By Robbie Carrasco

The mosquitos buzzed and the sun
pierced the canopy as we slowly made our way through the dense tangled webs of
mangrove roots and knee-deep mud. Moving through a mangrove forest is a
humbling experience where you can feel trapped and claustrophobic, but at the
same time feeling awed by the sheer density and volume of the above-ground root
systems. The first thing that came to my mind while trekking through these
forests to our sampling site was that of being an ecological Indiana Jones, but
instead of uncovering ancient human artifacts we were digging into mother
nature’s history books by measuring the carbon stored deep in these beautiful
yet intimidating wetlands.

Mangroves are known to be one of
the most dense carbon storage systems on earth “containing on average 1,023Mg
carbon per hectare” with the soils accounting for “49-98% of carbon storage in
these systems” making them at least twice as effective carbon stores when compared
to other tropical forests (Donato, D.C., Kauffman, J.B.,
Murdiyarso, D., Kurnianto, S., Stidham., and M. Kanninen, 2011). This high degree of
carbon storage is due primarily to the tendency of water-logged soil to become
anaerobic or devoid of oxygen quicker and at a higher level than most other
soils. This lack of oxygen hinders microbial decomposition, thus allowing
carbon rich soil to be stored for an almost indefinite amount of time
especially if undisturbed. With humans releasing unprecedented amounts of
greenhouse gases into the atmosphere and deforestation being the second leading
cause of anthropocentric CO2 emissions, it is clear that we must take the
necessary steps to protect these natural carbon sequestration systems from land
use change.

Programs such as the United Nations
REDD+ programme (un-redd.org) and
Mangroves for the Future’s “Income for Coastal Communities for Mangrove Protection
(mangrovesforthefuture.org) support projects that measure carbon values of
mangrove forests and help gather data on how to help protect and save mangroves
from land use changes. By collecting samples and data from within these forests
we can measure the amount of carbon stored in the mangroves and the underlying soils.
This allows us to assign numerical values to the services that the forests
provide through carbon sequestration. Such information gained from this
research is a powerful tool to spur conservation and restoration, thus making
it easier for us to make informed decisions regarding mangrove forests and
their future land use. And with mangroves being lost at about 1% per year (FAO, 2007) it makes it more
important than ever to have a clear idea of exactly what goods and services these
forests provide to society before we let them disappear.

Jacob Bukoski, a graduate student
at the Yale School of Forestry and Environmental Studies, is currently writing
his thesis in which he describes a predictive model of mangrove carbon stocks in
Southeast Asia. MAP has had the privilege of helping support Jacob’s field work
because we see it as very valuable for the community and for mangrove
conservation and restoration. I had the pleasure of spending a week with Jacob
and our Thai helpers on Koh Klang in the Krabi province assisting him with his
field work. While Jacob uses CIFOR’s “Protocols for the measurement, monitoring
and reporting of structure, biomass and carbon stocks in mangrove forests” (Kauffman,
J.B. and Donato, D.C., 2012) as a manual for his
research, my story-telling below is a rough outline of the guide in accordance
to our field work research.

As you can see, there are many components
to the collection of field data. Everything must be accomplished precisely in
accordance to the pre-determined protocols to ensure valid and useful data. These
data are subsequently entered into a larger equation that can be used to
calculate the overall carbon content of the forest. Jacob can then use his work
here to verify his model that predicts the overall carbon content of mangrove
forests using a set of inputs like latitude, precipitation, tree size, etc.

The ultimate goal is to accurately
predict the carbon content of a pinpoint area of mangrove forest by using
simple and inexpensive data instead of relying on costly field work. Jacob’s
work is a part of the larger “Income for coastal communities for protecting
mangroves project” which “aims to
develop a low cost mechanism enabling investors to responsibly promote mangrove
conservation, carbon emissions reduction and sustainable development, through
the provision of funding to local communities for livelihood diversification,
resource enhancement and coastal protection.” (https://www.mangrovesforthefuture.org/grants/regional-grant-facilities/income-for-coastal-communities-for-mangrove-protection/).

Thanks to Jacob’s research MAP has
been able to use this opportunity to obtain and analyze soil core samples from other
sites on Koh Klang Island which are in the MAP Ecosystems Protecting
Infrastructure and Communities (EPIC) program. These two sites, which are
within several kilometers of where Jacob’s plots are located in the Krabi river
estuary, will offer us a view into the soils degradation from shrimp farming
practices, primarily its predicted loss of carbon content. This will allow us a
close comparison between the secondary growth of the sampled plots in the Krabi
River Estuary and the soil of abandoned shrimp farms located in former mangrove
forests. With this information MAP will be able to determine the levels of
carbon present in the abandoned shrimp farms which have been devoid of mangrove
vegetation for about the past thirty years. This valuable information will help
us better understand the value of our conservation and restoration work in terms
of carbon sequestration. The soil cores will provide evidence as to whether
shrimp farming releases large amounts of the carbon stored in these soils into
the atmosphere. An update on this section will be released once the soils have
been analyzed and we have received the appropriate data, but for now we expect
that the EPIC site soil holds significantly less amount of carbon than the
healthy mangrove forest soils at the plots in the Krabi river estuary.

Many times in the field we were met
with an incredible diversity of physical and mental challenges, but we carried
on just as Indiana Jones would carry on regardless of the hardships. Whether
assaulted by mosquitoes, stuck in knee-deep mud, or swimming back to our boat
because high tide came without us noticing, we could only laugh and joke about
these predicaments, dismissing them with the saying “mai bpen rai” which
translates to “no worries”. We found no hidden jewels or great treasure in our
trek through the forest, but we knew that the overarching goals of this
endeavor is actually of much greater value: a stabilized climate, sustainable
enterprise and environmental justice.

And exploring these forests gave me
a new appreciation for the things in life that at first glance may seem as useless,
dull and expendable which I suppose those who bulldoze these magical forests must
feel. But when we look more closely you come to realize the splendor in every
aspect of these forests–and as you look even closer it all comes alive before
your eyes. The crabs scuttle, the mud skippers bicker, the mangrove tree leaves
rustle in the wind and you are reminded of the importance of this special place
between land and sea for its intrinsic natural beauty, carbon sequestration and
its support of sustainable livelihoods, coastal protection, habitat, erosion
mitigation, and so much more.

Donato, D.C., Kauffman, J.B., Murdiyarso, D., Kurnianto,
S., Stidham., and M. Kanninen. (2011). Mangroves among the most carbon-rich
forests in the tropics. Nature Geoscience, Vol. 4. DOI:
10.1038/NGEO1123.

FAO, U. (2007). The World’s Mangroves 1980-2005,
FAO Forestry Paper 153. Rome: Forest Resources Divison, FAO. The Food and
Agriculture Organization of the UN.

Kauffman, J.B. and Donato, D.C. (2012). Protocols
for the measurement, monitoring and reporting of structure, biomass and
carbon stocks in mangrove forests. Working Paper 86. CIFOR, Bogor,
Indonesia: Center For International Forestry Research.

By Robbie
Carrasco

Project Development
Assistant

Mangrove
Action Project