metadata

Title

Nation-wide litter fall data from 21 forests of the Monitoring Sites 1000 Project in Japan

AUTHORS

Satoshi N. Suzuki^{1, *}, Masae I. Ishihara^{1, a}, Masahiro Nakamura^{1, b}, Shin Abe², Tsutom Hiura³, Kosuke Homma⁴, Motoki Higa², Daisuke Hoshino⁵, Kazuhiko Hoshizaki⁶, Hideyuki Ida⁷, Ken Ishida⁸, Motohiro Kawanishi⁹, Kazutaka Kobayashi¹⁰, Koichiro Kuraji¹¹, Shigeo Kuramoto^{12, c}, Takashi Masaki², Kaoru Niiyama^{2, d}, Mahoko Noguchi^12,d, Haruto Nomiya¹³, Satoshi Saito², Takeshi Sakai^{12, e}, Michinori Sakimoto¹⁴, Hitoshi Sakio⁴, Tamotsu Sato², Hirofumi Shibano^{11, f}, Mitsue Shibata², Maki Suzuki¹⁵, Atsushi Takashima¹⁶, Hiroshi Tanaka², Masahiro Takagi¹⁷, Naoaki Tashiro¹⁸, Naoko Tokuchi¹⁴, Toshiya Yoshida¹⁹, Yumiko Yoshida¹⁵

¹Network Center of the Forest and Grassland Survey of the Monitoring Sites 1000 Project, Japan Wildlife Research Center, Tomakomai, Japan

² Forestry and Forest Products Research Institute, Tsukuba, Japan

³Tomakomai Research Station, Field Science Center for Northern Biosphere, Hokkaido University, Tomakomai, Japan

⁴Field Center for Sustainable Agriculture and Forestry, Faculty of Agriculture, Niigata University, Sado, Japan

⁵ Tohoku Research Center, Forestry and Forest Products Research Institute, Morioka, Japan

⁶Faculty of Bioresource Sciences, Akita Prefectural University, Akita, Japan

⁷ Institute of Nature Education in Shiga Heights, Faculty of Education, Shinshu University, Yamanouchi, Japan

⁸ Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, Japan

⁹ Faculty of Education, Kagoshima University, Kagoshima, Japan

¹⁰ Botanical Gardens, Tohoku University, Sendai, Japan

¹¹ Ecohydrology Research Institute, The University of Tokyo Forest, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Seto, Japan

¹² Shikoku Research Center, Forestry and Forest Products Research Institute, Kochi, Japan

¹³ Kyushu Research Center, Forestry and Forest Products Research Institute, Kumamoto, Japan

¹⁴Field Science Education and Research Center, Kyoto University, Kyoto, Japan

¹⁵The University of Tokyo Chichibu Forest, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Chichibu, Japan

¹⁶ Yona Field, Subtropical Field Science Center, Faculty of Agriculture, University of the Ryukyus, Kunigami, Japan

¹⁷ Faculty of Agriculture, University of Miyazaki, Miyazaki, Japan

¹⁸Ashoro Research Forest, Kyushu University, Ashoro, Japan

¹⁹Uryu Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University, Horokanai, Japan

Present addresses:

^a Field Science Center for Northern Biosphere, Hokkaido University, Hokkaido, Japan

^b Nakagawa Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University, Horokanai, Japan

^c Hokkaido Research Center, Forestry and Forest Products Research Institute, Sapporo, Japan

^d Tohoku Research Center, Forestry and Forest Products Research Institute, Morioka, Japan

^e Forestry and Forest Products Research Institute, Tsukuba, Japan

^f The University of Tokyo Hokkaido Forest, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Furano, Japan

^*Author for correspondence: Satoshi N. Suzuki

Network Center of Forest and Grassland Survey, Monitoring Sites 1000 Project, Japan Wildlife Research Center
Present affiliation: Institute of Mountain Science, Shinshu University, 8304 Minami-Minowa, Kamiina, Nagano 399-4598, Japan
Email: satosuzuki@shinshu-u.ac.jp
Telephone number: +81-265-77-1656
Fax number: +81-265-77-1656

