NORTH-SOUTH CENTRE - ETH - North-South Centre North-South ...

Agroforestry for carbon sequestration to
improve small farmers’ livelihoods
Sustainable agroforestry can increase resilience against
environmental change, enhance carbon sequestration and
generate income. Improved plant health is an indispensable
prerequisite to render the concept of agroforestry
attractive to small farmers and promising to policy-makers.
Subproject 1 aimed to assess the response of plant productivity
to future climate change in different land use systems
in Panama. In addition, it aimed to quantify the carbon
sequestration potentials in these systems, providing baseline
information for adaptive management decisions and
the very first data sets to policy-makers.
During the dry seasons, assimilation and thus crop yields
were lower in the traditional pasture than in the improved
afforestation system. The opposite was true during the rainy
seasons. Probably due to overgrazing, total ecosystem
respiration was always higher for pasture than for afforestation.
Overall, the pasture lost about 350g C/m² from
June 2007 to June 2009, while the eight-year-old afforestation
gained about 320g C/m² during the same period.
Thus, the carbon budgets determined for our afforestation
site confirm the general carbon sink pattern for forests. In
contrast, our pasture site clearly acted as a carbon source.
In the future, avoidance of overgrazing will help to convert
the pasture source into a carbon sink.
Subproject 2 aimed to take novel natural-based approaches
to increase plant health and reduce insect pests in afforestation
and silvopastoral livestock systems. This subproject
shall support timber tree establishment on current
pastures as a future source of income to the rural poor.
Different afforestation planting regimes influenced tree
growth rather than tree survival. The best growth was
found for trees protected by insecticides. Tabebuia rosea
trees excelled other native species tested, as it performed
well under different conditions. Herbivore insects, however,
seem to reduce growth substantially. The key herbivore
species identified were a pyralid caterpillar and a chrysomelid
beetle. T. rosea trees surrounded by a companion
fodder tree species hosted significantly lower numbers of
the pyralid herbivore. This indicates timber tree protection
by the respective planting regime. There were no indications
for any interspecific competition among timber
and companion trees. Therefore, applying the combination
timber and companion tree within the silvopastoral system
may offer additional sources of income for small-scale
livestock farmers.
38 Project leaders
Nina Buchmann
Silvia Dorn
Research collaboration
Livestock systems research
Contact persons
Werner Eugster
Sebastian Wolf
Karsten Mody
Mirco Plath
Collaborators
Catherine Potvin, STRI, Panama and McGill University, Canada;
Hector Barrios, Universidad de Panama and STRI, Panama
Duration
July 2006 – March 2010
Thematic cluster
Livestock and environment
Local expert evaluating herbivory on Tabebuia rosea,
the most promising native timber species identified