Comment Log Display

In addressing the benefits of natural and working lands for
addressing Greenhouse Gas emissions it is essential include the
following items.

* Encompass all natural lands, including lands in southern
California that are not utilized for livestock grazing.  For
example mature chaparral ecosystems in southern California can be a
significant carbon sink (Luo et al, 2007).

* Recognize and assist major ongoing conservation.  County-scale
Natural Community Conservation Plans and regional Habitat
Conservation Plans being prepared or implemented across the state
will, when completed, provide permanent conservation of over 2
million acres. This includes significant acreage in addition to
acres protected to mitigate for impacts of economic activities.
Until protected, most of these lands are threatened by development.
The conservation protects existing sequestered carbon, and provides
opportunities for additional carbon sequestration.    The
requirement for management plans and adaptive management programs
will, in many cases, provide opportunities for habitat-friendly
management that increases carbon sequestration.

* Utilize both conservation easements and fee simple acquisition,
as appropriate in individual situations, for the permanent
protection of natural and working lands.

* Recognize the importance of soil carbon (Potter, 2010) 

* Recognize that the loss of natural ecosystems is severe and
ongoing.  Liu et al (2012) projected that 17 percent of the
grassland and shrubland areas in California's Mediterranean climate
region will be lost to conversion between 2005 and 2050.  The major
causes are urban/suburban/rural development and conversion to
orchards and vineyards.  Essentially all of the remaining coastal
sage scrub habitat in southern California that is not protected as
conservation land (primarily through Natural Community Conservation
Plans) will be lost to suburban and rural development.  All of
these conversions will result in substantial release of CO2 into
the atmosphere.  For example, conversion of natural ecosystems to
agricultural land results in loss of 25 to 50 percent of the
original organic carbon (Lal, 2001).

* When natural and working lands are converted to urban / suburban
or rural development there are two carbon impacts.  The first is
loss of vegetation and soil carbon from land clearing and grading. 
The second is long term increased carbon emissions by vehicles and
other uses in the developed areas.  For example, a recent UC Davis
study if Yolo County shows that the annual carbon emissions level
of urban lands is 219-fold higher than rangelands and 70-fold
higher than irrigated croplands (Jackson et al, 2012).  

* Build on existing research and data for non-forest, non-wetland
ecosystems. There have been measurements of carbon fluxes at a few
California rangeland locations; grasslands, oak savanna, and
southern California chaparral.  In dry years, rangelands are often
a carbon sink, absorbing more carbon than is emitted into the
atmosphere by respiration.  In wetter years, particularly when
there is some summer rainfall, increased respiration may result in
a rangeland area being a carbon source.  There is data showing that
natural lands with woody vegetation, including oak woodlands an
chaparral, are net carbon sinks. For example, Liu et. al. (2012)
determine that grasslands and shrublands in Mediterranean climate
California are a carbon sink ( -6.4 to +0.3 teragrams of carbon a
year for the entire area).  Silver (2009) and DeLonge et. al.
(2014) state that California rangelands have the potential for
considerable carbon sequestration in the soil.  Baldocchi (2009)
states that oak woodlands are carbon sinks ( - 92 +/- 43 gms carbon
per square meter per year). A mature, 100 year old growth chamise
chaparral stand was found to sequester 58 grams of carbon per
square meter per year on average over a seven-year period).  Walter
Ochel and colleagues at San Diego State University have conducted
broader studies on Southern California Chaparral and concluded that
chaparral ecosystems are a significant carbon sink. (Oechel, 2013)

* Recognize the full variety of co-benefits from the conservation
of natural and working lands.  These include protection and
restoration of healthy watersheds, groundwater recharge, retention
of floodwaters in natural and agricultural floodplains, protection
and restoration of healthy ecosystems with their essential
ecosystem function and processes,  recreation and nature
appreciation opportunities for urban dwellers, tourism, sustaining
family ranches and farms and rural communities

References

Baldocchi D. (2009)  Carbon and Water Exchange of an Oak-grass
Savanna and Peatland Pasture Ecosystem.  Berkeley Faculty
Roundtable on Environmental Services in Rangeland Production
systems.  March 20 2009.  University of California, Berkeley.

DeLonge MS, Owen JJ and Silver WL. (2014) Greenhouse Gas Mitigation
Opportunities in California Agriculture: Review of California
Rangeland Emissions and Mitigation Potential. Nicholas Institute
GGMOCA R 4. Durham, NC: Duke University

Jackson L. et.al. (2012) Adaptation Strategies for Agricultural
Sustainability in Yolo County, California.  California Energy
Commission Publication number: CEC-500-2012-032.

Lal R. (2001) World Cropland Soils as a Source or Sink for
Atmospheric Carbon, Advances in Agronomy. 71:145-191.

Liu S. et. al. (2012) Baseline and Projected Future Carbon Storage
and Greenhouse-Gas Fluxes in Ecosystems of the Western United
States. In Zhu S and Reed BC, eds. Baseline and Projected Future
Carbon Storage and Greenhouse-Gas Fluxes in Ecosystems of the
Western United States. Chapter 5. U.S. Geological Survey
Professional Paper 1797. Reston VA.

Luo H. et.al. (2007) Mature Semiarid Chaparral Ecosystems can be a
Significant Sink for Atmospheric Carbon Dioxide. Global Change
Biology. 13:386-396.

Oechel W. (2013) The Effects of Climate Change: Elevated CO2,
Climate Variability, and Fire, on the Functioning and Atmospheric
Feedbacks of Chaparral of Southern California and the Desert of
Baja California, Mexico.  Powerpoint presentation.  February 6
2013.
www.otmed.fr/IMG/pdf/Walter_Oechel_06_February_2013.pdf

Potter C (2010) The Carbon Budget of California.  NASA Publications
81 http://digitalcommons.unl.edu/nasapub/81

Silver WL, Ryals R and Eviner V. (2010) Soil Carbon Pools in
California's Annual Grassland Ecosystems.  Rangeland Ecology and
Management. 63:128-136.