ABSTRACT

This data paper reports litter fall data collected in a network of 21 forest sites in Japan. This is the largest litter fall data set freely available in Japan to date. The network is a part of the Monitoring Sites 1000 Project launched by the Ministry of the Environment, Japan. It covers subarctic to subtropical climate zones and the four major forest types in Japan. Twenty three permanent plots in which usually 25 litter traps were installed were established in old-growth or secondary natural forests. Litter falls were monthly collected since 2004, and sorted into leaves, branches, reproductive structures and miscellaneous. The data provide seasonal patterns and inter-annual dynamics of litter falls, and their geographical patterns, and offer good opportunities for meta-analyses and comparative studies among forests.

KEYWORDS

data-base; forest; litter trap; litter fall; Japan; leaf phenology; LTER; plot network; spatiotemporal dynamics; the Monitoring Sites 1000 Project

INTRODUCTION

As litter plays a fundamental role in the nutrient cycling and in the carbon transfer from plants to soil, litter fall is one of the major components of biogeochemical cycle in forest ecosystems (Gosz et al. 1972; Gower et al1992; Sundarapandian 1999). Further, leaf fall is a good index of canopy foliage dynamics (Eriksson et al. 2005; Richardson et al. 2006), which is strongly connected with NPP (net primary production) of ecosystems (Clark et al. 2001). Therefore, a number of researches have reported annual litter productions and seasonality of litter falls in ecosystems since the International Biological Program in 1960s (Bray and Gorham 1964; Lonsdale 1988; Berg and Meetmeyer 2001; Chave et al. 2010). However, most of them are not available as consecutive time-series data, and late years’ data are very limited. To understand ecosystem response to recent climate change and elevated CO₂, database which accumulates latest litter fall data in multiple-sites covering large geographic area is necessary.

This data paper reports litter fall data collected in a network of 21 natural forest sites during 2004 and 2009, the only litter fall data set of multiple-sites ever published in Japan. The network is part of the Forest and Grassland Survey of the Monitoring Sites 1000 Project launched by the Ministry of the Environment, Japan (Ishihara et al. 2007; Ishihara et al. 2010). Tree census data from the project have already published as a Data Paper (Ishihara et al. 2011). Some sites participate in the Japan Long-Term Ecological Research Network (JaLTER), a member of the International Long-Term Ecological Research Network (ILTER).

The network ranges from the subarctic to subtropical climate zones, and covers four major forest types in Japan (evergreen conifer forest, broadleaf and conifer mixed forest, deciduous broadleaf forest, and evergreen broadleaf forest). Twenty three permanent plots in which usually 25 litter traps were installed within 1 ha were established in old-growth or secondary natural forests. Litter falls were monthly collected throughout the year, except snow cover periods. The data provide seasonal patterns and inter-annual dynamics of litter falls, and their geographical patterns.

These data have been used for ecological studies at each site (Sato et al. 2010; Ishihara and Hiura 2011) as well as for the reports published by the Ministry of the Environment, Japan (Ministry of the Environment, 2009). The data can be used for meta-analysis on leaf phenology and ecosystem functions.

METADATA

1. Title

Nation-wide litter fall data from 21 forests of the Monitoring Sites 1000 Project in Japan

2. Identifier

ERDP-2012-04

3. Contributor

A. Data Set Owner

Both the Ministry of the Environment, Japan and the following individuals have the ownership of the data.

