Student Water Evapotranspiration Network (SWETNET):

A High School Research Experience Course between the

North Carolina School of Science and Mathematics and Duke University.

Linda, Schmalbeck1

, Myra Halpin1

, Connor Erwin1,2

, Michael Jones1

, Ariane Nabor1

, Victoria Nneji1

, A. Christopher Oishi3

, Eric Ward3

, Jean-Christophe Domec2,3

, Sari Palmroth3

, Christopher Maier4

, Ram Oren3

.1

North Carolina School of Science and Mathematics, Durham, North Carolina, USA; 2

North Carolina State University, Raleigh, North Carolina, USA

3

Nicholas School of the Environment and Earth Sciences, Duke University, Durham, North Carolina, USA: 4

U.S.D.A. Forest Service, Durham North Carolina, USA

SWETNET Timeline

A S O N D J F M A M J

2009 2010

Leaf Litter Collection and analysis Bud Break timing range

Historic Heat Sums

Heat Sums Data

Weekend on Campus Weekend on Campus Weekend on Campus

NCSSM Research Symposium

Develop collaborative research questions > >>>>>Conduct research > >>>>>>>>>Students complete research

2009

March April May June

Red

map

le (k

g h2O

tree-1

day-

1 )

0

2

4

6

8

10

12

14

Lobl

olly

pin

e (k

g h2Ot

ree-1

day-

1 )

0

10

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50Red maple L.Pine

mm

day

-1

010203040

Precipitation

Scientific Goals:

The scientific goals of the SWETNET program are to create a network of sap monitoring sites at, or

near, North Carolina schools where students will run the network and to collect and analyze data in

the context of the larger scientific community’s work on forest transpiration and ecosystem

physiology.

 The SWETNET sapflow measurements will be used as a proxy for the end of leaf expansion in

deciduous ( Figure 1.)

The distribution of sampling sites from mountain regions through the piedmont and the coastal

areas will provide insight into seasonal and latitudinal variation.

Introduction

A well-designed project at the high school level can open the door to future educational and career opportunities. In

2008, students from the North Carolina School of Science and Mathematics (NCSSM), a competitive entry residential

public high school for 11th

and 12th

grade, participated in a pilot seminar supported by NCSSM faculty as well as

scientists and graduate students from Duke University.

The seminar opened with activities that focused on the application of a STELLA framework to model whole tree water

transport and carbon allocation in trees. The method first used published measurements of sap flux performed in

loblolly pine and sweetgum trees, and then collected and analyzed data from sapflow sensors installed in loblolly pine

trees in an unmanaged stand on the high school grounds.

The students installed a sap flux and climatic monitoring system modeled on those used at the Duke FACE site on

their campus. Seminar students had to make, install, record and analyze

the data to predict water use of trees growing in urban conditions.

Online Research Experience Course

As a natural continuation of the above activities, we have

just started an NCSSM Online Research Experience course

called SWETNET (Student Water Evapo Transpiration

Network), which involves high school students

from across the state of North Carolina. 

The course is part of a larger outreach effort by NCSSM and includes students who are eligible for admission to NCSSM

but that exceed the schools housing capacity. Most of their academic courses are taken at their home high schools

while enrichment courses, taught by NCSSM faculty are taken online. The program includes four weekends on campus

when students and instructors have extended time to work on projects face to face.

SWETNET has both educational and scientific goals. The course is designed to provide scientific research experience

opportunities for qualified students even those who live in remote regions of the state. The scientific goal is to create a

student network with sap monitoring sites at, or near, each of their schools and collect data as part of this course. 

Setting the course online represents certain challenges, but for the first time it presents a potential to generate data that

so far has been available only to scientists who rely on observational data, such as sightings of birds and butterflies or

determination of the timing of bud break and flowering.

With this sort of network coordinated, statewide seasonal dynamics of forest transpiration can be readily followed and

water and carbon uptake modeled. This modeling experience and the experience of discussing experimental design and

progressing through the sensor production

demonstrated that environmental studies can be adapted to instruct high school students in using cutting edge scientific

research of

ecosystem physiology.

Acknowledgements

We greatly appreciated the technical support of Alligator River Wildlife Refuge as well as John S. King and Asko Noormets from

NC State University for letting use their study site for sap flow measurements.

Figure 3: Daily fluctuations in whole tree water use (transpiration rate) for two tree species growing in a ~75 year-

old naturally regenerated forested wetland along the lower coastal plain of North Carolina (Alligator River National

Wildlife Refuge). The data show that the deciduous species (red maple, Acer rubrum) reached full transpiration

rate (~12 kgh2otree-1

day-1

) by the end of April due to total leaf expansion. For comparison, the evergreen species

(loblolly pine, Pinus taeda L.) maintained high transpiration rate throughout the whole measurements period during

rainless days

Figure 1. Excerpt from student presentation of preliminary data from the NCSSM SWETNET site in spring of 2009.

Figure 2. NCSSM Online Schools with SWETNET Schools Shown in red..