FFPRI FluxNet / 森林総合研究所フラックス観測ネットワーク

Observation Site

Updated: 2016-02-15

Sapporo forest meteorology research site (SAP)

Overview of this site

Sapporo forest meteorology research site is located in a hilly area neighboring urban district of Sapporo city. It is a secondary boreal deciduous broadleaf forest which had grown after wildfire. Century-old japanese white birch is its dominant species but it is on the wane and oak trees are gradually taking over the forest. The climate of this area is classified in cool-temperate, with relatively hot and dry summer and heavily snowing winter (air temperature falls below -15°C and snows more than a meter in depth). We are observing the CO2 and energy budget in a typical secondary forest of northern Japan under various climatic conditions.

The forest around the observation tower was badly damaged by typhoon in September 2004. Most of the fallen trees are untouched to study the natural transition of ecosystem. The observation tower had restarted its operation in June 2005, after the recovery from damage.

The site is supporting the continuous research activities on ecology, physiology, pedology and hydrology and accumulating the results for the future studies which especially focus on transition of forest ecosystem.

Position42 deg 59.210 min N (42.9868 deg N),
141 deg 23.117 min E (141.3853 deg E)
Climate ClassificationContinental (Dfb, Continental - Fully humid - Warm summer)
Annual Mean Temperature7.0°C(year 2000-2003)
Annual Mean Precipitation980mm(year 2000-2003)
Annual Mean Solar Raadiation12.7MJm-2day-1(year 2000-2003)
Monthly mean temperature and precipitation
(year 2000-2003)
Monthly mean solar radiation (year 2000-2003)
VegetationBoreal deciduous broadleaf forest
Areaapprox. 80ha
Fetch500 ~ 1500m
Dominant SpeciesBetula platyphylla (japanese white birch), Quercus crispula (japanese oak), Kalopanax septemlobus, Tilia japonica (japanese lime), Acer Mono, Populus Sieboldi, Populus Maximowiczii (japanese popular)
Canopy Heightapprox. 20m
Breast High Diameterapprox. 25 cm (japanese White Birch)
Ageapprox. 100 years (japanese White Birch)
Leaf Area Index1999~2004: approx. 4 in max.
2004~present, after wind damage: N/A
Community StructureOverstory, understory, forest floor: Sasa
Soil TypeModerately moist black soil, BlD
Artificial DisturbanceMinimum distance from residential area is approx. 600m. Forest around the site is recreational area for citizens for wildplant-picking, mushroom-picking, strolling and cross-country skiing. Vehicle entery into the experimental forest including the site is restricted only to the concerned researchers. Wind-fallen trees are unattended except for the forest roads.
Observation Period
Period15 Aug. 1999 ~ 8 Sept. 2004
June 2005 ~ present
Tower Height41m
Access to Tower TopPossible
Electric Power SupplyCommercial power supply AC100V 20A(30A max.)
Communication EquipmentNot available
AccommodationNot available


 Name and ModelLevel
Downward Short-wave RadiationKipp&Zonen, CM-6F41.3 m
Upward Short-wave RadiationKip&Zonnen, CM-6B39.2 m
Downward Long-wave RadiationEppley, PIR-F41.3 m
Upward Long-wave RadiationEppley, PIR39.2 m
Downward PPFDLI-COR, LI190-SA41.3 m
Upward PPFDLI-COR, LI190-SA39.2 m
Downward PPFD below CanopyLI-COR, LI190-SA2.4 m
Downward Short-wave Radiation below CanopyEKO MR-402.4 m
Air temperaturePlatinum resistance thermometer;
Vaisala HMP-155
Vaisala HMP-45D

33.5, 29.6, 25.8, 20.1 m
16.3, 10.5, 3.6 m
HumidityCapacitive hygrometer;
Vaisala HMP-155
Vaisala HMP-45D

33.5, 29.6, 25.8, 20.1 m
16.3, 10.5, 3.6 m
Wind Speed & Direction Vaisala WMT-5233.5, 29.6, 25.8, 20.1 m
16.3, 10.5, 3.6 m
Barometric PressurePTB-1001 m
Soil TemperaturePlatinum resistance thermometer;
0.02, 0.05, 0.1, 0.2, 0.4, 0.8 m deep
Soil Heat FluxEKO, MF-810.02 m deep
Soil Water ContentTDR soil-moisture meter;
Campbell CS-650
Tensiometer; Sankeirika inc. SK5500

0.1 m deep
0.05, 0.15, 0.30, 0.50, 0.90 m deep
Snow DepthUltrasonic distance sensor;
Campbell SR-50
2.5 m
Groundwater LevelPressure type water gauge; Druck PDCR9401.4 m deep
Rainfall DurationWetness sensor; PREDE PPS-0241 m
PrecipitationTipping bucket raingauge; Yokogawa B-071-12approx. 1.8m, Open space
Data Logger
Sampling PeriodEvery 10 seconds
Averaging Period5 minutes
RecorderCampbell, CR-1000
Media Internal memory

Turbulence Fluctuation Method (Eddy Covariance Method)

SystemClosed-path and Open-path
Sonic Anemometer-thermometerKAIJO DAT-600-3T,TR-61c Sensor span0.2m
Level28.5 m
Height from Canopy Surface8 m
Gas(CO2) analyzer
LI-COR LI-6262 Distance between
gas intake and analyzer
approx. 40 m
Height of intake28.3 m
Height from Canopy Surface8 m
Distance between
gas intake and analyzer
0.25 m
Gas(CO2) analyzer
LI-COR LI-7500 Distance between
anemometer and analyzer
Relative humidity sensorVaisala HMP155 Distance between
anemometer and sensor
0.5 m
BarometerVaisala PTB-210Level28 m
Data Logger
Sampling MethodContinuous
Averaging Period0 second
Sampling Frequency 10 Hz
Filters for AntialiasingAvailable
CutOff Frequency24 Hz
Recording RangeAll data
RecorderCampbell CR3000
Media CF card
Flux Calculation
Calculation Period1800 s
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
Level29.6, 20.1, 16.3, 10.5, 3.6 m
Sampling PeriodEvery 120 seconds at a level x 5 levels
Averaging Period15 seconds
RecorderCampbell CR1000

Other Observation

MethodPhotosynthesis of sunny crown, transpiration rate, diurnal variation of stomatal conductance
InstrumentLI-COR LI-6400
Observation FrequencySeveral times a year, on the basis of typical air temperature and vapor pressure deficit
Soil Respiration
Methodautomatic switching chamber
Observation FrequencyContinuous
MethodLitter Trap
Observation FrequencyEvery second week in defoliation period
MethodTree diameter and height (calculated by hight-diameter curve)
Observation FrequencyEvery year

Japan-US Inter-Comparison Measurements (Aug., 2001)

There are several research networks for carbon dioxide flux studies now, and they are well maintained and reinforced by the scientists with the common interest. For a cooperative studies, it is important to know the characteristics of individual observation systems and analytical approaches and recognize the difference in the obtained data.

Concerning such issue, a proposal of inter-comparison measurements was brought up from AmeriFlux and it was conducted in two flux observation sites in Hokkaido (Tomakomai Flux Research Site, NIES and Sapporo forest meteorology research site, FFPRI) from 10 August 2001 for ten days.
More details


YAMANOI Katsumi, MIZOGUCHI Yasuko, UTSUGI Hajime(2015): Effects of a windthrow disturbance on the carbon balance of a broadleaf deciduous forest in Hokkaido, Japan. Biogeosciences, 12: 6837-6851.

MIZOGUCHI Yasuko, YAMANOI Katsumi(2015): Forty-year meteorological statistics of the Hitsujigaoka Experimental Forest. Bulletin of FFPRI, 14(4): 209-218.

KITAMURA Kenzo, NAKAI Yuichiro, SUZUKI Satoru, OHTANI Yoshikazu, YAMANOI Katsumi, SAKAMOTO Tomoki(2012): Interannual variability of net ecosystem production for a broadleaf deciduous forest in Sapporo, northern Japan. Journal of Forest Research, 17(3):323-332.

ISHIZUKA Shigehiro, SAKATA Tadashi, SAWATA Satoshi, IKEDA Shigeto, TAKENAKA Chisato, TAMAI Nobuaki, SAKAI Hisao., SHIMIZU Takanori, KAN-NA, Kensaku, ONODERA Shin-ichi, TANAKA Nagaharu, TAKAHASHI Masamichi(2006): High potential for increase in CO2 flux from forest soil surface due to global warming in cooler areas of Japan. Annals Forest Science, 63(5):537-546

SUZUKI Satoru, ISHIZUKA Shigehiro, KITAMURA Kenzo, YAMANOI Katsumi, NAKAI Yuichiro (2006): Continuous estimation of winter carbon dioxide efflux from the snow surface in a deciduous broadleaf forest. Journal of Geophysical Research, 111:D17101

WATANABE Tsutomu, NAKAI Yuichiro, KITAMURA Kenzo, UTSUGI Hajime, TOBITA Hiroyuki, ISHIZUKA Shigehiro (2005): Scaling energy and CO2 fluxes from leaf to canopy using a Multilayered Implementation for Natural Canopy-Environment Relations (MINCER). Phyton, 45:353-360

NAKAI Yuichiro, KITAMURA Kenzo, SUZUKI Satoru, ABE Shin (2003): Year-long carbon dioxide exchange above a broadleaf deciduous forest in Sapporo, Northern Japan. Tellus B, 55(3):305-312

Research Fund

- Major Facility Installation for Carbon Dioxide Monitoring, Forestry Agency, MAFF*

- Research Grant, FFPRI

- Research Fund (Evaluation, Adaptation and Mitigation of Global Warming in Agriculture, Forestry and Fisheries: Research and Development), MAFF*

- Research Revolution 2002, MEXT**

- Grant-in-Aid for Scientific Research, MEXT**

- Global Environment Research Account for National Institutes, MOE***

* MAFF: Ministry of Agriculture, Forestry and Fisheries of Japan
** MEXT: Ministry of Education, Culture, Sports, Science and Technology
*** MOE: Ministry of the Environment



Cooperative Researchers

Hajime UTSUGI, Hiroyuki TOBITA, Akira UEMURA, Tadashi SAKATA, Masayoshi TAKAHASHI (Hokkaido Research Center, FFPRI)

Contact Information

Cold Regions Environment Conservation Research Group,
Hokkaido Research Center,
Forestry and Forest Products Research Institute (FFPRI)
Address: Hitsujigaoka-7, Toyohira, Sapporo, Hokkaido, 062-8516 Japan
TEL: +81-11-851-4131 (main)