Plot identification code of the data	Owners and contact individual(*)	Affiliation	Contact
Plot identification code of the data	Owners and contact individual(*)	Affiliation	Address	Phone	Fax	Email address
UR-BC1	Toshiya Yoshida*	Uryu Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University	Moshiri, Horokanai, Uryu, Hokkaido 074-0741, Japan	+81-1653-8-2125	+81-1653-8-2410	yoto@fsc.hokudai.ac.jp
AS-DB1; AS-DB2	Naoaki Tashiro*	Ashoro Research Forest, Kyushu University	1-85 Kita5, Ashoro, Ashoro, Hokkaido 089-3705, Japan	+81-156-25-2608	+81-156-25-3050	nao@forest.kyushu-u.ac.jp
TM-DB1	Tsutom Hiura*	Tomakomai Research Station, Field Science Center for Northern Biosphere, Hokkaido University	Takaoka, Tomakomai, Hokkaido 053-0035, Japan	+81-144-33-2171	+81-144-33-2173	hiura@fsc.hokudai.ac.jp
KM-DB1	Kazuhiko Hoshizaki*	Faculty of Bioresource Sciences, Akita Prefectural University	Shimoshinjo-Nakano, Akita, Akita 010-0195, Japan	+81-18 872-1608	+81-18 872-1677	khoshiz@akita-pu.ac.jp
KM-DB1	Daisuke Hoshino*	Tohoku Research Center, Forestry and Forest Products Research Institute	92-25 Nabeyashiki, Shimokuriyagawa, Morioka, Iwate 020-0123, Japan	+81-19-648-3941	+81-19-641-6747	dhoshi@affrc.go.jp
AO-BC1	Kazutaka Kobayashi*	Botanical Gardens, Tohoku University	12-2 Kawauchi, Aoba-ku, Sendai, Miyagi 980-0862, Japan	+81-22-795-6789	+81-22-795-6789	kazutaka@m.tohoku.ac.jp
OS-EC1; KS-DB1	Kosuke Homma*	Field Center for Sustainable Agriculture and Forestry, Faculty of Agriculture, Niigata University	94-2 Koda, Sado, Niigata 952-2206, Japan	+81-259-61-6006		homma-k@f2.dion.ne.jp
OG-DB1	Takashi Masaki*, Hiroshi Tanaka, Mitsue Shibata, Shin Abe	Forestry and Forest Products Research Institute	Tsukuba, Ibaraki, 305-8687, Japan	+81-29-829-8223	+81-29-874-3720	masaki@ffpri.affrc.go.jp
OG-DB1	Kaoru Niiyama	Tohoku Research Center, Forestry and Forest Products Research Institute
KY-DB1; OT-EC1	Hideyuki Ida*	Institute of Nature Education in Shiga Heights, Faculty of Education, Shinshu University	Shiga-Kogen, Yamanouchi, Shimo-Takai, Nagano 381-0401, Japan	+81-269-34-2607	+81-269-34-3229	pida@shinshu-u.ac.jp
OY-DB1	Hitoshi Sakio*, Motohiro Kawanishi, Motoki Higa	Sado Station, Field Center for Sustainable Agriculture and Forestry, Faculty of Agriculture, Niigata University	92-2 Koda, Sado, Niigata, 952-2206, Japan	+81-259-78-2613	+81-259-78-2929	sakio@agr.niigata-u.ac.jp
CC-DB1; CC-DB2	The University of Tokyo Chichibu Forest*	The University of Tokyo Chichibu Forest, Graduate School of Agricultural and Life Sciences, The University of Tokyo	1-1-49 Hinoda-machi, Chichibu, Saitama 368-0034, Japan	+81-494-22-0272	+81-494-23-9620	chichibu@uf.a.u-tokyo.ac.jp
AU-EC1	Michinori Sakimoto*	Field Science Education and Research Center, Kyoto University	Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan	+81-75-753-6424	+81-75-753-6451	sakimoto@kais.kyoto-u.ac.jp
AI-BC1	Ecohydrology Research Institute*	Ecohydrology Research Institute, The University of Tokyo Forest, Graduate School of Agricultural and Life Sciences, The University of Tokyo	Goizuka, Seto, Aichi 489-0031, Japan	+81-561-82-2371	+81-561-85-2838	eri@uf.a.u-tokyo.ac.jp
KG-EC1	Michinori Sakimoto*	Field Science Education and Research Center, Kyoto University	Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan	+81-75-753-6424	+81-75-753-6451	sakimoto@kais.kyoto-u.ac.jp
WK-EC1	Naoko Tokuchi*	Field Science Education and Research Center, Kyoto University	Oiwake-cho, Kitashirakawa, Sakyo-ku, Kyoto, Kyoto 606-8502, Japan	+81-75-753-2268	+81-75-753-2268	tokuchi@kais.kyoto-u.ac.jp
IC-BC1	Mahoko Noguchi*	Shikoku Research Center, Forestry and Forest Products Research Institute	2-915, Asakura-nishimachi, Kochi, Kochi 780-8077, Japan	+81-88-844-1121	+81-88-844-1130	mahoko@ffpri.affrc.go.jp
	Shigeo Kuramoto	Hokkaido Research Center, Forestry and Forest Products Research Institute
	Takeshi Sakai	Forestry and Forest Products Research Institute
AY-EB1	Haruto Nomiya*	Kyushu Research Center, Forestry and Forest Products Research Institute	4-11-16 Kurokami, Kumamoto, Kumamoto 860-0862, Japan	+81-96-343-3730	+81-96-344-5054	nomiya@ffpri.affrc.go.jp
AY-EB1	Satoshi Saito, Tamotsu Sato	Forestry and Forest Products Research Institute
TN-EB1	Masahiro Takagi*	Faculty of Agriculture, University of Miyazaki	11300 Otsu, Tano, Miyazaki 889-1702, Japan	+81-985-86-0036	+81-985-86-2551	mtakagi@cc.miyazaki-u.ac.jp
AM-EB1	Ken Ishida*	Graduate School of Agricultural and Life Sciences, The University of Tokyo	1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan	+81-3-5841-5499	+81-3-5841-0827	ishiken@es.a.u-tokyo.ac.jp
YN-EB1	Atsushi Takashima*	Yona Field, Subtropical Field Science Center, Faculty of Agriculture, University of the Ryukyus	685 Yona, Kunigami, Okinawa 905-1927, Japan	+81-980-41-2242	+81-980-41-2189	a-taka@agr.u-ryukyu.ac.jp

