Influence of Northern Forest Canopies on Microclimate
and Plant Species Regeneration
J. G. Isebrands, R.M. Teclaw, J.C. Zasada
USDA Forest Service, North Central Research Station
Rhinelander, WI 54501
Abstract:
More information is needed on the effects of silvicultural treatments and forest canopy
structure on microclimate and plant species regeneration in northern forest ecosystems.
Our objective is to gain an understanding of the influence of forest canopies on the
understory and overstory microclimate on selected northern forest ecosystems and to assess
the effects of microclimate on plant species regeneration and early stages of forest
succession. Research will be conducted at the Willow Springs Ecosystem Processes Site
within the footprint of the existing Ameriflux tower on the Chequamegon/Nicolet National
Forest near Park Falls, WI. Environmental monitoring is being conducted in natural forests
and in manipulated forest canopies with standard monitoring stations. Monitoring is on a
year-round basis using Campbell CR-10 dataloggers. Vegetative surveys of woody and
herbaceous plants on the sites are conducted periodically and canopy leaf area index
(LAI) is estimated using sunfleck ceptometer methods. Our group also provides local
technical and scientific support for CHEAS scientists working on the Ameriflux tall tower
and associated flux towers, and is the primary USDA Forest Service contact for the team.
1. Objectives
-Gain an understanding of the influence of the forest canopy on microclimate of forest
sites.
-Assess the effects of microclimate on forest plant species regeneration and early
stages of forest succession (e.g., effects of frost on seedling development.
2. Field Activities
Location
The Willow Springs Ecosystem Processes Site is located on the Park Falls district of the
Chequamegon/Nicolet National Forest in northern Wisconsin, (45 degrees 47 minutes N. Lat.,
90 degrees 3 minutes W. Long.) 50 km southeast of Park Falls, WI.
Measurements
Meteorological conditions are being monitored at three monitoring stations. Each station
is located in the center of a 8 hectare (20acre) block of unique overstory conditions,
including a clearcut, a shelterwood with an overstory canopy density of 50% crown cover,
and a control. The stations were deployed in 1993 and have been operational since. The
clearcut and shelterwood blocks have experienced significant overstory and understory
development since the 1988 logging operation. This development has been documented with
regeneration, total vegetation surveys, and periodic leaf area index measurements.
Monitored parameters common to all three stations are:
-relative humidity and temperature at 2 and 10 meters
-wind speed and direction at 2 and 10 meters
-photosynthetically active radiation (PAR) at 2 meters
-precipitation - rain gauges and snowstakes
-air and soil temperature profiles at 2m, 1m, 0.75m, 0.5m, 0.25m, soil surface, 0.05m,
0.1m, 0.2 0.5m, and 1.0m
In addition to the aforementioned measurements, total solar radiation is measured in the
clearcut and net radiation is measured with a roving sensor that is rotated to each block
during the year. Soil water content is also monitored at the control station with time
domain reflectometry technology. Soil water content is recorded every three hours at
three locations at depths from the surface to 30 cm, and 50 to 80 cm.
Time Table
The above measurements have been documented on a continuous basis since 1994 with the
exception of the soil water content measurements which began in 1996 and will be
continuing in 1998. The 50% crown cover block will be thinned to a density of 25
trees per hectare (10 trees per acre) in the winter of 1998-1999. This harvest
(Dec. 1998) will provide opportunities for some selective measurements achieved
through destructive harvesting. Interest in participation in such activities must be
scheduled with us before the summer of 1998. Leaf area index measurements will be made
in conjunction with the Gower and Bolstad teams.
3. Derived Products
Transmitted Photosynthetically Active Radiation (TPAR)
Leaf Area Index (LAI)
4. Research Team Support
North Central Research Station in Rhinelander, WI provides local on-site support for
several CHEAS research activities: 1) Support at the WLEF tower includes general
maintenance and forwarding of raw data from a LiCor CO2 analyzing system and a gas
chromatograph, 2) Support for a NCAR radarbased system that characterizes CO2 boundary
layer development near the WLEF tower. Weather balloon deployments will also be
conducted during 1998 at the radar site, and 3) Support at the Willow Creek Flux
tower will consist of routine maintenance of a Campbell data logger system including
verification that system is operating according to protocol, forwarding of data sets
and maintenance of AC power generator. Our research is a cooperative venture with W.E.
Heilman of the North Central Research Station in East Lansing, MI and K.J. Davis of the
University of Minnesota.
5. Relevant Publications
Davis, K.J., P.S. Bakwin, C. Zhao, W.M. Angevine, D.F. Hurst, and J.G. Isebrands, 1996.
