British Columbia Mine Reclamation Symposia

Some economic considerations in forest land rehabilitation 2010

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Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation SOME ECONOMIC CONSIDERATIONS IN FOREST LAND REHABILITATION Paper Presented by William W. Carr Department of Soil Science University of British Columbia Vancouver, B.C. Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation SOME ECONOMIC CONSIDERATIONS  IN FOREST LAND REHABILITATION INTRODUCTION The interior forest regions of British Columbia accounted for approximately 60% of wood products produced and 75% of the land clearcut in 1980 (Annual  Report, Min. of Forests, 1980-81).    The predominant harvesting technique in these regions is ground-based yarding with tractor or skidders.    Ground-based yarding requires the construction of skidroads and landings of timber extraction,  sorting, and loading. However, the construction of skidroads and landings is an extreme form of site disturbance that poses land rehabilitation problems.    The construction of skidroads and landings can not only lead to soil erosion but also reduced forest productivity through scarification and compaction (2, 3, 7, 8, 9, 10, 11). The results of a 1981 Ministry of Forests survey of the percent of cut- over area occupied by skidroads and landings  for the interior regions are presented in Table 1 (based on internal memos).    There is a wide range in the estimates  for each category from the various regions. Although regional  terrain and season of logging will  influence the amount of disturbance on cut-over land, one would expect areas that are logged by the same method to receive relatively the same level  of disturbance.    Except for the Cariboo Region,  the Ministry of Forests estimates appear very conservative.    This can be demonstrated using the Nelson Region as an example. Table 2 presents a comparison of percent area occupied on cut-over lands by skidroads and landings from three sources.    The Ministry of Forests estimate is  from the regional   headquarters (internal  memo, Jan. 1982),  the Canadian Forest Service (C.F.S.)  estimate is  from Smith and Wass (1979), and the Pacific Northwest estimate summarized from Dyrness (1965),  Lull   (1959),  Steinbrenner (1955), Steinbrenner and Gessel (1959),  and Froehilch (1973).    The Ministry of Forests estimate approximately half of the C.F.S. estimate  for the same region.    The C.F.S. data compares  favourably with the Pacific Northwest estimates from Oregon and Washington.    This comparison points out the conservative  nature of the Ministry of Forests estimates. Using the Ministry of Forests estimates and combining them with the area clear-cut in the 1970's, the amount of land degraded by skidroads and landings is substantial  (Table 3).    From 1971-1980, approximately Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation   124 TABLE 1 PERCENTAGE OF AREA ON CUT-OVER LANDS  Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation   TABLE 2 PERCENTAGE OF AREA ON CUT-OVER LAND (COMPARISON) 125  Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation     126 TABLE 3 AREA OCCUPIED ON CUT-OVER LAND 1971-1980 (000 HA)  Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation 110,000 ha of forest land have been subject to scarification and compaction during landing and skidroad construction.  If estimates of the percent area occupied were modified to more closely resemble the values reported in the literature (3, 4, 7, 8, 9, 10, 11),  the result would be a near doubling of the area effected to approximately 200,000 ha (Table 4 and 5).    The reduced productive capacity of these degraded sites represents a form of internal   land alienation from the future forest land base. EFFECT ON FOREST PRODUCTIVITY Skidroads, which can occupy up to 35% of cut-over land,  are often scarified to a depth greater than 25 cm (7).    Landings,  which may occupy an area as large as 0.5 ha; are usually scarified to depths greater than 1.0 m.    Although both are subject to compaction, landings receive more severe treatment due to continual  equipment operation. The negative impacts of landings and skidroad construction on soil are: 1. nutrient removal  during scarification (7, 10); 2. increased bulk density,  ranging  from 15-20% (2, 3, 4, 9,     11); 3. decreased infiltration,  ranging  from 35-93% (9, 10); 4. loss of macropore structure,  ranging  from 10-68% (2,9, 10); 5. decrease in micropore space (2). The resulting effects on forest site productivity are: 1. regeneration delay,  ranging  from 3-12 years (2, 7, 9,); 2. reduced stocking (9,  11); 3. poor tree vigor (9); 4. reduced tree growth,  ranging  from 6-14% (4, 7, 9, 10, 11); 5. volume reduction,  prorated over the entire cut-over area, ranging  from 12-15% (4, 7, 11). In an attempt to quantify the effect on forest productivity  for the interior forest regions,  the following assumptions were made: 1. on skidroads,  prorated volume reduction over the entire area, 0.45% reduction for each 1% skidroads (4, 7, 11); 2. landings, only 50% of landing area will  support future tree growth (based on Ministry of Forests, Prince George Region estimate, Jan.  1982 memo). 