the study of silvics __________________. references klinka, worrall, skoda and varga. 2000. the...
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The Study of Silvics__________________
References
Klinka, Worrall, Skoda and Varga. 2000. The distribution and synopsis of ecological and silvical characteristics of tree species of British Columbia’s forests. Order from Canadian Cartographics Ltd.
• Required text.
Burns and Honkala. 1990. Silvics of North America. Agriculture Handbook 654. Washington, DC: USDA, Forest Service.
• Supplementary reading, mainly for life history.
http://www.na.fs.fed.us/spfo/pubs/silvics%5Fmanual
Readings for today’s lecture
• Klinka et al. 2000. Pages 1-19.
• Burns and Honkala. Pages 1-11.
What is silvics?
Silvics: – Is the ecological study of forest trees– Includes life history and general characteristics of forest trees
and stands– Environmental factors– Population genetics– Basis for the practice of silviculture
Silviculture: – the science and art of cultivating forests based on knowledge of
silvics. – The theory and practice of controlling the establishment,
composition, growth and structure of forests.
Role of Silvics in Forestry
• Management and restoration of forests, and maintaining/promoting desired attributes:
– Tree species choice– Methods of regeneration– Methods of cultivation– Effects of regeneration and cultivation on productivity and quality
• This requires knowledge of– ecological characteristics of trees species– how environment affects behaviour and growth of trees.
Role of Silvics in Ecosystem Classification • Intimately integrated• Ecological study of forest trees encompasses
the conditions under which they grow ---climatic, topographic, edaphic and biotic (i.e., their ecological niche).
• With knowledge of silvics and ecosystems, basic interpretations about each ecosystem type (BEC) can be made:– Stand composition (tree species choice)– Silviculture system (regeneration cuttings)– Potential productivity– Hazards– Biodiversity
Tree species
Conifers (18)•Western hemlock (Hw)•Mountain hemlock (Hm)•Western redcedar (Cw)•Alaska yellow cedar (Yc)•Amabilis fir (Ba)•Grand fir (Bg)•Subalpine fir (Bl)•Douglas-fir (coast, interior) (Fdc, Fdi)•Sitka spruce (Ss)•Engelmann spruce (Se)•White spruce (interior spruce) (Sw, Si, Sxw)•Black spruce (Sb)•Western white pine (Pw)•Whitebark pine (Pa)•Lodgepole pine (Pl)•Jack pine (Pj)•Juniper•Western yew
Deciduous (10)•Red alder (Da)•Mountain alder•Sitka alder•Bigleaf maple•Pacific madrone•Garry oak•Bitter Cherry•Western Flowering Dogwood•Black cottonwood (Act)•Trembling aspen (At)•Balsam poplar (Ab)•Paper birch (Ep)
Main Silvics Topics
General description (nomenclature, distribution, identification characteristics, botanical features)
Ecological characteristics (habitats, associates, tolerances)
Life history (seed production, germination, form and size of mature trees)
• Genetic variationSilvicultural applications
Ecological characteristics
Geographic range (distribution in western North America)
Climatic amplitude (climate class, BEC zones)Orographic amplitudeEdaphics (SMR, SNR)Shade and exposure toleranceFrost and flood resistanceResistance and risk to damaging agentsSilvical characteristicsSpecial adaptations
Geographic range
Area Region
1. Western North America 1.1 Pacific
1.2 Mainly Pacific and less Cordilleran
1.3 Pacific and Cordilleran
1.4 Mainly Cordilleran and less Pacific
1.5 Mainly Cordilleran and marginally Central
1.7 Pacific, Cordilleran, and central
2. Eastern North America 2.1 Cordilleran and more northern Central
2.2 Cordilleran and more southern Central
2.3 Central and Atlantic, marginally Cordilleran
3. Northern American transcontinental
3.1 Complete (Atlantic to Pacific)
3.2 Incomplete (Atlantic to east of Pacific)
4. Asian and North American
5. Circumpolar 5.1 Transcontinental complete
5.2 Transcontinental incomplete
Climatic amplitude
• Indicates species climatic tolerances
• Characterized by climatic regions and climatic characteristics of BEC zones
Climatic regions used to describe climatic amplitude
Climatic region Characteristics
Arctic tundra
=High Arctic
MTWM<10oC; MMT<0oC 9-11 mo.
Alpine tundra MTWM<10oC; MMT<0oC 7-9 mo.
Subarctic Cold, snowy climate with MTWM>10oC; 2 mo. with MMT>0oC.
Montane boreal † Cold, snowy climate with MTWM>10oC; MTCM<-3oC; <4 mo. with MMT>10oC.
Subalpine boreal † Similar to montane boreal but higher snowfall, shorter growing season, and cooler daytime temp.
Temperate * † Cold, snowy boreal climate but > 4 mo. with MMT>10oC.
Semi-arid Evaporation>precipitation; no headwaters
Mesothermal * † Mild, rainy climate with MTCM<18oC and >-3oC
Tropical MTCM>18oC
* Cold (< 4 mo. MMT>10oC), cool (MTWM<22oC), warm (MTWM>22oC)† dry, wet (no distinct dry season)
Continentality strata
Stratum Characteristics
Hypermaritime Outer coast under dominant influence of Pacific Ocean
Maritime Coastal areas on windward side of Coast Mountains under prevailing influence of Pacific Ocean
Submaritime Coast-interior ecotone on leeward side of Coast Mountains under strong influence of Pacific Ocean
Subcontinental Coast-interior ecotone adjacent to Coast Mountains under weak influence of Pacific Ocean
Continental Interior areas east of Coast Mountains under prevailing influence of continental air masses. Winter-cold, summer-warm to hot climates.
