Carbon Sequestration Vs Agroforestry trees

Dr N Irabanta Singh *

Phayeng Umang community reserved forest :: Pix - Rajiv Ningthoujam

Introduction : There is a considerable interest to increase Carbon storage capacity of terrestrial vegetation through land use practices such as afforestation, reforestation and natural regeneration of forests, silvicultural systems and agroforestry.

The global climate change is caused by the level of CO2 and other green house gases which is recognized as a serious environmental issue of the 21st century. The role of the land use system in stabilizing the CO2 levels and increasing Carbon sink potential has attracted considerable scientific attention in the recent past, especially after the Kyoto Protocol to the United Nation Framework Convention on climate change (UNFCCC).

The Kyoto Protocol recognizes the role of afforestation, reforestation and natural regeneration of forests in increasing the C-storage capacity of terrestrial ecosystems. The Post Kyoto Protocol discussions on climate change are also heavily oriented towards an agenda on mitigating the rising atmospheric CO2 levels through C sequestration in terrestrial vegetation systems.

In this article, the writer wish to express the role of different types of land use systems in stabilizing the atmospheric CO2 concentration and reducing the Carbon sink in forestry and agroforestry.

Carbon sequestration : It is the process involved in Carbon capture and long term storage of atmospheric carbondioxide and other forms of carbon to mitigate or defy global warming. It has been proposed as a way to reduce the atmospheric and marine accumulation of green house gases, which was released by burning fossil fuel (Wikipedia).

Agroforestry : It is a land use management system in which trees or shrubs are grown around or among crops or pastureland. It combines shrubs and trees in agricultural and forestry technologies to create more diverse production, profitable, healthy, ecologically sound and sustainable land use systems. Agroforestry comes from ecology via agroecology. Thus, it is one of the three principle land use sciences. The other two are agriculture and forestry (Wikipedia).

Carbon Sequestration Potential (CSP) for Agroforestry System (AFS) : The carbon sequestration potential values are direct manifestation of the ecological production potential system, depending on a number of factors including site characteristics land use types, species involved, stand age and management practices.

Agroforestry attracted special attention as a C- sequestration strategy following its recognization as a C- sequestration activity under the afforestation (A) and Reforestration (R) activities of the Kyoto Protocol. This was in recognition of the perceived advantages of the large volume of above ground biomass (AGB) and deep root systems of trees in accomplishing that task.

Consequently, a large number of estimates and reports on C-sequestration potential of various agroforestry systems under different ecological region have become available since the mid 1990. Thus, most of the available reports on C- sequestration in Agroforestry system (AFS) are estimate of C-stocks, how much C is or potentially could be accumulated and stored in above and below ground compartments of AFS under different conditions of ecology and management.

Case study of Carbon sequestration potential of certain agroforestry trees : The total Carbon biomass of 7 (seven) agroforestry trees (Albizia lebbeck; Melia azadarach; Duabanga grandiflora; Ficus benjaminca; Alstonia scholaris and Bauhinia variegate ) and Carbon sequestration of the same 7( seven) agroforestry trees revealed that the highest Carbon biomass was in Alstonia scholaris (462.93 kg/tree) whereas the lowest Carbon biomass was in Michalia champaca (143.09 kg/tree). The highest Carbon sequestration potential was in Alstonia scholaris (22.04 kg/annum) and lowest was in Duabanga grandiflora (4.49 kg/annum).

Discussion : Farm forestry is the major instrument for increasing Carbon sequestration while supplying wood and non-wood products to meet both domestic and market requirements (Singh et al., 2000). The amount of Carbon sequestration depends largely on the system put in the place. The structure and function of which are lose great extend determined by environmental and socio- economic factors. Other factors influencing Carbon storage in agroforestry systems which include tree species and system management (Albucht and Kandji, 2003).

The Carbon biomass stock in a particular agroforestry tree species depends upon its total biomass with significant variation in the Carbon stored in different agroforestry trees. Carbon sequestration potential (kg/tree) of Alstonia scholaris was found highest among 7 (seven) tested tree species.

Conclusion and recommendation : Alstonia scholaris and Melia azadarach sequestered more Carbon as compared to other tree species whereas low carbon was sequestered by Michalia champaca, Duabanga grandiflora and Ficus benjamina.

In order to reduce CO2 emission or on increasing Carbon sink, we need to plant maximum number of Carbon sequestration potential agro-forestry tress.