B. Data Set Creators

Satoshi N. Suzuki. Network Center of the Forest and Grassland Survey of the Monitoring Sites 1000 Project, Japan Wildlife Research Center

Masae I. Ishihara. Field Science Center for Northern Biosphere, Hokkaido University, Hokkaido, Japan

Masahiro Nakamura. Nakagawa Experimental Forest, Field Science Center for Northern Biosphere, Hokkaido University

4. Project

A. Title:

The Monitoring Sites 1000 Project

B. Personal:

Organization: Biodiversity Center of Japan, Ministry of the Environment, Japan

Address: 5597-1, Kenmarubi, Kamiyoshida, Fujiyoshida City, Yamanashi Prefecture 403-0005 Japan

Phone: +81-555-72-6031 (voice)

Phone: +81-555-72-6035 (fax)

Web Address: http://www.biodic.go.jp/

C. Funding:

Biodiversity Center of Japan, Ministry of the Environment, Japan

D. Objectives:

(The following paragraph was extracted from the First term report of the Forest and Grassland Survey, the Monitoring Sites 1000 (Ministry of the Environment 2009), and revised by the Ministry of the Environment in May 2011.)

"The goal of the Monitoring Sites 1000 Project is to detect signs of ecosystem change by long-term monitoring surveys that accumulate and analyze quantitative data on various types of ecosystems throughout Japan. The results of this monitoring can contribute to the development of appropriate measures for conservation of the natural environment. The project surveys about 1,000 sites throughout Japan and to continue monitoring them over the long term. This project was initiated in 2003 in accordance with the National Biodiversity Strategy of Japan (as revised in 2002). In the first phase (2003-2007), the design of survey methods for each ecosystem, locating the 1,000 monitoring sites, and building up the operational frameworks were completed and preliminary surveys were carried out. In 2008, the project entered its second phase in which full surveys were initiated. The monitoring project targets various types of representative ecosystems in Japan, including terrestrial ecosystems (alpine zones, forests/grasslands, and satoyama), inland water ecosystems (lakes and mires/marshes), and marine ecosystems (sandy beaches and rocky shores, tidal flats, seagrass beds, algal beds, coral reefs, and small islets). By developing a collaborative operational network with scientists, local experts, NPOs, and other relevant entities, the project will continue monitoring those ecosystems over a long-term period."