Monitoring regional forest-atmosphere exchanges of carbon dioxide. In: Proc. American
Meteorological Society 76th Annual Meeting, January 1996. Atlanta, GA. pp. 302-305.
Davis, K.J., P.S. Bakwin, C. Zhao, R.M. Teclaw, and W.M. Angevine, 1995. Regional
atmosphere/forest exchange and concentrations of carbon dioxide. In:
Proc. South-Central Regional Center for National Institute for Global Environmental Change
(DOE). New Orleans, LA. October 12-13, 1995. (Abstract)
Davis, K.J., P.S. Bakwin, C. Zhao, R.M. Teclaw, W.M. Angevine, D.H. Lenschow, and S.P.
Oncley, 1995. Observations of carbon exchange over boreal forests: A planetary
boundary-layer perspective. In: Proc. Tenth Annual US Forest Service Workshop.
Boulder, CO. November 9-10, 1995. (Abstract)
Heilman, W.E. and J.C. Zasada, 1998. Modeling the atmospheric dynamics within and above
vegetation layers. In: Proc. of the Seventh Symposium on Systems Analysis in Forest
Research, Traverse City, MI. (Accepted).
Heilman, W.E., J.C. Zasada, R.M. Teclaw, and D.S. Buckley, 1996. Harvesting effects on the
microclimate of northern hardwood forests in the upper Great Lakes region.
In: Proc. of the 22nd Conference on Agricultural and Forest Meteorology, Atlanta,
GA. pp. 397-400.
Hurst, D.F., P.S. Bakwin, K.J. Davis, C. Zhao, and R.M. Teclaw, 1997. Landscape-scale
surface fluxes of methane and hydrogen in a North American boreal forest. In: Proc.
CMDL Annual Meeting, March 5-6, 1997. Boulder, CO. (Abstract)
Hurst, D.F., P.S. Bakwin, C. Zhao, K.J. Davis, and R.M. Teclaw, 1996. Landscape-scale
surface fluxes of methane and hydrogen in a North American boreal lowland and wetland
forest. In: Proc. AGU Fall Meeting, EOS Trans. A.G.U., 77(46), F124-125.
Isebrands, J.G., S.L. Steele, and J. Van Cleve, 1995. Photosynthetically active radiation.
In: Cline, S.P. (ed). Environmental monitoring and assessment program: Forest Health
Monitoring: Quality assurance project plan for detection monitoring project. Washington,
D.C. U.S. Environmental Protection Agency, Office of Research and Development: Sec.
5.4, 1-14.
Nauertz, E.A., D.S. Buckley, R.M. Teclaw, T.F. Strong, and J.C. Zasada. Effects of
silviculturaltreatments and forest structure on temperature at various scales in
northern hardwood forests. In: Proc. 1st Biennial North American For. Ecol. Workshop,
Raleigh, NC. June 24-26, 1997. (In press)
Teclaw, R.M. and J.G. Isebrands, 1991. Artificial regeneration of northern red oak in the
Lake States. In: Laursen, S.B. and J.F. DeBoe (eds). The oak resource in the upper
midwest: implications for management. June 3-6, 1991. Winona, MN. Pp. 187-197.
Teclaw, R.M., J.C. Zasada. D.E. Riemenschneider, and J.G. Isebrands. 1994. Quercus
rubraregeneration in the northern Great Lakes region, USA. In: Proc. Centre National
de Formation Forestiere, August 29 - September 1, 1994. Nancy, France. (Abstract)
6. Key Personnel
Principal Contact: J.G. Isebrands, Tree Physiologist
USDA Forest Service
North Central Research Station
5985 Highway K
Rhinelander, WI 54501
Phone: 715-362-1116
Fax: 715-362-1166
Email: jisebran@newnorth.net
R.M. Teclaw, Biologist
USDA Forest Service
North Central Research Station
5985 Highway K
Rhinelander, WI 54501
Phone: 715-362-1151
Fax: 715-362-1166
Email: rteclaw@newnorth.net
J.C. Zasada, Forest Ecologist/Silviculturist
USDA Forest Service
North Central Research Station
5985 Highway K
Rhinelander, WI 54501
Phone: 715-362-1126
Fax: 715-362-1166
Email: jzasada/nc_rh@fs.fed.us
Modeling Forest Overstory Effects on Forest Microclimates
Warren E. Heilman, Brian E. Potter
USDA Forest Service - North Central Research Station
East Lansing, MI
J.C. Zasada, J.G. Isebrands, R.M. Teclaw
USDA Forest Service - North Central Research Station
Rhinelander, WI
Abstract
The USDA Forest Service=s Northern Global Change Research Program has provided funding for
quantifying the effects of disturbance on forest succession and microclimate in the upper
Great Lakes region. As part of this overall research effort, this study proposes to improve
our understanding of models of the effects of canopy cover on forest microclimates.
