Vegetation Management Alternatives

Section II. What are the alternatives and what is their silvicultural effectiveness?

Al Wiensczyk, FORREX...

What are the Alternatives?Methodology

Reviewed the scientific literature for information

Used experiential knowledge of project team and others

Gathered info on species autecology and treatment effectiveness

Very limited info on some treatments, quite extensive on others

Similarly very limited data on some competitive species – lots on others

Canadian Forest Management Database Dean Thompson http://www.glfc.forestry.ca/cfpm/index.cfm?lang=eng

What are the Alternatives?CCFM Database

What are the alternatives? Non-crop vegetation in the boreal forest

Positive or negative effects on crop trees Depends on

Autecology of respective species (including reproductive strategy).

Non-crop species density Non-crop species size relative to that of the crop

trees Differences in site quality

Effect may change over time

What are the alternatives? Autecology information

Life Form/species

Reproductive strategy

Uses and Benefits Effects on conifers

TreesTrembling aspen Populus tremuloides

• Suckers• Basal sprouts

(rare)• Seed: wind

(rare)

• Crop tree• Nutrient rich litter aids in

nutrient cycling and increases soil fertility.

• May reduce weevil damage• Provides browse, cover and

nesting habitat for ungulates, small mammals and birds.

• Provides food for beaver• Buds are eaten by ruffed grouse

• Reduces light availability

• Competes for growing space

• Competes for rooting space

• May cause whipping damage

ShrubsSitka/green alder Alnus viridis/ Alnus crispa

• Seed: wind/water

• Basal sprouts

• Nitrogen fixation improves site fertility

• Builds up site organic matter• Stabilizes slopes and controls

erosion• Suppresses grass and raspberry

competition

• Reduces light availability

• Reduces moisture availability

• Reduces nutrient availability

• May cause snow press

What are the alternatives? Autecology Information

Life Form/Species

Response to Disturbance

Overstory removal

Fire Cutting Mechanical Site

PreparationLow

intensityMedium to

high intensity

Trembling aspen Populus tremuloides

•Root suckering, some stump sprouting

•Winter logging 4x more suckers

•Regen from seed on exposed mineral soil

•Vigorous sprouting when organic layer disturbed but not removed and root systems not damaged

•Adapted to environment with recurring fires;

•Regenerates from suckers

•Spring fires – increased regeneration

•Sprout from stump or suckers;

•Cutting in June – lower number of suckers

•Sucker production proportional to degree of cutting;

•Girdling during growing season effective

•Surface treatment will increase sucker production

•Seeding on mineral soil (minimal)

•High cultivation treatments may control aspen

Sitka/green alder Alnus viridis - Alnus crispa

•Increase in stem numbers

•Stimulated more by winter than summer logging.

•Often favoured by burning;

•Killing cambium at ground level will kill plant.

•If only stem killed will resprout from stumps.

• Control

•Increase in stem numbers through stump sprouts; July and August – least sprouting and height growth

•Treatments that remove roots – greater success

•Seeds in to disturbed sites

Vegetation Management Treatment Options Decision Making Process (from Wagner et al. 2001)

What are the alternatives?

Silvicultural activities

(harvesting, site

preparation, thinning)

Autecological characteristics of unwanted forest plants

Desired stand

Yes

Yes

No

Prevention loop

Removal loop

Release treatments

Favourable environment

No

Alter silvicultural activities

What are the alternatives? Treatment Groups

Harvesting Systems Physical Thermal Cultural Chemical and Biological spray

What are the alternatives? Silviculture and harvest systems

Silviculture System Clearcut, modified clearcut, shelterwood, selection

Harvest disturbance Influenced by

Harvest system Season of harvest Equipment used Operator training and skill

Harvest System Full tree, tree length, cut-to-length

Mechanical Site preparation Brushing

Manual Motor-manual Mechanical

Girdling Mulches

What are the alternatives? Physical Treatments

What are the alternatives? Thermal Treatments

Prescribed Fire Steam

Vegetative Reproduction Sexual Reproduction

Shoot OriginSprouts

Root Origin SproutsWindborne

SeedSeed Bank

e.g., maple, alder, birch,

dogwood, hazel, willow,

Labrador tea

Roots inorganic layer

Roots inmineral soil

e.g., grasses, birch, fireweed, poplar, willow

e.g., dogwood, cherry, rose, raspberry, blueberrySilvicultural

treatment Microsite Category e.g., grasses,

blueberrye.g., poplar,

rose, raspberry

None Undisturbed 0 0 0 0 0

Harvest Overstory removed; ground undisturbed 0 to

Mechanicalsite

preparation

Upland mineral soil

Organic partially displacedL and part of F (e.g. shallow screef)