HM
M SM SC
Example: Climatic amplitude of Amabilis fir
• Maritime subalpine boreal –(wet cool temperate) – wet cool-cold mesothermal
• Description includes (1) continentality stratum, (2) temperature or precipitation variations where they exist, (3) climate class
• Ordered left to right from coldest to warmest
Frequency of occurrence
• (infrequent): species is uncommon or rare, not throughout latitudinal class (north, central, and southern)
• frequent: species is common and generally present through class
• very frequent: species is abundant throughout class
Orographic amplitude(general relief in conjunction with climate)
Orographic class
Species distribution
Submontane At foot of mountains, on lowlands, and on plains and bottomlands
Montane On hills or mountain slopes between lowlands and subalpine boreal climates
Subalpine Middle and low latitudes at high elevations with subalpine boreal climates; also low elevations in subarctic
Alpine Middle and low latitudes in highest mountains with tundra climate; also low elevations in arctic
Species occurrences in biogeoclimatic zones
Biogeoclimatic Zone Abbrev. Climate
Alpine Tundra AT Alpine tundra
Mountain Hemlock MH Maritime subalpine boreal
Coastal Western Hemlock CWH Wet cool (cold) mesothermal
Coastal Douglas-fir CDF Dry cool mesothermal
Engelmann spruce-subalpine fir ESSF Cool continental subalpine boreal
Spruce-Willow-Birch SWB Cold continental subalpine boreal
Montane Spruce MS Mild continental subalpine boreal
Boreal White and Black Spruce BWBS Cold continental montane boreal
Sub-boreal Spruce SBS Mild continental montane boreal
Sub-boreal Pine - Spruce SBPS Cool continental montane boreal
Bunchgrass BG Cool semiarid
Ponderosa Pine PP Dry cool temperate
Interior Douglas-fir IDF Moist cool temperate
Interior Cedar-Hemlock ICH Wet cool temperate
Edaphic amplitude
Soil Moisture Regime
1. XD (extremely dry)
2. ED (excessively dry)
3. VD (very dry)
4. MD (moderately dry)
5. SD (slightly dry)
6. F (fresh)
7. M (moist)
8. VM (very moist)
9. W (wet)
10. VW (very wet)
• (infrequent), light green on edatopic grid• frequent, green• very frequent, dark green
Amabilis fir: SMR (slightly dry) – fresh – moist – very moist – (wet)SNR: very poor – poor – medium – rich – very rich
Soil Nutrient Regime
1. VP (very poor)
2. P (poor)
3. M (medium)
4. R (rich)
5. VR (very rich)
Soil m
i ne ral iza
ble N
Water deficitAET/PET<1.0
No water deficitDemand=supply
Water table present in growing season
Edatopic grid for the CWHdm subzone upland sites, fluctuating water table sites, and floodplains
Shade tolerance and exposure classes
Class Description
Shade tolerant
Moderately shade tolerant
Shade intolerant
Protection requiring Require short- or long-term protection from parent stand; very shade tolerant or moderately shade tolerant species
Exposure tolerant In some situations survive and grow successfully without protection, even more so in open areas; shade tolerant or moderately shade tolerant
Exposure requiring Require full exposure to light for survival and growth; shade intolerant
Variation in shade tolerance? Shade tolerance appears to increase as climate becomes warmer or cooler and the soil becomes drier.
Species tolerances
Tolerances Criteria
Frost Freezing resistance of dormant buds and twigs
Heat Resistance to heat injury
Drought Ability to endure or avoid drought (stomatal closure, deep roots)
Flooding Ability to endure fluctuating or permanent water table
Nutrient deficiency or excess
Based on growth responses to nutrient conditions and ecological amplitude along soil nutrient gradient
Damaging Agents
Damaging agent Criteria
Snow resistance or resilience
Depends on crown architecture and stem and branch wood structure.
Wind resistance Uprooting and bole breakage. Depends on roots, crowns, height, HDR, wood structure.
Fire resistance and risk Species resistance (e.g., bark thickness) and risk in climatic region
Insect and pathogen risk
Depends on host specificity, climate, longevity, genetics
Resistance classes:•Low (L): frequent damage•Intermediate (M): some damage•High (H): rare damage
Risk classes:•Low (L): infrequent or rare damage•Intermediate (M): damage may be frequent but not all stands affected•High (H): damage frequent
Successional role and tree species associates
•Successional role (primary, secondary, stand developmental stages)•Occurrence in naturally established stands•Occurrence in pure and mixed species stands•Area and extent of association with other tree species
Silvical characteristics
Characteristic ConsiderationsReproduction capacity
Minimum cone or fruit bearing age; seed crop frequency, crop size, seed soundness, potential for vegetative reproduction
Seed dissemination capacity
Speed of seed fall, seed weight, seed structure
Potential for natural regeneration in low light and in the open
Seed durability and longevity, seed germination and stratification requirements, germination requirements, seedbed suitability, shade tolerance
Potential for initial growth rate (<5 years)
Species and site
Response of advance regeneration to release
Time delay for increased growth, shade tolerance, the need for protection/exposure
Silvical characteristics
Characteristic ConsiderationsSelf-pruning capacity in dense stands
Species, site and stand density
Crown spatial requirements
Species differences in length, width, and weight of live-crown, as unaffected by stand density
Light conditions beneath mature closed canopy
Understory vegetation development
Potential productivity Site index trends geographically and orographically
Longevity Low < 100 years; Medium >100 but <300; high > 300 years