phd project proposal: what we won’t talk about today ...amcintos/lab_presentation.pdf · what we...
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PhD Project Proposal:Effects of Simulated Mountain
Pine Beetle Attack on Vegetation and Below-Ground Attributes in Lodgepole Pine Forests of the
Western Alberta Foothills
Anne McIntosh
Macdonald Lab Lunch
May 7, 20082
What We Won’t Talk About Today(Pablo Pina’s PhD Project)
This project also seeks to determine initial effects of variable intensity of simulated MPB on stand water balance/hydrology
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Outline
• Introduction
• Objectives
• Methods
• Preliminary Results
• Discussion
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Mountain Pine Beetle (MPB)
Dendroctonus ponderosae
• Native bark beetle of western North America pine forests
• “Most damaging biotic disturbance agent in mature lodgepole pine in western Canada”
• The current BC outbreak is order of magnitude > in area and severity than all previous recorded
• Highly evolved mutualistic relationship withophiostomoid “blue stain” fungi
• Kills trees by girdling them – mass attack
MPB Life Cycle
a.Galleries in phloem
b. Eggs ingalleryc. Mature larvad. Pupae. Teneral/new
adultsf. mature adult 6
MPB as a Disturbance Agent
• Larger & older trees selectively killed – but remain standing (vs logging) � needles can remain 3-5 yrs+
• Understory & soil layers not directly affected (vs logging or fire)
• Return of nonvolatile nutrients to the soil & response of vegetation production are slower (vs stand-replacing fire)
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Lodgepole Pine(Pinus contorta var. latifolia)
• Fire-dependent pioneer species (*serotinous cones)
• Fire suppression changes trajectory
• In Alberta, pine represents ~ 41% of coniferous forests (7x106 ha)
MPB + PICO =From Green to Red…
• The majority of pine in Alberta islodgepole pine and jack pine (P.banksiana Lamb.)
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MPB Climate Change
Implications Are Big
(Kurz et al. 2008)
• BC cumulative impact 2000–2020 = 270 Mt C released (~36-g-C/m2/yr over 374,000 km2)
• Worst yr � impacts from MPB ~75% of mean annual direct forest fire emissions from all of Canada 1959–1999
• From sink � large net C source
Next Stop: Alberta
• MPB research has 1°focused on BC, > history of epidemics
• Former climatically hostile environments will become climatically benign, allowing MPB to significantly expand its range
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MPB Expansion:Jack Pine (Pinus banksiana)
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Native � Invasive
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Outline
• Introduction
• Objectives
• Methods
• Preliminary Results
• Discussion
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Objective 1 - Overstory
• Characterize the overstory forest structure for a set of mature lodgepolepine stands in the western Alberta foothills before, and 1 & 2 yrs after 4 levels of simulated MPB kill and/or forest management
– Baseline data for other aspects of the study
– Insight into standing above-ground C pools
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Objective 2 - Understory
• Quantify differences in the understory plant community composition before, and 1 & 2 yrs after 4 levels of simulated MPB kill and/or forest management in lodgepole pine forests in the western Alberta foothills
– Seedlings/Saplings (pine, spruce, balsam)
– Vascular plants (shrubs, forbs, graminoids)
– Non-vascular plants (bryophytes, lichens)
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Objective 2 - Hypothesis
As tree mortality increases there will be an increase in:– Vascular plant cover
– Plant diversity will peak with medium-level of disturbance (increased stand heterogeneity – more niches)
– Growth of seedlings/saplings (advance regeneration) present – but limited change in overall seedling/sapling abundance b/c of serotiny
Release from competition with trees for water, nutrients, & light* (likely not much change in the light over the duration of this study except salvage harvest– that will follow when needles drop)
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Objective 2a
