Upload
ecoshare
View
976
Download
1
Tags:
Embed Size (px)
DESCRIPTION
Jerry Franklin - Early seral forest: a diminishing resource?
Citation preview
What is a “good” forest What is a “good” forest opening?opening?
•Is the future a concern?Is the future a concern?
Early Successional Early Successional CommunitiesCommunities
•What is high quality early What is high quality early seral forest habitat?seral forest habitat?
•How has it been created in How has it been created in the past?the past?
•Where will it be provided in Where will it be provided in the future?the future?
•What silvicultural tools can What silvicultural tools can provide for this habitat?provide for this habitat?
Well, let’s take a look at Well, let’s take a look at nature’s varieties of early nature’s varieties of early successional communities successional communities
on forested siteson forested sites
* Most notably, they are not* Most notably, they are not
dominated by trees!dominated by trees!
Attributes of Early Attributes of Early Successional Successional
Communities on Communities on Forest SitesForest Sites
Jerry F. Franklin and Mark SwansonJerry F. Franklin and Mark Swanson
University of WashingtonUniversity of Washington
Definition:Definition:
Early successional Early successional communities are the communities are the communities that occupy communities that occupy potentially forested sites potentially forested sites between the time of a stand-between the time of a stand-replacement disturbance and replacement disturbance and re-establishment of a closed re-establishment of a closed forest canopyforest canopy
Early Successional Early Successional CommunitiesCommunities•Altered (non-forest-Altered (non-forest-
dominated) microclimatedominated) microclimate•Structurally rich (with most Structurally rich (with most
natural disturbances)natural disturbances)•Biodiversity richBiodiversity rich•Process rich (alterations in Process rich (alterations in
ecosystem functions)ecosystem functions)
Altered microclimate:Altered microclimate:
•Not dominated by trees!Not dominated by trees!•Sunny, greater microclimate Sunny, greater microclimate
extremesextremes•HeterogeneityHeterogeneity• Terrestrial (non-tree) and Terrestrial (non-tree) and
aquatic ecosystems “bloom”aquatic ecosystems “bloom”
Structurally rich:Structurally rich:
•Wood legacies (snags & logs)Wood legacies (snags & logs)– HabitatHabitat– Long-term energy/nutrient Long-term energy/nutrient
sourcesource– Physical interactionsPhysical interactions– PERSISTS & ONLY SOURCE of PERSISTS & ONLY SOURCE of
CWD for MANY DECADESCWD for MANY DECADES•Diversity and balance Diversity and balance
(evenness) in plant life forms(evenness) in plant life forms
Biologically rich:Biologically rich:
•Most biodiverse of forest stagesMost biodiverse of forest stages•Diversity composed ofDiversity composed of– Legacy speciesLegacy species– Opportunists (weeds?)Opportunists (weeds?)– Habitat specialistsHabitat specialists– Predators (land & water)Predators (land & water)
•Adapted, native tree genotypesAdapted, native tree genotypes
Black-backed woodpecker.
Photo: Dr. R. Hutto
Three-toed woodpecker.
Photo: Dr. R. Hutto
Mountain Bluebird. Photo: Dr. R. Hutto
Olive-sided Flycatcher. Photo: Dr. R. Hutto
Western meadowlark.
Photo: Dr. R. Hutto
White-crowned sparrow. Photo: Dr. R. Hutto
Garter Snake. Photo: Dr. C. Crisafulli.
Process Alterations Process Alterations (Terrestrial):(Terrestrial):
•Significant nitrogen fixationSignificant nitrogen fixation•Accelerated nutrient cyclingAccelerated nutrient cycling•Diversity in primary Diversity in primary
productivityproductivity– More complex food websMore complex food webs– Increased herbivoryIncreased herbivory
• Effects on hydrologic cycleEffects on hydrologic cycle– Often, increased flowsOften, increased flows
Process Alterations Process Alterations (Aquatic):(Aquatic):
•Significant primary Significant primary productivityproductivity
•More diverse allochthonous More diverse allochthonous inputsinputs
•Richer food websRicher food webs•Greater fish productionGreater fish production
Other Attributes of ESFCs:Other Attributes of ESFCs:
•Duration – highly variable Duration – highly variable depending upon disturbance depending upon disturbance size, type, and chancesize, type, and chance– Example short: small windthrowExample short: small windthrow– Example long: large or repeated Example long: large or repeated
wildfire or fire on severe sitewildfire or fire on severe site•Heterogeneity – initial & Heterogeneity – initial &
developmentaldevelopmental
Ecological Importance of Ecological Importance of ESFCsESFCs
•Opportunity for organisms and Opportunity for organisms and processes absent/poorly processes absent/poorly represented under closed forestrepresented under closed forest
•Opportunity for nutrient Opportunity for nutrient rechargerecharge
•Regional and local hotspots of Regional and local hotspots of biological diversity (source biological diversity (source areas)areas)
So, what is high quality So, what is high quality early successional early successional
habitat? habitat? Early successional communities Early successional communities
with a large array of structural with a large array of structural and organismal legacies and and organismal legacies and
Exhibiting heterogeneity in Exhibiting heterogeneity in space and time andspace and time and
Diverse in life forms, food webs, Diverse in life forms, food webs, and ecosystem processesand ecosystem processes
Does the job! Does the job!
Provides for the richness ofProvides for the richness of
BiodiversityBiodiversity
Functional diversityFunctional diversity
That we want to sustain in our That we want to sustain in our forest landscapesforest landscapes
How has it been created How has it been created in the past?in the past?
How (where) will it be How (where) will it be provided for in the provided for in the
future?future?
