Forest Investment Account (FIA) - Forest Science Program
FIA Project Y081192

    Twenty-year effects of mechanical site preparation and burning on soil properties and lodgepole pine nutrition in sub-boreal British Columbia
Project lead: Boateng, Jacob (BC Ministry of Forests and Range)
Author: Boateng, Jacob 0.
Subject: Forest Investment Account (FIA), British Columbia
Series: Forest Investment Account (FIA) - Forest Science Program
Mechanical site preparation (MSP) has been widely used in northern and central British Columbia to surmount environmental constraints to conifer seedling establishment that commonly exist on boreal and sub-boreal sites. These factors include low soil and air temperature, excess soil moisture, poor soil aeration, and reduced light availability (e.g., Örlander et al. 1990). In particular, the use of MSP in British Columbia increased in the mid-1980s when extensive efforts were undertaken to rehabilitate backlog areas, and as the use of prescribed burning declined (von der Gönna 1994). During that era, a large project was established under FRDA (Project 1.10) to study the effects of various forms of MSP on conifer performance and on a variety of micro-environmental factors. Individual studies were established in the SBS, BWBS, and ESSF zones of the (now) Northern Interior Forest Region. Various types of equipment were investigated, and on some study sites these treatments were compared with chemical and burning site preparation treatments. These studies focused on white spruce (Picea glauca) and lodgepole pine (Pinus contorta) responses, and in particular, sought to examine methods of altering soil physical characteristics in order to improve soil temperature and moisture conditions, as well as to alter physical structure to facilitate root growth. Extensive soils and micro-environmental information were collected early in the study to help interpret the mechanisms driving conifer response. Twenty-year data regarding conifer responses at selected FRDA 1.10 sites is currently being collected, and the results are indicating which of the treatments have influenced conifer survival and growth over the long-term. In some cases the results are substantially different from those anticipated based on early assessments (e.g., Boateng et al. 2006). We propose to collect soils data that will help interpret these results, and that will also provide information about the long-term effects of MSP and broadcast burning on soil physical and chemical properties. We would like to know whether changes in soil characteristics such as bulk density or nutrient availability that were identified early in the study persist after 20 years. This work provides a good fit with the Sustainability program theme 1.0, under topic 1.2 “Soil biology, ecology, and productivity”. Long-term data such as these are rare and valuable, and can make a valuable contribution to our understanding of the eventual outcomes of treatments that we apply operationally. The results will demonstrate to the scientific and business communities that sustainable forest management is being practiced in BC. Although mechanical treatments continue to be the most commonly used form of site preparation in British Columbia, their application in absolute terms has decreased since 1990. This is mainly due to the perceived high cost and to the potential for site degradation if treatments are not carefully applied. However, there are indications that moderate use of MSP treatments can be cost-effective and beneficial to the future timber supply (Hawkins et al. 2006). The work proposed herein will contribute to our ability to weigh the economic and biological costs and benefits of applying MSP and burning treatments in north-central BC. We propose to carry out soil and foliar sampling at the Bednesti (SBS zone) and Tanli (ESSF zone) sites, across a range of mechanical treatments, as well as on burned and control treatments. Bulk density will be determined, and comprehensive analysis (matching tests conducted at previous sampling dates) will be conducted to describe chemical characteristics of both forest floor and mineral horizons. Foliar nutrient analysis will also be conducted to facilitate the synthesis of conifer response and soil characteristics. Similar work has recently been published for the related Inga Lake study site (Macadam and Kabzems 2006).
Citations for entire proposal Boateng, J.O., Heineman, J.L., McClarnon, J., Bedford, L. 2006. Twenty-year responses of white spruce to mechanical site preparation and early chemical release in the boreal region of northeastern British Columbia. Can. J. For. Res. 36(10): 2386-2399. Brockley, R. 2001. Foliar sampling guidelines and nutrient interpretative criteria for lodgepole pine. MOFR Research Branch, Ext. Note 52. Hawkins, C.B.D., Steele, T.W., and Letchford, T. 2006. The economics of site preparation and the impacts of current forest policy: evidence from central British Columbia. Can. J. For. Res. 36: 482-494. Macadam, A., Kabzems, R. 2006. Vegetation management improves early growth of white spruce more than mechanical site preparation treatments. North. J. Appl. For. 23(1): 35-46. Örlander, G., Gemmel, P., Hunt, J. 1990. Site preparation: a Swedish overview. For. Can. and B.C. Min. For., Victoria, BC. FRDA Rep. No. 105. von der Gönna, M.A. 1994. Site prepartion : microsite selection and planting stock performance. Regen Note No. 5. Silviculture Br., BC Min. For., Victoria, BC.
Related projects:  FSP_Y092192FSP_Y103192
Contact: Boateng, Jacob, (250) 387-8905,


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Updated August 16, 2010 

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