Download Why We Should and How We Could Manage to Increase Resilience

Why We Should and How We Could
Manage to Increase Resilience
Constance Harrington
Pacific Northwest Research Station
Matt Horning, Pacific Northwest Region
With slides from:
Andy Bower, PNW Region
Tim Harrington and Kevin Ford, PNW Research Station
John Bailey, OSU
Resilience = ?
Resilire latin to rebound or recoil
Introduced into English language early 17th century
1818 Thomas Tredgold described why some woods
were able to accommodate sudden & severe loads
without breaking (bridges, roofs, etc)
1850s Robert Mallet defined modulus of resilience
as energy required to rupture material as a result of
force being applied (naval fighting ships)
Torrens Resilience Institute
Resilience = ?
Crawford Holling 1973 – Resilience and Stability of
Ecological Systems
Resilience = Ability of an ecosystem to absorb changes
and still exist
Stability = Ability of a system to return to its
equilibrium state after a temporary disturbance
Richard Kline argued these definitions imply
ecosystems are stable but in fact they are dynamic
and constantly responding to change
http://torrensresilience.org/ecological-resilience
Resilience = ?
Ability to cope with stress
Capacity to recover from disturbance
Capability to adapt to stress and change
Braatz - FAO report on adaptation to climate
change
Over past 2 decades a concept used liberally and
enthusiastically by policy makes, practitioners and
academics
Rewritten laws
Established institutes and research programs
Offered academic degrees
Torrens Resilience Institute
Why We Should and How We Could
Manage In Response to Climate
Change
Minimize mortality to short- & long-term events
Minimize reductions in short-term growth
responses
Return to pre-disturbance growth rates
Return to pre-disturbance functions
Harrington and Horning
Increased frequency of extremes
Duffy and Tebaldi 2012. Climate change 111:487-495
Stations recording new Max temperature records
exceed those recording new Min records
Annual number of Tmin and Tmax
records summed over the western US
Meehl et al.2009 GeoPhys Res Letters 36 L23701
Increased frequency of extreme
precip events
Source: NOAA/EPA
Based on 20 global climate models
RCP= Representative Concentration Pathways
Tree mortality and top dieback
near Olympia, WA 9/18/2015
Large trees died near salt water – restricted rooting
(west of Olympia, 9/2015)
WINTER temps
From NOAA
weather stations
Lots of variability
year to year but
trend, esp for
Salem is upward
Date of BB for DF
predicted from
winter air
temperatures
Lots of variability
but generally
happening
earlier over time
Douglas-fir
Pred. Δ in days to Budburst between recent past and 2080
Earlier BB
Later BB
You want BB to
shift to earlier
date – tree can
complete more
growth before
hot/dry times
Harrington and Gould 2015
fpls.2015.00120
Will changes in phenology track climate change?
A study of growth initiation timing in coast Douglas-fir
Kevin R. Ford ([email protected]), Constance A. Harrington, Sheel Bansal
USDA Forest Service Pacific Northwest Research Station
Introduction
Plants require more forcing at low chilling
• The timing of annual growth initiation in plants has large
impacts on species distributions and ecosystem function,
and is sensitive to climate
• Warmer spring temperatures that trigger the beginning of
growth and have generally led to earlier growth initiation
in temperate plants
• But many species also require exposure to cool
temperatures (“chilling”) as well as warm temperatures
(“forcing”) during the winter/spring to initiate growth in
sync with favorable climatic
conditions
• Warmer winters could disrupt
this process and prevent plants
from tracking climate change
Height-growth initiation:
ln 𝐹𝐹 = 𝑎𝑎 − 𝑏𝑏ln𝐶𝐶
Diameter-growth initiation:
w=
𝐶𝐶 γ
βγ + 𝐶𝐶 γ
𝐹𝐹 = 𝑎𝑎 − 𝑏𝑏
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑d
𝑎𝑎 − 𝑏𝑏
1
2
1
2
1−w +
w
Photo credit: Teresa Vail
Study design
turtle
We studied height- and diameter-growth initiation timing
in coast Douglas-fir by combining data from 9 climatically
diverse field sites (where plants experienced medium to
large amounts of chilling) and greenhouse studies (where
we manipulated the amount of chilling plants experienced
from low to medium).