LFH removed and mineral soil either:

Depressed (deep screef) to

Level (screef) to

Raised (mineral soil mound) to

LFH inverted with mineral soil cap (mineral mound on organic layer)

to to

LFH and mineral soil mixed (tilling) to to

Lowland Organic soil

Part of Of removed (e.g., by shearblading) to N/A

Drainage of layer (e.g., by ditching) N/A 0

Prescribed fire

Light

Moderate

Severe

Cutting Active < 25 cm - -

> 25 cm - -

Dormant < 25 cm - -

> 25 cm - -

Microsite descriptionEffect of disturbance on reproduction = promotes ( = strongly promotes)0 = no effect = discourages ( = strongly discourages)

What are the alternatives? Cultural Treatments

Seedling Culture Cover Crops Grazing

What are the alternatives? Chemical and Biological Spray Treatments

Herbicides Application methods

Biologicals

Vegetation Management Alternatives

Section III: What are the environmental consequences of using silviculturally effective alternatives?

Kathie Swift, FORREXWayne Bell, OMNR

What are the environmental consequences? Environmental effects

Lots of literature available on the effects of some treatments, less for others

Due to complexity of responses, focus put on principal messages

Treatments can have a positive effect on one element and a negative effect on another

Air Quality Soil Properties/Nutrition Water Quality and Quantity

Photo: Utah Bureau of Land Management Photo: Rhodes University

What are the environmental consequences? Abiotic Values

Plants (diversity) Fish/Fish Habitat Terrestrial Invertebrates Amphibians and Reptiles Song birds Small Mammals Mid-large Mammals

What are the environmental consequences? Biotic Values

Stand/Landscape changes

What are the environmental consequences? Spatial Values

Environmental Value

Harvesting System Physical Treatments

Thermal Treatment Cultural Treatments

Chemical and Biological Spray

Treatments

Water Quality/ Quantity

All harvest systems

Sedimentation issues

Road construction machine use around streams and stream crossings.

Steep slopes Can change soil

properties → surface water flow

→ risk of erosion (Wells and Jorgensen 1979).

Windthrow post harvest

→ sedimentation during seasonal runoff

MSP Can ground

water table. Can change soil

properties

→ overland flow

→ soil erosion and nutrient loss

→ water quality and the aquatic environment (Chang 2006).

Steep slopes can exacerbate the issue.

Prescribed Fire Addition of

biocarbonates, nitrates, ammonium, and organic nitrogen from ash

Not usually concentrated enough to pose a health risk to humans or animals (Chandler et al. 1983, Richter et al. 1982)

However some issues identified in northern Quebec and Alberta studies

Grazing by ungulates

Poor livestock management practices

allowing grazing ungulates to concentrate in streams and riparian zones

→ water contaminants → water temperatures (Foster 1998).

Ground and aerial application

Potential contamination of streams principle concern

May enter forest streams by

direct application, leaching through soil profile,

mass overland flow Rapid dilution with

downstream movement reduces concentration.

No hazard when care taken to protect streamside vegetation, and stream from direct contamination (Pritchett 1979)

What are the environmental consequences? Example of how information is presented

What are the environmental consequences? Example of how information presented

Silviculture practice

Biotic Biotic/Abiotic Abiotic

Canopy # Tree species

Treediameter

Snags Downed woody material

Organic matter (LFH)

Mineral soil Rutting or Compaction

Physical

Logging ↓↓ ↓↓ ↓↑ ↓↓ ↓↑ ↓ ↑ ↑↑

Thinning ↓ ↓ ↑ ↓ ↓ ↓ ↑ ↑

Mechanical SIP

↓ ↓↑ ↑ ↓ ↓ ↓ ↑ ↓↑

Brushing & girdling

↓ ↓ ↑ ↑ ↑ ↓ 0 0

Mulching - - ↑ - - ↓ ↓ ↑

Thermal

Prescribed burning

↓↓ ↓ ↓ ↓↓ ↓↓ ↓↓ ↑↑ 0

Cultural

Seedling ↓↓ 0 ↑ ↓↑ 0 0 ↑ ↓↓ 0

Cover cropping

↓ 0 ↑ 0 0 ↑ ↓↓ 0

Animal grazing

↓ ↓ ↑ 0 ↓ ↓ ↑ ↓

Chemical & Biological

Chemical ↓ ↓ ↑ 0 0 0 0 0

Biological ↓ ↓ ↑ 0 0 0 0 0

Fertilization ↑ 0 ↑ 0 0 ↓ 0 0