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Soil Disturbance Workshop. M.Curran, PhD,P.Ag. BCFS, Research. The path to “Pedo-righteousness”. Know your soil Know what you are doing to it Know the effects of this (on- and off-site) Adapt your practices (reliable process) over time as more knowledge becomes available
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Soil Disturbance Workshop • M.Curran, PhD,P.Ag. • BCFS, Research
The path to “Pedo-righteousness” • Know your soil • Know what you are doing to it • Know the effects of this (on- and off-site) • Adapt your practices (reliable process) over time as more knowledge becomes available • “Science-based” management • None of this is new, but integration might be...
Outline • Office for this afternoon: • Background • FRPA • (wildfire if you wish) • Field tommorrow (bring lunch) • - TaTa/Airport?? cutblock field evaluation • - may be time for another block?
Outline • Background • Soil disturbance concerns • Local soils research and results • FRPA • Soil conservation provisions in FRPA • identify and discuss opportunities/issues for C&E (eg, MPB) • FREP soil protocol if of interest (eg low level detailed photos) • Briefly discuss harvesting strategies to manage soil disturbance (influence inspection approach
Background: Forest Sciences • Branch and Regional forest science teams • Applied research, problem solving, extension, consulting • Decentralized, close to the scene of the action • Unique service in BC & talent rich • Respected in MOF and externally • A continued MOF core function
Six Core FSP Disciplines • Soil Conservation • Plant Ecology • Hydrology • Geomorphology • (Silvicultural Systems) • (Wildlife Ecology)
F.S.P. Clients Public Licencee’s D.M.’s Field Services Primary Clients Industry Woodlot Public Public RMT BCTS Public
Primary Focus (Earth Sciences) • Implementation and testing of policy related to soil and water conservation. • Done by: • Policy development support • Policy implementation support (Guidance documents, C&E) • Testing policy and developing tools • (Effectiveness, Validation)
Recent Nelson soils work • Erosion control consultation/reviews of active fires • Work on Soil Conservation Framework and Surveys LMHs (guidance documents that include airphoto approach to monitoring) • FRPA Soils Leader during drafting and start of FREP • FREP Protocol development • Continued monitoring on LTSP • Promotion of a common approach to soil disturbance in North America (for FRPA)
Sustainability/certification protocols (eg, MP, CCFM) • Soil Disturbance common element • FSC BC often more stringent than FPC/FRPA • However, protocols like the Montreal Process have a number of “b-type” indicators that require field validation (eg, compaction) • Therefore, compliance with standards is often used as a proxy (eg, CCFM C&I)
“Continual Improvement”(“Science-based resource mgt.) Strategic Direction Data/results Guidelines R & D Monitoring (C&E) Training OPERATIONS Best Mgt.Practices
Provincial Soil Conservation issues Soil “foundation” affects Other Resources • Site productivity • “Hydrologic function” • Erosion and sedimentation • Organic matter • Rooting medium • Soil moisture Timber, Habitat supply Water Global Carbon Aesthetics Operations
Soil Disturbance (a Proxy) • Any physical, biological, or chemical disturbance to the soil caused by ground-based equipment (operations) • May be inconsequential, beneficial, or detrimental depending on the net effect on growth limiting factors and hydrologic properties
Soil Disturbance as a proxyfor productivity/hydrologic effects • In many NA ecosystems, we need at least 10 to 20 years data to draw conclusions about the effects of various practices • Therefore, we use soil disturbance as a proxy that we can observe and regulate at the time of harvesting, site preparation, etc. • However, when we discuss or read about “Soil Disturbance” there are inconsistent approaches and methods a common approach is needed.