127 Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation    128 TABLE 4 PERCENTAGE OF AREA ON CUT-OVER LANDS (REVISED)  Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation TABLE 5 REVISED AREA OCCUPIED ON CUT-OVER LAND 1971-1980 (000 HA)                       129  Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation This was combined with the revised estimate of percent area occupied (Table 4) and the amount of land clearcut in 1980-81 (from the annual report) to produce an estimate of the area annually created (Table 6) and the reduction in forest productivity due to landing and skidroad construction (Table 7). On forest land harvested by ground-based yarding, the productive capacity is reduced by approximately 9%. The result is a loss of almost 4 million cubic metres of wood products in the next rotation on the internal alienation of nearly 11,000 ha equivalent land base in one year. Obviously, corrective measures for soil decompaction and nutrient retention or enhancement must be incorporated into management policy. LANDING AND SKIDROAD REHABILITATION POLICY The Ministry of Forests is directed to maintain and improve the forest and range resources of the province. Soil is the fundamental resource to be preserved in the case of landing and skidroad construction and rehabilitation. Over the past five years, all forest regions have instituted a landing policy that deals not only with landing construction but also rehabilitation. Most of the regional policies are based on the Cariboo Regional Policy, the first regional landing policy in the province. A summary of the rehabilitation measures are(3): 1. ripping or scarification to a depth of 30 cm, if deemed necessary; 2. burning of slash piles; 3. respreading of topsoil and ash pile on the landing. These measures are aimed at soil decompaction and restoration of soil nutrients. Unfortunately, a policy is not effective unless properly adhered to or enforced. The results of a 1981 survey of landing rehabilitation in the Cariboo Region revealed the following (6): 1. poor landing location resulted in excessive site disturbance; 2. topsoil was removed and seldom respread; 3. scarification did not always conform to policy, only 8% in the I.D.F. (b) subzone while 90% in the S.B.S. zone; 4. compaction reduced only at the soil surface; compaction remained high below 15 cm; 130 Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation TABLE 6 REVISED AREA OCCUPIED ON CUT-OVER LAND 1981 CLEAR CUT (HA) 131  Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation  132 TABLE 7 1981 REDUCTION IN FOREST PRODUCTIVITY  Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation 5. slash disposal conformed to policy except where dirty piles reduced the effectiveness of the burn; 6. planted spruce did not appear healthy and were growing poorly. Among the recommendations of Mitchell's survey, the following pertain to landing rehabilitation    (6): 1. restrict the size of landings to reduce the rehabilitation problem; 2. push topsoil  into one retrievable pile; 3. pile and burn slash away  from topsoil; 4. rip compacted surfaces to a depth of 20 cm; 5. spread the ashes and topsoil  as evenly as possible over the landing; 6. plant landings with hardy stock (i.e. lodgepole pine); 7. maintain accurate and current information on all  areas; 8. enforce the landing guidelines. Based on these recommendations, a new landing policy is being drafted for the Cariboo Region.    Additionally,  the Research Branch is investigating the practice of deep ripping (50 cm) and the use of legumes in landing rehabilitation (E.P. 834:07).    The deeper ripping allows for a greater unrestricted rooting zone for regeneration.    The use of legumes may assist in the recovery of nitrogen lost from the site during scarification or slash burning.    The results from this work should be available in 1983-84. CONCLUSIONS There is no doubt that landings and skidroads occupy a large portion of cut-over forest land.    These areas are scarified and compacted, resulting in a decrease in future forest productivity.    Although the future cost of the internal   land alienation is difficult to assess, the forest industry cannot afford the equivalent loss of 11,000 ha per year of productivity.    Both preventative and corrective measures must be applied to alleviate the problem of land degradation due to harvesting activities.    Although some modification of current landing construction and rehabilitation policies is needed, these policies must be fully integrated into forestry planning and operations.    If ignored, the future role of forestry in British Columbia may be greatly reduced. 133 Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation BIBLIOGRAPHY 1. B.C. Ministry of Forests.  1981.  Annual report: 1980-81. Queen's Printer, Victoria, B.C.  49 pp. 3. Dickerson, B.P.  1976.  Soil  compaction after tree length    Skidding in northern Mississippi.  Soil  Sci.  Soc. Am.    J. 40: 965-966 4. Dyrness, C.T.  1965.  Soil Surface conditions following    tractor and high-lead logging in the Oregon Cascades J.    Forestry  63: 272-275 4. Froechlich, H.A. 1979.  Soil compaction from logging equipment: Effects on growth of young ponderosa pine. J. of Soil  and Water Cons. 34(6): 276-278. 5. Lull,  H.W.  1959.  Soil  compaction on forest and range land.    Misc. Publ.  No. 768.  U.S. Department of Agricultural,    Washington, D.C.    64 pp. 6. Mitchell, W.K.  1982.  The construction and rehabilitation of logging landings in the Cariboo Forest Region. Research Brief #20, B.C. Ministry of Forests, Cariboo Forest Region, Williams Lake, B.C.  30 pp. 6. Smith, R.B. and E.F. Wass.  1979.  Tree growth on and adjacent    to contour skidroads in the subalpine zone, southeastern    B.C. Environment Canada, Forest Service BC-R-2.    Victoria, B.C. 26 pp. 8. Steinbrenner, E.C.  1955.  The effect of tractor logging on physical  properties of some forest soils in southwestern Washington.  Soil  Sci.  Soc. Am.  Proc. 19: 372-376. 9. Steinbrenner, E.G. and S.P. Gessel.  1955.  Effect of tractor logging on soils and regeneration in the Douglas-fir region of southwestern Washington.  Soc. Am. For.  Proc. 1955: 77-80. 10. Youghbert, C.T.  1959.  The influence of soil conditions,    following tractor logging, on the growth of planted    Douglas-fir seedlings.    Soil  Sci. Am.  Proc. 23:    76-78. 134 Proceedings of the 7th Annual British Columbia Mine Reclamation Symposium in Victoria, BC, 1983. The Technical and Research Committee on Reclamation 11. Wert, S. and B.R. Thomas.  1981.  Effects of skid roads on diameter, height, and volume growth in Douglas-fir.  Soil Sci. Soc. Am. J. 45:  629-632. 135

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