Long-term monitoring of subcanopy atmospheric temperature, humidity, wind, net radiation,
photosynthetically-active-radiation, precipitation, and soil temperatures, provides data
usable for analysis of the variations forest canopy cover produces in these quantities.
Conditions are monitored on three sites; one regenerating clearcut, one control plot, and
one where overstory was reduced by 50%. Analysis involves basic statistical techniques
and complex meteorological models. Where and when possible, the physical processes
responsible for differences in microclimate will be determined.
1. Objectives
-Provide a detailed multi-year data set of meteorological variables appropriate for studies
of forest microclimate under different canopy covers.
-Assess the effects of forest canopy manipulation on the microclimate of northern forest
ecosystems in the northern Great Lakes region.
-Assess the effects of different forest overstory conditions on disturbance occurrence in
northern forest ecosystems in the northern Great Lakes region.
-Develop models to predict microclimatic conditions and associated plant growth in a
changing environment.
2. Field Activities
Location
The field site for this study at the Willow Springs Ecosystem Processes Site is on the
Chequamegon/Nicolet National Forest, 50 km from Park Falls, Wisconsin. In 1988 the
study site was divided into 8 ha sections; one was left uncut, one had half of the
overstory removed, and the third was clearcut. The plots are on level to gently-sloping
terrain, with moderately well-drained sandy loam soil and a canopy height of ca. 20 m.
Tree species dominant on the wooded sites include white ash, sugar maple, basswood, and
red oak.
Measurements
During the summer of 1993, we erected a 10 m tower in each of the three study plots, with
instruments to measure and record atmospheric conditions. The instruments record
hourly-average values of temperature, relative humidity, wind speed, wind direction,
and photosynthetically active radiation (PAR) at 2.5 and 10 m above the ground. In
addition, three 2 m tall stakes in each plot are equipped with thermocouples to measure
air temperature at 0.25, 0.5, 0.75, and 1.0 m. Each plot also has one rain gauge.
Thermocouples at 0.05, 0.10, 0.20, 0.50, and 1.0 m measure soil temperatures in three
pits on each site.
Time Table
We are analyzing data on a continuing basis as needed for specific studies. We are
producing climatological summaries and a meteorological data archives on a continuing
basis. As there is no anticipated termination of the data collection, there is no planned
date to have all summaries and modeling studies complete.
3. Supporting Data
Surface and upper-air meteorological data, analyses, and forecasts
National Climate Data Center (NCDC) climatic data
4. Derived Products
-Yearly comprehensive observational and modeling data bases for the Willow Springs
Ecosystem Processes Site, including hourly temperatures, relative humidities, wind
speeds, wind directions, net radiation, photosynthetically-active-radiation, and soil
temperatures.
-Yearly climatological summaries of within-canopy conditions at the Willow Springs study
site.
5. Modeling Activities
We have used air and soil data in a boundary-layer turbulence model (Heilman and Dobosy
1985; Heilman and Takle 1991)to simulate nocturnal mean and turbulence characteristics
in the lower inversion layer during frost episodes at the site. These simulations showed
the importance of forest overstory densities in affecting frost occurrence at the surface.
We have been using the air and soil temperature, wind, and humidity data collected in
1994 and 1995 in model simulations of nocturnal cooling on calm nights. The model used
for this study is a radiative transfer model (Potter 1998) with limited microphysics
(condensation and evaporation). The purpose of these simulations is to better understand
the physical processes that dominate under conditions conducive to early growing-season
frost episodes before the trees have flushed.
6. Relevant Publications
Heilman, W. E., and R. Dobosy. 1985. A nocturnal atmospheric drainage flow simulation
investigating the application of one-dimensional modeling and current turbulence schemes.
J. Climate Appl. Meteor. 24:924-936.
Heilman, W. E., and E. S. Takle. 1991. Numerical simulation of the nocturnal turbulence
characteristics over Rattlesnake Mountain. J. Appl. Meteor. 30:1106-1116.
Heilman, W. E., J. C. Zasada, R. M. Teclaw, and D. S. Buckley. 1996. Harvesting effects
on the microclimate of northern hardwood forests in the upper Great Lakes region. In:
Proceedings of the 22nd Conference on Agricultural and Forest Meteorology, Atlanta, GA.
pp. 397-400.