5. Geographic coverage

A. Geographic Description:

Japan

B. Bounding Coordinates:

West: 128.23

East: 143.51

North: 44.37

South: 26.74

Geographic coordinate system is WGS84

6. Temporal coverage

A. Begin:

2004

B. End:

2009

7. Taxonomic coverage

Gymnosperm and Angiosperm trees

8. Methods

A. Study sites and sampling design

The data were obtained at 23 forest permanent plots in 21 sites. These plots cover major climate zones and biogeographic regions in Japan (Ministry of the Environment 2001, http://www.env.go.jp/press/file_view.php?serial=2872&hou_id=2908) (Fig. 1, see also Ishihara et al. 2011). Furthermore, these plots cover major four forest types found in Japan: evergreen conifer forest (EC), broadleaf and conifer mixed forest (BC), deciduous broadleaf forest (DB), and evergreen broadleaf forest (EB). We classified each plot into one of the four forest types by the dominance of evergreen broadleaf, deciduous broadleaf and conifer tree (Ishihara et al. 2011).

Most of these forests are old-growth or old secondary forests but some are secondary forests that are younger than 100 years. We classified forests into one of three age categories: old-growth (OG), old secondary (OS), and secondary (S) (Ishihara et al. 2011; see SiteList.csv, Appendix.pdf).

We assigned to each plot an alphanumeric code as [abbreviated site name]-[forest type code][plot number] (see SiteList.csv). For example, AS-DB2 represents the second plot of deciduous broadleaf forest (DB) in the site, Ashoro (AS).

Mean annual temperature, mean annual precipitation, and mean maximum snow depth during 1971 to 2000 were extracted from the database Mesh Climate Data 2000, distributed by the Japan Meteorological Agency (2002). The database provides climate variables estimated at the spatial resolution of 1-km. Mean annual temperature was corrected for altitudinal difference between the plot and the 1-km grid mean by the lapse rate of 0.6°C·100m^-1. Snow depth from the database might underestimate or overestimate the snow depth of the plots because snow depth is highly spatially heterogeneous. Therefore, we provide snow depth reported in other publications or according to personal observations in Appendix.pdf.

Fig. 1. Geographic distribution of 21 sites over Japan.

B. Field method

B-1. Permanent plots

One or two permanent plots were established in each site for litter collection. The sizes of the plots are usually 1 ha (100×100 m) ranging from 0.12 to 1.2 ha (see SiteList.csv). The shapes of the plots are normally squares or rectangles but some plots have different shapes because we avoided edges of the forest that face artificial forest, roads, or buildings. Each plot was usually divided into 10×10 m grid cells. Tree census has been conducted in each plot at 1-year or 5-years intervals (see Ishihara et al. 2011).

Fig. 2. Layout of normal 1-ha permanent plot. Closed circle indicates location of each litter trap.

B-2. Data collection

Usually, 25 conical litter traps with a circular collection area of 0.5 m² were installed in each plot. Exceptions were AY-EB1 where 42 traps with a collection area of 0.58 m² were installed, OY-DB1 where traps had a collection area of 0.785 m², IC-BC1 where 20 out of 25 traps had a collection area of 0.58 m² for the first two years, OT-EC1 where only 20 traps were installed, and CC-DB2 where only 12 traps were installed. The traps were located on the corner of grid cells and 20-m apart from each other as shown in Fig. 2, but exceptions were UR-BC1, KM-DB1, OG-DB1, CC-DB2, OY-DB1, WK-EC1 and AY-EB1 (see Appendix.pdf). The traps were supported ca. 1 m above the ground level.

The litter-fall caught in the traps was collected usually every month. At the sites where snow covers the ground during winter, traps were uninstalled or placed them on the ground throughout the winter (see SiteList.csv).

The litter-fall samples were firstly air-dried in the laboratory and then sorted into (1) leaves, (2) branches, (3) reproductive structures (flowers, fruits and seeds) and (4) miscellaneous (bud scale, stem bark, a part of body and excreta of animals and other debris). After sorting, samples were dried at 70°C for 72 hours and weighted. In some sites, dry weights of samples were estimated from the air-dried weight and the average rate of water content estimated for sub-samples. For reproductive structures, seeds (including fruits) were further sorted by species, counted and weighted although the species-level data were not included in this data paper.

