BEC Management Interpretations

Indicator Plants

Management Interpretations, Examples Species selection Free-growing guidelines Site Index (SIBEC), Productivity Class Vegetation Potential Site preparation Silvicultural systems Wildlife habitat (by species) Sensitive ecosystem mapping and description Rare plants Cultural values Minerals Watershed values

BEC Field Guides

http://www.for.gov.bc.ca/hfd/pubs/Lmh.htm

Management Interpretations, Examples

Management Interpretations: Site Index What is site index?

For a particular target species, site index is the height of the largest diameter (at breast height) site tree on a 0.01 ha plot at breast height age 50

Why is site index important for forest management?

• provides a numeric description of site productivity

• Silviculture prescriptions

• Projections of yield (Timber supply)

• Inventory projections

Management Interpretations: Site Index How can we measure site index?

Available tools suitable stands

Growth Intercept Models Ages 15-50

Height over age curves Ages 50-140

SIBEC Ages < 15 or > 140

http://www.for.gov.bc.ca/hre/sibec/SIBEC_RDM_Section_2.htm

Management Interpretations: Site Index and Vegetation Potential

Old format

Site class: I, II, III, IVVegetation Potential: L, M, H, VH

Management Interpretations: Site Index

Douglas-fir site index in CWHdm

New format based on SIBEC

Example from SIBEC tables

Management InterpretationsSite Index of lodgepole pine across moisture regimes SBS zone

Interior Indicator Plants

Amelanchier alnifoliaSaskatoon, dry-moist

Artemesia tridentataBig sage, dry-fresh

Arnica cordifoliaHeart-leaf arnica, fresh-moist

Basic indicator plant concepts

Based on niche concept, where each species is uniquely affected by a complex suite of environmental factors (site quality)

Ecological amplitude=niche breadth, which is usually measured by one or more factors (e.g., SMR, SNR)

Advantages of using the indicator plant concept

Quicker than detailed physical and chemical measures of site quality

Don’t fluctuate over short time periods

Integrate several factors that govern site quality (e.g., SMR depends on precip, radiation, moisture demands, soil properties that affect soil water storage capacity, etc.)

Ecological amplitude ≠ Physiological amplitude

Ecological amplitude=niche breadth, depends on competitive influence of neighbouring plants

Physiological amplitude=optimal growing conditions without competition; most plants grow best in fresh, rich, neutral soil

At extremes of ecological amplitude, plant are sporadic in cover and vigour is low (e.g., salal on stumps and CWD in wet, rich sites)

Ecological vs physiological amplitude of lodgepole pine

SMR

physiologicalamplitude

ecological amplitudeCoast:

SMR

physiologicalamplitude

ecological amplitudeInterior:

Attributes of good indicator plants

Narrow amplitudes

Limited to three contiguous classes

Plants with intermediate ranges also considered indicator plants (e.g., swordfern)

Should consider all indicator attributes (climate, SMR, SNR, substrate)

Local versus global indicators Global: occurs across a wide range of

indicator values (e.g., fireweed is a global indicator of exposed mineral soil in full light)

Local: restricted to a narrow range (e.g., salal is local indicator of cool mesothermal climates on acidic soils)

Indicator Groups=Differentiated group

Groups of species that have similar indicator values for particular indicator attributes

Indicator attribute: SMR SMR=long-term balance between available soil water

and plant water demand

Use actual SMR when choosing indicator plants

Actual SMR=based on actual annual water balance

Relative SMR: relatively driest in any climate to relatively wettest

Both actual and relative SMR can be classified into nine classes

SMR Indicator Groups, Coastal BC

MOIST 1: Lichen group, VX-X

MOIST 2: Kinnickinnick group, X-SM

MOIST 3: Oregon grape group, SM-M

MOIST 4: Deer fern group, M-SHG

MOIST 5: Salmonberry group, SHG-HG

MOIST 6: Skunk cabbage group, HG-HD

Indicator attribute: SNR

SNR=average amount of essential soil nutrients available to plants over several years

Actual SNR=based on rooting zone mineralizable nitrogen as the single differentiating characteristic

Relative SNR: relatively poorest to relatively richest

Both actual and relative SNR can be classified into five classes (VP-VR)

Substrate Indicator Groups, Coastal BC

NITR 1: Salal group, VP-P

NITR 2: One-leaved foam-flower group, M

NITR 3: Three-leaved foam-flower group, R-VR

Indicator attribute: Ground Surface Material (Substrate)

Soil surface is source of plant water and nutrients, and influences vegetation composition;

Decomposition releases nutrients, and therefore humus form is index of available nutrients

Substrate Indicator Groups, Coastal BC

GSM 1: Red huckleberry group, Mors

GSM 2: Sword fern group, Moders and Mulls

GSM 3: Pearly everlasting, mineral soil

GSM 4: Sellaginella group, very shallow and rocky soils

GSM 5: Sphagnum group, wet soils

Indicator Plants to Learn

-see course website for Indicator Plant List and photos

The url is: http://courses.forestry.ubc.ca/frst211

Premise of using indicator plants in BEC

The occurrence and vigour of a plant species on a particular site reflects the quality of the site (because we know each plants’ ecological amplitude)

Indicator values Can be integers or names that refer to classes

along environmental gradients BEC: names for SMR (VX-HD), SNR (VP-VR);

convert to integers Ellenberg (1974): Used values 1-9 for gradients of

light, temperature, soil moisture, soil nitrogen, soil acidity

The indicator value for a species reflects its correlation with its environment

Best site quality indicator factors

Soil moisture regime, soil nutrient regime, climate, substrate

All affect plant physiology, yet are relatively environmentally stable