Progress and Prospects at the Boreal Ecosystem Research and Monitoring Sites

Alan Barr, Warren Helgason, Andy Black, Andrew Ireson, Colin Laroque, Jill Johnstone,

Garth van der Kamp, Bruce Davison

Faizan Ahmed, Jilmarie Stephens, Jason Maillet, Magali Nehemy, Mahtab Nazarbakhsh,

Amber Peterson, Bruce Johnson

• How can we use the observed responses to inter-annual climate variability at flux towers to inform the most likely responses to climate change?

• How can we improve models to better link hydrology, ecosystem productivity and vegetation dynamics?

`

Understanding the role of hydrology in mediating the southern boreal forest’s

response to climate change

Boreal Ecozone Research and Monitoring Sites

Old Aspen(Deciduous)

Old Black Spruce(Wet Coniferous)

Old Jack Pine(Dry Coniferous)

100 km

Fen(Wetland)

Mature Sites (still in operation)

Core, long-term observations of the carbon, water and energy balances, anchoring: • process studies of ecosystem function • evaluation and improvement of

hydrological and land-surface-process models

• remote sensing studies

Strategy

Ecosystem Function

Annual Carbon Fluxes: NEP = GEP – REOld Aspen 1997-2017 (Jilmarie Stephens, UBC)

drought defoliation

Gross Ecosystem

PhotosynthesisEcosystem Respiration

Net Ecosystem Production

13 May 2016

Forest Tent Caterpillar Outbreak at Old Aspen in 2016as seen from Harvard PhenoCam

2 June 2016

13 May 2016

13 May 2016

26 June 2016

Old Aspen 2016 Carbon & Water Fluxes

GEP RE

NEP ET

Measured No Defoliation (reconstructed)

Aspen Black Spruce Jack Pine

Annual Carbon FluxesBERMS Forest Sites 1997-2017

(Andy Black, Warren Helgason)

Aspen Black Spruce Jack Pine

Soil Temperature and Ecosystem RespirationBERMS Forest Sites 1997-2017

Year

Forest Carbon Dynamics, Dendrochronology(Colin Laroque, Jill Johnstone)

Pine Aspen

Changing Forest Stem Density and Tree Mortality, 1994-2016

(Colin Laroque, Jay Maillet)

ΔC DebrisΔC Dead TreesΔC Live Trees

Flux Tower

Pine Aspen

ForestFloor?

Comparing Cumulative Flux-Tower NEPWith Measured C Stock Changes, 1994-2016

(Colin Laroque, Jay Maillet)

Tree Rings Analysis for Early Warning Signals of Tree Mortality

(Steve Mamet, Jill Johnstone)

SubhygricSubxeric

Submesic

Water Table Level as a Major Determinantof Tree Radial Growth, BERMS Fen

(Magali Nehemy, Colin Laroque)

BlackSpruce

Larch CentreLarchEast

0.6

0.4

0.2

0.0-0.2

-0.4

-0.6

-0.8

Apr May Jun Jul Aug Sep Oct

Co

rrel

atio

n C

oef

fici

ent

Wiley Interdisciplinary Reviews: Water 2: 505–521.

Hydrology

Stand-Level Water BalancesBy Vegetation Type

(Alan Barr, Garth van der Kamp)

Aspen Spruce Pine Harvested Fen Streamflow

Annual Streamflow in Relation to Precipitation, White Gull Creek

Hydrologic Years (Oct-Sept, 1997-98 to 2014-15)

2010-11: High P, wet landscape

2003-04: High P, rewetting landscape

Normalized May-Sept Storage (mm)

Annual Stand-Level Outflow Rin Relation to Soil Water Storage

‘94 ‘97 ‘00 ‘03 ‘06 ‘09 ‘12 ‘15

Hydrograph, White Gull Creek

Model Evaluation

Adding slope (lateral exchange) improved model performance

But unable to capture extreme peak flows of 2011

Need to represent wetland storage

MESH Modelling of White Gull Creek Watershed

(Bruce Davison, ECCC)

MESH Modelling

Observed Modelled

NOAH-MP Modelling at BERMS Old AspenInclusion of a forest-floor soil organic layer

(Liang Chen and Yanping Li)

Annual Cycles of Soil Temperature

NOAH-MP +OrganicObserved

40

-10

0

10

-40

0

-10

cm

CTEM Modeling: Vegetation Dynamics at the Forest-Grassland Ecotone

(Omer Yetemen, Andrew Ireson)

Long-term

mean CMI

(CMI from Ted Hogg, CFS)

ObservedSHAWCRHMCLASS

Sno

w W

ate

r E

quiv

ale

nt

(mm

)Snow Accumulation and Melt

Evaluating SHAW, CRHM and CLASSOld Jack Pine (Faizan Ahmed, Amber Peterson)

Oct Nov Dec Jan Feb Mar Apr May Jun

Links to Remote Sensing

Monitoring Freeze/Thaw Cycles L-Band Radiometers for SMAP Satellite Mission

(Alexandre Roy, U. Montreal, Chris Derksen ECCC)

Comparing start day of photosynthesis from flux towers with snow clearance day

from microwave remote sensing (Pulliainen, Finnish Met Institute)

Photosynthetic Efficiency (LUE) of Northern Forests

from MODIS Photochemical Reflectance Index (PRI) (EM Middleton, NASA Goddard)

• 20+ years of CWE (carbon, water and energy) flux measurements above aspen, spruce, pine and fen

• Finally! a severe insect defoliation event

• Enhanced focus on snow melt and spring thaw

• Value-added observations of freeze-thaw processes, tree water relations, sapflow, and dendrochronology

• Widespread use of the data in multi-site syntheses and as ground-truth in remote sensing

Accomplishments: Observations

• Characterization of the large variations in evapotranspiration and outflow across the boreal forest mosaic

• Enhanced understanding of inter-annual variability, including aspen defoliation and recovery; emerging trends?

• Importance of wetland storage and upland-wetland lateral exchange; use of tree rings as proxy for water table depth

Accomplishments: Process Understanding

• Importance of lateral exchange processes in the boreal forest upland-lowland-wetland mosaic

• Progress in linking water stress to vegetation dynamics in CLASS-CTEM

• Importance of forest-floor organic soil horizons

• Evaluation of SHAW, CHRM, and CLASS -- snow accumulation, snow melt and soil thaw; model differences in timing of spring melt and thaw related to differences in structure

Accomplishments: Modelling

• Role of hydrology in mediating the boreal forest’s response to climate change

• Snowmelt and soil thaw processes

• Influence of plant phenological phases and seasonal precipitation inputs on the forest’s sources of water

• Forest management under a changing climate

Ongoing and Emerging Questions: