Operational plans must identify areas of soils that differ significantly in their susceptibility to disturbance. The maximum allowable amount of soil disturbance from harvesting and regeneration treatments as well as the maximum area in roads and landings must also be specified in operational plans.
Bladed or excavated logging trails must be constructed in a manner to facilitate their rehabilitation; they must be rehabilitated upon completion of harvesting. Such trails are not permitted in community watersheds on areas of highly erodible soils or moderate to high likelihood for landslides. Outside of community watersheds, such trails may be permitted on areas with moderate to high likelihood for landslides unless a detailed terrain stability assessment determines that constructing the trails will not cause the terrain to become unstable.
Soil productivity must also be restored on temporary roads and landings.
Operations must stop if they are causing excessive soil disturbance. Causing excessive soil disturbance is an offense subject to a substantial financial penalty.
Any soil disturbance above the maximum amount specified in operational plans must be rehabilitated at the licensee's expense. Refusal to rehabilitate excess soil disturbance may result in suspension of timber harvesting rights.
Operation of heavy equipment for site preparation is prohibited when soils are wet and therefore subject to compaction. Soil Erosion Hazard Ratings (EHR's) are submitted with harvest plans. EHR's for areas of 20 acres (about 8 ha) or larger must be shown on maps; the minimum map area for high and extreme EHR's is 10 acres (about 4 ha). The EHR's are determined by an RPF following procedures given in the Board Technical Rule Addendum # 1, February 1, 1990.
General conservation methods include maintaining a mixed forest cover to prevent the leaching of nutrients and the acidification of the soil. Nutrient leaching is prevented by leaving young trees or patches of forest, or by producing two-tiered stands, for example growing spruce beneath a birch nurse crop (Finnish Forest and Park Service). Mixing or alternating broadleaf and conifer species also reduces acidification of the soil. Reducing the size of cut areas on steep slopes, orienting cut areas to run parallel to the contours of the land, and preparing sites so that water will soak into the soil rather than run off it, are also recommended for areas susceptible to soil erosion.
There are specific erosion prevention guidelines for forest roads. Roads are not constructed in erosion prone areas unless alternate routing is not possible. If the roads are necessary, techniques such as the construction of bottom dams, breaking drain and ditch lines, and terracing side-ditch bottoms are incorporated into the road design (Finnish Forest and Park Service).
Effective January, 1994 the use of mineral-based oils in forest machines will be prohibited in state forests. Only biodegradable hydraulic oils and lubricating oils will be permitted. As well, contracts will include a clause requiring work sites to be litter free both during and following the forest operation. The use of degradable materials will be encouraged and waste recycling will be promoted where possible (Finnish Forest and Park Service).
Federal Republic of Germany
Soil conservation is regulated by a separate federal framework law, the Soil Protection Law. The law provides general soil protection regardless of land use. Soil protection regulations are also included in the Nature Preservation Law. In both cases, the use of appropriate forestry is allowable under the law.
The Federal Forest Act does refer to soil conservation and erosion control in Sections 6 and 12. A basic principle for State forestry outlined in Section 6 states that site conditions should not be depleted and stresses the protection of soil productivity. Section 12 of the Federal Law allows for the declaration of Protection Forests. Forests subject to soil erosion can be declared protection forests.
Baden-Wurttemberg
Baden-Wurttemberg developed state regulations for its Soil Protection Law in 1992. As in the federal framework law, appropriate forestry is allowable.
The State Forest Law refers to soil management in Sections 14, 19 and 30. Section 14 states that soil and soil fertility must be retained, Section 19 requires minimal disturbance to the soil during road construction, and Section 30 allows the designation of Soil Protection Forests.
Steeply sloping areas are declared Soil Protection Forests. Planned forest activities within the Soil Protection Forests must follow the special regulations governing silviculture and reforestation within protected forests. Information regarding soil type, soil conservation practices, and slope stability has been gathered for all forests of Baden-Wurttemberg, thus precluding the need for pre-activity assessments of terrain or soil stability. The information was collected at a scale of 1:10,000. There is no State requirement for soil rehabilitation.
Bavaria
Article 9 of the Bavarian Forest Law states that every action that destroys or damages the productive capacity of the forest soil is forbidden. Non-compliance with this article may result in a DM 50,000 (approx. $55,000 Canadian) fine (Article 46). Special management practices are defined for areas declared protection forests because of their unstable soils or steep slopes. Called woodlands of special significance for soil conservation the goal of the protection forests is to minimize soil disturbance so that erosion, due to water, snow, wind, soil impoverishment, rockfall, slides, and soil creeping are prevented.
Soil stability assessments are available for all forest activities in the Alps, including road building and trails within the protection forests (Brinkmann, pers. comm.). The four soil stability classes used to classify the mountain soils are stable, moderate, unstable, and very unstable.
Air pollution is acidifying Bavaria's soils. In response, Bavaria has developed a forest soil inventory aimed at reducing the harmful effects of the air pollutants. Soil inventories have been conducted and observation plots established. A precipitation measuring network is in place and research is ongoing. Research results will aid in the selection of adapted tree species and help identify the most beneficial soil management practices (Brinkmann, pers. comm.).
