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

Our goal is to provide authentic research experiences for NCSSM Online students throughout North Carolina through

a network of sap monitoring sites located at, or near, participating schools. Students will run the network, collecting

and analyzing data with guidance from scientists who study forest transpiration and ecosystem physiology.

SWETNET sapflow measurements can be used as a proxy for the end of leaf expansion in deciduous ( Figure 3.)

The distribution of sampling sites across the state will provide insight into seasonal and latitudinal variations. 

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-

1day

-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..

Figure 4. Chris Oishi (left) and Eric Ward demonstrating probe construction and teaching students NCSSM students at S

WETNET site