • | Slope stability: roadcuts across sloping terrain and clearing of vegetation on the slopes resulting in landslips and landslides | • | Supervise logging to reduce damage and encourage rapid regeneration. |
| • | Nutrient loss: loss of nutrients from timber harvesting and increased leaching; exposed, disturbed soils where vegetation has been removes. | • | Use low impact harvesting equipment and methods and minimise skid trail distances. |
| • | Temperature: dramatic increase in temperature after removal of forest canopy, killing soil organisms or drying the soil to extent that regeneration is hindered. | • | Locate log landing in well drained, easily accessible areas downslope so a straight skid road can be followed. |
| • | Structure: compaction and loss of organic matter altering soil structure, and reducing infiltration, water holding capacity, aeration and root penetration, laterization. | ||
| • | Restore land by grading and reseeding disturbed areas, including guidelines, locating them away from slopes and water, and keeping them well maintained. | ||
| • | No whole-tree harvest in areas of low nutrient levels, leaving all but holes on the site. | ||
| 2. | Vegetation | 2. | |
| • | Species composition: species diversity decreased by selectively harvesting the best stems of valuable species. Soil conditions and light regimes created by various harvesting methods influencing regeneration dynamics of forest stands. | • | Collect information or sponsor research on plant community dynamics, regeneration biology and silviculture of forest type. |
| • | Consider (and perhaps research) various regeneration and harvesting methods. | ||
| • | Weeds: opening of the forest canopy resulting in invasion of weeds, impeding natural regeneration and reforestation efforts | ||
| • | Choose silvicultural system that will ensure regeneration and sustainable production and minimise damage (leave adequate number and quality of seed trees, selective harvest, small cuts to avoid large gaps. | ||
| • | Slash: logging debris as a fire hazard and impediment to regeneration. | ||
| • | Blow downs: increased danger due to opening up patches by logging. | • | Establish preserves/parks of ecologically significant forest areas, ensuring that area is large enough to maintain biological diversity, ecological processes, and cultural assets. |
| 3. | Wildlife | 3. | |
| • | Fisheries: sedimentation, nutrient loading, changes in streamflow and water temperature caused by logging causing domestic changes to fish populations. | • | Maintain inventory of and collection of research results on species present in the area. |
| • | Wildlife habitat: disruption of habitat, loss of tree species on which wildlife species depend, and disturbing migratory routes of wildlife leading to depletion of wildlife. | • | Plan harvesting intensity, methods and timing based on this information. |
| • | In particular, ascertain presence of or migratory use by endangered species through contact with wildlife professionals in government, NGOs and universities. | ||
| • | Presence of machines and people: disturbance of wildlife through logging and transport activities. | ||
| • | Poaching: increased poaching of wildlife due to influx of people resulting directly and indirectly from forestry activities. | ||
| 4. | Air | 4. | |
| • | Dust: logging activities and timber transportation on dirt roads generating large amounts of dust in dry season or semi-arid zones. | • | Reduce burning. |
| • | Avoid creating large tracts of open land. | ||
| • | Limit operations when dust and fire are a problem and plan transport routes to avoid population centres. | ||
| 5. | Water | 5. | |
| • | Extremes of flow: soil infiltration and water holding capacity of harvested areas reduced such that water runoff is much more pronounced, aggravating flooding when rains come and low flow during dry season. | • | Maintain vegetation as buffer zones adjacent to every body of water. |
| • | Ground water recharge: rainwater recharge of aquifers reduced as increased runoff. | • | Assess impact of forestry on sediment and nutrient loading on stream flow and methods used to reduce impact. |
| • | Ponding and stagnation: land form changes, water course obstruction and soil compaction causing localised ponding and stagnation. Increased sedimentation altering natural aquatic biology and water course features. | • | Provide adequate waste disposal facilities. |
| • | Increased temperature: opening of the forest canopy adjacent to water body increasing water temperature, which alter aquatic biology and water chemistry. | • | Procedure for use and storage of chemicals, oil and fuel to minimise potential for pollution. |
| • | Contamination: pollution from petroleum products, herbicides and organic waste associated with forestry operations. Turbidity due to increased sediment loading altering sunlight penetration, affecting aquatic plants and damaging fish species. | ||
