Estimation of Carbon Storage and Its Change in the Tokyo University Forest in Chiba : Comparison between 1995 and 1909

東京大学農学部附属千葉演習林を対象として森林簿およびGISによって1995年と1909年の炭素蓄積量を推定し，時期の違いおよび手法の違いによる炭素蓄積量の比較を行った。結果は表に加え，GISによる炭素蓄積地図として示した。その解析には林木材積に樹種固有の炭素密度を乗じて炭素蓄積量（ton）を求める「積み上げ法」を用い，天然生林樹種構成は現地調査と文献から推定した。千葉演習林全体の炭素蓄積量は1909年から1995までの間に約3.8～3.1倍増加した。また，1995年の千葉演習林における人天別炭素蓄積量を比べると，単位面積当たり平均炭素蓄積量で約1.5倍人工林の方が大きかった。千葉演習林における単位面積当たり炭素蓄積量と森林クラスとの相関を見ると，炭素蓄積量100～200（ton/ha）は人工林の70～90年生，200～300（ton/ha）は森林クラスにかかわらず100年生以上の林分が多かった。Forests have recently been highlighted for their long-term carbon absorbing function with the expectation that they can moderate global warming. This study aims to estimate the amount of carbon storage at two different times in the University Forest in Chiba where management plans have been kept since 1905. The amount of carbon in the years 1909 and 1995 were estimated, mainly with calculations based on the inventory database. Though carbon density differs by species, there was no precise species composition information in inventory database for either year. So temporal field measurement plots were established to estimate the species composition of the present natural forests. In addition to the estimated results, GIS maps were made from forest type maps for comparing the two times. As a result firstly, the total amount of carbon storage in the University Forest in Chiba in 1995 is estimated to be about 3.1 to 3.8 times larger than that in 1909. Secondly, plantation forest is superior to natural forest in terms of carbon absorption. Plantation forest absorbs about 1.5 times more carbon per hectare. Therefore, this study revealed that the afforestation activities since the establishment of the University Forest in Chiba is effective from the viewpoint of carbon storage. In the near future, it will also be necessary to develop a method to estimate carbon in the soil, which will lead to an estimate of the total amount of carbon storage in the forest