C. Data verification procedures

Data were manually digitized and checked for typos by the investigators. Furthermore, data were checked for typos by staff of the Network Center (S. N. Suzuki, M. I. Ishihara, and M. Nakamura). If any suspicious value remained, the value was recorded as an error (see 11. D.).

9. Data status

A. Latest Update: 27 December 2011

The data span the period 2004-2009. Data will be collected continuously after 2009 and the database will be updated as collected and verified.

B. Metadata status: Metadata are complete for this period and stored with the data

10. Accessibility

A. License and Usage Rights:

1) Acceptable use. The dataset should not be used for illegal purpose or to violate the rights of the others. Use of the dataset will be restricted to academic, research, educational, government, recreational, or other not-for-profit professional purposes.

2) Citation. Data users should properly cite this Data Paper in any publications or in the metadata of any derived data products that were produced using the dataset. As the metadata and the dataset can be updated at any time, the date of update should be shown in bibliography.

3) Acknowledgement. Data users should acknowledge as follows in any publications where the dataset contributed to its content: "Data for XXX was provided by the Ministry of the Environment, Monitoring Sites 1000 Project".

4) Notification. Data users will notify the Data Set Contact when any derivative work or publication based on or derived from the Data Set is distributed. The data users will provide the Data Set Contact with two reprints or a PDF file of any publications resulting from use of the data set.

5) Collaboration. Data users are strongly encouraged to consider consultation, collaboration and/or co-authorship with the data owners.

6) Disclaimer. In no event shall the authors, data owners, or the Ministry of the Environment, Japan be liable to for loss of profits, or for any indirect, incidental or consequential damages arising from the use or interpretation of the data.

B. Contact:

Data Set Contact

Network Center of the Forest and Grassland Survey of the Monitoring Sites 1000 Project,

c/o Tomakomai Experimental Forest, Hokkaido University, Takaoka, Tomakomai, Hokkaido 053-0035, Japan

Telephone: +81-144-33-2171

Email: moni1000f_networkcenter@fsc.hokudai.ac.jp

Contact for details of each site

For details of each site, contact the data contact (3. A).

C. Storage location:

The Biodiversity Center of Japan, Ministry of the Environment and the data owners store the original data (in Japanese).

11. Data Structure

A. Data tables:

Data file name	Description
SiteList.csv	Site-wise information table. Sites are listed by latitude from north to south.
LitterfallData-2004-2009.csv	Data of litter falls in 21 sites

B. Format type:

The data files are in ASCII text, comma delimited (csv).

C. Header information:

Headers corresponding to variable names (see 11.D.) are included as the first row in the data files.

D. Variable definitions:

The variables are listed in the order they appear in each data file. Variable names are headers included as the first row in the data files. "NA" is the code for errors and missing values for all variables.

Data file name	Variable name	Variable definition
SiteList.csv	Code	Plot code. The third and fourth digits are unique to each site and the fifth and sixth digits are plot numbers.
	PlotID	Alphanumeric plot code
	SiteName	Site name
	Type	Alphabetical code for forest type: BC = Broadleaf conifer mixed forest DB = Deciduous broadleaf forest EB = Evergreen broadleaf forest EC = Evergreen coniferous forest
	Status	Forest age classifications (See 8.A and Appendix.pdf) S: Secondary OS: Old secondary OG: Old growth
	Latitude and Longitude	WGS84 latitudinal and longitudinal coordinates in decimal degrees (°) to 2 decimal places.
	Altitude	Elevation above mean sea level (m). The precision is 5 m.
	Area	Plot area (ha). The precision is 0.01 ha.
	Shape	Shape of plot
	Census	Census year
	Winter	Alphabetic code for the ways of litter collection in winter T: Collected monthly throughout year. O: Traps were laid on the ground over winter and litter falls were collected in the next spring. N: Not installed in winter.
	Temp30yr	Mean of mean annual temperature during 1971 to 2000 (°C). The precision is 0.1 °C.
	Rain30yr	Mean of annual precipitation during 1971 to 2000 (mm). The precision is 0.1 mm.
	Snow30yr	Mean of annual maximum snow depth during 1971 to 2000 (m). The precision is 1 cm.
LitterfallData-2004-2009-ver1.csv	plot	Alphanumeric plot code (see PlotID in SiteList.csv)
	trap_id	Trap identification code. Usually an integer between 1 and 25, but there are some exceptions (see Appendix.pdf)
	trap_area	Collection area of the trap (m²)
	trap_xcord, trap_ycord	X and Y coordinates of the litter trap in the plot (m). The coordinate system is identical to that of tree census data published by Ishihara et al. (2011). The precision is 1 m.
	s_date1, s_date2	The date when the trap was installed and the date when litter fall in the trap was collected in yyyymmdd format; s_date1 = 20090125 indicates that the trap was installed in January 25, 2009.
	wdry_leaf, wdry_branch, wdry_seed, wdry_rep, wdry_other	Dry weights (g) of leaf, branch, seed, reproductive structure and others in the trap. wdry_rep includes weights of seeds, flowers, fruits and so on. wdry_seed is optional. The precision is 0.01 g. NA = missing value or not measured due to any reasons. 0.001 = little sample less than 0.01 g 0 = no sample
	error_leaf, error_branch, error_seed, error_rep, error_other	Numeric code indicating error in each dry weight measurement. 0 = normal value 1 = missing value or anomalous value

