Impact of rising temperature on carbon input, partitioning, loss and storage in tropical wet forests

Figure 1b. Location of nine permanent plots across a 5.2°C mean annual temperature gradient.  Plots are located in The Hawaii Experimental Tropical Forest (Laupahoehoe Unit) of the USDA Forest Service, and the Hakalau Forest National Wildlife Refugee of the US Fish and Wildlife Service.

In collaboration with Dr. Christian Giardina of the Institute of Pacific Islands Forestry, we are conducting a study to examine how rising temperatures will impact carbon cycling in tropical wet forest ecosystems.  Terrestrial ecosystem carbon storage in soils and vegetation exceeds that in the atmosphere by a factor of four, and represents a dynamic balance among carbon input, partitioning, loss, and storage.  This balance is likely being altered by climate change, but the response of terrestrial carbon cycling to rising temperatures remains poorly quantified.  Importantly, temperature-induced changes in ecosystem carbon flux and storage have the potential to feedback into atmospheric CO₂ levels and global climate.  In this study we are examining how tropical forest ecosystems will respond to rising temperature by examining ecosystem carbon storage (live biomass, coarse woody debris and soil organic matter); carbon input (gross primary production; GPP); carbon fluxes (litterfall, aboveground net primary productivity (ANPP), soil-surface CO₂ efflux, and total belowground carbon flux (TBCF)); and carbon partitioning (fraction of GPP partitioned to aboveground vs. belowground) across a 5.2°C mean annual temperature (MAT) gradient on the Island of Hawaii.  Along the MAT gradient, substrate type and age, dominant overstory vegetation, disturbance history, and plant available water are constant, allowing us to isolate the impacts of temperature on ecosystem carbon cycling.  This work is funded by the National Science Foundation, the USDA Forest Service, and the College of Tropical Agriculture and Human Resources, University of Hawaii at Manoa.

If you are interested in conducting research utilizing our existing experimental design across the MAT gradient, please complete and email this

Publications to Date

Iwashita D, Litton CM, Giardina, CP (In revision). Temperature impacts on tree species diversity in Hawaiian montane wet forest. Pacific Conservation Biology.

Sleeter BM, Liu J, Daniel CJ, Hawbaker TJ, Wilson TS, Fortini LB, Jacobi JD, Selmants PC, Giardina CP, Litton CM, Hughes RF (2017) Projected future carbon storage and carbon fluxes in terrestrial ecosystems of Hawai‘i from changes in climate, land use, and disturbance. Pages 107-128 in Selmants PC, Giardina CP, Jacobi JD, Zhu Z, (eds). Baseline and projected future carbon storage and carbon fluxes in ecosystems of Hawai‘i. U.S. Geological Survey Professional Paper 1834. (PDF)

Pierre S, Hewson I, Sparks JP, Litton CM, Giardina C, Groffman PM, Fahey TJ (2017) Ammonia oxidizer populations vary with nitrogen cycling across a tropical montane mean annual temperature gradient. Ecology, 98, 1896-1907. (PDF)

Selmants PC, Adair KL, Litton CM, Giardina CP, Schwartz E (2016) Increases in mean annual temperature do not alter soil bacterial community structure in tropical montane wet forests. Ecosphere, 7, e01296. (PDF)

Bothwell LD, Selmants PC, Giardina CP, Litton CM (2014) Leaf litter decomposition rates increase with rising mean annual temperature in Hawaiian tropical montane wet forests. PeerJ, 2, e685. (PDF)

Giardina CP, Litton CM, Crow SE, Asner GP (2014) Increased total belowground carbon flux, and not soil carbon loss, drives temperature related increases in soil respiration. Nature Climate Change 4: 822-827. (PDF)

Selmants PC, Litton CM, Giardina CP, Asner, GP (2014) Ecosystem carbon storage does not vary with mean annual temperature in Hawaiian tropical montane wet forests. Global Change Biology 20: 2927-2937. (PDF)

Mascaro J, Litton CM, Hughes RF, Uowolo A, Schnitzer SA (2014) Is logarithmic transformation necessary in allometry? Ten, one-hundred, one-thousand-times yes. Biological Journal of the Linnean Society, 111, 230-233. (PDF)

Iwashita DK, Litton CM, Giardina CP (2013) Coarse woody debris carbon storage across a mean annual temperature gradient in tropical montane wet forest. Forest Ecology and Management, 291, 336-343. (PDF)

Litton CM, Giardina CP, Albano JK, Long MS, Asner GP (2011) The magnitude and variability of soil-surface CO2 efflux increase with temperature in Hawaiian tropical montane wet forests. Soil Biology & Biochemistry, 43, 2315-2323. (PDF)

Mascaro J, Litton CM, Hughes RF, Uowolo A, Schnitzer SA (2011) Minimizing bias in biomass allometry: Model selection and log-transformation of data. Biotropica, 43, 649-653. (PDF)

Litton CM, Giardina CP (2008) Belowground carbon flux and partitioning: Global patterns and response to temperature (Invited article). Functional Ecology, 22, 941-954. (PDF)