Oil palm is an important crop for global vegetable oil production, and is widely grown in the humid tropical regions of Southeast Asia. Projected future climate change may well threaten palm oil production. However, oil palm plantations currently produce large amounts of unutilised biological waste. Oil palm stems – which comprise two-thirds of the waste - are especially relevant because they can contain high levels of non-structural carbohydrates (NSC) that can serve as feedstock for biorefineries. NSC in the stem are also considered a potent buffer to source-sink imbalances. In the present study, we monitored stem NSC levels and female reproductive growth. We then applied convergent cross mapping (CCM) to assess the causal relationship between the time-series. Mutual causal relationships between female reproductive growth and stem NSC were detected, with the exception of a relationship between female reproductive organ growth and starch levels. NSC levels were also influence by long-term cumulative temperature, with the relationship showing a seven-month time lag. The dynamic between NSC levels and long-term cumulative rainfall showed a shorter time lag. The lower temperatures and higher cumulative rainfall observed from October to December identify this as a period with maximum stem NSC stocks.

Time series data of female reproductive growth, non-structural carbohydrates (soluble sugar and starch) in oil palm stem, cumulative temperature and cumulative rainfall were collected between October 23rd 2012 and March 31st 2016. Causal relationships between the time series data were analyzed by emperical dynamic modeling.

Eight studied oil palm trees were grouped into two artificial treatments, namely, four trees under non-artificial treatment (NAT) and the other four trees under pruned fruits treatments (PFT). The average of soluble sugar content collected from three point of single oil palm stem (upper, middle and lower points in height) was scored with column names, like, NAT_sugar1 to NAT_sugar4 (1st to 4th trees in NAT) and PFT_sugar1 to PFT_sugar4 (1st to 4th trees in PFT). The average of starch content collected from three point of single oil palm stem (upper, middle and lower points in height) was also scored with column names, like, NAT_starch1 to NAT_starch4 (1st to 4th trees in NAT) and PFT_starch1 to PFT_starch4 (1st to 4th trees in PFT). On reproductive growth, due to fruits pruning on PFT trees, no time-series data are existed on PFT trees.The column names, NAT_FROV1~4, are volumes of female reproductive organs of 1st to 4th trees of NAT. The column names, NAT_FROG1~4, are growth of female reproductive organs from previous measurement (1 month before) of 1st to 4th trees of NAT. The cumulative rainfall and temperature from 1 to 60 days are recorded as rain1~60 and temp1~60, respectively.