managing the effects of forest harvesting on soil quality in b.c

Managing the Effects of Forest Harvesting on Soil

Quality in B.C.

M.Curran, Ph.D,P.Ag. BCFS, Research

Outline Tutorial case description “Sustainability” as context for guidelines Soil information for planning Soil disturbance processes (hazards) Soil disturbance standards Practical Application Questions/Discussion Tutorial Assignment

Case specific learning outcome:

Understand the common characteristics of forest soils– with an emphasis on soil physical

attributes and management tools to prevent compaction.

Accomplish the following tasks:

Interpret the results of a harvesting experiment and apply this knowledge to a new harvest site.

Describe your learning in written format (as individual students) and orally (as a working team).

Post on the course web site responses to the guiding questions.

References for tutorial:

Biophysical Resources of the East Kootenay Area: Soils by L.E. Lacelle. 1990.

Hazard Assessment Key Guidebook Soil Conservation Guidebook Soil Conservation Surveys

Guidebook

“Sustainable Forest Soils”

“Ensuring that the biological, chemical and physical integrity of the soil remains for future generations of ___(people, trees, etc.)

Addressed at many levels, through operations, standards, and now protocols

Often tracked in terms of Criteria and Indicators…

BUT the adaptive management process is likely just as important as the indicators

Adaptive Mgt. Process

Strategic Direction

Data/results Guidelines

Training

Best Mgt.PracticesOPERATIONS

Monitoring (C&E)R & D

“Sustainability Protocols”

Set Criteria and specific Indicators of sustainable forestry

Encourage countries to report on the status of these Indicators

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)

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

BUT, what does compaction mean on a given forest site?

Bad air?

MP talks about area with “significant compaction”

Soil Disturbance as a proxy for 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.

@ 3 YRS @ 10 YRS

@ 15 YRS

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Mean Douglas-fir volume - Gates Creek

(Smith & Wass, 1991; Wass & Senyk, 1999)

Mean Douglas-fir volume - Gates Creek

(Smith & Wass, 1991; Wass & Senyk, 1999)

Soils information for planning

Soil maps provide general information on the soils and landforms present

Site-specific data collection verifies and (OR) provides information used in determining soil disturbance limits

Harvest planning should use both of these whenever maps are available.

“Soil Landscapes”

Soil = f (t) { pmtl + topog + veg + climate } Soil will vary with above Soil will be similar with above… Therefore, repeating units across landscape We can map these units and interpret them Maps = framework for communication of

experience with soil

Primary criteria for mapping

Origin of parent material Lithology (mineralogy) of coarse

fragments Texture (coarse frag’s; fine fraction)

Above of interest to Forest Engineering

Some secondary criteria

Soil development– degree of weathering– depth of horizons

Diagnostic horizons (eg, clay rich) Organic matter content

Survey Intensity Level (SIL)

SIL / Planning level

4 reccie / Regional 3 “baseline” 2 detailed / Local 1 site-specific

Field checks / scale

25 %, 1:100,000 50 %, 1:50,000 90 %, 1:20,000 100 %, 1:5,000

Typical soil individuals (map)

Soil Associations (typical maps)– “similar parent material and

development” Soil Series (detailed, agricultural

maps)– “same parent material, development,

texture”

Map Reliability

Reliability = how well it reflects a given point on the ground

Function of scale, access, surveyor skill

Will vary with the property of concern– eg, texture versus actual development– general purpose or specific mapping?

Soil Disturbance – is it all Degradation?

Tree growth limiting factors

Any factors that limit growth Concept of most limiting factor May be direct or indirect factors

Direct growth limiting factors

Direct growth limiting factors

Water Nutrients Light Aeration (CO2, O2) Temperature (soil, air)

Indirect growth limiting factors

Affects direct factors, eg:

Indirect growth limiting factors

Affects direct factors, eg: Competing vegetation

– light– water

Rooting substrate (volume) Root rot

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 0.88Track 1613 1405 0.001

RakedRake 1469 1373 0.23Track 1671 1469 0.03

Scalped Scalp 1119 1210 0.20Track 1724 1420 0.000

Aeration Porosity (Nakusp)

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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)

Soil Plasticity (Approx., CSSC)

Non-Plastic

Very Plastic

Slightly Plastic

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)

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)

Types of counted disturbance

Machine traffic (compaction)– excavated and bladed trails– compacted areas– main (nonbladed) trails– ruts greater than 5 or 10 cm

Types of counted disturbance

Displacement– deep gouges– long gouges– wide gouges– very wide scalps

Forest and Range Practices Act (replaces Forest Practices Code)

“Simplified” planning steps Sets “results-based” standards for

11 values like Riparian, SOILS, etc. FPRA Objectives for Soils

– “conserve the productivity and hydrologic function of soils.”

FRPA Soil Disturbance Stds(others for drainage, revegetation, etc.)

