Rainforest

Rainforest – Outputs

 

The conceptual models were compiled by researchers in collaboration with a wide range of stakeholders from Natural Resource Management groups, universities and government agencies and based on available scientific information[1].

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Most of the N within a rainforest is recycled within it and little is exported[6]. Outputs of N from rainforests are mainly the release of gaseous nitrogen through denitrification and N₂O production, and the export of DON and litter.

Air

Denitrification

Denitrification is higher in wetter rainforests, and will cause the release of gaseous N[5].

N₂O production

Export of nitrogen as N₂O is likely to occur as a result of incomplete denitrification and nitrification. Less than 0.2% of denitrified N is converted to N₂O[4]. N₂O emissions are higher in mature forests compared to secondary forests[3].

Water

Vegetation litter and dissolved N export

Litterfall in rainforest areas of the Great Barrier Reef has maximum values (44% of the total) falling in the spring and minimum in the winter[1]. Most of the litterfall is recycled within the rainforest[6], but some of it is exported to streams and waterways with values of approximately 9.8 (0-50) g/ha/day^*[1]. Small amounts of N as dissolved organic nitrogen (DON) or litter from rainforests can be leached[2].

^*_{Nitrogen quantities are displayed as an average followed by a minimum and maximum (range), e.g. “average (min. of range - max. of range) units”.}

References

1. ^ a b Benson, LJ & Pearson, RG (1993), 'Litter inputs to a tropical Australian rainforest stream', Australian Journal of Ecology, vol. 18, no. 4, pp. 377-383.
2. ^ Brookshire, ENJ, Hedin, LO, Newbold, JD, Sigman, DM & Jackson, JK (February 2012), 'Sustained losses of bioavailable nitrogen from montane tropical forests', Nature Geoscience. [online], vol. 5, no. 2, pp. 123-126. Available at: http://www.nature.com/articles/ngeo1372 [Accessed 2 November 2020].
3. ^ Davidson, EA, De Carvalho, CÃJR, Figueira, AM, Ishida, FÃY, Ometto, JPHB, Nardoto, GB, Sabá, RT, Hayashi, SN, Leal, EC, Vieira, ICÃG & Martinelli, LA (2007), 'Recuperation of nitrogen cycling in Amazonian forests following agricultural abandonment', Nature, vol. 447, no. 7147, pp. 995-998.
4. ^ Kiese, R, Hewett, B & Butterbach-bahl, K (2008), 'Seasonal dynamic of gross nitrification and N2O emission at two tropical rainforest sites in Queensland, Australia', Plant and Soil, vol. 309, pp. 105-117.
5. ^ Robertson, GP (1984), 'Nitrification and nitrogen mineralization in a lowland rainforest succession in Costa Rica, Central America', Oecologia, no. 61, pp. 99-100.
6. ^ a b Vitousek, PM (1984), 'Litterfall, nutrient cycling, and nutrient limitation in tropical forests', Ecology, vol. 65, no. 1, pp. 285-298.

Last updated: 2 August 2021