Study map
Calculating chilling and
forcing units
Climate change and phenological
responses together determine growing
conditions plants experience
Climate change affects growth initiation
timing differently across the range
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑d
Conclusions
𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑𝑑d--
• In the higher latitude/elevation portions of the coast
Douglas-fir range, climate change will likely lead to
earlier growth initiation, with plants tracking shifts in
the onset of favorable climatic conditions
• However, towards lower latitude/elevation range
limits, climate change could lead to delayed growth
initiation and plants failing to track shifts in the timing
of favorable conditions
• These maladaptive phenological responses could
reduce the resilience of coast Douglas-fir to climate
change near the warm edges of its range
My website: kevinford.weebly.com
Douglas-fir
Northwest Climate Conference, Nov. 2015
Northwest Climate Conference Nov. 2015
What CAN we do?
Manage competing veg/establishment
Manage different species
Plant different species or seed lots
Manage stands to lower densities
Monitor for pests and pathogens
Manage to reduce fire danger
Think outside the box
Recognize much of what we “know” about forest
mangement comes from ‘70s, 80’s, 90’s
Past rules of thumb may not apply
Stand Establishment
Most sensitive stage of stand development
Options:
Reduce competition
Select drought tolerant species
Consider mixtures
Select different seed lots
Don’t rely on natural regeneration
Manage veg. during establishment to increase soil water
= CV controlled
= CV present
Establishment period critical
T Harrington et al. 2013. FEM 296:41-52
Consider Managing Different Species
ID areas most likely to be drought sensitive
(2015 problems near me mostly associated with
impaired rooting – road cuts, parking lots, near salt water
or standing water – where did you see problems?)
Consider drought tolerance lists
Try more drought tolerant species in small
areas
Tree Diversity Does not Always Improve Resistance of
Forest Ecosystems to Drought
Grossiord et al. 2013
5 forest types in Europe; 160 forest stands
Evaluated drought from wet to dry year using C isotopes in late wood
3 forest types - no effect of tree species diversity
2 forest types - tree species diversity enhanced resistance to drought
Drought prone environments
Conclusion: high tree species diversity does NOT assure adaptability to drought
Proc. Natl. Acad. Sci. 111(41):14812-5
Will plants naturally adapt to rapid
climate change?
Three possibilities when environments change:
1. Move
Migrate to new habitats
2. Stay
Acclimate by modifying individuals to
new environment (phenotypic plasticity)
Evolve through natural selection
3. Disappear
Extinction of local population
Aitken et al. 2008. Evolutionary Applications 1: 95-111.
Natural Plant Movement Rates
Estimates of past migration rates vary
– Davis and Shaw 2001: 200-400 m per yr
– Aitken et al. 2007: 100-200 m per yr
But current rates of climate change might
require 3000-5000 m/yr (1.5 – 3 miles/yr)
– Seed migration may not be sufficient
– Pollen flow may be ineffective due to
non-synchronous flowering phenology
Diversity (Genetic Variation) provides
insurance
Phenological variation in Prairie junegrass Variable frost damage in different sources
of Douglas-fir seedlings
•Plant in higher densities (?)
•Do not rely on natural regeneration
•Keep track of what you do!
Uncertainty and Variation
Uncertainty and differences among
– Geographic areas
– Planting sites
– Seed sources
– Nursery materials
– Species
(generalist vs. specialist)
Climates are not
static and are
changing at a
pace that some
trees may not be
able to keep up
with
Seed zones designed to ensure
adaptability
Seed zones have
been developed
for most major
tree species in
the PNW
But these zones
assume climates
remain static
Randall and Berrang
(2002) WA Dept Nat
Resources
Randall (1996) OR Dept of Forestry
Seed zones last revised for Oregon in
1996 and Washington in 2002
Generally fewer, less restrictive
– Mostly expanded in a
north-south direction
– Elevational guidelines
mostly unchanged
Differ by species
May need to update again
Detecting genetic differences in
northern Rockies (Rehfeldt 1994)
Species
Elev. (m) Frost-free Evolutionary
days
mode
Douglas-fir
200
18
Specialist
Lodgepole pine
220
20
Specialist
Engelmann spruce
370
33
Intermediate
Ponderosa pine
420
38
Intermediate
Western larch
450
40
Intermediate
Western redcedar
600
54
Generalist
none
90
Generalist
Western white pine
13
Variation within PNW Seedzones:
