Soils

Research into soils in all areas of the province addresses a wide variety of issues affecting natural resource management, including soil productivity, conservation and carbon.

The Long-Term Soil Productivity Study of British Columbia: Effects of Organic Matter Removal and Compaction on Stand Productivity after Two Decades - EN126

The Long-Term Soil Productivity (LTSP) study was borne out of concerns regarding detrimental soil disturbance resulting from timber harvest and mechanical site preparation. Specifically, scientists identified two key changes in soil properties that could reduce subsequent forest productivity: losses in soil porosity and aeration, caused by compaction under repeated machine traffic; and organic matter removal, which can occur with whole-tree harvest and displacement of surface organic horizons (forest floor). Retrospective studies of soil disturbance effects on stand productivity were often equivocal; consequently, in the 1990s, an effort was made to establish a more rigorous experimental design that would test the long-term, interactive effects of compaction and organic matter removal on forest soils. There are now well over 50 of these LTSP installations in North America (Page-Dumroese et al. 2021).

A Description of Soils and Foliar Data Collected from 1988 to 2018 in Association with the EP0995 SitePreparation Study in North-Central British Columbia - TR132

In the mid-1980s, Experimental Project 0995 (EP0995) was established to investigate conifer seedling survival and growth responses to various site-preparation techniques in sub-boreal and boreal British Columbia. This technical report is intended to advise researchers of the availability of a file report describing unpublished EP0995 soils results, and to describe how to access EP0995 soils and foliar data files relating to both published and unpublished work. References to a selection of publications related to EP0995, in particular those that fully describe methodologies related soils and foliar data and the associated results, are also included. The EP0995 project has generated numerous publications concerning conifer survival and growth responses to site preparation up to 25 years post-planting (Boateng et al. 2006, 2009, 2011; McClarnon et al. 2016; Powelson et al. 2016; Bedford et al. 2017). At three of the sites—Bednesti in the Stuart variant of the dry, warm Sub-Boreal Spruce subzone (SBSdw3); Inga Lake in the moist, warm Boreal White and Black Spruce subzone (BWBSmw); and Tanli in the Kluskus variant of the moist, cold SBS subzone (SBSmc3)—soils and foliar data were also regularly collected to examine the long-term effects of site preparation on soil chemical and physical properties and tree nutrition.

Long-term Soil Productivity Study: the Effects of Soil Compaction and Organic Matter Retention on Long-term Soil Productivity in British Columbia - TR122

The Long-term Soil Productivity (LTSP) study addresses two key factors— soil porosity and site organic matter—that potentially limit tree growth and site productivity in the timber-harvesting land base and that can be affected by forestry operations. These factors regulate basic site processes through their many roles; for example, in the exchange of water and gas, in creating physical restrictions on rooting, and in soil biological activity. The experimental design used in this study was a factorial combination of organic matter removal (stem only, whole tree, and tree+forest floor removal) and compaction (no compaction, light compaction, and heavy compaction) treatments, and included the major commercial tree species of interior British Columbia (lodgepole pine, hybrid white spruce, interior Douglas-fir, trembling aspen, and western white pine). This coordinated research network of 100+ field installations in Canada and the United States is being used to examine how these pulse changes affect soil processes that support vegetation growth and stand productivity. This report provides information on the LTSP sites in British Columbia so that future researchers can collaborate at forest productivity research sites where treatments are not confounded by other site disturbances, can directly assess compaction and organic matter loss, and can have a baseline comparison.

Macrofungus Species of British Columbia - TR108

In 1997, Redhead wrote Macrofungi of British Columbia: Requirements for Inventory, in which some 1250 of British Columbia’s macrofungi species were listed based on literature reports. Over the past few years, efforts have been made to compile a current list of these species for the province. In this report, we list 3009 species of macrofungi, 90% of which are represented by specimens in either of British Columbia’s fungal herbaria—the Forest Pathology Herbarium at the Pacific Forestry Centre, or the University of British Columbia Herbarium Fungal Collection. Because exploration of the province for macrofungi is ongoing and research is continuing to clarify the identity of species thought to occur here, this list is not yet complete. Periodic updating of the list is therefore warranted.

Maintaining Soil Productivity in Forest Biomass Chipping Operations Best Management Practices for Soil Conservation - EN98

Forest harvesting operations that use portable chipping systems to generate biomass chips from logging residue are currently in use in British Columbia. Leaving deposits of residual materials after harvest has been completed can reduce productivity and affect soil hydrologic function. We summarize the research on the effects of chipped woody material accumulations, and then interpret these findings within the British Columbia context and provide guidance for best management practices to maintain long-term site productivity. Soils in cooler climates, on fine-textured soils, and/or with a high water table are at a greater risk of detrimental effects than well-drained, coarse-textured soils in warmer environments. Integration of conventional and biomass harvesting can reduce repeated equipment traffic on forest sites.

Best Management Practices for Soil Conservation in Mountain Pine Beetle Salvage Operations - EN91

In December 2005, the Chief Forester released guidance on landscape- and stand-level structural retention in large-scale mountain pine beetle (mpb) salvage operations (Snetsinger 2005). Soil conservation was included in elements of that guidance, for instance: • retain areas with live trees as a first priority in order to maximize the potential to move water from the soil through evapotranspiration • maintain stand-level retention for the rotation [which addressed the fact that] these retention areas provide an important source of dead wood, standing and down structure, and intact forest floor, which assists with hydrologic stability and provides biodiversity and habitat value throughout the stand rotation—potentially “lifeboating” species until the newly regenerated stand matures sufficiently and provides higher levels of biological diversity.

