著者

Bibian Diway Ling Chea Yiing Mohd Effendi Wasli Yayoi Takeuchi

出版者

JAPAN SOCIETY OF TROPICAL ECOLOGY

雑誌

Tropics (ISSN:0917415X)

巻号頁・発行日

vol.32, no.1, pp.1-14, 2023-06-01 (Released:2023-06-01)

参考文献数

54

被引用文献数

1

---

In Sarawak, Malaysia, logging is conducted with a 25-year harvesting cycle; however, it remains largely unclear if this cycle length is sufficient for forest recovery. This study aims to investigate how the structure of logged forests recovered along the periods after logging. We conducted this study in the Anap-Muput Forest Management Unit (AMFMU), Sarawak. We first established permanent sample plots with different logging history; that is, from 5 years to more than 37 years after the most recent logging. Using the various sample plots, we assessed the stem density, basal area (BA), proportion of dipterocarps, growth and mortality. To compare the forest structure of the logged over forests with that of primary forests, we used our previous data of a primary forest in Batang Ai National Park. We found significant differences in the stem density, total BA, and the proportion of dipterocarp among the plots. Generally, the stem density and total BA increased with the period after logging and decreased with diameter at breast height (DBH) size classes, except of tree of ≥60 cm DBH in several plots. The growth rates and mortalities were higher in more recent logged forests. These results indicated that logged forest was recovering with periods after logging partly because of higher growth rate; however, even in a forest of 37 years after logging, the forest structure was not fully recovered compared to the primary forest. Thus, we concluded that a 25-year harvesting cycle in the selective logging system would not be sufficient for the AMFMU forest to recover. We further need other effective strategies with systematic monitoring.

著者

Bibian Diway Yasuo Yasui Hideki Innan Yayoi Takeuchi

出版者

JAPAN SOCIETY OF TROPICAL ECOLOGY

雑誌

Tropics (ISSN:0917415X)

巻号頁・発行日

vol.30, no.4, pp.71-82, 2022-03-01 (Released:2022-03-01)

参考文献数

37

---

A new Rafflesia population was found in Naha Jaley, Sarawak, in 2012. This study aimed to identify this Rafflesia species and investigate its bud growth. First, we described the flower characteristics and compared them with Rafflesia keithii and R. tuan-mudae, which are candidate species for the flower. Also, we investigated the phylogenetic position of this Rafflesia within Rafflesiaceae using DNA analysis. To estimate bud growth curve, we observed bud development from April 2013 to November 2013 in the field. Based on morphological comparisons and phylogenetic analysis, we confirmed the newly discovered population of the Rafflesia at Naha Jaley was R. tuan-mudae, which is the new locality of the species at the most Eastern side of the known distribution for this species. The results indicated that absolute growth rate was greater in larger buds. We also estimated that it took a year to bloom from the initial bud stage. The mortality in one of our sites was very high, with more than 80 % of buds dead prior to flower opening. This flower would be vulnerable to extinction due to their extraordinary characteristics and anthropogenetic effects. Finally, we discussed how Rafflesia populations in Naha Jaley can be conserved both in-situ and ex-situ.