Nayana Wijetilaka

Carbon a member of group 14 on the periodic table, it is nonmetallic and tetravalent. It is one of the least abundant elements in the Earth’s crust, but the fourth most abundant element in the universe by mass after hydrogen, helium, and oxygen. Carbon is present in all known life forms, and it is the chemical basis of all known life.

Tropical forests are the one of the largest carbon pools on earth and make a big contribution to the global carbon cycle. The scientists try to estimate the carbon stock in different carbon pools from a long time ago. They have followed different methods, techniques and approaches to assess the carbon stocks and balances in different stocks. This paper is a critical reassessment of the quality and the robustness of these models across tropical forest types and a good approach to test the allometric regression models which is crucial when estimating the above ground biomass.

They have made a big assumption when estimating the carbon stock which not mention in the paper was the carbon stock is equal to the above ground biomass. Have neglected the dead wood which comprises a minor potion of the total amount of carbon stock.

They have partitioned the forests as young and old-growth forests but have not stated the decisive factor used to split them. So the decision can be subjective when using the common sense. Further they have categorized the forest types to understand the allometric patterns based on rainfall data. As rainfall is not the only factor that affect to the tree growth this partitioning may not accurate when applying the regression analysis as example a heath forest and a rain forest can be appear in the same group based on the rainfall data but their allomatric relationships are totally different.

They have tested two models, biomass-diameter-height regression and biomass-diameter regression models and they predict four best representative models for four forest types which is useful for future estimations.

The global warming will becoming the most challenging environmental impact in upcoming centaury and the concept of carbon trading getting more popular day by day.  To implement such kind of concepts these findings may really useful.

References:

1. R. B. Myneni et al. A large carbon sink in the woody biomass of Northern forests, Proc. Natl. Acad. Sci. USA, 10.1073/pnas.261555198, 2001
2. Heather Keith, Brendan G. Mackey, and David B. Lindenmayer
   Re-evaluation of forest biomass carbon stocks and lessons from the world’s most carbon-dense forests
   PNAS 2009 106: 11635-11640.