How Increasing Temperatures Affect Tropical Forests Active
Tropical forests take in and store more carbon than any other biome in the world, but increasing temperatures may pose a threat to this invaluable service. This research aims to explore how temperature affects key tropical forest functions, such as plant photosynthesis and soil respiration. To do this, the Tropical Responses to Altered Climate Experiment (TRACE) project will use infrared heating to warm the soil and plants of the understory, as well as warming individual leaves and branches in the forest canopy. Within TRACE, scientists are working together to measure the potential impacts of increasing temperatures on tropical forest productivity, carbon cycling, plant physiology, and soil fertility. The ultimate goal of the work is to improve our understanding of how tropical forests will respond to altered temperatures, and to determine how their response could be important at local, regional, and global scales. This integrated experiment is the first of its kind in any tropical forest, and we expect to learn important truths about the fundamental relationships between temperature and how tropical forests work.
Background & Importance
Tropical forests contain ~25% of Earth’s terrestrial biomass and exchange more carbon and energy with the atmosphere than any other type of ecosystem. Accordingly, our poor understanding of how tropical forests will respond to changing temperatures severely hold back our understanding of how tropical forests will function into the future. To meet the increasing need for improved understanding of tropical forest responses to changing temperature, we have constructed a field warming experiment in a wet tropical forest in Puerto Rico. This research will allow us to assess temperature responses of the most influential and active rain forest tissues and organisms: leaves, fine roots, and soil microbes. Our research focus on both above- and belowground parts of the forest will provide an integrated understanding of carbon storage and flux, which is critical to considerations of how temperature and precipitation effects on tropical forests will create feedbacks to future carbon cycling and climate at the global-scale. Our specific objectives are two-fold:
1) Assess the mechanisms behind and effects of warming on carbon and nutrient cycling and storage in tropical forest soils
2) Investigate threshold temperature responses of both canopy and understory tropical tree foliage
We expect this work to make significant advances in our understanding of coupled biogeochemical processes in a globally important and poorly understood ecosystem that has strong potential to create feedbacks to future climate. Also, this field warming experiment is the first of its kind in any tropical forest, and the experimental research would be the first to investigate warming response to tropical processes from coordinated plant-soil perspectives. Our focus on the mechanisms regulating temperature responses will allow us to consider the results beyond that of a single tropical forest site, and the work will provide critical information regarding the vulnerability and adaptation potential of the only tropical forest in the U.S. National Forest System (The Luquillo Experimental Forest inside El Yunque National Forest).
General Methods
We warm the understory vegetation and upper layers of soil with an array of infra-red heaters. We use a complimentary warming of individual canopy leaves and branches to assess the relationship between temperature and canopy photosynthesis and respiration. We assess many fluxes of CO2 (including leaf photosynthesis and respiration and soil respiration), as well as monitoring the stocks and fluxes of numerous carbon and nutrient pools. At the same time, we are assessing the effect of altered temperature on plant and soil microbial community composition and soil moisture.
This is a highly collaborate research endeavor and involves scientists from USGS, the U.S. Forest Service, U.S. National Laboratories, and Michigan Tech University. Additionally, we together with a USGS Powell Center (https://powellcenter.usgs.gov/) data synthesis activity, where we are using published data and modeling approaches to helping assess how tropical forests will respond to increasing temperatures.
Below are publications associated with this project.
Incorporating phosphorus cycling into global modeling efforts: a worthwhile, tractable endeavor
Urgent need for warming experiments in tropical forests
Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization
Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes
Tropical forests in a warming world
Below are partners associated with this project.
- Overview
Tropical forests take in and store more carbon than any other biome in the world, but increasing temperatures may pose a threat to this invaluable service. This research aims to explore how temperature affects key tropical forest functions, such as plant photosynthesis and soil respiration. To do this, the Tropical Responses to Altered Climate Experiment (TRACE) project will use infrared heating to warm the soil and plants of the understory, as well as warming individual leaves and branches in the forest canopy. Within TRACE, scientists are working together to measure the potential impacts of increasing temperatures on tropical forest productivity, carbon cycling, plant physiology, and soil fertility. The ultimate goal of the work is to improve our understanding of how tropical forests will respond to altered temperatures, and to determine how their response could be important at local, regional, and global scales. This integrated experiment is the first of its kind in any tropical forest, and we expect to learn important truths about the fundamental relationships between temperature and how tropical forests work.
