Abstract Detail

Tropical Biology

Nagahama, Ai [1], Tagane, Shuichiro [2], Ngoc, Nguyen Van [3], Binh, Hoang Thi [3], Suyama, Yoshihisa [4], Yahara, Tetsukazu [5].

Phenology of tropical montane forests in southern Vietnam: leafing is associated with precipitation but flowering is not.

Phenology of tropical montane forests has been less well studied than tropical lowland forests. To bridge this gap, five plots were installed at the elevation range from 1460 m to 1920 m in Bidoup-Nui Ba National Park in southern Vietnam, where monthly average temperature fluctuated from 16.7 ºC in January to 20.3 ºC in May, and monthly precipitation fluctuated from 10 mm in January to 281 mm in September. In this area, the rainy season is from April to November, and the dry season is from December to March. We recorded leafing, flowering, and fruiting events of 20 dominant tree species in each plot (five individuals per species; in total 94 species consisted of four deciduous and 90 evergreen trees) for seven times; in June, September, and December 2018, and April, July, and October 2019, and January 2020. As a result, 98.9 %, 73.7 %, and 63.2% species we monitored showed leafing, flowering, and fruiting, respectively. The number of leafing species varied from 4 spp. in September to 92 spp. in April. On the other hand, the number of flowering species varied from 15 spp. in September to 32 spp. in December. The number of fruiting species varied from 5 spp. in January to 29 spp. in July. Deciduous species [Acer erythranthum and A. flabellatum (Sapindaceae), Engelhardtia serrata (Juglandraceae), Meliosma pinnata (Sabiaceae)] developed new leaves from dry-season (January) to the beginning of wet-season (April), bloomed in dry-season (January) or wet-season (July), and developed fruits at low frequency. In contrast, evergreen species [mainly Fagaceae (11 spp.) and Lauraceae (10 spp.), with the other 73 species in 31 families] developed new leaves through the year except September, bloomed in early wet-season (April–July) or from late wet-season to the beginning of dry-season (September–December), and 12 spp. developed fruits at high frequency but the others did not. In conclusion, leafing is associated with the increase of precipitation in deciduous species, but flowering is not associated with the increase of precipitation, while both leafing and flowering were not associated with the increase of precipitation in evergreen species. We recorded flowering only for 73.7 % of species, implying that supra-annual flowering might be common for dominant tree species in tropical montane forests in Vietnam.

1 - Kyushu University, Graduate school of systems life science, 744, Motooka, Fukuoka, 819-0373, Japan
2 - Kagoshima University, The Kagoshima University Museum, 1-21-30 Korimoto, Kagoshima, Japan
3 - Dalat University, 01 Phu Dong Thien Vuong, Dalat, Vietnam
4 - Tohoku University, Kawatabi Field Center, 232-3 Yomogida, Naruko-onsen, Osaki, Japan
5 - Kyushu Open University, 744 Motooka, Fukuoka, Japan

Keywords:
leafing phenology
flowering phenology
fruiting phenology
tropical montane forest
precipitation
temperature.

Presentation Type: Poster
Session: P, Tropical Biology Posters
Location: Virtual/Virtual
Date: Thursday, July 30th, 2020
Time: 5:00 PM Time and date to be determined
Number: PTB003
Abstract ID:522
Candidate for Awards:None