In the previous study (Komiyama et al. 2005 ; J.Trop.Ecol. 21:471-477), a common allometric equation for predicting the above-ground weight was developed for mangrove tree species based on a biological theory of statical model of plant form. In the present study, I examine whether this equation is applicable to a wide variety of tree species growing in East-Asia, including mangroves. The 387 tree data consisted of over 71 species were collected from tropical to temperate forests located in Indonesia, Thailand, and Japan. A common allometric equation between the above-ground tree weight and trunk diameter held significantly for these trees adding the wood density of trunk as a variable. The relative error between actual and estimated above-ground weight was 19.5% for this equation.In 110-year-old secondary forest, Net primary production (NPP) of aboveground=9.96 ton/ha/year. NPP of underground=0.97 ton/ha/year. Thus, in 110-year-old secondary forest, NPP=10.93 ton/ha/year. On the other hand, net ecosystem production (NEP) is calculated by subtraction of heterotrophic respiration (HR) from NPP. HR assumes half of soil respiration and carbon content also assumes half of tree and/or li

Our aim is to assess the influence of ecosystems on global warming based on the budgets of three greenhouse-effect gases (CO_2,CH_4,N_2O) between the atmosphere and ecosystems. The data of the gas fluxes were obtained from in situ measurements by some chamber methods and survey of previous papers. Here, gas influx to the ecosystem has a positive unit, and gas efflux from the ecosystem a negative unit. Based on global warming potential (GWP,IPCC 1996), the fluxes of CH_4 and N_2O were converted into an equivalent of CO_2. The sum of CO_2 flux and CO_2-equivalent fluxes of CH_4 and N_2O is defined as ecosystem global warming potential (EGWP).1.EGWPs in various types of ecosystemsStudied ecosystems (forest, grassland, wetlands, agroecosystems including croplands, rice paddy fields, orchards) were a sink for CO_2, a sink for CH_4 except wetlands, N2O and a weak source for N_2O. The strongest source of N_2O was croplands which were supplied with chemical fertilizer. The calculated EGWPs were positive in all the ecosystems, and the magnitude differed between ecosystems. Forests showed the highest EGWP, and wetlands the lowest EGWP. In agroecosystems, EGWP assessment revealed that croplan

The Qinghai-Tibetan Plateau is the highest plateau in the world. Covering mainly by alpine grasslands, the plateau plays an important role in the region's carbon budget. The plateau is characterized by high irradiance, low atmospheric pressure, and low temperature. To examine the carbon dynamics of grassland ecosystems on the plateau, we developed a new simulation model, the carbon dynamics model for alpine grasslands (CDMag). CDMag is composed of a gross photosynthesis (Ac) submodel including pbotoinhibition simulation, an ecosystem respiration (ER) submodel that considers both autotrophic and heterotrophic respiration, and an intercellular CO_2 partial pressure and canopy conductance submodel. A photoinhibition simulation is included to describe the gross production of alpine ecosystems in response to the high-irradiance environment A multilayered irradiance transfer scheme is adopted to estimate the irradiance on sunlit and shaded leaves within grassy canopies, and a coupled canopy conductance - net photosynthesis function is integrated into the Ac submodel. CDMag was used to simulate the carbon dynamics of the most extensively distributed alpine grassland, a Kobresia meadow eco

Carbon dynamics and budgets were investigated in different successional stage ecosystems in cool temperate deciduous forest. The experiments were carried out in 0 year-old, 50 year-old and 110 year-old deciduous forest and Miscanthus sinensis grassland in central Japan, between April 2000 and March 2003. Carbon budgets were different among the different successional stage ecosystems. The annual carbon balance (NEP) was estimated to be -172 gCm^<-2> for the 0 year-old forest (just after deforestation), +117 gCm^<-2> for the 50 year-old forest and +16 gCm^<-2> for Miscanthus sinensis grassland, respectively. Moreover, the balance was estimated to be -270〜-320 gCm^<-2> for the upland single-cropping field, -160〜-270 gCm^<-2> for the upland double-cropping field, and only -20 gCm^<-2> for the paddy rice single-cropping field. These results suggest that 0 year-old forest ecosystem and the upland agricultural ecosystems may contribute to the increase in the carbon dioxide concentration of the atmosphere as the carbon accumulated in the soil is constantly being released in the atmosphere. On the other hand, the carbon balance for the grassland ecosystem and the paddy ecosystem were in