current vs. future climate
F. Kilkenney, et al.
Mean annual temp. (C°)
11
9
7
5
3
1961-1990
0k-1k
2050
1961-1990
1k-2k
2050
1961-1990
2k-3k
2050
1961-1990
3k-4k
2050
1961-1990
4k-5k
2050
13
Variation within PNW Seedzones:
current vs. future climate
F. Kilkenney, et al.
Mean annual temp. (C°)
11
9
7
5
3
1961-1990
0k-1k
2050
1961-1990
1k-2k
2050
1961-1990
2k-3k
2050
1961-1990
3k-4k
2050
1961-1990
2050
4k-5k
Select seed lots for current/future climate, not for the past
Move up in elevation and/or move from S to N
Plant different species or seed lots
Adaptive Management* – Try new approaches
and learn from experience (requires you keep
track of sources)
Hedge your bets – Mix it up and hope for the
best (Great to try new things – but if mixed sources within unit
can you learn from what you did?)
*Adopting a new “best guess” strategy w/o monitoring and evaluation is NOT
adaptive management
What About Stands That are
Already established?
Thinning
Monitoring
Fire management
Thinking
Manage stands to lower densities
Seems logical – but
could reduced
density increase
transpiration or
understory plants
utilize additional
moisture?
-- Assume most sites
which respond to
Thin w/inc growth
are responding to
increased soil moist.
(would like to test)
Sites Differ!
During hot, dry year (2015)
at Stone, diameter growth
completed by July 1
But at cooler sites in WA,
diameter growth
continued until
September
Monitor pests/pathogens/abnormalities
Manage to reduce fire danger
Can’t control landscape threats
Can create fire breaks
Safer Rx burns
Back fires/wildfire
Can reduce
fuel ladders
John Bailey
Manage to reduce fire danger
Can’t control landscape threats
Can create fire breaks
Can reduce
fuel ladders
John Bailey
May
June
July
Thinking?
Tree improvement programs
select for high growth rates &
against very early budburst
(and for other characteristics
related to wood quality and
survival)
May want to consider
summer phenology in
selections also - i.e.,
advantage on some sites in
completing Ht growth early?
Aug
Videoclip of growth
https://youtu.be/KipZfWnjkB4
Think
outside the box
Regeneration – when do you plant? What
stock? What techniques do you use?
Intermediate treatments – How will changes
in climate AND your silviculture affect trees -Log values? Ecosystem values?
Rotation length – how long do you hold a
stand (how often do you regenerate?)
(4”)
Site near Centralia, WA
Root growth unlikely to occur below 5C (41F). But can occur above 5 and lots of
growth > 10C (50F). What is the soil temp on your site?
(20”)
(4 in)
Site near Bandon, south Oregon Coast – winter soils are warm.
If seedlings have active root tips, and soil moist, could fall plant on more sites.
(20”)
To inc. root growth before summer
The Dithering: 2005-2060
A.k.a. “wasted years”
2005: United Nations climate
change conference developed
Montreal Action Plan to negotiate
deeper cuts in greenhouse –gas
emissions
Let’s not dither!
Let’s get moving!
[email protected]
[email protected]
Year Global warming?
1990 Will enhance greenhouse
effect, resulting in average
warming
1995 Detected a significant change
in warming
2001 Projected rate of warming
much larger than 20th century,
likely to be without precedent
2007 Warming of climate system is
unequivocal
Human influence?
Emissions are substantially increasing
concentrations of greenhouse gases
Observed warming is unlikely to be
entirely natural in origin
New and stronger evidence most
warming last 50 years attributable to
human activities
Most of the observed increase is very
likely due to increase in
anthropogenic greenhouse gases
2013 Warming of climate system is It is extremely likely human influence
has been the dominant cause of the
unequivocal and since the
1950s many of the changes are observed warming since the mid 20th
unprecedented
century
http://www.c2es.org/science-impacts/ipcc-summaries/growing-certainty