12. Supplementary Information

A. Notes in Japanese:

Although a number of notes/comments were recorded in the original data in Japanese, they were removed from the data of this Data Paper. If you need the notes/comments, consult the Network Center (10. B).

B. Related data:

Dataset of this data paper are also available in Japanese from web site of the Biodiversity Center of Japan, Ministry of the Environment, Japan (http://www.biodic.go.jp/moni1000/findings/data/index.html).

Litter falls in some sites have been collected since before the project was launched (see Appendix.pdf). If you are interested in these extra data, consult the Data Set Contact (10.B) or the data owners.

The Forest and Grassland Survey of the Monitoring Sites 1000 Project is also monitoring ground-dwelling beetles by pitfall traps and birds by spot-censuses. If you are interested in these data, consult the Data Set Contact (10. B).

13. Acknowledgements

We thank Shigeru Niwa for valuable comments on the early version of the manuscript. We thank also all individuals who have contributed to obtain the data reported here (see also Appendix.pdf). The data was collected as Monitoring Sites 1000 Project of Ministry of the Environment, Japan. The study was partly supported by the Environmental Research and Technology Development Fund (S-9-3) of the Ministry of the Environment, Japan.

14. Literature Cited

Berg B, Meentemeyer V (2001) Litter fall in some European coniferous forests as dependent on climate: a synthesis. Can J For Res 31: 292-301. DOI 10.1139/cjfr-31-2-292

Bray JR, Gorham E (1964) Litter Production in Forests of the World. Adv Ecol Res, 2: 101-157

Chave J, Navarrete D, Almeida S, Alvarez E, Aragao LEOC, Bonal D, Chatelet P, Silva-Espejo JE, Goret J-Y, Hildebrand P, von Jimenez E, Patino S, Penuela MC, Phillips OL, Stevenson P, Malhi Y (2010) Regional and seasonal patterns of litterfall in tropical south America. Biogeosciences 7: 43-55. DOI 10.5194/bg-7-43-2010

Clark DA, Brown S, Kicklighter DW, Chamber JQ, Thomlinson JR, Ni J. (2001) Measuring net primary production in forests: concepts and field methods. Ecol Appl 11: 356-370.

Eriksson H, Eklundh L, Hall K, Lindroth A. (2005) Estimating LAI in deciduous forest stands. Agr For Meteorol 129: 27-37.

Gosz JR, Likens GE, Bormann FH. (1972) Nutrient content of litter fall on the Hubbard Brook experimental forest, New Hampshire. Ecology 53: 769-784.

Gower ST., Vogt KA., Grier CC. (1992) Carbon dynamics of Rocky Mountain douglas-fir: Influence of water and nutrient availability. Ecol Monogr 62: 43-65.

Ishihara M, Toyota A, Nakamura M (2007) Monitoring Sites 1000 (Forest Survey) (in Japanese). J. Jpn J Ecol 57:438-442

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