The objectives of the practices regarding soil in The Code of Practice for Timber Management Operations in Riparian Areas are to avoid areas of high erosion risk and to avoid excessive exposure of mineral soil and excessive soil compaction (TMG/Riparian, 1991:3). Roads should not be constructed on hilly, steep terrain, on erodible or shallow soils, and landings should be on high ground to avoid rutting. Erosion control and sedimentation control measures must be taken to protect water quality. Natural vegetation should be maintained as much as possible to minimize soil exposure (TMG/Riparian, 1991:3). Clearcuts should not occur on steep slopes where erosion is likely (TMG/Tourism, 1989:48). Selection of equipment should consider soil characteristics and topography, and care must be taken to prevent excessive scalping or transport of mineral soil which may lead to erosion on steep slopes (Silvicultural Guide, Vol. 6, 1989, 53). To reduce the risk of erosion on slopes, extra-long winch cables should be used, skid trail locations should be carefully selected, skidding should occur along the slope contours where safe to do so, repeated use of the same skid trail should be avoided, and slope contours should be followed when using heavy equipment (COP - Riparian Areas, 1991:4). On sites that are susceptible to rutting or compaction, high flotation equipment must be used in the summer, or operations should be limited to dry periods or frozen ground (TMP/Riparian, 1991:5). While there is no specific requirement to re-establish vegetation, it is a suggested practice to control erosion (Environmental Guidelines for Access Roads and Water Crossings, 1988:45).
Written plans are required for logging in high risk sites, defined as slopes steeper than 65%; steep headwalls; highly dissected land formations; areas exhibiting frequent high intensity rainfall periods, faulting, slumps, slides or debris avalanches.
Revegetation and rehabilitation of disturbed sites may also be required under forest practices or other rules.
Section 10, which states harvesting is performed to promote a new stand or enhance an existing stand, implies no heavy damage to the ground or to root systems. Section 15 grants the government the authority to designate areas in need of protection against sand or soil erosion as protected forest land. If an area is designated as protected, harvesting can be prohibited or will only occur under strictly regulated conditions, such as a requirement to leave shelterwood.
Soil conservation is also considered in Section 30 of the Forestry Act. This section gives the County Forestry Boards the authority to prescribe regulations "on the degree of respect to be extended to nature conservation and cultural heritage preservation interests...". Soil rehabilitation is also required under section 30 of the Act when public paths or paths of cultural heritage have been damaged, for example after timber transportation. However, the standards for soil rehabilitation are limited.
Problems with soil erosion and slope stability are generally not a factor in Sweden since harvesting in mountainous terrain is restricted (Forestry Act, Section 15 and 18). The terrain in the majority of harvesting areas is not steep and the soils are mostly very stable. Soil erosion is very rare (P. Kjellin, pers. comm.).
For determining terrain/soil stability, field assessment must be completed, and should include determination of majority slopes, erodibility class of soils, and wet or dry season harvesting criteria. A harvesting machinery guide must also be used to determine what type of machinery can be used based on slope, erodibility, and season. (FPC, 1993:25). Ground based logging equipment must be avoided on saturated soils to minimize erosion, puddling, mixing and compaction of the soil and minimize adverse effects on water quality (FPC, 1993:28). Following heavy rainfall, to allow drying of the soil, forest operations should be stopped. Carting on wet, rutted roads must be avoided to reduce excessive turbid runoff which may adversely affect water quality (FPC, 1993:28). In extreme weather conditions, where there is a risk of environmental damage, a complete closure of forest operations may be required (FPC, 1993:28).
The following sub-sections provide specific information regarding soil conservation measures.
Soil erosion is mitigated through the rules concerned with roads and landings, especially those on road maintenance and abandonment. Other relevant parts of the Rules are those concerned with riparian and wetland management (RMZ and WMZ). Erosion problems are also avoided through identification of potentially unstable slopes at the forest practices application stage. DNR keeps soil and geological data in a GIS at their headquarters and applications are checked against this information.
Under the Watershed Administrative Unit (WAU) analysis procedure, areas of potential surface and mass erosion are identified and mapped. Details are given in Washington Forest Practices Board (1994).
Soils that may be sensitive to compaction during site preparation are given protection under the reforestation rules [222-34-040 (1)(a)].
Damaged soil is defined as soil which has been subject to any or all of the following:
In wet weather conditions soil damage can occur in a relatively short period. The F.O.I.C. may prohibit or stop any logging operation if, in his opinion, excessive soil damage is, or may take place. Surveys will be conducted to determine how much soil damage has occurred. If soil damage exceeds a specified level, the F.O.I.C. will require the contractor to repair all soil damage at the contractors expense (COLP, 1990:25). In selectively cut forest areas, soil damage must not exceed 10%, and in clearcut areas the limits are 5% with respect to landings, and 20% overall. Erosion control work must be done at the completion of harvest or during any temporary work stoppage (COLP, 1990:24).Soil rehabilitation is monitored by a F.O.I.C. If not repaired to specified standards, work will be done at Contractor's expense (COLP, 1990:25). Rehabilitation work must be carried by the first day of May following logging. Filter strips are required near streams or reservoirs to filter water runoff. Logging must cease within 40m of reservoirs at the first sign of excessive soil disturbance or erosion likely to cause turbidity (COLP, 1990:91).