@ 15 YRS @ 10 YRS @ 3 YRS Mean Douglas-fir volume - Gates Creek (Smith & Wass, 1991; Wass & Senyk, 1999) 150 125 100 R / R % of volume on undisturbed soil S / NR 75 T / NS T / R 50 T / NR 25 0
Net effect on tree growth • Resulting tree growth is sum of positive and negative effects • Common negative effects: • reduced aeration from compaction • loss of nutrients and organic matter • Common positive effects: • reduced competition • warmer soils
Soil disturbance processes • what is soil disturbance • what is soil degradation • what processes lead to degradation • (strategies to manage disturbance)
Soil Disturbance • Any physical, biological, or chemical disturbance to the soil • May be beneficial or detrimental, depending on net effect on growth limiting factors
Beneficial Disturbance • Foresters often create disturbance on purpose as site preparation to ameliorate seedling growth-limiting factors • Net effect would have to be positive • Growth is limited by most limiting factor • Identify and manage for these • Don’t compromise long-term productivity
Soil degradation • Any disturbance that negatively affects soil productivity • In B.C. Forestry, trees are the “bioassay” • FPC/FRPA targets potentially detrimental disturbance • some of concern for drainage as well (FRPA)
Processes leading to degradation: • Compaction • Displacement (min. soil; forest floor) • Erosion • Mass Wasting (cut/fill failures) • (Part of management framework)
Erosion • Surface soil eroded primarily by water (splash, sheet, rill erosion) • Loss of fertile topsoil layers • Loss of effective rooting volume • Exposure of unfavourable subsoils • Drainage diversion • Sedimentation of watercourses
Erosion • Controlling factors: texture, coarse fragments, slope, climate • Manageable factors: machine traffic, degree of scalping, drainage control
Mass Wasting • “Minor” cut and fill failures • Often result in drainage diversion • Can lead to larger landslides • Loss of productive growing site • Impacts on downslope values • Safety concerns • Also use slope stability indicators (LMH47)
Mass Wasting • Controlling factors: parent material, climate, slope, topography • Manageable factors: amount and extent of excavation, drainage control, machine traffic, seasonal soil conditions (wetness, snow, frost)
Compaction • Compaction and Puddling result in the alteration / loss of soil structure (architecture of pores) • Bulk Density increase (penetrability) • Infiltration decreases (more runoff) • Aeration decreases (less biological activity)
Compaction • Controlling factors: texture, coarse fragments, forest floor depth/type, (soil depth, mineralogy) • Manageable factors: machine traffic, machine type/dynamic loading, seasonal soil conditions (wetness, snow, frost)
Table 3. Bulk density (kg m-3) of 0-10 cm soil depth in 1981 and 1997 among three treatments and two disturbances at Gates Creek. Treatment Disturbance Year Prob>T 1981 1997 Non-stumpedUndisturbed 1231 1246 0.88 Track 1613 1405 0.001 Raked Rake 1469 1373 0.23 Track 1671 1469 0.03 Scalped Scalp 1119 1210 0.20 Track 1724 1420 0.000
Dispersed traffic = concern • Aeration porosity definitely affected • Literature suggests is could affect trees • Therefore, need to monitor and check • Institute BMP for now • Adjust guidelines as hard data available • Hard data needs a framework (plasticity)
Mean Douglas-fir Volume • Both sites sandy-loam texture • BUT, Clay varies • Ratings need validation
Soil Plasticity (Approx., CSSC) Very Plastic Plastic Slightly Plastic Non-Plastic
Displacement • Displacement of fertile mineral topsoil and forest floor layers of concern • Loss of available nutrients • Loss of effective rooting volume • exposure of unfavourable subsoils • Loss of water holding capacity • Increased runoff, drainage diversion
Displacement • Controlling factors: slope, topography, soil depth, subsoil type • Manageable factors: amount and extent of excavation, machine size/type, seasonal soil conditions (wetness, snow, frost)
Outline • Background • Soil disturbance concerns • Local soils research and results • FRPA • Soil conservation provisions in FRPA • identify and discuss opportunities/issues for C&E (eg, MPB) • FREP soil protocol if of interest (eg low level detailed photos) • Harvesting strategies to manage soil disturbance (can influence inspection approach if a good strategy appears to have been used)
BC Soil disturbance stds • 1988 start, FPC in 1995, now FRPA • Disturbance types of concern evolved from bladed trails to compacted trails, ruts • Limits set in Silviculture Prescription (Site Plan) based on soil dist.hazards • Monitoring based on transects • Disturbance at sample point categorized
Historical Disturbance Levels • late 70’s / early 80’s • over 20 % common • Interim Harv. guidelines (1988) • 13 % without rehab. • 1993 Harv. guidelines • 13 % WITH rehab. • 1995 FPC Act, now FRPA • 10 % AFTER rehab. “10 + 3”(5)