| 6. | Social and Cultural | 6. | |
| • | Local economic and social customs: impacts on labour market and labour availability for food production, a shift to more cash-based economy, alteration of daily living patterns and political power structure changes are common. | • | Incorporate local communities in planning and execution of project. |
| • | Land tenure and traditional forest uses: hunting, gathering and traditional exploitation of forest resources disrupted; limitation of access to resources by local populations. | • | Develop local infrastructure to handle increase in population (ie waste disposal, school, health care and law enforcement). |
| • | Overloading of infrastructure and social services (eg. housing, education and health services) by in-mitigation of forest workers and spontaneous settlers, and social problems such as an increase in crime, alcoholism, disease, and violence. | • | Protect significant cultural landmarks and traditional land and resource use patterns. |
| • | Establish clear, long-term jurisdiction over the forest to avoid illegal harvesting or settlement. | ||
| • | Monitor and control disease. | ||
| Indirect: General | |||
| 7. | 7. | ||
| • | Increased access: roads opening forest areas causing uncontrolled population in-migration with subsequent problems. | • | See “Rural Roads” section. |
| Indirect: Road Construction and Transport | |||
| 8. | 8. | ||
| • | Direct impacts (eg. Increased soil erosion and sedimentation of surface water) and indirect impacts of road construction (see “Rural Roads” section). | • | Align route, drainage works, etc. (See no. 7). |
| 9. | 9. | ||
| • | Degradation of existing public roads by heavy timber loads | • | Restrict load size. |
| • | Use road taxes to upgrade road. | ||
| External | |||
| 10. | 10. | ||
| • | Cattle-ranching operations that clear forests for pasture. | • | See “Livestock and Rangeland Management Section” |
| 11. | |||
| • | Conversion to commercial agriculture (rubber, oil palm, coffee, rice, etc.) | ||
Source: World Bank (1991)
| Potential negative impacts | Mitigating measures | ||
|---|---|---|---|
| Direct: Site Preparation | |||
| 1. | |||
| 1. | Soil erosion from clearing site. | • | Reestablishment of forest cover as soon as possible after clearing |
| • | Use of fast growing, intermediate tree crops or mulching of exposed soils | ||
| • | No clearing on steep, unstable slopes or highly erosive soils | ||
| • | Limitation of plantation size or stand sizes | ||
| • | Limitation of site preparation to dry season | ||
| 2. | |||
| 2. | Soil compaction and puddling by machinery | • | Limitation of use of machinery |
| • | Manual site preparation | ||
| 3. | 3. | ||
| • | Loss of organic matter and nutrients by removal of vegetation and leaching. | • | Rapid replanting |
| • | Cover crops | ||
| • | Development of hardpans and laterization | • | Mulching |
| 4. | 4. | ||
| Where burning is involved, air pollution from smoke | • | Limitation of use of fire and size of burn where possible | |
| • | Burning in wet season | ||
| Direct: Plantation Management and Harvesting | |||
| 5. | |||
| 5. | Soil erosion from harvesting | • | Replanting as soon as possible after cut |
| • | Avoidance of clear cutting; practice of “small cope logging” (characterised by checkerboard pattern of alternating small cuts with unlogged areas). | ||
| • | Limitation of harvesting to dry season or season of low rainfall | ||
| • | Planning of felling to minimise log skidding and avoidance of skidding logs parallel to slope | ||
| • | Stabilise skid trails as soon as possible after use | ||
| • | Use of animals instead of skidders for extraction | ||
| 6. | Loss of nutrients from the system by thinning and clear cutting and by whole-tree harvest | 6. | |
| • | Logging debris left on ground after harvesting and removal of boles only (no whole-tree harvesting) | ||
| • | Planting of cover crops between rotations; addition of fertilizer to compensate for nutrient loss | ||
| 7. | Use of fertilizer, pesticides and herbicides having negative impacts on-site and on quality of local water bodies | 7. | |
| • | Limitation of potential of pest and disease infestations by choice of resistant species | ||
| • | Choice of chemicals with least potential negative impacts | ||
| • | Controlled use of chemicals | ||
| 8. | |||
| 8. | Chemical and biological changes in the soil as litter becomes dominated by one or a few species and decomposition dynamics are altered | • | Limitation of size of stands and interspersal with stands of native vegetation |
| 9. | 9. | ||
| • | Direct damage in harvesting operations by dragging and skidding logs causing compaction | • | Use of manual methods or animal power for clearing forest instead of mechanical means |
| • | Localised soil erosion and unequal distribution of debris and organic matter over the site | • | In short rotation plantations plan use of same tracks and loading areas in harvesting operations to protect as much of site as possible |
