Title: Science Enabled by New Measurements of Vegetation Structure
1Science Enabled by New Measurements of Vegetation
Structure (ICESat-II, DESDynI, etc.) Â Some
Ecological Considerations Jon Ranson Hank
Shugart Co-Chairs
2Science Question
- How are the Earth's carbon cycle and ecosystems
changing, and what are the consequences for the
Earth's carbon budget, ecosystem sustainability,
and biodiversity?
The CARBON CYCLE Carbon in the atmosphere is a
controlling factor on climate and hence on
ecological productivity and the sustainability of
life.
Earth Science Enterprise Strategy, October
2003 Science Mission Directorate Draft Science
Plan, 2006
3Science Question
- How are the Earth's carbon cycle and ecosystems
changing, and what are the consequences for the
Earth's carbon budget, ecosystem sustainability,
and biodiversity?
- How are the Earth's carbon cycle and ecosystems
changing, and what are the consequences for the
Earth's carbon budget?
Earth Science Enterprise Strategy, October
2003 Science Mission Directorate Draft Science
Plan, 2006
4Science Question Components
The question requires measurements of
three-dimensional vegetation structure to
estimate
- Carbon in Aboveground Vegetation
- Ecosystem Properties
Carbon in the aboveground biomass of forests
represents about 85 of the total carbon in the
Earths aboveground biomass. Olson et al.
1983 http//cdiac.ornl.gov/epubs/ndp/ndp017/ndp017
.html
Composited NDVI map from MODIS showing global
forest extent
5- Aboveground biomass and carbon storage
- Terrestrial vegetation biomass surveys at
regional and global scales are fundamental to
quantify the strength, location and extent of
land carbon sinks and sources. - To estimate biomass regionally and globally we
must measure forest structure attributes, harvest
the trees, weigh all components and develop
allometric relationships. - Currently measurements can only be done in situ
over limited areas.
3-D structure of terrestrial vegetation Critical
not only for biomass surveys and biomass change
but also for quantifying the location, nature,
cause and extent of disturbance in rapidly
degrading or recovering terrestrial ecosystems.
Current global measurements of carbon in
vegetation are very laboriously obtained
6Largest remaining uncertainties about the Earths
carbon budget are in its terrestrial components.
Global Carbon Budget (Canadell et al., 2007)
To Atmosphere
Unidentified (missing)Terrestrial Sink
Ocean Uptake
Fossil Fuels
Atmospheric Carbon
Land Use Change
Peta (1015) grams of carbon/year
To Land/Ocean
7Uncertainty in the magnitude of carbon emissions
from land use changes is 66 of the estimated
input (1.5 petagrams)
8Climate and human-induced ecosystem changes are
reflected strongly in the vertical height and
density distribution of vegetation and its
horizontal heterogeneity.
USA China
Fire
Both human-induced and natural disturbance are
major driving forces that determine the
transition of forest stands, landscapes, and
regions from carbon sink to source and back
again.
ChinaChina USA
9 Changes in landscape spatial heterogeneity -
vegetation type, height profiles and biomass
relate strongly to ecosystem state and condition.
Ecosystem structure may change in response to
climate. Top change in tree form from bush to
erect Bottom Pinus siberica appearing in the
understory of a Larix forest in Siberia
10Science Question
- How are the Earth's carbon cycle and ecosystems
changing, and what are the consequences for the
Earth's carbon budget, ecosystem sustainability,
and biodiversity?
- How are the Earth's carbon cycle and ecosystems
changing, and what are the consequences for the
Earth's ecosystem sustainability?
Earth Science Enterprise Strategy, October
2003 Science Mission Directorate Draft Science
Plan, 2006
11Ecosystem sustainability implies a capacity to
measure and predict the state of the planets
ecosystems.
Baobab Grove in NXia Pan, Botswana
12A Primer on the Dynamics of Forest Ecosystems
Tropical Rain Forest Canopy in the Brazilian
Amazon
13In a mature forest, one expects the canopy to be
a mosaic of spatial elements about the size of a
large tree crown. These elements go through a
cyclical recovery cycle.
What do gap dynamics tell us about forest biomass
dynamics?
14Carbon disturbance recovery dynamics are
non-linear as the all-aged successional patches
become desynchronized to produce the mixed-aged
mature-forest mosaic.
Carbon Source
Carbon Sink
Carbon Sink
Mature forest is a mosaic.
Successional patches recovering from disturbance
15Depending on antecedent history, a forest with
the biomass level associated with a mature
forest, could be storing carbon, losing carbon or
staying the same.
This means that a single biomass snapshot does
not completely reveal forest carbon dynamics.
16La Selva Footprint Level Height Change (2005-1998)
17Science Question
- How are the Earth's carbon cycle and ecosystems
changing, and what are the consequences for the
Earth's carbon budget, ecosystem sustainability,
and biodiversity?
- How are the Earth's carbon cycle and ecosystems
changing, and what are the consequences for the
Earth's biodiversity?
Earth Science Enterprise Strategy, October
2003 Science Mission Directorate Draft Science
Plan, 2006
18The three-dimensional structure of vegetation
provides habitats for many species and is a
control on biodiversity.
Vegetation height and the vertical distribution
of leaves and branches influence where and how
other species utilize the ecosystem for food,
shelter, and territory.
19The horizontal pattern of habitat-use varies by
several orders of magnitude depending on species
This implies a need for wall-to-wall coverage of
vegetation structure to capture all of these
multiple scales
20The End