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
20
30
40
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..