Background & Importance
Tropical forests contain ~25% of Earth’s terrestrial biomass and exchange more carbon and energy with the atmosphere than any other type of ecosystem. Accordingly, our poor understanding of how tropical forests will respond to changing temperatures severely hold back our understanding of how tropical forests will function into the future. To meet the increasing need for improved understanding of tropical forest responses to changing temperature, we have constructed a field warming experiment in a wet tropical forest in Puerto Rico. This research will allow us to assess temperature responses of the most influential and active rain forest tissues and organisms: leaves, fine roots, and soil microbes. Our research focus on both above- and belowground parts of the forest will provide an integrated understanding of carbon storage and flux, which is critical to considerations of how temperature and precipitation effects on tropical forests will create feedbacks to future carbon cycling and climate at the global-scale. Our specific objectives are two-fold:
1) Assess the mechanisms behind and effects of warming on carbon and nutrient cycling and storage in tropical forest soils
2) Investigate threshold temperature responses of both canopy and understory tropical tree foliage
We expect this work to make significant advances in our understanding of coupled biogeochemical processes in a globally important and poorly understood ecosystem that has strong potential to create feedbacks to future climate. Also, this field warming experiment is the first of its kind in any tropical forest, and the experimental research would be the first to investigate warming response to tropical processes from coordinated plant-soil perspectives. Our focus on the mechanisms regulating temperature responses will allow us to consider the results beyond that of a single tropical forest site, and the work will provide critical information regarding the vulnerability and adaptation potential of the only tropical forest in the U.S. National Forest System (The Luquillo Experimental Forest inside El Yunque National Forest).General Methods
We warm the understory vegetation and upper layers of soil with an array of infra-red heaters. We use a complimentary warming of individual canopy leaves and branches to assess the relationship between temperature and canopy photosynthesis and respiration. We assess many fluxes of CO2 (including leaf photosynthesis and respiration and soil respiration), as well as monitoring the stocks and fluxes of numerous carbon and nutrient pools. At the same time, we are assessing the effect of altered temperature on plant and soil microbial community composition and soil moisture.
This is a highly collaborate research endeavor and involves scientists from USGS, the U.S. Forest Service, U.S. National Laboratories, and Michigan Tech University. Additionally, we together with a USGS Powell Center (https://powellcenter.usgs.gov/) data synthesis activity, where we are using published data and modeling approaches to helping assess how tropical forests will respond to increasing temperatures.
- Publications
Below are publications associated with this project.
Incorporating phosphorus cycling into global modeling efforts: a worthwhile, tractable endeavor
Myriad field, laboratory, and modeling studies show that nutrient availability plays a fundamental role in regulating CO2 exchange between the Earth's biosphere and atmosphere, and in determining how carbon pools and fluxes respond to climatic change. Accordingly, global models that incorporate coupled climate–carbon cycle feedbacks made a significant advance with the introduction of a prognosticAuthorsSasha C. Reed, Xiaojuan Yang, Peter E. ThorntonUrgent need for warming experiments in tropical forests
Although tropical forests account for only a fraction of the planet's terrestrial surface, they exchange more carbon dioxide with the atmosphere than any other biome on Earth, and thus play a disproportionate role in the global climate. In the next 20 years, the tropics will experience unprecedented warming, yet there is exceedingly high uncertainty about their potential responses to this imminentAuthorsMolly A. Calaveri, Sasha C. Reed, W. Kolby Smith, Tana E. WoodLarge divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization
Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (AuthorsW. Kolby Smith, Sasha C. Reed, Cory C. Cleveland, Ashley P Ballantyne, William R. L. Anderegg, William R. Wieder, Yi Y Liu, Steven W. RunningTropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes
Tropical forests play a major role in regulating global carbon (C) fluxes and stocks, and even small changes to C cycling in this productive biome could dramatically affect atmospheric carbon dioxide (CO2) concentrations. Temperature is expected to increase over all land surfaces in the future, yet we have a surprisingly poor understanding of how tropical forests will respond to this significant cAuthorsTana E. Wood, Molly A. Cavaleri, Sasha C. ReedTropical forests in a warming world
No abstract available.AuthorsS.C. Reed, T.E. Wood, M.A. Cavaleri - Partners
Below are partners associated with this project.