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measurements to estimate how fast the forest can grow vertically. One of objectives
for going to the Rufiji Delta was to determine how much carbon was stored in the
forest and how and where that carbon goes over time. The loss or gain of carbon,
particularly for these carbon-rich environments, can help contribute to or reduce
carbon dioxide – a greenhouse gas – in the atmosphere. The more carbon dioxide in
the atmosphere, the greater the potential for a warmer climate. Mangrove forests
have adapted to hold onto carbon. The trees have some of the densest wood, holding
on to more carbon per cubic inch than most other trees around the world. In addition, the forests also capture and hold onto all of the dead leaves and branches that
fall from the trees. And because they are flooded nearly year-round, the carbon in
the soils that would normally decompose like in other forests can stay around for
centuries.
We can estimate the amount of carbon stored in trees by literally hugging them –
a special tape measure is wrapped around the base of the tree at chest-height, 1.3 m
(4.3 ft) from the ground. The measuring tape that would normally measure the circumference of the tree accounts for the properties of a cylinder and can measure
diameter directly. Along with the diameter of the tree, we also measure the height
using a laser range finder that can also estimate angles. With a little trigonometry
(no one wants to do math when you are swatting bugs and knee-deep in mud) the
height of the tree can be estimated with three well-placed laser shots at eye level, the
base of the tree and the treetop. So, after we “hug” and “shoot” all the trees within
a given field plot that we have carefully paced out, we trudge back out to the boat
and go to the next site. Depending on the site and the sampling strategy, the number
of field plots can range anywhere from 18 and 180. So that means trudging through
literally miles of mud. The data are recorded in a write-in-the-wet book, so that we
can work in most conditions (waist deep in water or during rainfall) and are later
transposed to an electronic spreadsheet.
After meeting with employees of the Tanzanian Forest Service and the professors
and students from the University of Dar es Salaam, we are now ready to drive to the
Rufiji Delta. Without the careful planning with our Tanzanian colleagues, it would
be near impossible to make it to the delta on our own. The transit involves a Land
Cruiser with the exhaust on the roof and a 3 h drive down a dirt road with lions
roaming the countryside (unfortunately, or fortunately, I did not see any lions on this
trip). At the end of the drive, we stretch our legs out and go straight to a meeting
with the village elders, a must for anyone visiting the coastal village. Our Tanzanian
colleagues were also our Swahili-English interpreters and have been working with
the village for some time, so it was not a surprise to the elders that Americans had
shown up in the village. The elders and the Forest Department had arranged for us
to stay on the department’s compound at the edge of the village (Fig. 13.6) – with
an incredible view of the Rufiji River.
The field crew totaled about 12 people, two of us from NASA, one from the US
Forest Service, three from the University (one professor and two students) and the
rest were employees across different sectors of the Tanzania Forest Department
(ecologists and GIS specialists). We pitched our tents on the edge of the river as our
dinner for the next few days clucked, picked, and scratched at the ground around us.
13 Pictures from Space and Feet in the Mud: Understanding the Value of the World’s…
measurements to estimate how fast the forest can grow vertically. One of objectives
for going to the Rufiji Delta was to determine how much carbon was stored in the
forest and how and where that carbon goes over time. The loss or gain of carbon,
particularly for these carbon-rich environments, can help contribute to or reduce
carbon dioxide – a greenhouse gas – in the atmosphere. The more carbon dioxide in
the atmosphere, the greater the potential for a warmer climate. Mangrove forests
have adapted to hold onto carbon. The trees have some of the densest wood, holding
on to more carbon per cubic inch than most other trees around the world. In addition, the forests also capture and hold onto all of the dead leaves and branches that
fall from the trees. And because they are flooded nearly year-round, the carbon in
the soils that would normally decompose like in other forests can stay around for
centuries.
We can estimate the amount of carbon stored in trees by literally hugging them –
a special tape measure is wrapped around the base of the tree at chest-height, 1.3 m
(4.3 ft) from the ground. The measuring tape that would normally measure the circumference of the tree accounts for the properties of a cylinder and can measure
diameter directly. Along with the diameter of the tree, we also measure the height
using a laser range finder that can also estimate angles. With a little trigonometry
(no one wants to do math when you are swatting bugs and knee-deep in mud) the
height of the tree can be estimated with three well-placed laser shots at eye level, the
base of the tree and the treetop. So, after we “hug” and “shoot” all the trees within
a given field plot that we have carefully paced out, we trudge back out to the boat
and go to the next site. Depending on the site and the sampling strategy, the number
of field plots can range anywhere from 18 and 180. So that means trudging through
literally miles of mud. The data are recorded in a write-in-the-wet book, so that we
can work in most conditions (waist deep in water or during rainfall) and are later
transposed to an electronic spreadsheet.
After meeting with employees of the Tanzanian Forest Service and the professors
and students from the University of Dar es Salaam, we are now ready to drive to the
Rufiji Delta. Without the careful planning with our Tanzanian colleagues, it would
be near impossible to make it to the delta on our own. The transit involves a Land
Cruiser with the exhaust on the roof and a 3 h drive down a dirt road with lions
roaming the countryside (unfortunately, or fortunately, I did not see any lions on this
trip). At the end of the drive, we stretch our legs out and go straight to a meeting
with the village elders, a must for anyone visiting the coastal village. Our Tanzanian
colleagues were also our Swahili-English interpreters and have been working with
the village for some time, so it was not a surprise to the elders that Americans had
shown up in the village. The elders and the Forest Department had arranged for us
to stay on the department’s compound at the edge of the village (Fig. 13.6) – with
an incredible view of the Rufiji River.
The field crew totaled about 12 people, two of us from NASA, one from the US
Forest Service, three from the University (one professor and two students) and the
rest were employees across different sectors of the Tanzania Forest Department
(ecologists and GIS specialists). We pitched our tents on the edge of the river as our
dinner for the next few days clucked, picked, and scratched at the ground around us.
13 Pictures from Space and Feet in the Mud: Understanding the Value of the World’s…