TRANSFORMATION OF LARCH-DOMINATED TRANSFORMATION OF LARCH-DOMINATED FORESTS AND WOODLANDS INTO MIXED FORESTS AND WOODLANDS INTO MIXED
TAIGATAIGA
E. Levine1, H. Shugart Jr.2, J. Ranson1, N. Mölders3,
J. Shuman2, R. Knox1, G. Sun4, V. Kharuk5 1NASA’s GSFC, Biospheric Sciences Branch, Greenbelt, MD
2Dept. of Environmental Sciences, University of Virginia, Charlottesville, VA3University of Alaska, Fairbanks, Geophysical Institute, Fairbanks, AK
4Dept. of Geography, University of Maryland, College Park, MD5Sukachev Forest Institute, Krasnoyarsk, Russia
Northern Boreal forest/Taiga biomeNorthern Boreal forest/Taiga biome
Siberian Taiga One of the largest unaltered boreal forest areas in the
world making up 19- 20% of the world’s forest area Significant carbon sink estimated to store 74 Pg C and
249 Pg C in the vegetation and soil, respectively Long, severe winters (up to 6 Long, severe winters (up to 6
months with mean temperatures months with mean temperatures below freezing) and short summers below freezing) and short summers (50 to 100 frost-free days) (50 to 100 frost-free days) Annual temperature range: -54°C to Annual temperature range: -54°C to
21°C (-65°F to 70°F ) 21°C (-65°F to 70°F ) with occasional extremes 73°C to 32 (-with occasional extremes 73°C to 32 (-
100°F to 90°F )100°F to 90°F )
mean annual precipitation: 38 to 51 cm mean annual precipitation: 38 to 51 cm (15 to 20 in)(15 to 20 in)
Major soils of the study areaMajor soils of the study area (US Soil Taxonomy) (Cryosol Working Group, 2003)
Permafrost thickness (cm) in the Permafrost thickness (cm) in the study areastudy area
Siberian Larch Siberian Larch (Larix sibirica)(Larix sibirica) Deciduous needleleaf conifer native to Russia and
northern China that loses it foliage each fall Occupies 270 million ha of boreal forest Siberian larch prefers light and is tolerant of both
heat and frost, allowing it to grow on permafrost sites, where it is often found
R R U U S S S S I I
A
A
In Northern SiberiaIn Northern Siberia Average temperatures have risen 1 to 3°C (3 to
5°F) over the past 30 years, compared to the worldwide average increase of 0.6°C (1°F)
Noticeable changes over the past few decades include increases in winter and fall precipitation winter warming higher soil temperatures permafrost thawing fires insect outbreaks ground subsidence
warming of the soil profile warming of the soil profile increased depth of active layerincreased depth of active layer increased organic decompositionincreased organic decomposition release of COrelease of CO22 and methane and methane change in soil moisture storagechange in soil moisture storage increased evaporationincreased evaporation increased runoff increased runoff change in forest specieschange in forest species Increased wildfiresIncreased wildfires
Some possible effects of Some possible effects of permafrost thawingpermafrost thawing
AREA 1
AREA 2
AREA 3
ObjectivesObjectives Use coupled forest gap and soil process models to
understand their process level interaction under different scenarios
Identify the extent of the evergreen conifer invasion using a combination of well-calibrated satellite data and ground measurements
Use these tools to forecast trends of forest species biodiversity in the region
QuestionsQuestions Are historical areas of larch dominance in Siberia Are historical areas of larch dominance in Siberia
transforming into a zone of mixed taiga in areas of transforming into a zone of mixed taiga in areas of disturbance? disturbance?
Will the trees in this ecosystem begin to grow faster Will the trees in this ecosystem begin to grow faster and gradually extend their reach farther north into and gradually extend their reach farther north into the treeless tundra?the treeless tundra?
Will extensive changes in the larch dominated and Will extensive changes in the larch dominated and adjacent forests impact the carbon, energy, and adjacent forests impact the carbon, energy, and water cycles of Siberia?water cycles of Siberia?
Will hotter, drier conditions inhibiting growth and Will hotter, drier conditions inhibiting growth and leave the forest prone to invasive species and leave the forest prone to invasive species and wildfires?wildfires?
Ecological Forecasts•Projected species composition and structure
Areal impacts•Model results mapped to stratified landscapes
COMBINED MODELINGForest Attributes
•Remote Sensing•Maps•Field measurements
•(e.g. forest type and structure, disturbance history)
Soil Attributes•Maps•Field Measurements
•(e.g. soil texture, bulk density, and horizon depths, moss thickness)
Climate•Weather Station Data•Warming and precipitation scenarios
MODEL INITIALIZATION
RESULTS
Remote Sensing•Predicted pixel level attributes•height •biomass •species composition•LAI
Field Measurements•Detailed ground knowledge
VALIDATION
Forest Model(FAREAST)
•Species composition •Stand structure •Seed sources•Others
Soil Model(HSTVS)
•Soil moisture flux•Soil temperature flux •Snow and moss insulation •Depth of active layer thaw •Others
FAREAST: A Boreal Forest SimulatorFAREAST: A Boreal Forest Simulator
Growth:•Available Light•Soil Moisture•Site Quality•Growing-Degree Days•Depth of Thaw•Diameter•Age•Height Mortality:
•Stress•Fire•Insects•Age
Regeneration:•Available Light•Soil Moisture•Site Quality•Depth of Thaw•Seed Bed•Seed Availability•Sprouting•Layering
Yan, X. and Shugart, H.H. (2005) FAREAST: a forest gap model to simulate dynamics and patterns of eastern Eurasian forests. Journal of
Biogeography, 32:1641-1658.
Krankina O.N., Krankina O.N., et al.et al. 2005. 2005. Effects of climate, disturbance, and species on forest biomass Effects of climate, disturbance, and species on forest biomass across Russia. across Russia. Can. J.For.ResCan. J.For.Res. 35: 2281-2293. 35: 2281-2293
Hydro-Thermodynamic Soil-Hydro-Thermodynamic Soil-Vegetation Simulation (HTSVS)Vegetation Simulation (HTSVS) Mölders, N., U. Haferkorn, J. Döring, G. Kramm, 2003: Long-term numerical investigations on the water budget quantities predicted by the hydro-thermodynamic soil vegetation scheme (HTSVS) Meteorol. Atmos. Phys., 84, 115-135.
Multi-layer soil model including peat, moss, and lichen
Multi-layer snow model Includes simulations of
heat conduction and water diffusion soil freezing and thawing and cross
effects release and consumption of latent heat effects of frozen soil layers on vertical
fluxes of heat, moisture and water vapor flux
HSTVS ResultsHSTVS Results Soil temperatures will be predicted more
accurately if frozen soil physics are considered The soil model captures the observed seasonal
course of soil temperature well and moisture acceptably
The largest uncertainty in simulated soil temperature occurs around freezing
Results are sensitive to soil properties Time steps larger than 10 minutes no longer
captures the active layer effectively Soil properties below 1meter are important 20 layers and a depth of -30m provide better
results
Tura field station, SiberiaTura field station, Siberia
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