Heilman, W. E., and J. C. Zasada. 1998. Modeling the atmospheric dynamics within and
above vegetation layers. In: Proceedings of the Seventh Symposium on Systems Analysis
in Forest Research, Traverse City, MI. (Accepted).
Potter, B. E. 1998. Passive frost-risk reduction for forest management in northern
hardwoods. In: Proceedings of the Seventh Symposium on Systems Analysis in Forest
Research, Traverse City, MI. (Accepted).
7. Key Personnel
Warren E. Heilman
USDA Forest Service - North Central Research Station
407 S. Harrison Road
East Lansing, MI.
Phone: (517) 355-7740
Fax: (517) 355-5121
Email: wheilman/nc_el@fs.fed.us
Brian E. Potter
USDA Forest Service - North Central Research Station
East Lansing, MI.
Phone: (517) 355-7740
Email: bpotter/nc_el@fs.fed.us
John C. Zasada
USDA Forest Service - North Central Research Station
Rhinelander, WI.
Phone: (715) 362-1124
Email: jzasada/nc_rh@fs.fed.us
J.G. Isebrands
USDA Forest Service - North Central Research Station
Rhinelander, WI.
Phone: (715) 362-1116
Email: jisebrands/nc_rh@fs.fed.us
R.M. Teclaw
USDA Forest Service - North Central Research Station
Rhinelander, WI.
Phone: (715) 362-1151
Email: rteclaw/nc_rh@fs.fed.us
Atmospheric Boundary-Layer Dynamics Within and Above
Forest Vegetation Layers
Warren E. Heilman, Brian E. Potter
USDA Forest Service - North Central Research Station
East Lansing, MI
J.G. Isebrands, R.M. Teclaw
USDA Forest Service - North Central Research Station
Rhinelander, WI
Abstract
Since 1994, atmospheric scientists have been examining the near-surface atmospheric
conditions under different types of forest overstory coverage at the Willow Springs
Ecosystem Processes Study Site on the Chequamegon/Nicolet National Forest. Because
of the limited heights (10 m) of the meteorological towers at the Willow Springs site,
forest-atmosphere interactions above the canopy layer at the site cannot be examined.
The erection of the 30 m Willow Creek flux tower on the Chequamegon/Nicolet National
Forest offers an opportunity to examine not only the atmospheric-boundary-layer dynamics
within a vegetation layer, but also the atmosphere-forest interactions at levels above
the forest overstory. As part of this proposed study, the Willow Creek flux tower will
be instrumented with temperature, wind speed, wind direction, relative humidity, net
radiation, and photosynthetically-active-radiation probes to provide a comprehensive
data base of atmospheric conditions within and above the vegetation layer at the site.
The data base will provide the foundation for observational analyses and boundary-layer
modeling work to assess a variety of forest-atmosphere interactions within and above
vegetation layers, including the development and evolution of nocturnal inversion layers,
frost occurrence in this type of environment, radiational processes within vegetation
layers, and the diurnal evolution of atmospheric turbulence characteristics.
1. Objectives
-Develop a comprehensive observational and modeling data base of atmospheric boundary-layer
conditions within and above a vegetation layer at the Willow Creek flux tower site that can
be distributed for use by the scientific community.
-Provide a better understanding of the atmospheric boundary-layer dynamics within and
above vegetation layers.
-Provide a better understanding of the development and evolution of nocturnal inversion
layers within and above vegetation layers.
-Assess the forest-atmosphere interactions that influence the development of frost
episodes within vegetation layers.
-Provide a better understanding of the role of atmospheric boundary-layer turbulence in
affecting the atmospheric environment within and above vegetation layers.
2. Field Activities
Location
Atmospheric boundary-layer and soil measurements will be made at the Willow Creek flux
tower located on the Park Falls District of the Chequamegon/Nicolet National Forest, 37
km from Park Falls, WI.
Measurements
In 1998, the Willow Creek flux tower will be instrumented with a variety of probes to
provide profile information for temperature, wind speed, wind direction, relative humidity,
photosynthetically-active-radiation, and net radiation. Temperature and relative humidity
measurements will be made at five levels: 3 m above the surface, just below the canopy
crown, within the canopy crown layer, just above the canopy crown, and at the tower top
(30 m). Wind speed and direction will be measured at 3 levels: 2 m above the surface,
just below the canopy crown, and just above the canopy top. Photosynthetically-active-
radiation and net radiation will be measured at 2 levels: 2 m above the surface and just
above the canopy top. Near surface and below-ground temperatures will be made near the
tower site at the following levels (2 m, 1 m, 0.75 m, 0.5 m, 0.25 m, surface, -0.05 m, -0.1
m, -0.2 m, -0.5 m, and -1.0 m). Soil moisture will also be measured near the tower site at
depths of -0.05 m, -0.5 m, and -1.0 m.