What management tools What management tools can provide for this can provide for this
habitat?habitat?
Best management tool Best management tool for early successional for early successional
habitat:habitat:CONSERVE IT WHEN AND CONSERVE IT WHEN AND WHERE NATURE CREATES WHERE NATURE CREATES
ITIT
Naturally-regenerated Naturally-regenerated ESFCs are likely to be more ESFCs are likely to be more
resilient under climate resilient under climate change due to change due to
- greater species diversity - greater species diversity - tree genotypes selected - tree genotypes selected
by nature (i.e., by nature (i.e., environmental stresses)environmental stresses)
Pacific Tree Frog. Photo: Dr. C. Crisafulli.
What is a “good” forest What is a “good” forest opening?opening?
•Is the future a concern?Is the future a concern?
Where management goals Where management goals are primarily oriented are primarily oriented toward characteristic toward characteristic biodiversity and ecological biodiversity and ecological processes,“hurrying” processes,“hurrying” ecosystem development ecosystem development through the pre-canopy through the pre-canopy closure stage is not closure stage is not appropriateappropriate
Salvage:Salvage:
• WILL eliminate key structural WILL eliminate key structural legacieslegacies– Key habitat and substrate, so many Key habitat and substrate, so many
secondary effects on biotasecondary effects on biota– This is a LONG TERM impact, since This is a LONG TERM impact, since
no new CWD for many decades no new CWD for many decades • WILL destroy/damage recovering WILL destroy/damage recovering
vegetationvegetation• MAY cause damage to aquatic MAY cause damage to aquatic
ecosystems and and soilsecosystems and and soils
Salvage logging never contributes directly to ecological recovery
Salvage logging is always a tax on ecological recovery; the tax may be large or small
Reforestation will Reforestation will usually:usually:•Reduce the duration of ESFCsReduce the duration of ESFCs•Reduce heterogeneity of the Reduce heterogeneity of the
process by which closed forest process by which closed forest canopy is re-establishedcanopy is re-established
•Alter genotype of planted species Alter genotype of planted species (less selection by environment)(less selection by environment)
•Homogenize composition of forestHomogenize composition of forest
Potential negative Potential negative managementmanagement• Early SFCs need full compliment of Early SFCs need full compliment of
biological legacies to fully functionbiological legacies to fully function• Salvage will reduce functionality Salvage will reduce functionality • Reforestation will truncate & Reforestation will truncate &
modify ESFCsmodify ESFCs• Naturally-regenerated ESFCs are Naturally-regenerated ESFCs are
more likely to be resilient to more likely to be resilient to climate change (more diverse, climate change (more diverse, good genotypes)good genotypes)
Blue Grouse. Photo: Dr. C. Crisafulli.
Principle 3: Conservation Principle 3: Conservation of biological legacies is of biological legacies is
critical for postfire critical for postfire reestablishment of reestablishment of
characteristic levels of characteristic levels of ecosystem processes & ecosystem processes &
biodiversitybiodiversity
Principle 5: Whatever Principle 5: Whatever activities are undertaken – activities are undertaken –
seek to avoid causing seek to avoid causing additional harm and to additional harm and to
enhance natural recovery enhance natural recovery processes!processes!
BIOLOGICALBIOLOGICALLEGACIESLEGACIES
•Organisms and Organisms and reproductive structuresreproductive structures
•Structures and organic Structures and organic mattermatter
•Organically-derived spatial Organically-derived spatial patternspatterns
Salvage of dead woodSalvage of dead wood
•Done to capture socio-Done to capture socio-economic valueeconomic value
•Has negative impacts on Has negative impacts on recoveryrecovery
•Removal of legacies is most Removal of legacies is most profound long-term impactprofound long-term impact
Timber salvage rarely, if Timber salvage rarely, if ever, contributes directly ever, contributes directly
to ecological recovery, to ecological recovery, including native including native
biodiversitybiodiversity
Salvage is always a tax Salvage is always a tax on ecological recovery!on ecological recovery!The tax may be large or The tax may be large or small depending upon small depending upon the salvage operation.the salvage operation.
Importance of Coarse Importance of Coarse WoodWood
• Habitat for Habitat for speciesspecies
• Organic seedbeds Organic seedbeds (nurse logs)(nurse logs)
• Modification of Modification of microclimatemicroclimate
• Protection of Protection of plants from plants from ungulatesungulates
• Sediment trapsSediment traps
• Sources of energy Sources of energy & nutrients& nutrients
• Sites of N-fixationSites of N-fixation• Special source of Special source of
soil organic mattersoil organic matter• Structural Structural
elements of elements of aquatic aquatic ecosystemsecosystems
The early post-The early post-disturbancedisturbance
period of forest period of forest ecosystem developmentecosystem development- pre-tree-canopy closure - pre-tree-canopy closure
––is profoundly important!is profoundly important!
Deer Mouse. Photo: Dr. C. Crisafulli.
Montane Shrew. Photo: Dr. C. Crisafulli.
Northern Pocket Gopher. Photo: Dr. C. Crisafulli.
Where management goals Where management goals are directed to sustaining are directed to sustaining ecosystem services and ecosystem services and
biodiversity, most biodiversity, most postdisturbance postdisturbance
“restoration” activities are “restoration” activities are inappropriateinappropriate
MAJOR EXCEPTION:MAJOR EXCEPTION:Human intercession may Human intercession may contribute ecologically contribute ecologically
where the disturbances are where the disturbances are unique (uncharacteristic) in unique (uncharacteristic) in
either intensity or either intensity or frequency or invasive frequency or invasive species are involvedspecies are involved