History


Forests and The Environment
WHAT ROLE DO
FORESTS PLAY
IN A MOSAIC OF
LAND USES?
HOW MUCH
CARBON DO
FORESTS
STORE?

HOW DO FORESTS
RESPOND TO
INCREASING
TEMPERATURES AND
AIR POLLUTION?

One of the key roles played by the SIGEO network is to define, quantify and analyze the benefits to human society that emanate from retaining forests as part of the land use mosaic. Such benefits are often referred to as “ecosystem services.”

How do forests respond to increasing temperatures and air pollution? How do vital processes like carbon sequestration and water regulation vary across the plot network? What are the main drivers of change?

A global forest carbon research initiative

Forests contain 38% of all carbon sequestered on land. In 2008, researchers across the plot network began to gather data on the amount of carbon in their forests and to compare the results across sites.

Accurate estimates of carbon storage involve painstaking measurement of tree trunks and branches, which may contain 40 to 50 percent of all forest carbon, as fine roots and associated soil that retain another 30 to 40 percent.

Tree heights and wood specific gravity and soil samples from each hectare of every plot yield comparable results. From five to 10 percent of tropical forest carbon is stored in fallen trees and branches as well as in standing dead trees.

Woody vines known as lianas pose an additional challenge because studies suggest they are increasing in tropical forests. Although they represent only a small carbon reservoir in themselves (one to three percent), they may have a significant influence on overall carbon

 

reservoirs when they suppress tree growth.

To catch unexpected ways that forests may be changing as atmospheric carbon increases, STRI scientist Joe Wright and colleagues monitor a series of forest traits: the production of flowers and seeds and the recruitment, growth and mortality of seedlings in four of the CTFS/SIGEO plots in Latin America representing more than 1,000 Neotropical tree species.

They place litter traps in each plot to measure carbon recycled from fallen leaves, fruits and flowers and carbon lost by decomposition. By conducting repeated censuses of standing dead trees and fallen trees and branches plot researchers compare rates of carbon input via mortality to output via decomposition. 

Network researchers also evaluate techniques for measuring below-ground carbon through soil respiration using 25 to 100 sampling points per plot. In tropical forests, about as much carbon is stored in the surface meter of soil as in the vegetation, yet little is known about the response of soil carbon to changes in climate or forest dynamics.

The CTFS/SIGEO Global Forest Carbon Research Initiative aims to measure the sizes of forest carbon pools and fluxes and how they vary through time and across regions. Then the drivers of this variation (topography, solar radiation, soils, climate, agriculture, etc) at multiple tropical and temperate forest sites around the globe can be pinpointed.          


History of SIGEO Forest Dynamics Looking Forward

Forest biologists from 21 countries and 75 partner institutions share the same passion to understand forest dynamics.

The network provides answers to scientific questions about forests that were impossible to address at isolated sites.

Federal and private funding has supported the development of this unique research platform as it has grown from a single...