• Examine the regeneration potential of these stands
• Investigate micro-site and neighborhood characteristics of advanced regeneration
• ?Cones
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Objective 2a - Hypothesis
There are more light, nutrients, and moisture available at safe micro-siteswhere seedlings/ saplings are developing, than other microsites in the stand
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Objective 2b - DWD
• Quantify the downed woody debris (DWD)
• Hypothesis: There will be an increase in DWD from fallen overstory mortality
– provide insight into standing above-ground C pools and susceptibility to fire 20
Objective 3 – Below-Ground
• Quantify differences in below-ground attributes before, and 1 & 2 yrs after 4 levels of simulated MPB kill and/or forest management in lodgepole pine forests in the western Alberta foothills– Microbial biochemical activity (community-
level-physiological profiling (CLPP))
– Nutrient availability
– Soil characteristics – moisture, temperature
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Objective 3 - Hypothesis
With increasing tree mortality there will be a change in:
– Microbial biochemical activity
– Nutrient availability
– Soil moisture
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Outline
• Introduction
• Objectives
• Methods
• Preliminary Results
• Discussion
Foothills
Montane / Alpine
Mixedwood
Parkland
Boreal
Boreal – Canadian Shield Study Area
MPB Aerial Survey Sites
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STUDY AREA
• Lodgepole pine
• ~ 100-110 yrs (‘mature’)
• Medium site index
• Sandy soils
• Mid-elevation
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Experimental Treatments
• Control (untreated),
• Simulated MPB attack (50% overstory kill)
• Simulated MPB attack (100% overstory kill)
• Clearcut - harvested to simulate “salvage logging” management
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Repeated Measures Study
• Three growing seasons
– 2008
– 2009 (“1 yr post-kill”)
– 2010 (“2 yr post-kill”)
*Trees will be killed in late spring 2009 using Triclopyr herbicide to simulate MPB kill
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NRH Block Meteorological Towers
• Each of 4 NRH plots has tower - data continuously recorded.
• Equipment on the tower includes:– Radiometer
– Wind direction
– Wind speed
– Relative humidity
– Temperature
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Three Vegetation
Blocks
North Ridge Hydro (NRH)
Horse Train Loop (HTL)
Power Shack Hill (PSH)
Note: There is now a large clearcut East of NRH block
N
Plot DesignMain Plots = 120 x 180 m (2.2 ha) 4 treatments (below) x 2.2 ha = 8.8 ha total
Stand water balance subplot (80 x 80 m; 0.64 ha)Vegetation subplot (80 x 60 m; 0.48 ha)
Control (undisturbed) 50% MPB kill 100% MPB kill Salvage logged (harvested) plot- no trees left standing
* 1 tree height (20m) exterior treated buffer between measurement plots & adjacent stand in all plots
Additional replicated vegetation plots = 120 x 100 m (1.2 ha ea) 4 treatments (below) x 2 replicates = 9.6 ha total
Control (undisturbed) 50% MPB kill 100% MPB kill Salvage logged (harvested) plot- no trees left standing
Study duration 3 yrs (1 yr pre-treatment, 2 yr. post-treatment)
- no trees left standing
Vegetation subplot (80 x 60 m; 0.48 ha)
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Vegetation Plots (0.48 ha)
80-m
60-m
10-m x 10-m
1-m x 1-m understory, LAI-
2000, soil moisture, temp
5 8-m radius (0.02 ha) tree
plots, hemispherical
photopoints
4-m radius, shrubs
Seedling/sapling neighborhood plots
19.8-m
woody debris
transects
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Methods – Objective 1: Overstory
• Tree plots (~8-m fixed radius plots – O.02 ha) (?5/plot)– Species
– Live status
– Dbh
– Ht
– ?Vigor (crown)
– ?Stem mapped
– ?Tagged – follow change
including falling
• ?Basal area sweeps (BAF4)
• Hemispherical Photography
• Leaf Area Index
– Crown radii (live)
– Decay class (dead)
– 2 perpendicular increment cores ?subset
• age
• radial growth
• Sapwood thickness (translucence, on-site – used to scale canopy leaf area and transpiration )
Hemispherical Photography
Photo points revisited after leaf out each year
Indirect Site Factor (ISF) to capture changes in cover over time
