Updated: 2012-09-05

Kawagoe forest meteorology research site (KWG)

Meteorological observation tower in Kawagoe site (25m)

Overview of this site

Kawagoe forest meteorology research site is located in a copse in Kawagoe city, Saitama pref. The dominant species of this deciduous broadleaf forest is Konara oak, red-leaved hornbeam, japanese sweetspire and Ilex macropoda. Litters from this forest are unusually collected sometime in January to be used in nearby farms as compost. Therefore the forest floor is bared from spring to summer season. Another characteristic of this site is artificial disturbance. There is a local street cuts across the forest and an automobile expressway, Kan-Etsu Dou is only 500m away from the forest. The area is belonging to the temperate climate with maximum temperature is around 35°C and minimum is -5°C and annual precipitation is about 1500mm. It snows a few times a year yet snow depth is less than a several centimeters. From 1995 to 2002, we have carried out a continuous observation of CO2 and energy budget to clarify the influence of forest onto climate and to collect fundamental data for modeling study.

Position35 deg 52 min 21 sec N (35.8725 deg N),
139 deg 29 min 13 sec E (139.4869 deg E) (WGS1984)
Climate ClassificationTemperate (Cfa, Temperate - Fully humid - Hot summer)
Annual Mean Temperature15.2°C(year 1997-1999)
Annual Mean Precipitation1569mm(year 1997-1999)
Monthly mean temperature and
precipitation (year 1997-1999)
Monthly mean solar radiation (year 1997-1999)
VegetationDeciduous broadleaf forest
Areaapprox. 40ha
Dominant SpeciesQuercus serrata (Konara oak), Carpinus laxiflora (red-leaved hornbeam), Clethra barbineris (japanese sweetspire), Ilex macropoda
Canopy Height15m
Breast High Diametermainly 10-15cm
Leaf Area Indexapprox. 5.5 at max in early summer
Community StructureOverstory, Understory
Soil TypeModerately moist black soil, BlD
Artificial Disturbancea local street goes through the forest
approx. 500m away from Kan-Etsu Expressway
fallen leaves are occasionally swept away
Observation Period
Period19 July 1995 ~ 31 December 2002
CO2: 15 April 1997 ~ 31 December 2002
Tower Height25 m
Access to Tower TopPossible
Electric Power SupplyCommercial power supply AC100V
Communication EquipmentWire telephone
AccommodationNot available


 Name and ModelLevel
Downward Short-wave RadiationEKO, MR-2225 m
Upward Short-wave RadiationEKO, MR-2225 m
Downward Long-wave RadiationEppley, PIR-F25 m
Upward Long-wave RadiationEppley, PIR-F25 m
All-wave Net Radiation (~2000.5)EKO, MF-1125 m
Downward PPFDEKO, ML-020P / LI-COR, Li190-SA25 m
Downward Short-wave Radiation below CanopyEKO, MR-222.5 m
Air temperaturePlatinum resistance thermometer Vaisala, HMP-35D
EKO, MH020S;MH021S
25.5,21,17.8,16,14,12,9,5,2.5 m
HumidityCapacitive hygrometer Vaisala, HMP-35D
25.5,21,17.8,16,14,12,9,5,2.5 m
Wind SpeedCup anemometer IKEDA, WM-30P25.9,21,18,16 m
Wind DirectionIKEDA, WD-1625.9 m
Barometric PressureVaisala, PTB-100A2.0 m
Soil TemperaturePlatinum resistance thermometer; thermocouple0.0, 0.02, 0.05, 0.1, 0.25, 0.5 m deep
Soil Heat FluxEKO, MF-810.02 m deep
Soil Water ContentIMKO, TRIME-MUX60.05, 0.2, 0.5, 1.0 m deep
PrecipitationTipping bucket raingauge IKEDA, RT-5approx. 0.6m, outsite of forest
Data Logger
Sampling PeriodEvery 60 seconds
Averaging Period5 minutes
RecorderEto Denki, ThermoDac-E and PC

