Ecosystems and Climate

 

Overview

Forests play critical roles in climate regulation, and the future of Earth’s forests will influence the course of climate change. As ForestGEO research helps to demonstrate, global change pressures—including climate change, deforestation, pollution, hunting, and the spread of invasive species—are affecting forests worldwide (news story). Understanding and predicting how forests are changing provides critical support for biodiversity conservation and climate change mitigation. 

ForestGEO is the world's only forest monitoring network making standardized measurements in all the world's major forest biomes and is strategically poised for monitoring, understanding, and predicting forest responses to global change. The ForestGEO Ecosystems and Climate Initiative, led by Dr. Kristina Anderson-Teixeira, seeks to understand how global change is altering forests around the world and how changes to forest ecosystems will either mitigate or exacerbate climate change. To this end, we (1) lead and participate in research on the dynamics of forest ecosystems globally and their interactions with climate, and (2) develop data and resources to facilitate ForestGEO ecosystems and climate research.

A broad variety of research relevant to ecosystems and climate occurs across the ForestGEO network. ForestGEO has been a central partner the NGEE-Tropics program to model tropical forest-climate interactions. Core census data is widely used to quantify carbon stocks and to calibrate and validate remote sensing and models. Supplementary measurements of ecosystem and environmental variables include major aboveground carbon stocks and fluxes (aboveground biomass, standing dead wood and coarse woody debris, woody productivity, litterfall, net ecosystem exchange); soil nutrients, carbon, and fine root biomass; bio-micrometeorology, and meteorology. 

The ForestGEO Ecosystems & Climate Research Lab at the Smithsonian Conservation Biology Institute (SCBI) in Virginia, USA focuses on (1) understanding forest ecosystem dynamics and how they are affected by global change drivers and (2) quantifying the climate regulation values of forests. Current projects include the following:

  • Hydraulic traits & forest ecosystem function – Hydraulic traits of trees can predict photosynthetic productivity, water use, and drought response, thereby providing a mechanism to better understand ecosystem hydraulic function and productivity of diverse forest communities. In collaboration with Lawren Sack (UCLA)  and others, we are measuring a broad suite of relatively easily measurable hydraulic traits across many species in diverse tropical forests of Panama and Malaysia and using the data to better understand the functioning of these ecosystems.
  • Role of tree size in forest carbon cycling and climate interactions-Recent research in the ForestGEO Ecosystems & Climate lab has leveraged ForestGEO census data to show that in forests globally, drought has a greater impact on the growth and mortality of large trees compared to smaller trees (Bennett et al. 2015; news story) and that these trees account for a large fraction of a forest’s carbon storage and flux, particularly in response to drought (Meakem et al. 2017). We are currently seeking deeper understanding of (1) the role of tree size in carbon cycling in globally distributed ForestGEO sites spanning broad climatic gradients and (2) how tree functional and hydraulic traits interact with tree size to mediate carbon cycling and drought responses.
  • Global patterns in forest carbon cycling We have led the development of the Global Forest Carbon Database (ForC), an open access database containing published measurements of ecosystem-level C stocks and annual fluxes. We are currently working to integrate data from the ForestGEO Carbon Program into ForC, analyze global patterns of forest carbon cycling, and develop ForC for broader use in scientific research and education.
  • Drivers and consequences of tree mortality -Rates of tree mortality have been increasing in many of the world’s forests as a result of climate change or other global change drivers including habitat fragmentation and altered atmospheric chemistry (e.g., McDowell et al. 2018; news story). Given the importance of forests for climate regulation and the significant impact that tree mortality can have on forest dynamics and climate feedbacks, understanding the drivers and consequences of tree mortality is critical to understanding forest responses and feedbacks to climate change. The spatial scale of ForestGEO plots provides sufficient sample size to understand how mortality rates vary across species or size classes, and an annual census can capture mortality events associated with global change-related disturbances such as droughts, storms, and pest/pathogen outbreaks. Since 2014, we have been conducting an annual tree mortality census at SCBI, which we are using in conjunction with full plot censuses to understand fine-scale dynamics of tree mortality at this site (Gonzalez-Akre et al. 2016). We further seek to understand how tree mortality shapes carbon cycling across the ForestGEO network.
  • Global change and forest ecosystems in Virginia – At the 26-ha ForestGEO plot at SCBI, we are analyzing tree rings to understand climate sensitivity of tree growth and how this varies across species and size classes. We are also using our annual mortality census to understand drivers of tree mortality. One important driver of tree mortality in the region is invasive insect pests and pathogens, currently including the Emerald Ash Borer. In collaboration with neighboring Shenandoah National Park, we are seeking to understand the broader context how such disturbances impact forests of Virginia’s Blue Ridge Ecoregion.
  • ForestGEO site data – This Github repository contains ForestGEO site data originally published in our 2015 review of CTFS-ForestGEO (Anderson-Teixeira et al. 2015, Global Change Biology), and since updated. In addition to basic site data, the repository also contains data on forest cover, loss, and fragmentation in surrounding landscapes and atmospheric deposition.
  • ForestGEO Climate Data Portal - This public repository is a portal for climate data and information for ForestGEO sites. It serves (1) as a source of information on available climate data and (2) as a data repository for climate data that is not publically archived elsewhere.
  • Global Forest Carbon database (ForC)ForC is an open access database, led by Dr. Kristina Anderson-Teixeira, containing published measurements of ecosystem-level C stocks and annual fluxes in forests globally. We are currently working to integrate data from the ForestGEO Carbon Program into ForC.
  • ForestGEO allometries database (allodb) – We are currently developing a public database of biomass allometries for ForestGEO, which will be integrated with the ForestGEO R package.
  • ForestGEO EcoClim Lab on Github – The ForestGEO Ecosystems & Climate lab manages data and code on Github (mix of public and private repositories).