The Soil Ecosystem of an ESSF Forest and its Response to a Range of Harvesting Disturbances - EN53

This extension note describes some of the effects of timber harvesting on the soils at the Sicamous Creek Silvicultural Systems Project study site for the 5-year period since harvesting. The study site is located in the ESSF zone near Sicamous, B.C. Five harvesting treatments were applied: no harvesting, single-tree selection, 0.1-, 1-, and 10-ha clearcuts. A variety of studies investigated the effects of opening size and distance from the edge of the cut area on soil nitrogen dynamics, nutrient cycling, soil food webs, ectomycorrhizae, and fine roots. Generalizations regarding short-term effects on the below ground organisms and processes are difficult. A complete absence of sporocarp fruiting, increased rates of nitrogen mineralization and increased nutrient leaching losses were noted in the first growing season after harvest. Decreased ectomycorrhizal diversity and fine-root biomass were measured after one growing season. Shifts in community structure occurred for micro-arthropods and bacteria while no discernible impact was detected for decomposition rates and total collembola numbers. All these changes persisted for up to 5 years after treatment, although nutrient leaching peaked after 3 years. The major influence of the forest edge into the opening occurred within approximately one-half of the tree canopy height of the uncut forest. Cutting practices that create a range of opening sizes would best maintain the widest variety of soil biological diversity and functions.

Foliar Sampling Guidelines and Nutrient Interpretative Criteria for Lodgepole Pine - EN52

Lodgepole pine forests in British Columbia’s interior are commonly nutrient deficient, and foliar analysis is widely used for evaluating their nutrient status. However, considerable uncertainty exists among users about the appropriate methodology to use when collecting and processing foliage samples and when interpreting results. This extension note presents updated conifer foliar sampling guidelines and revised foliar interpretative criteria for diagnosing lodgepole pine stand nutrient status. Foliar analysis offers a useful and convenient method for evaluating the nutrient status of forested sites. It is based on the concept that the tree, not the soil, is the best indicator of soil nutrient availability. By measuring the concentration of essential nutrients in foliage, foliar analysis reflects both soil nutrient availability and the degree to which trees require, or are capable of using, soil nutrients.

Forest Productivity and Soil Conditions on Rehabilitated Landings: Interior British Columbia - EN40

In British Columbia, soil rehabilitation aims to restore productivity to forest roads, landings, and trails that are no longer needed for access, and to areas that have suffered unavoidable or accidental damage as a result of forestry operations. Soil rehabilitation is an important component of management strategies to maintain or enhance timber supply in the working forest. Restoring productivity to degraded soils can also enhance other environmental values, and contribute to successful ecosystem or watershed restoration.

Soil rehabilitation research was initiated in British Columbia over two decades ago (e.g., Vyse and Mitchell 1977), and numerous contributions since that time have been reviewed by Bulmer (1998) and Sanborn et al. (1999a). In addition, a network of new research sites has been established to test new approaches to soil rehabilitation and to improve cost-effectiveness (Berch and Xiao 1998; Dykstra and Curran 1998; Inland Timber Management Ltd. 1998; Bulmer and Curran 1999a; Sanborn et al. 1999b; Venner 1999). Despite significant progress in the past, and new information expected in the future, there is a need for information to guide operational projects that are currently under way. In particular, information is needed on the long-term effectiveness of soil rehabilitation efforts, and the extent to which operational soil rehabilitation can contribute to the timber supply. We examined tree growth and soil conditions on sites that were rehabilitated in 1991 in the British Columbia interior. The objectives of the work were (1) to document a minimum of 5 year's growth of lodgepole pine on rehabilitated landings, and compare it to growth on sites that were simply harvested, and (2) to document soil conditions affecting site productivity on the rehabilitated areas.

Soil Compaction on Forest Plantations following Cattle Use - EN34

Grazing cattle on forest plantations in the interior of British Columbia is a common practice. Soil compaction can occur following cattle use, although this may vary with stocking rate, vegetation type and age, soil type, soil water content, and climate. Several studies have shown that increased soil compaction can have a negative impact on growth of young tree seedlings and on productivity in older plantations. These negative impacts result from restricted root development, reduced water and nutrient availability, and reduced soil aeration. This study evaluated the effects of cattle grazing and domestic forage seeding on soil bulk density and soil penetration resistance (pr) in lodgepole pine plantations in the Montane Spruce very dry cool biogeoclimatic subzone. The study was replicated on three sites near Kamloops, B.C.

Forest Soil Rehabilitation in British Columbia: A Problem Analysis - LMH44

The focus of this report is on techniques for restoring soil productivity, with the implied objective of re-establishing a productive forest ecosystem on a site that has suffered degradation. The causes of forest soil degradation and avoidance techniques are not addressed in detail, as these are dealt with else-where (e.g., Lousier 1990; Lewis 1991; and various Forest Practices Code guidebooks). Also, techniques for stabilizing slopes, preventing erosion, and for manipulating and restoring drainage patterns (i.e., techniques for road deactivation) are not specifically discussed, as these practices are also described elsewhere (e.g., Carr 1980; Chatwin et al. 1994; Moore 1994).

Various terms, such as "restoration," "reclamation," and "rehabilitation," have been used to describe a range of mitigation activities to counter the effects of environmental degradation. In this report, the term "soil rehabilitation" refers to activities that aim to improve soil productivity to a state where a productive forest can develop on sites that have suffered some form of soil degradation. This usage reflects terminology adopted in the Forest Practices Code.

The objectives of this project were:
1) to review the literature on techniques for forest soil rehabilitation;
2) to describe the current and projected extent of forest soil rehabilitation activities in the province based on consultation with rehabilitation specialists working for industry, government, and other agencies; and
3) to identify gaps in the information base, and the need for future research