Turbulence Fluctuation Method (Eddy Covariance Method)

SystemClosed-path & Bandpass
Three-dimensional Sonic
KAIJO, DAT-300;DAT-600-3T Sensor span0.2m
Level20.0 m
Height from Canopy Surface5 m
Gas Analyzer
LI-COR, LI-6262 Distance between
gas intake and analyzer
approx. 28m
Height of intake20 m
Height from Canopy Surface5 m
Relative humidity sensor
Vaisala, HMP35A
Data Logger
Sampling MethodContinuous
Averaging Period0 second
Sampling Frequency5 Hz
Filters for AntialiasingAvailable
CutOff Frequency24 Hz
Recording RangeAll data
RecorderTEAC, DRM2a; DRM3a
Flux Calculation
Calculation Period1800 seconds
MethodDetrendingw, u, Ta, CO2, H2O
Coordinate RotationCorrected
Line AveragingNot-corrected
Sensor SeparationNot-corrected
Humidity Correction of Virtual TemperatureCorrected

Vertical profiling CO2 Concentration in Canopy

InstrumentsLI-COR Li-6262
Sampling1 second
Sampling Period1999.4~2000.3: Every 5 minutes at a level x 4 levels (16, 12, 8, 4 m)
2000.3~: Every 1 minute at a level x 4 levels (16, 12, 8, 4 m)
Averaging Period1999.4~2000.3: recording the average of last 3 minutes
2000.3~: recording the average of last 15 seconds
PurposeTo obtain CO2 storage change in canopy

Other Observation

InstrumentLI-COR, LI-6400
Observation FrequencyOnce or twice in a month
Soil Respiration
MethodAutomatic switching closed-chamber
Observation FrequencyContinuous
MethodLitter Trap
Observation FrequencyEvery second week
MethodTree diameter and height
Observation FrequencyIrregular


YASUDA Yukio, WATANABE Tsutomu (2001): Comparative measurements of CO2 flux over a forest using closed-path and open-path CO2 analyzers. Boundary-Layer Meteorology, 100(2):191-208.

WATANABE Tsutomu, YAMANOI Katsumi, YASUDA Yukio (2000): Testing of the bandpass eddy covariance method for a long-term measurement of water vapour flux over a forest. Boundary-Layer Meteorology, 96(3):473-491.

YASUDA Yukio, WATANABE Tsutomu, OHTANI Yoshikazu, OKANO Michiaki, Nakayama Keiichi (1998): Seasonal variation of CO2 flux over a broadleaf deciduous forest. Journal of Japan Society of Hydrology & Water Resources, 11(6):575-585 [in Japanese with an English abstract].

WATANABE Tsutomu, OHTANI Yoshikazu (1998): A comparative study on Calculation Method of Heat Conduction in Trees Stems. Journal of Agricultural Meteorology, 54(1):47-54 [in Japanese with an English abstract].

YASUDA Yukio, WATANABE Tsutomu, YAMANOI Katsumi, OHTANI Yoshikazu, TANI Makoto, NAKAYAMA Keiichi (1997): Measurement of Scalar Flux from a Forest Using the Bandpass Covariance Method. Journal of Agricultural Meteorology, 52(5):493-496.

MIZOGUCHI Yasuko (2009): Study on variability characteristics of forest floor CO2 efflux. Bulletin of the Forestry and Forest Products Research Institute, 7:1-50 [in Japanese with an English abstract].

Research Fund

- Research Grant, FFPRI


Yukio YASUDA, Yasuko MIZOGUCHI, Tsutomu WATANABE (currently at Hokkaido Univ.), Yoshikazu OHTANI

Cooperative Researchers

Yukihiro CHIBA

Contact Information

Department of Disaster Prevention, Meteorology and Hydrology,
Forestry and Forest Products Research Institute (FFPRI)
Address: 1 Matsunosato, Tsukuba, Ibaraki, 305-8687 Japan
TEL: +81-29-829-8239