Forest Investment Account (FIA) - Forest Science Program
FIA Project Y072093

    Recovery of soil carbon and nitrogen ten years after harvesting and site preparation at Sicamous Creek
Project lead: Hope, Graeme
Author: Hope, Graeme D.
Imprint: [Victoria, B.C.] : [British Columbia Ministry of Forests and Range], 2007
Subject: Forest Investment Account (FIA), Forest Management, British Columbia, Soil Ecology
Series: Forest Investment Account (FIA) - Forest Science Program
This project involves repeat sampling of soil chemical and nutrient properties 10 years after harvesting and site preparation at the Sicamous creek silvicultural systems site. It relates to Theme 3 in the FSP Sustainability program, Sustainable forest management indicators, targets and monitoring systems. It directly relates to topic 3.1, Indicators and monitoring systems. The indicators are specifically, soil carbon and nitrogen measures. The study will also provide direction for monitoring the Soil Value within FRPA. The proposal also relates to criteria and indicators developed for the Canadian Council of Forest Ministers (Criterion 3.1: Rate of compliance with locally applicable soil disturbance standards, and criteria 4.1.1 and 4.1.2: Net change in forest ecosystem carbon, and forest ecosystem carbon storage by forest type and age class). Maintenance of soil properties, processes and productivity within any silvicultural system is an important aspect in the long-term sustainability of forest management practices. Soil indicators of sustainability have been proposed to include some measure of soil chemical and biological properties (see Adams, Ramakrishna, and Davidson 1998). In the short-term, the most successful plantations in the ESSF zone in the Southern Interior appear to be on sites that have had the severest soil disturbance or prescribed burns. As tree demands on the soil increase over the medium term, however, the soil properties that exist after harvesting and site preparation may not be sufficient to sustain productivity. There have been no published studies investigating medium-term changes in soil properties in the high elevation forests of Interior BC. Early post disturbance soil investigations at Sicamous Creek included sampling for total chemical properties (so-called 'slower- changing’ soil properties) and more dynamic nitrogen availability measures. While changes in total nutrients, especially carbon (C) and nitrogen (N), are probably as powerful as more intense measures at trailing long-term changes in soil sustainability (Binkley et al. 1990), the use of short-term, more sensitive measures may enable earlier predictions of long-term effects. Total amounts of carbon and nitrogen in the soil at Sicamous Creek over the 5-year post harvest period were largely unaffected by harvesting. Site preparation altered the chemistry of those elements associated with organic matter. Early post-disturbance measures of soil N dynamics at Sicamous Creek determined that openings larger than a single tree have elevated soil N levels, and that these levels are still elevated 7 growing seasons after harvest (Prescott et al. 2003). The effect of harvesting was more significant on N availability than was that of site preparation. Comparing these early changes with measures at 10 years builds on previously collected and published data, and will enable us to identify properties that will be meaningful in monitoring soil productivity. The broad objectives of the soil ecology component of the Sicamous Creek project are to gain an understanding of the properties and processes affecting soil productivity and the effects of harvesting and site preparation disturbance on those processes. The current proposal will provide information that begins to meet these objectives in the medium term. More specific objectives for this LOI proposal are: 1, to establish if short-term changes in soil carbon and nitrogen after harvest and site preparation have been sustained into the medium term (10 years); and 2, to determine if simple soil chemical measures of soil organic matter, soil N and foliar nutrients are useful in monitoring long term changes in soil sustainability. A description of Sicamous Creek is available in the attached cover letter. We will sample the untreated, burn, mound and scalped treatments in the 10 and 0.1 ha openings and uncut forest for less dynamic soil nitrogen and carbon measurements. Soil samples will be collected and analyzed for total N, total C, pH, and mineralizable N. More dynamic N availability will be measured in the same treatments using the buried bag method. Data from the 10-year sampling will be compared to previously collected data. In addition, foliar samples will be collected (and analyzed) from seedlings planted in the site preparation plots, thereby linking soil and tree productivity measures.
Related projects:  FSP_Y061093
Contact: Hope, Graeme, (250) 828-4166,


Executive Summary (25Kb)

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Updated August 16, 2010 

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