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Leaf Area Index (m2/m2) LAI-2000
• Rapid, non-destructive measurements of LAI
• Measure at multiple times in the season– Early growing season (June)
– Mid growing season (July)
– Late growing season (August)
• Measure at multiple heights:– At the forest floor layer
– Below the tall shrub layer
– Above the tall shrub layer
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Methods - Objective 2: Understory
– Seedlings/Saplings (pine, spruce, balsam)
– Vascular plants (shrubs, forbs, graminoids)
– Non-vascular plants (bryophytes, lichens)
– Woody debris/fuels
– Data will be collected using PDAs
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Methods – Objective 2: UnderstorySampling Protocol
• Seedlings/sapling - very few on the landscape – neighborhood approach
• ?1-m x 1-m quadrats – low shrubs, forbs, graminoids, non-vascular plants
• 4-m radius plots – tall shrubs
• Line-intercept method – woody debris
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Vegetation Plots (0.48 ha)
80-m
60-m
10-m x 10-m
1-m x 1-m understory, LAI-
2000, soil moisture, temp
5 8-m radius (0.02 ha) tree
plots, hemispherical
photopoints
4-m radius, shrubs
Seedling/sapling neighborhood plots
19.8-m
woody debris
transects
Understory Seedlings/Saplings
Balsam fir Lodgepole pine Spruce
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Methods - Objective 2: Seedlings/saplings – neighborhood approach
• tagged, GPSed
• height
• diameter
• terminal leader growth
• # of living branches for each whorl
• nutrient availability (PRS)
• soil moisture, temp
• light
• free-to-grow competitors (stems within 1.78-m) ht, diameter
• Very little advanced regeneration currently present
• Closed cones suggest that seeds are in large supply, but…
• seed predators
• Damping-off fungi (fungal-caused mortality from germination to just after seedling emergence) that kill seedlings
• it’s not getting warm enough in the absence of fire…
Club-moss (Lycopodium annonitum)bunchberry (Cornus canadensis)
The Understory
Bog cranberry (Vaccinium vitis-idaea), moss Studded leather lichen (Peltigera aphthosa)
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Labrador tea (Ledum groenlandicum) Green alder (Alnus crispa)
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Methods - Objective 2: 1-m x 1-m quadrats
• Species (?Genus or other grouping for non-vascular)
• % cover– Cover classes (e.g. <1, 1–3, 4–10, 11–25, 26–50, 51–75, >75%)
• Plant species
• Bare rock
• Woody debris (?by decay class)
• Litter – needles, cones
• Forest floor depth in 4 corners of the quadrat (cm)
• LAI
• ?hemispherical photos
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Methods - Objective 2: Beyond 1-m x 1-m vascular plants
• In larger area of the plot identify rarespecies not captured by the transects/quadrats
– size (e.g., Kurulok & MacDonald 100-m2 area)
– time
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Methods - Objective 2: 4-m radius tall shrub plots (0.05 ha)
• Species
• % cover– Cover classes
(e.g., <1, 1–3, 4–10, 11–25, 26–50, 51–75, >75%)
(Daubenmire - 0-1, 1-5, 5-25, 25-50, 50-75, 75-95, 95-100%)• Basal diameters of individual woody stems
(e.g., green alder)
Methods – Objective 2b Down Woody Debris/Fuels
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Methods – Objective 2b Down Woody Debris/Fuels
• Brown’s (1971) planar intersect method
• Total # of transects – min. 100 DWD pieces
• Diameter size classes � theoretical amt of time needed to respond to changes in atmospheric moisture (timelag)
• For each 19.8-m transect:
– # pieces 0-0.64 cm (1-h timelag) 0.64-2.54 cm (10-h timelag) from 1.5 to 3.6 m;
– # 2.54-7.62 cm (100-h timelag) diameter fuels tallied from 1.5 to 6.1 m
– fuels > 7.62 cm (1,000-h timelag) tallied from 1.5 to 19.8 m.
• 1,000-h fuels measure: diameter, decay class (1-5)50
Methods – Objective 3: Below-ground
• Microbial biochemical activity –community-level physiological profiling
• Nutrient availability (PRS probes)
• Soil moisture
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Methods – Objective 3: Below-ground
• Microbial biochemical activity –Community-Level Physiological Profiling (CLPP)
Bacteria
Who are
they?
What are they
doing?
