Teak forest in southern Myanmar. Credit: FAN Zexin

Teak (Tectona grandis) is a tropical, deciduous, broad-leaved tree species indigenous to Southeast Asia. Despite its high dendroclimatological potential, only a few studies have analyzed the relationships between teak ring-width and climate variability in Myanmar.

In a study published in Geophysical Research Letters, researchers from Xishuangbanna Tropical Botanical Garden (XTBG) extended the spatial coverage of high-resolution regional climate proxies in southern Myanmar by producing a new drought reconstruction from a new location.

The researchers developed a 226-year long ring-width chronology of teak, providing evidence for November–April drought variability in southern Myanmar. The three teak-bearing forest sites were namely Bago (West Yoma Forest Reserve, BAG), Mindon (Zaungtu Forest Reserve, MDN), and Paukkhaung (Phyu-Kun Forest Reserve, PKG) in southern Myanmar.

They found that teak radial growth was mainly controlled by moisture availability, making teak a suitable species for assessing drought variation in southern Myanmar.

They reconstructed the November-April drought history of southern Myanmar for the past 215 years based on a well-replicated regional teak ring-width chronology. They found prolonged droughts occurred in 1808–1823, 1837–1843, 1863–1876, 1883–1891, 1895–1901, 1908–1912, 1922–1930, 1941–1945, 1952–1963, 1976–1994, and 2010–2015.

They also found a strong association between variability in southern Myanmar and in the Pacific and Indian Oceans, as well as the El Nino‐Southern Oscillation (ENSO) phenomenon.

"Our study confirmed the huge potential to study long-term climate change and its impacts in the tropical regions of Southeast Asia by establishing and extending climate-sensitive tree ring networks," said Prof. Fan Zexin, principal investigator of the study.

"It provides a newly developed regional teak tree ring-width chronology for a better understanding of regional hydro- in Myanmar," added Dr. Fan.

More information: Zaw Zaw et al. Drought reconstruction over the past two centuries in southern Myanmar using teak tree‐rings: linkages to the Pacific and Indian Oceans, Geophysical Research Letters (2020). DOI: 10.1029/2020GL087627

Journal information: Geophysical Research Letters