Atmospheric measurements will be made continuously, 24 hours a day, 365 days a year.
At a minimum, atmospheric measurements will be reported each hour based on averages
computed from a set number (to-be-determined) of observations within that hour.
Data from the atmospheric and soil probes will be sent to an on-site datalogger and
then transferred to portable media (e.g. JAZ Disks, CD-ROMs) for archiving.
Time Table
The Willow Creek flux tower will be erected during the late winter or early spring of
1998, with instrumentation of the tower to follow in the spring of 1998. Testing of the
instrumentation and the development of appropriate measurement protocols will be
established during the spring months of 1998. This will ensure that measurements from
this study can be effectively integrated with concurrent eddy flux measurements carried
out in concurrent studies. Measurements will then continue throughout the remaining months
of 1998 and for at least two more years (through 2000).
Quality assurance and quality control activities for the observational data collected each
year for the duration of the project will be carried out during the months of January-April
for data collected in the previous year. Quality-controlled data for each year will be
archived according to established protocols and made available in the latter months of the
following year.
Preliminary analyses of the observational boundary-layer data will commence during the fall
of 1998. These analyses will focus on diurnal temperature, humidity, and wind speed trends
at the different measurement levels on the tower. Analyses of the data will continue in
following years to address.
3. Supporting Data
Eddy flux data from concurrent studies
Surface and upper-air meteorological data, analyses, and forecasts
National Climate Data Center (NCDC) climatic data
4. Derived Products
-Yearly comprehensive observational and modeling data bases including hourly (at a minimum)
temperatures, relative humidities, wind speeds, wind directions, net radiation,
photosynthetically-active-radiation, soil temperatures, and soil moisture available
on CD-ROM.
-Yearly climatological overviews of within- and above-canopy conditions at the Willow Creek
flux tower site.
5. Modeling Activities
In conjunction with the analyses of the observational data, boundary-layer model (Heilman
and Dobosy 1985; Heilman and Takle 1991) and radiational model (Potter 1998) simulations
will be carried out to further examine the fundamental diurnal turbulence structure
(turbulent kinetic energy, turbulence anisotropy, turbulent heat and moisture fluxes,
momentum fluxes, turbulent diffusion) and radiational processes that characterize
vegetation layers. Observational data collected at the flux tower site will provide
crucial boundary and initial conditions for the modeling effort along with model
verification information.
6. Relevant Publications
Heilman, W. E., and R. Dobosy. 1985. A nocturnal atmospheric drainage flow simulation
investigating the application of one-dimensional modeling and current turbulence schemes.
J. Climate Appl. Meteor. 24:924-936.
Heilman, W. E., and E. S. Takle. 1991. Numerical simulation of the nocturnal turbulence
characteristics over Rattlesnake Mountain. J. Appl. Meteor. 30:1106-1116.
Heilman, W. E., J. C. Zasada, R. M. Teclaw, and D. S. Buckley. 1996. Harvesting effects
on the microclimate of northern hardwood forests in the upper Great Lakes region. In:
Proceedings of the 22nd Conference on Agricultural and Forest Meteorology, Atlanta, GA.
pp. 397-400.
Heilman, W. E., and J. C. Zasada. 1998. Modeling the atmospheric dynamics within and above
vegetation layers. In: Proceedings of the Seventh Symposium on Systems Analysis in Forest
Research, Traverse City, MI. (Accepted).
Potter, B. E. 1998. Passive frost-risk reduction for forest management in northern
hardwoods. In: Proceedings of the Seventh Symposium on Systems Analysis in Forest
Research, Traverse City, MI. (Accepted).
7. Key Personnel
Warren E. Heilman
USDA Forest Service - North Central Research Station
1407 S. Harrison Rd., East Lansing, MI.
Phone: (517) 355-7740
Fax: 517-355-5121
Email: wheilman/nc_el@fs.fed.us
Brian E. Potter
USDA Forest Service - North Central Research Station
East Lansing, MI.
Phone: (517) 355-7740
Email: bpotter/nc_el@fs.fed.us
J.G. Isebrands
USDA Forest Service - North Central Research Station
Rhinelander, WI.
Phone: (715) 362-1116
Email: jisebrands/nc_rh@fs.fed.us
R.M. Teclaw
USDA Forest Service - North Central Research Station
Rhinelander, WI.
Phone: (715) 362-1151
Email: rteclaw/nc_rh@fs.fed.us
