Figure 7a – Carbon Cycle – Plant photosynthesis by absorbing carbon dioxide (greenhouse gas) – trees maintain equilibrium in the ecosystem.
Retrieve: http://www.starsandseas.com/SAS%20Ecology/SAS%20chemcycles/cycle_carbon.htm

Retrieved: Library Thinkquest. What is carbon cycle? [cited 2008 October 26] Available from: http://library.thinkquest.org/11226/why.htm.

As discussed earlier, the Catalpa genus is a plant that takes in carbon dioxide while exhaling oxygen. As a result, Catalpa trees are important in reducing carbon in the atmosphere which limits the greenhouse gases in the atmosphere (Carb on cycle see Fig 7 and b).[i] The Catalpa tree is a low nitrogen fixation plant. This means that the Catalpa contributes little to the role in the Nitrogen cycle. Despite this fact, it still plays a minor role because this tree still fixes some nitrogen bacteria which helps break down and create nitrogen in the ecosystem.[ii] This plant does contribute to the limiting factors of Carbon and also provides food for herbivores such as Catalpa Sphinx and many other insect. As a result, this tree is always damaged or infested with insects to feed on. This tree is a primary producer which supports many species of insects in this environment.[iii] Therefore, the pyramid of number at the bottom would say one because of one tree while the second and third layer of the pyramid of numbers could have over 1000 species. Without the Catalpa tree, many primary consumers (Herbivores) would die and the secondary consumers that feed on the herbivores would not have any more food to eat and would also die. Finally, the Catalpa tree shows the important as the foundation of the ecosystem.[iv]

The Root of the Catalpa tree contribute to the decomposers in the soil because once the roots died in the Catalpa tree, it releases the nutrients back into the soil for decomposers, other plant and organism to feed on. Therefore, Catalpa trees help recycle these nutrients back into the ecosystem.[v] Moreover, after the death of the tree, this tree would allow decomposers to eat away the tree and break down the tree until it becomes humus, which is a fertile layer of soil that is left over from the organism and is very rich in minerals. Furthermore, the Catalpa trees such as the Northern and Southern Catalpa are Allelopathic plants in which these plants can emit a chemical substance from their roots that can prevent seeds from growing.[vi] This is important in keeping the plants in check and prevents the tree from overcrowding the region and becoming invasive.[vii]

[i]                 .United States Department of Agriculture: Natural Resources Conservation Service [Internet]. [updated 2008 October 11] United States: Department of Agriculture, Natural Resource Conservation Service; [cited 2008 October 26, 2008]. Available from http://plants.usda.gov/java/ClassificationServlet?source=profile&symbol=CATAL&display=31.

[ii] Vines R. A. 2004. Trees, shrubs and woody vines of the southwest. Austin: University of Texas Press. P. 926-927.

[iii] Waldbauer G. 2003. What good are bugs?: Insects in the web of life. Cambridge. Harvard University Press. 82 – 86.

[iv] Waldbauer G. 2003. What good are bugs?: Insects in the web of life. Cambridge. Harvard University Press. 82 – 86.

[v] Vines R. A. 2004. Trees, shrubs and woody vines of the southwest. Austin: University of Texas Press. P. 926-927.

[vi] Waldbauer G. 2003. What good are bugs?: Insects in the web of life. Cambridge. Harvard University Press. 82 – 86.

[vii] Waldbauer G. 2003. What good are bugs?: Insects in the web of life. Cambridge. Harvard University Press. 82 – 86.