Permanent access 7 % or less Temporary access up to 5 % Sensitive Soils 5 % “disturbance” Less-sensitive 10 % Roadside work areas 25 % Based on soil sensitivity

Types of monitoring

1. Implementation (Compliance)1. Did they meet the contract?2. (speeding?)

2. Effectiveness1. Contract and practices effective?2. (are ticketting, signing, etc. reducing it)

3. Validation (research)1. Underlying assumptions correct?2. (speeding causes more fatalities there?)

Field Map: Planned transects

B.C. has 5 replicated LTSP installations

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Challenge Wallace Owl Vista Central CampCamp

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10-YR BIOMASS RELATIVE TO COMPACTIONON FIVE LTSP SITES IN CALIFORNIA

Rehab (amelioration)Plot on LTSP study

RehabilitatedHaul Road

“Soil test sites”

Harvesting strategies Independant of climate/weather Longer season, less shutdowns Can rehab. as you go, but stay under Rehab. can be haul roads, unbladed trails

– close trail spacing– close road spacing– designated/random skidding– hoe-chucking

Closer Trail Spacing

Gentle to moderate slopes (45 %?) Avoid seepage sites Avoid VH Mass Wasting, Compaction Avoid H Mass Wasting if clayey Minimize cuts into unfavourable

subsoil

Dispersed (Random)

Plan for designated trails (can’t be the preferred strategy) Take advantage of weather windows Can accomplish site preparation Can use feller buncher

Hoe-chucking (Interior)

Can augment other strategies Can often operate when wetter Good for complex topography in

W.Koot. Complements cable harvesting

Seasonal soil factors

How Wet is Too Wet discussed before

How Much Frost? How Much Snow? How Much Helium?

How wet is too wet? (1 pass)

Non-plastic soils– squeezed soil leaves < 100 % moisture

on hand Plastic soils

– squeezed soil leaves < 50 % moisture on hand

– AND clod breaks apart with easy finger pressure (tapping)

How much frost is enough?

7.5 cm (3 in.) in mineral soil PROVIDED not too wet below “can’t penetrate with body weigth on

a 3/8” rod with a 30 degree cone”

How much snow is enough?

Compressible snow: 30 cm? Dry snow: 60 cm? Try a “jump” or boot test... Frozen snow: 15 cm?

– (do a single pass at end of first day on it)

PROVIDED soil not too wet below!

Harvesting strategies

– close trail spacing– close road spacing– designated/random skidding– hoe-chucking

Adaptive Management Process (a package deal)

Strategy / Database

Data/results Tools / Guidelines

Training

Best Mgt.PracticesOPERATIONS

Monitoring (C&E)Research

Execution

Regional Database Indicators/Thresholds

Validation Implementation

Environmental Framework

Inherent Soil Sensitivity (HAZARD)– Compaction– Displacement– (Erosion and Mass Wasting [non-

alcoholic]) Potential Effects: (CONSEQUENCE)

– On-site (forest productivity)– Off-site (fish, water, property, life)

Recommendations BC Interior Winter log? Processors onsite for sensitive? Consider the “4 strategies” roadside reduce disturbance? Larger blocks and rehab all roads (all NAR) Equipment size? Operator effect is number one often Operator training materials

Funding sources

Invermere “enhanced mgt pilot” Science Council (FRBC) FIA/FII In-kind MoF Regions, Branch, District In-kind CFS Victoria, Edmonton In-kind UBC In-kind Tembec, Slocan, Kalesnikoff

Session 1 questions

Based on the combination of five soil forming factors (parent material, topography, biota, climate, and time) describe the processes of the formation or genesis of the Rocky Mountain Trench soils.

Briefly describe soil diagnostic features of these soils that could be significant for forest management consideration.

List some soil quality indicators, with emphasis on soil physical properties that could be used to monitor the sustainability of the management of the Rocky Mountain Trench.

Session 2 questions The soil physical properties are derived from the

complex interaction of the soil mineral and organic colloids, weathering processes, vegetation, and past management. Given the information for the three soils in the attached materials, what are important indicators of its physical conditions for plant growth under the various disturbances studied?

Why does compaction take place on forest soil? What are the ways of preventing soil compaction on

forest lands? Why would soil erosion take place on forest soils? What are the ways to prevent soil erosion on forest

lands?

Session 3 questions What are general recommendations for sustainable

management of a forest soil in a semi-arid region like the southern interior of BC?

What are potential effects of the soil organic matter displacement on the soil physical properties of the site in southern interior of BC?

What is likely the “leading soil disturbance hazard” on benchland soils in the Rocky Mountain Trench? What are ground-based harvesting strategies to manage these concerns?

What is likely the leading hazard on steeper soils in the Purcells? In the Rockies? What are cable or ground-based harvesting strategies to manage these concerns?

Useful website?http://www.for.gov.bc.ca/

Forest Practices Code Guidebooks: Land Management Handbooks

Cool research: Southern Interior Forest Region – Active Projects - Nelson Test Site Directory

[email protected]

The end…

The truth is out there

For every argument, it is often possible to find an example to support it in the natural world.

For us, what matters is which argument is most commonly correct, and what conditions dictate which holds true…

Need a system to track this knowledge and put it into practice…. [hazards/disturbance]

Desirable Attributes for Indicators (CCFM C&I):

Relevant? (related/sensitive/responsive)

Measurable? (scientifically valid, practical)

Understandable? (forest managers, public)

Can be Forecast? (expected future condition) Have Reference Values? (performance check

Climate change effects?

Precision?

The “Holy Grail” - TODAY’S SESSION

Calcareous Soils

Special case Limestone derived High pH Unfavourable subsoil.

Nutrient availability vs. pH

Calcareous pts (Golden Mt 7)

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FPC Disturbance (Mt 7)

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Leaching study: FF pH

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Site and Treatment Vs. Available Iron

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McMurdo Bloom Grave Lussier Hudu Caven Bell

Availabe Fe (ppm)

Height of lodgepole pine in presence or absence of CO3

CO3

DepthGood Medium Poor

< 40 cm 650 24 589 27 382 27

> 40 cm 752 48 649 34 465 34

Lussier Provenance trial (20 year growth of 5provenances in each category.

Marl Ck. Stumping trial

Disturb. Growth CO3

(9)No CO3

(12)Ttest

Track Dbh(cm)

2.6 5.3 0.02

0-10 cm Height(cm)

264 448 0.01

Volume(cm3)

4390 13, 649 0.008

managing the effects of forest harvesting on soil quality in b.c

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