Upload
hoangliem
View
244
Download
2
Embed Size (px)
Citation preview
Pre- and Post-Wildfire Forest Management for Ecological Restoration and Fire Resiliency
McClellan Park, Sacramento CA
February 9-11, 2010
John A. Helms
Professor Emeritus
University of California, Berkeley
Session 2
Post-Fire Management Responses
Reforestation Options
Richard Harris and Herb Baldwin
Photo Acknowledgements
1. Prompt post-fire assessment of condition and risk
2. Identify:
desired future mosaic of conditions, reserves, priorities and
rate of attainment
costs and source(s) of funding
3. Plan sequence of treatments (kinds, levels, timing)
4. Monitor to permit adaptive management
5. Evaluate success (criteria, when?)
6. Subsequent treatments
Summary -- for effective reforestation
From science-based & societal perspectives
“Systems Thinking”
Condition – immediately after burn
1. Post Fire Assessment by interdisciplinary team
A.
Baldwin, 2006
What to do?
Harris, 2007
Harris, 2007
Baldwin, 2006
Erosion Hazard?
Beetle Epidemic?
Restoration?
Partial
Salvage?
Ecological
Reserves?
Current Conditions:
– ecological, habitat, societal considerations
Changed Silvicultural Approach?
Risks -- ecological, environmental,
societal, and economic
of doing nothing
of applying treatments
B.
Increased Runoff &Erosion Potential
Baldwin, 2006
Baldwin, 2006
Effects on regeneration
of doing nothing
Loss of site productivity? (depends on soil depth, slope …)
Where does sediment go?
Baldwin, 2006
Baldwin, 2006
Risk of „permanent‟ brushfields?
(~2 million dormant brush seeds/ac)
Schmechel, 2004
Habitat for wildlife?
Benefits to society?
Fire return interval?
Treatments?30-year-old brushfield
20-year-old brushfield
Reality Check!
“Revegetation after Four Stand-Replacing Fires in
the Lake Tahoe Basin”
W.H. Russell, J. McBride, and R. Rowntree. Madroño 45(1) 1998
None of the four sites were planted
“All sites were, or will be, dominated by shrubs for 50-75 years”
Year Tree Age (yrs)
Burned in 1998
1. 1890s 21-95 (70) aerial photos in 1940 showed no trees
72% after >100 years
2. 1937 20-54 (39) <10% after 50 years
3. 1978 Too small <10% after 30 years
4. 1987 Too small <10% after 20 years
Tree Cover
Baldwin, 2006
What is the future of this stand in: 10 years, 20 years?
What might have been done 5 years ago?
Are any treatments warranted now?
Dominance Potential
Perc
ent O
ccupancy
Time
Sprouting hardwoods
and shrubs
Germinating conifers:
100%
Importance of planting early – i.e., immediately after burn
Germinating shrubsSeeds already in ground
Delayed Seed Year?
Baldwin, 2006
What are the
futures of these two
plants in:
10, 20, 50 years?
Relative capacity to
capture soil water?
Relative rate of
production of leaf
area and root
volume?
Treatment?
Relative dominance potential?
Mosaic of stands -- slope, aspect, landscape level
How soon needed -- rate of achievement with-and-
without treatments
Knowledge of stand dynamics and plant succession
Effects of treatments of different kinds, intensities,
and timing -- both potentially positive and negative
2. Identify Desired Stand Conditions
Silviculture: Even-aged, Uneven-aged, Variable?
“Minimum necessary to ensure regeneration hastemporary advantage”
Reallocation of site resources - especially water
Spot vs. areal
Piling and burning – machine or by hand
Mastication
Effect on soil productivity
Keep soil in place! Soil the most important resource
Site Preparation
3. Plan Sequence of Treatments
Natural Regenerationperiodicity of seed crops provides uncertainty
Direct seedingspring or fall? stratification?
germination on surface?
food for birds, insects, fungi, and rodents
no control over stocking (none to zillions)
Plantingspecies – one or several; preference to intolerants
container vs. bare root – from local seed zone ?
stocking rate – supplement natural regeneration
animal protection?GMOs and non-native species?
Regeneration
Mastication
What’s the future
of these sites?
water, light, nutrients
competition
Photos: Harris, 2007
Planting under snags
Baldwin, 2006
Seedlings planted before shrubs dominate
Planting
Manual TreatmentSite prep adequate?
Water availability?
Photos: Harris
What‟s the future of these stands?
Hydrophobic Layer
Commonly forms 0.5 – 3 inches below soil surface
Waxy substance penetrates as gas, solidifies on cooling
Reduces infiltration, increases overland flow and erosion
Test: use water – if beads, maybe hydrophobic
Treat: logs across slope, rake or hoe, mulch
Baldwin, 2006
Environmental
Societal
Managerial
Costs / Benefits of Alternatives
Of doing nothing Of treatments
Determined at the time of “success”
To evaluate: Survival Growth Ingrowth (trees, shrubs, ground cover)
Developing structure, composition
To permit adaptive management
4. Monitoring
Achieving desired mosaic of standconditions within desired time frame
5. Determining Success
Criteria? When?
Thinning / DensityDepends on desired stand/mosaic goals, fuels, habitat, water yields, next entry, etc.
Species compositionDesired proportion of grasses, shrubs, hardwoods, and conifers at the landscape level. Dynamics of competition.
Habitat
Aesthetics
6. Subsequent Treatments?
Influences regeneration decisions
Treatment Opportunities to attain Desired Condition?
Photos: Harris
?
?
Planted to intolerant pines
Invasion of tolerant firs
Desirable shrubs
Or plant and thin mixed species?
Global Climate Change Considerations
In Regeneration
Assist Migration?
Use local seed?
Global, regional, and local models of climate change?
Identify Connectivity? Refugia?
BUT . . .
Issues are rate of change / novel climates / novel ecosystems
As risk (lack of confidence in predictions) increases …
… need more flexible management decisions
1. Prompt post-fire assessment of condition and risk
2. Identify:
desired future mosaic of conditions, reserves, priorities and rate of
attainment -- climate change?
costs and source(s) of funding
3. Plan sequence of treatments (kinds, levels, timing)
4. Monitor to permit adaptive management (climate change?)
5. Evaluate success (criteria, when?)
6. Subsequent treatments
Summary -- for effective reforestation
From science-based & societal perspectives
“Systems Thinking”
Thank you