| 10. | |||
| 10. | In semi-arid zones depletion of soil moisture and lowering of water table in plantation area. | • | Choice of low water demanding species |
| • | Water catchment and conservation techniques to minimise runoff and evaporation losses and minimise infiltration | ||
| 11. | Buildup of organic matter under plantations posing a fire hazard | 11. | Periodic clearing or burning to keep volume low |
| 12. | Increased sedimentation of streams | 12. | |
| • | Buffer zones of undisturbed forest 20–40 m wide along streams | ||
| • | Avoidance of earthfill dams across streams as crossings | ||
| • | Sediment traps in streams | ||
| • | Avoidance of skidding trees in stream | ||
| 13. | Increased organic matter entering surface waters in form of leaf litter and logging debris or from logs transported on river leading to decrease in water quality and perhaps eutrophication, and navigational hazards | 13. | |
| • | Buffer zones along streams | ||
| • | Spaced transport of logs in river over time | ||
| 14. | Soil erosion from logging roads | 14. | |
| • | Siting of roads on ridge tops or valley bottoms and avoidance of steep grades on hillsides | ||
| • | Engineering to ensure proper drainage or provision of drainage measures | ||
| • | Stabilization of road cuts with mulch, wood chips, etc. | ||
| • | Minimised use of borrow pits or stabilization after use | ||
| • | Proper road maintenance | ||
| • | Use of rivers for log transport (see also “Rural Roads” section) | ||
| Displacement of Other Ecosystems | |||
| 15. | |||
| 15. | Loss of habitat and decreased biological diversity by replacement of natural forest by plantations with limited number of species and increased uniformity of forest structure | • | Protection of natural forest area with particularly high or unique biological diversity |
| • | Limitation of plantation establishment to degraded sites or sites of low diversity | ||
| • | Increase in number of species planted and avoidance of monocultures over large areas | ||
| • | Restriction of size of individual stands and mixing of stands of various age classes | ||
| • | Conservation of islands of untouched forest or natural vegetation | ||
| • | Separation of stands by belts of native vegetation and use of native species as plantation species | ||
| 16. | Increased potential for massive loss by pests or pathogens (through simplification of natural ecosystem, provision of abundant food for pest, increased pest habitat absence of natural controls (eg. In the case of introduced exotic tree species) | 16. | |
| • | Use of native species | ||
| • | Choice of species and provenances with pest or disease resistance | ||
| • | Rotation length to minimise susceptibility (eg. Cutting before trees are over mature) | ||
| • | Thinning and other stand improvement measures to remove dead and diseased material, and wood residues which act as centres for infection | ||
| • | Direct pest or disease control | ||
| 17. | Loss of forest products from native species | 17. | Careful evaluation of local use of forest products to accommodate continued use and determine feasibility of developing local industries based on these goods |
| 18. | Spread of plantation species outside of plantation becoming a nuisance, competing with native species and becoming weeds in agricultural fields | 18. | Species choice to avoid ones that will grow out of control from desired site |
| Socioeconomic Impacts | |||
| 19. | Social impacts from influx of people from outside, both wage earners and spontaneous settlers, induced by road building into remote area (direct and indirect impacts) | 19. | See the following sections: “New Land Settlement”; “Indigenous Peoples”; and “Induced Development” |
| 20. | Problems related to land tenure and land and resource use rights leading to unequitable sharing of costs and benefits of the project | 20. | |
| • | Genuine integration of local communities and peoples in project planning and implementation | ||
| • | Pre-project socioeconomic surveys and assessments and land and resource use studies | ||
| • | Provision of alternatives which fairly compensate local people who incur losses | ||
Source: World Bank (1991)
| Potential negative impacts | Mitigating measures | ||
|---|---|---|---|
| Direct: Site Selection | |||
| 1. | Siting of plant on/near sensitive habitats such as mangroves, estuaries, wetlands, coral reefs. | 1. | |
| • | Locate plant in industrially zoned area, if possible, to minimize or concentrate the stress on local environmental services and to facilitate the monitoring of discharges. | ||
| • | Integrate site selection process with natural resource agencies to review alternatives. | ||
| 2. | Siting along water courses causing their eventual degradation. | 2. | |
| • | Site selection process should examine alternatives that minimize environmental effects anad not preclude beneficial use of the water body. | ||
