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ForestGEO’s second plot, the Pasoh Forest Reserve in Malaysia, gets its 8th census.

The 8th census at the Pasoh Forest Dynamics Plot in Malaysia is underway! We asked plot technician Musalmah Nasardin a few questions about the census progress and the other ongoing fieldwork at the Pasoh Forest Reserve.

3 individuals smile at the camera while holding clipboards in a forest
Syahzariman, Aidiel and Hazira. One of the census groups at the Pasoh plot.

Every five years, each ForestGEO plot completes a census. This entails measuring every free-standing woody stem that measures ≥1 cm DBH, identifying species, measuring mapping, and tagging every stem that has recruited to the plot since the last census. Repeating the census protocol at all long-term and large-scale ForestGEO sites allows researchers to answer major questions about forest dynamics. 

ForestGEO’s 50-ha plot in the Pasoh Forest Reserve in Malaysia was established in 1986, the second ForestGEO plot.  It has completed seven censuses in 1985, 1990, 1995, 2000, 2005, 2010, 2015, and is currently finishing up its eighth in 2023. The 8th census was slightly delayed due to the constraints of the Covid-19 pandemic. The plot is host to more than 800 tree species and approximately 340,000 individual trees – which over 8 censuses amounts to more than 2.7 million individual measurements.

a woman stands in the forest, surrounded by 3 team members. She is measuring a tree.
Musalmah Nasardin checking the tree tag number during the Pasoh Census.

Musalmah Nasardin, lead technician at Pasoh, has been working on the plot since the sixth census in 2010. She described how the census aims to provide basic information for spatial and temporal study of the dynamics of tropical forest trees. According to Musalmah, the census at Pasoh typically takes about 18 months to complete with 14 people – one project leader, one botanist, and 12 highly-skilled field technicians. The data collected are tree diameter, location, species, and the status of each stem that has reached 1 cm in diameter.

A benefit of taking regular censuses is finding trends and changes in a forest’s makeup over time. We asked Musalmah if there were any trends they were seeing now that varied from the last census. Musalmah and her team estimate that this year’s census will result in higher recruitment rates due to the African Swine Flu epidemic that hit the forest from April to June 2022. This epidemic caused a huge decrease in the wild boar population in the forest. Because the wild boar kill small trees for their nests, the absence of the wild boar has allowed for small trees to recruit and grow in much higher numbers.

a group of people (the census team) stand in front of the edge of the forest, smiling. Many are holding up peace signs or thumbs up.
The 2023 Pasoh census team – from left: Muhammad Syamsul Nizam Yaakub, Muhammad Fariz Zamri, Nur Aidiel Hakimie Mazlizam, Muhamad Syahzariman Muhammad Syahrel, Hazira Md Hazif, Nur Emilia Natasha Zulfakar, Muhamad Khairul Etot, Zulkarnaen Muniran, Stuart Davies, Musalmah Nasardin, Muhammad Zulhelmie Mustapa, Nurul Noor Fatiha Ahmad, Asmiezal a/k Wong Choy and Khuzaifah Ali.

When the plot is not being censused, other research is performed such as mortality surveys (used to gain information about the role tree mortality and dead biomass play in a forest, as well as learning what may cause tree mortality), dendrometer measurements (used to obtain precise estimates of diameter growth), and seed rain monitoring (documents seed production, seedling recruitment, and seedling growth and survival, as well as timing of flowering and seed fall).

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