Are the long-term flowering patterns of Fraxinus platypoda synchronized between males and females?

2016 Fiscal Year Final Research Report

• Project/Area Number: 25450209
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: Forest science
• Research Institution: Niigata University
• Principal Investigator: Sakio Hitoshi 新潟大学, 自然科学系, 教授 (20449325)
• Project Period (FY): 2013-04-01 – 2017-03-31
• Keywords: シオジ / 雌雄異株 / 開花 / 結実 / 種子生産 / 豊凶 / 温暖化 / 気候変動

Outline of Final Research Achievements

I examined whether the flowering of Fraxinus platypoda a dioecious tree, is synchronized between male and female trees, and whether this flowering and seed production patterns are changed for about 30 years. I found clear annual fluctuations in flowering in three populations over the 30 years. Mast and lean years occurred synchronously at 3 years interval in three populations until 1998. During this period, synchronous flowering clearly occurred between females and males in each population. Flowering patterns in three populations changed after 1999, with male trees undergoing stably much flowering, females displaying a shorter flowering cycle, and less synchrony between sexes. No flowering occurred in male trees in three populations after 1998 and flowering degree of female increased. As the tree age is different among three populations, the cause of these changes after 1998 may not result from maturity in life history, but climate change such as increase of temperature.

Free Research Field

森林生態学