| • | Plants with liquid discharges should only be located on a watercourse having adequate waste-absorbing capacity. | ||
| 3. | Siting can cause serious air pollution problems for local area. | 3. | Locate in an area not subject to air inversions or trapping of pollution, and where prevailing winds are towards relatively unpopulated areas. |
| Direct: Plant Operation | |||
| 4. | 4. | ||
| • | Inadequate or non-existent forest management resulting in soil erosion, diminishing biotopes. | • | In project design phase, develop a forest management plan based on an environmental impact study. |
| • | Unchecked pesticide application causing toxicologic effects on beneficial organisms and undesirable changes in forest ecosystems. | • | Do not select wood supply from primary forest reserves (for further discussion, see sections on “Natural Forest Management” and “Tropical Forests”). |
| 5. | Release of gaseous wastes | 5. | |
| • | Sulphur dioxide | Sulphur dioxide | |
| • | Total reduced sulphur compounds (TRS) | • | Control by proper operations such as liquor recovery furnace. |
| • | Particulates | • | Select appropriate auxilliary fuels. |
| • | toxic organic compounds (eg. chlorine, hydrogen sulphide) | • | Fuel desulphurization, flue gas scubbing, and process modification. |
| TRS | |||
| • | Collection by headers, scrubbed with alkali solution, and then burned. | ||
| Particulates | |||
| • | Removal by evaporator-scrubbers, cyclones or electrostatic precipitators. | ||
| Air Toxins | |||
| • | Prevent/control releases through process design. | ||
| 6. | Release of liquid wastes to water bodies | 6. | In-plant operating and housekeeping measures |
| Conventional pollutants cause the following impacts: | • | Pulp washing, chemical and fibre recovery, treatment and reuse of selected waste streams, collection of spills, and prevention of, and collection of tanks for accidental discharges. | |
| • | changes in pH and toxicity | ||
| • | dissolved and suspended solids | • | Monitoring of sewers, drainage channels, and discharges to warn off spills. |
| • | eutrophication | • | Load levelling of treatment facilites by use of storage basins and other measures. |
| • | foam and scum | • | Recycling of barking water. |
| • | slime growth | External effluent treatment: | |
| • | thermal effects | • | Primary-sedimentation basins, gravity clarifiers, and dissolved air flotation. |
| • | changes in taste, colour and odour | • | Secondary-oxidation ponds, trickling filter, aerated lagoon, activated sludge, irrigation, sedimentation basin (to remove biiological solids) and secondary clarifier. |
| • | fish-flesh tainting | • | Toxins control by substitution of less/non-toxic chemicals. |
| • | Toxins such as trichlorophenol, pentachlorophenol, and zinc | ||
| 7. | Disposal of solid wastes on the land | 7. | Source reduction, source segregation, by-product utilization, appropriate planning and management of disposal sites such as lining of disposal sites with collection system for run-off water and leachate (see “Solid Waste Collection and Disposal Systems” section). |
| • | subsurface leaching with subsequent contamination of ground and surface water | ||
| • | Destruction of ecologically sensitive areas such as marshes and other wetlands. | ||
| • | Proliferation of rodents, scavengers, and insects harmful to human health. | ||
| • | Fires, health hazards, and unsightly conditions. | ||
| 8. | Sludge incineration | 8. | |
| • | Dewatering by vacuum filtration and chemical conditioning to prepare sludges for burning. | ||
| Incinerators: | |||
| • | waste only | ||
| • | burning in the bark boiler | ||
| • | burning in power boiler | ||
| Indirect: | |||
| 9. | Occupational health effects on workers due to: | 9. | Facility should implement a Safety and Health Program designed to: |
| • | Special pulp mill operations such as preparing logs (chipping and grinding). | • | identify, evaluate, monitor, and control hazards to employees |
| • | Handling and storing of pulpwood and paper chips, and raw materials other than pulpwood. | • | design safe operating procedures |
| • | Chemical processes used in making pulp, bleaching, and stock preparation. | • | provide training in safety practices and the handling of emergencies |
| • | Handling of spent liquors and machine room operations involves dust, fumes and gases, as well as special equipment such as shredders, clippers, cutters, heavy mobile equipment, etc. | ||
| 10. | Transit patterns disrupted, noise and congestion created, and pedestrian hazards aggravated by heavy trucks transporting raw materials, fuel and final products to/from the facility. | 10. | |
| • | Site selection can mitigate some of these problems. | ||
| • | Special transportation sector studies should be prepared during project feasibility stage to select best routes to reduce impacts. | ||
| • | Follow transportation regulations and develop emergency contingency plans to minimize risk of accidents. | ||
Source: World Bank (1991)
