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Recent rapid increases in ambient CO2 are largely attributed to deforestation in tropics. However, the carbon emissions from terrestrial ecosystem are mostly based on the area-wise statistics of “forest land” which is defined as an area with minimum crown coverage >10%, while extensive biomass (more than 50%) has been removed through “forest degradation” processes resulted from the over-harvesting in legitimated logging regime or illegal logging. Therefore, if the carbon losses accompanied by the forest degradation had been added on the forest statistics, actual carbon losses and emissions could have been larger than those were reported. Therefore, recovery process accompanied after forest degradation needs to be thoroughly monitored and reviewed in order to evaluate long term NET carbon losses.<br>  
 
Recent rapid increases in ambient CO2 are largely attributed to deforestation in tropics. However, the carbon emissions from terrestrial ecosystem are mostly based on the area-wise statistics of “forest land” which is defined as an area with minimum crown coverage >10%, while extensive biomass (more than 50%) has been removed through “forest degradation” processes resulted from the over-harvesting in legitimated logging regime or illegal logging. Therefore, if the carbon losses accompanied by the forest degradation had been added on the forest statistics, actual carbon losses and emissions could have been larger than those were reported. Therefore, recovery process accompanied after forest degradation needs to be thoroughly monitored and reviewed in order to evaluate long term NET carbon losses.<br>  
 
In these respects and backgrounds, we studied biomass and canopy structural changes in a lowland tropical rain forest in the Pasoh Forest Reserve (PFR) of Peninsular Malaysia after selective logging in 1950s, and found that total aboveground biomass (AGB) has not fully recovered yet to the level observed in a primary forest plot within PFR. On this site, we also conducted canopy height mapping using an airborne light detection (LiDAR) in 2003 and 2011, and found that the average canopy height in the logged forest was still lower than that in the primary forest. The coefficient of variation of canopy height was also lower in the logged forest plot, suggesting that the highly heterogeneous features in canopy surface height commonly seen in the pristine old growth forest, known as typical features tropical rain forest, has not fully recovered yet. These studies suggest delay of recovery process, not only in AGB but in forest structures will possibly result in underestimate of the carbon emission from forest sectors, and “forest degradation” needs to be thoroughly studied and should be incorporated properly into the climate mitigation measures.
 
In these respects and backgrounds, we studied biomass and canopy structural changes in a lowland tropical rain forest in the Pasoh Forest Reserve (PFR) of Peninsular Malaysia after selective logging in 1950s, and found that total aboveground biomass (AGB) has not fully recovered yet to the level observed in a primary forest plot within PFR. On this site, we also conducted canopy height mapping using an airborne light detection (LiDAR) in 2003 and 2011, and found that the average canopy height in the logged forest was still lower than that in the primary forest. The coefficient of variation of canopy height was also lower in the logged forest plot, suggesting that the highly heterogeneous features in canopy surface height commonly seen in the pristine old growth forest, known as typical features tropical rain forest, has not fully recovered yet. These studies suggest delay of recovery process, not only in AGB but in forest structures will possibly result in underestimate of the carbon emission from forest sectors, and “forest degradation” needs to be thoroughly studied and should be incorporated properly into the climate mitigation measures.
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*<正義>の生物学―生物多様性を保全する理由―
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山田俊弘<br>
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広島大学大学院統合生命科学研究科<br>
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演者は、2007年から広島大学で担当してきた講義、「保全生物学」の中で、多くの生き物が絶滅しかけている。私たちは彼らを絶滅から守るべきだろうか?それとも特別なことをする必要などないのだろうか? どちらかを理由とともに選べ。という問いを学生に投げかけ、学生とともにその答えを模索してきた。そして、探し当てた問いへの(ひとつの)解答を2020年、『<正義>の生物学 トキやパンダを絶滅から守るべきか』にまとめ、上梓した。<br>
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演者がたどり着いた答えは、生物多様性の保全は必要であり、その理由は、(1)生き物の恵み(特に供給サービス)を得るため、(2)生き物の恵み(特に基盤サービス)を得るため、(3)それが正しい行いだから、という3つだった。<br>
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『<正義>の生物学』では、これら3つについて解説したが、3つの理由のそれぞれがとても大きなテーマなため、本シンポジウムですべてを紹介することができない。そこで本シンポジウムでは、3つ目の理由である、「それが正しい行いだから」に注目し、この考えを紹介したい。<br>
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生物多様性の保全が正しい行いだと考える立場は、命の重さを尊重する。ここでいう命にはヒトのものだけでなく、すべての種のものが含まれる。ヒトの命は当たり前に大切なものである。対してヒト以外の命は、ヒトの 命ほどの重みはないと考えられがちである。本発表ではまず、ヒトとそれ以外の種の命の重みに差があるかどうかを考えてみたい。そして、その考察の上、これからのヒトがもつべく思考態度について議論したい。
  
 
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2020年12月14日 (月) 21:48時点における版

ヒコビアミニレター No. 519(2020年12月10日)

