Effect of high nitrogen loading on growth of cool temperate trees raised under free-air O3 exposure

2016 Fiscal Year Final Research Report

• Project/Area Number: 26292075
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: Hokkaido University
• Principal Investigator: Koike Takayoshi 北海道大学, (連合)農学研究科(研究院), 教授 (10270919)
• Co-Investigator(Kenkyū-buntansha): 佐藤 冬樹 北海道大学, 北方生物圏フィールド科学センター, 教授 (20187230) ; 高木 健太郎 北海道大学, 北方生物圏フィールド科学センター, 准教授 (20322844) ; 渡辺 誠 東京農工大学, (連合)農学研究科(研究院), 准教授 (50612256) ; 渡部 敏裕 北海道大学, (連合)農学研究科(研究院), 准教授 (60360939)
• Co-Investigator(Renkei-kenkyūsha): KITA Kazuhito 北海道総合研究機構, 林業試験場, 主査 (90414250)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 越境大気汚染 / 対流圏オゾン / 窒素沈着 / 冷温帯樹種 / 光合成生産 / 成長 / 開放系施設 / 老化

Outline of Final Research Achievements

With rapid increase of ground-surface ozone (O3) and nitrogen loading (N) in the northeastern part of Asia, some tree species showed declining symptoms, especially around volcano, such as somma of Lake Mashu. Trees are suffering from combination stresses of the two. We examined effects of elevated O3 and N on hybrid larch and related species grown in brown forest soil (BF) and immature volcanic ash soil (VA) with use of a free-air O3 fumigation system of our university. With recent analysis of transboundary particle matter, we should examine (NH4)2SO4 as N source. O3 alone clearly suppressed growth of the trees tested but we did not find any marked decrease of soil pH of around 5.0 with 50kgN/hr・yr. No combination effects were also found. Based on our experiments, we may conclude that N loading accelerates tree growth as acting as N resources to plants to some extent. But we should carefully check an increase of SO4 ion affecting soil pH in future.

Free Research Field

森林生理生態学