Add Soil Sample
Incubate
20°C
Cleavage of chemical substrates due to enzymatic activities releases purple dye that can be quantified spectrophotometrically
Microtiter Plate Assays for Each Sample
31 C-substrates with 3 reps /plate
One sample per growing season
Assess functional diversity of microbes
Methods – Objective 3: CLPP
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CLPP Multivariate Analysis – NMS(e.g., bigleaf maple canopy soil vs ground)
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Methods – Objective 3: Below-groundNutrient Availability – PRS Probes
• - and + ion-exchange resin membranes
• Nutrient sorption phenomena closely resemble plant root surface
• Assesses nutrient supply rates by continuously adsorbing charged ionic species over the burial period
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Nutrient Availability – PRS Probes• Install (+/-) centered at 10 cm
depth in mineral soil
• Install adjacent to seedlings, and at random 1-m
2quadrat
centers
• ?Sampling efficiency – have $ for 30/plot/yr
• Capture growing season in one measurement vs.– Early growing season (June – mid-
July)
– Later growing season (mid-July –September 56
Methods – Objective 3: Below-groundSoil Moisture
• Time-domain-reflectrometry (TDR) long-term measurements in all plots systematically (Kevin Bladon taking lead)
• Spot measurements at each of the 35 1-m
2quadrats
– Recorded at least monthly during the growing season
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Outline
• Introduction
• Objectives
• Methods
• Preliminary Results
• Discussion
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Preliminary Results - Overstory
Basal area at mean plot level ranges from ~30-50 m2/ha
BA vs Block
0
10
20
30
40
50
60
70
HTL NRH PSH
Block
Bas
al
Are
a (
m2/h
a)
BAF BA vs Block
0.0
10.0
20.0
30.0
40.0
50.0
60.0
70.0
HTL NRH PSH
Block
Bas
al
Are
a (
m2/h
a)
Series1
Circular
Plots
BAF4
Prism
Sweeps
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Preliminary Results - Overstory
Mean Basal Area vs Block
0
10
20
30
40
50
60
HTL NRH PSH
Block
Bas
al
Are
a (
m2/h
a)
BAlive
BAdead
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Preliminary Results - Overstory
Mean TPH vs Block
0
500
1000
1500
2000
2500
3000
HTL NRH PSH
Block
TP
H tphlive
tphdead
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Preliminary Results - Overstory
Tree Count (7.5-m radius plot) vs Block
0
10
20
30
40
50
60
HTL NRH PSH
Block
Tre
e C
ou
nt
(>5
cm
db
h)
countlive
countdead
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Preliminary Results – OverstoryMean DBH vs Block
0
5
10
15
20
25
30
HTL NRH PSH
Block
Mean
db
h (
cm
)
dead
live
N=86 111 175 313 47 90
25 cm dbh � shift from beetle sinks to beetle sources (Safranyik et al. 1974)
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Preliminary Results - Overstory
25 cm dbh � shift from beetle sinks to beetle sources (Safranyik et al. 1974)
Mean Basal Area by Block and Treatment
0
10
20
30
40
50
60
100%
kill
50%
kill
co
ntr
ol
salv
age
100%
kill
50%
kill
co
ntr
ol
salv
age
100%
kill
50%
kill
co
ntr
ol
salv
age
HTL HTL HTL HTL NRH NRH NRH NRH PSH PSH PSH PSH
Block and Treatment
Basal
Are
a (
m2
/ha)
dbh<25 cm
dbh>=25 cm
Total
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Preliminary Results –Seedlings/saplings
• In sampling 24 7.5-m radius plots in the three blocks:
– 23 seedling/saplings: 54/ha (0.3 – 1.8 m tall)
– 7 PICO seedling/saplings: 17/ha
* 11 of the spruce seedling/saplings were in a single
plot of HTL
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Preliminary Observations Understory species census
• Species tend to be clumped in patches
• Low diversity of species
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Outline
• Introduction
• Objectives
• Methods
• Preliminary Results
• Discussion
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Discussion
• Methods for understory
– Line intercept vs 1-m x 1-m quadrats
– Cover classes vs absolute estimates
– Litter
– Capturing patchiness of the understory
• Standardization of methods – the ideal scenario!
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Acknowledgements
• NSERC – Canada Graduate Scholarship
• Foothills Model Forest
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Questions?
Species 2
Species 1
Total/Combined
The Line-Intercept Method
Cover = (Understory Distance)*100
(Transect Length)
Species 3