Title: Infrared heater system for warming tropical forest understory plants and soils

Abstract

Abstract The response of tropical forests to global warming is one of the largest uncertainties in predicting the future carbon balance of Earth. To determine the likely effects of elevated temperatures on tropical forest understory plants and soils, as well as other ecosystems, an infrared (IR) heater system was developed to provide in situ warming for the Tropical Responses to Altered Climate Experiment ( TRACE ) in the Luquillo Experimental Forest in Puerto Rico. Three replicate heated 4‐m‐diameter plots were warmed to maintain a 4°C increase in understory vegetation compared to three unheated control plots, as sensed by IR thermometers. The equipment was larger than any used previously and was subjected to challenges different from those of many temperate ecosystem warming systems, including frequent power surges and outages, high humidity, heavy rains, hurricanes, saturated clayey soils, and steep slopes. The system was able to maintain the target 4.0°C increase in hourly average vegetation temperatures to within ± 0.1°C. The vegetation was heterogeneous and on a 21° slope, which decreased uniformity of the warming treatment on the plots; yet, the green leaves were fairly uniformly warmed, and there was little difference among 0–10 cm depth soil temperatures at the plot centers, edges,more » and midway between. Soil temperatures at the 40–50 cm depth increased about 3°C compared to the controls after a month of warming. As expected, the soil in the heated plots dried faster than that of the control plots, but the average soil moisture remained adequate for the plants. The TRACE heating system produced an adequately uniform warming precisely controlled down to at least 50‐cm soil depth, thereby creating a treatment that allows for assessing mechanistic responses of tropical plants and soil to warming, with applicability to other ecosystems. No physical obstacles to scaling the approach to taller vegetation (i.e., trees) and larger plots were observed.« less

Authors:

Kimball, Bruce A.  ^[1];

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Alonso‐Rodríguez, Aura M. ^[2]; Cavaleri, Molly A. ^[3]; Reed, Sasha C. ^[4]; González, Grizelle ^[5]; Wood, Tana E. ^[2]

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+ Show Author Affiliations

1. The Greenleaf Group Phoenix AZ USA
2. International Institute of Tropical Forestry USDA Forest Service Luquillo PR USA
3. School of Forest Resources and Environmental Science Michigan Technological University Houghton MI USA
4. U.S. Geological Survey Southwest Biological Science Center Moab UT USA
5. International Institute for Tropical Forestry USDA Forest Service Río Piedras PR USA

Publication Date:

Mon Jan 15 00:00:00 EST 2018

Research Org.:

Michigan Technological Univ., Houghton, MI (United States); Southwest Biological Science Center (SBSC), Moab, UT (United States)

Sponsoring Org.:

USDOE Office of Science (SC), Biological and Environmental Research (BER)

OSTI Identifier:

1417058

Alternate Identifier(s):

OSTI ID: 1417059; OSTI ID: 1508634

Grant/Contract Number:  

DE‐SC‐0011806; DE‐SC0012000; SC0012000; SC0011806

Resource Type:

Published Article

Journal Name:

Ecology and Evolution

Additional Journal Information:

Journal Name: Ecology and Evolution Journal Volume: 8 Journal Issue: 4; Journal ID: ISSN 2045-7758

Publisher:

Wiley Blackwell (John Wiley & Sons)

Country of Publication:

United Kingdom

Language:

English

Subject:

54 ENVIRONMENTAL SCIENCES; climate change; global warming; heater array; infrared warming; proportional integrative derivative control; trees