 2020年12月5日(土)の第642回植物観察会は,2020年度第24回ヒコビアセミナ-を兼ねて,勉強会として「Zoomミーティング」を用いたオンライン形式で行われた.参加者は34名.天気ははれ.13時開場,13時30分からヒコビア会の山口会長の挨拶の後,セミナ-を開始した.発表は5題あり,前半は「Taxonomic revision of genus Marchantia L. in Japan.」(鄭 天雄),「Effects of logging and land use changes on the lowland tropical rain forest in Malaysia」(奥田敏統),「著書『〈正義〉の生物学 トキやパンダを絶滅から守るべきか』について」(山田俊弘)について発表があった.10分間の休憩をはさんで,「堀川式三面分布図の現代版を支えるデータベース」(垰田 宏),「宮島自然植物実験所に保管されている貴重な維管束植物標本」・「ヤッコソウを訪ねて」(いずれも,関 太郎)について発表があった.セミナ-としては16時50分ころ終了したが,その後オンライン上で歓談した.

(H. Tsubota, S. Uchida & Y. Inoue 記)

要旨

  • Taxonomic revision of genus Marchantia L. in Japan

Tian-Xiong Zheng
Laboratory of Plant Taxonomy and Ecology Hiroshima University

  • Effects of logging on the lowland tropical rain forest in Peninsular Malaysia

Toshinori Okuda (Graduate School of Integrated Sciences for Life, Hiroshima University), co-authored with; Toshiro Yamada, Tetsuro Hosaka, Masahiro Miyasaku, Mazlan Hashim, Alvin Lau Meng Shin, Saw Leng Guan, Ken Shima, Toshihiro Yamada, Kaoru Niiyama, Yoshiko Kosugi, Tsuyoshi Yoneda, Eng Seng Quah
Recent rapid increases in ambient CO2 are largely attributed to deforestation in tropics. However, the carbon emissions from terrestrial ecosystem are mostly based on the area-wise statistics of “forest land” which is defined as an area with minimum crown coverage >10%, while extensive biomass (more than 50%) has been removed through “forest degradation” processes resulted from the over-harvesting in legitimated logging regime or illegal logging. Therefore, if the carbon losses accompanied by the forest degradation had been added on the forest statistics, actual carbon losses and emissions could have been larger than those were reported. Therefore, recovery process accompanied after forest degradation needs to be thoroughly monitored and reviewed in order to evaluate long term NET carbon losses.
In these respects and backgrounds, we studied biomass and canopy structural changes in a lowland tropical rain forest in the Pasoh Forest Reserve (PFR) of Peninsular Malaysia after selective logging in 1950s, and found that total aboveground biomass (AGB) has not fully recovered yet to the level observed in a primary forest plot within PFR. On this site, we also conducted canopy height mapping using an airborne light detection (LiDAR) in 2003 and 2011, and found that the average canopy height in the logged forest was still lower than that in the primary forest. The coefficient of variation of canopy height was also lower in the logged forest plot, suggesting that the highly heterogeneous features in canopy surface height commonly seen in the pristine old growth forest, known as typical features tropical rain forest, has not fully recovered yet. These studies suggest delay of recovery process, not only in AGB but in forest structures will possibly result in underestimate of the carbon emission from forest sectors, and “forest degradation” needs to be thoroughly studied and should be incorporated properly into the climate mitigation measures.

  • <正義>の生物学―生物多様性を保全する理由―

山田俊弘
広島大学大学院統合生命科学研究科
演者は、2007年から広島大学で担当してきた講義、「保全生物学」の中で、多くの生き物が絶滅しかけている。私たちは彼らを絶滅から守るべきだろうか?それとも特別なことをする必要などないのだろうか? どちらかを理由とともに選べ。という問いを学生に投げかけ、学生とともにその答えを模索してきた。そして、探し当てた問いへの(ひとつの)解答を2020年、『<正義>の生物学 トキやパンダを絶滅から守るべきか』にまとめ、上梓した。
演者がたどり着いた答えは、生物多様性の保全は必要であり、その理由は、(1)生き物の恵み(特に供給サービス)を得るため、(2)生き物の恵み(特に基盤サービス)を得るため、(3)それが正しい行いだから、という3つだった。
『<正義>の生物学』では、これら3つについて解説したが、3つの理由のそれぞれがとても大きなテーマなため、本シンポジウムですべてを紹介することができない。そこで本シンポジウムでは、3つ目の理由である、「それが正しい行いだから」に注目し、この考えを紹介したい。
生物多様性の保全が正しい行いだと考える立場は、命の重さを尊重する。ここでいう命にはヒトのものだけでなく、すべての種のものが含まれる。ヒトの命は当たり前に大切なものである。対してヒト以外の命は、ヒトの 命ほどの重みはないと考えられがちである。本発表ではまず、ヒトとそれ以外の種の命の重みに差があるかどうかを考えてみたい。そして、その考察の上、これからのヒトがもつべく思考態度について議論したい。

参考

山田俊弘(Zoomのチャットより)


デジタル自然史博物館 / 広島大学 / 宮島自然植物実験所 / 植物観察会のトップ / 過去のヒコビアミニレター / 古いNews | 植物 にもどる