Three methods are applied on croplands, forestlands and grasslands in order to evaluate sustainability of production, and developed comprehensive indices for it.【1!○】 Index using carbon dynamics : Carbon budgets were compared under 3 different cropping systems. As the results of calculation of carbon budgets, paddy field is the most sustainable system, then followed double cropping and fee worst was single cropping of upland field. While, carbon storage in a cool-temperate deciduous forest by a precise field sampling method. As the results, it was clarified that 107tC/ha was stored in plants, 334tC/ha in soils. Soil is a large sink of carbon in forest ecosystem.【2!○】 Index using diversity index : Grassland sustainability may be evaluated by diversity of botanical composition and spatial heterogeneity of plant distribution. Grassland team applied beta-binomial distribution on grassland survey in Inner Mongolia steppe. As the results, the process of recovering after fence protection was manifested by beta-binomial index.【3!○】 Modeling and remote sensing approach : Real time monitoring is the most important which makes possible the sustainable grassland management. N

In order to propose an ecological management plan for Kiso rivers, 15 scientists belonging to 8 institutes were enrolled during the term of 1999 to 2001. Several new methods and important technologies had developed in the results of the project.(1) Development of new method to evaluate basin environment(1) New technology was developed to detect movement of land surface using satellite borne microwave SAR data (2) Technology was applied to evaluate environment of tea plantation examining insect fauna as indicator in the field with and without chemicals. (3) Change of landscape structure was analyzed by old maps and aerial photos during these 100 years. (4) Method was proposed to evaluate forest biomass judging from canopy area taken in aerial photos. (5) More precise land use classification became capable applying correction methods of solar angle and DEM on Landsat data, and it permitted to estimate nitrogen absorption in the whole Nagara river basin.(2) Clarification of matter cycling in ecosystems(6) Matter cycling was measured in an artificial needle-leaved forest, and broad-leaved forests cut in different years. (7) Also carbon storage map was created in one ha of a cool-temper

This project included three subprojects locus on carbon cycle of various ecosystems across the Japanese archipelago : (1)Long-term monitoring on carbon dioxide, water vapor and heat fluxes over various types of ecosystems, (2)Understanding the characteristics of matter cycle for various types of ecosystems, and (3)Development of biosphere-atmosphere interaction model The aims of this project were (1) to estimate CO_2, H_2O and heat exchanges between ecosystem and atmosphere, and especially concerning the various forest ecosystems and grassland ecosystems (subproject 1) ; (2) to clarify driven factors on CO_2, H_2O and heat exchanges for the studied ecosystems by the means of plant physiological, ecological and micrometeorological analysis (subproject 2) ; and (3) to integrate results of flux measurements and analysis to mathematic models (subproject 3), and finally to understand interactions within carbon cycle of terrestrial ecosystems and their environmental variables.Use of the limited research fluid to achieve the maximum results, flux measurements were concentrated on the five sites in which the flux tower has been built up in advance, i.e. an evergreen coniferous forest, a de

平成21年度は土壌呼吸に対するリター呼吸の寄与率を明らかにするために、冷温帯放牧草原において以下の実験を行った。陸域生態系は地球規模の炭素循環の中核を担っている。土壌からの土壌CO2フラックスは68～77×1015gC/yrと推定されており、これは植物の推定NPP量(50～60×1015gC/yr)を上回る。したがって、土壌呼吸の量的評価及び発生機構の解明なしに地球規模の炭素循環系を理解することはできない。その中でも草原生態系は陸域生態系においてその面積と炭素貯蓄量の30-40%を占めている主要な生態系の一つでありながら、その土壌呼吸の量的評価についての研究は少なく、とりわけ地上部リター呼吸の土壌呼吸に対する寄与率についての報告は少ない。しかしながら、リターは分解が遅いため地上に多くが蓄積されており、また、地下部と異なって周囲の環境要因の変動を受けやすく、その動態を知ることは重要である。本研究は岐阜県高山市のシバ型放牧草原にて行なった。2007年4月か

平成21年度は管理放棄されたカラマツ林において炭素動態に関する研究を行った。1997年の京都議定書において日本の温室効果ガスの削減目標が決定され、2002年にはマケラシュ合意によりその削減目標内において森林の炭素蓄積増加による吸収量が認められることとなった。日本においては人工カラマツ林の炭素固定能が高いことが認められ、今後炭素吸収林としての役割を含めた人工林の増加が予想される。一方で、日本林業の現状として放棄人工林の面積は増大し人工林の約40%は管理放棄されているとの報告もある。しかし管理放棄された森林の炭素循環に関する情報は不足している。そこで本研究では「管理放棄されたカラマツ林」という一つの生態系に着目し、炭素の動態と収支の解明を行うことを目的とした。調査は岐阜県高山市、樹齢平均約50年の管理放棄されたカラマツ林を対象に2007年から2009年の3年間にわたり行われた。植生はカラマツと林床のクマイザサの2種で構成され