Oil Palm and Rubber Tree Water Use Patterns: Effects of Topography and Flooding

Abstract

Oil palm and rubber plantations extend over large areas and encompass heterogeneous site conditions. In periods of high rainfall, plants in valleys and at riparian sites are more prone to flooding than plants at elevated topographic positions. We asked to what extent topographic position and flooding affect oil palm and rubber tree water use patterns and thereby influence spatial and temporal heterogeneity of transpiration. In an undulating terrain in the lowlands of Jambi, Indonesia, plantations of the two species were studied in plot pairs consisting of upland and adjacent valley plots. All upland plots were non-flooded, whereas the corresponding valley plots included non-flooded, long-term flooded, and short-term flooded conditions. Within each plot pair, sap flux densities in palms or trees were monitored simultaneously with thermal dissipation probes. In plot pairs with non-flooded valleys, sap flux densities of oil palms were only slightly different between the topographic positions, whereas sap flux densities of rubber trees were higher in the valley than at the according upland site. In pairs with long-term flooded valleys, sap flux densities in valleys were lower than at upland plots for both species, but the reduction was far less pronounced in oil palms than in rubber trees (-22 and -45% in maximum sap flux density, respectively). At these long-term flooded valley plots palm and tree water use also responded less sensitively to fluctuations in micrometeorological variables than at upland plots. In short-term flooded valley plots, sap flux densities of oil palm were hardly affected by flooding, but sap flux densities of rubber trees were reduced considerably. Topographic position and flooding thus affected water use patterns in both oil palms and rubber trees, but the changes in rubber trees were much more pronounced: compared to non-flooded upland sites, the different flooding conditions at valley sites amplified the observed heterogeneity of plot mean water use by a factor of 2.4 in oil palm and by a factor of 4.2 in rubber plantations. Such strong differences between species as well as the pronounced heterogeneity of water use across space and time may be of relevance for eco-hydrological assessments of tropical plantation landscapes.

Ecohydrological changes after tropical forest conversion to oil palm

“…Existing studies (e.g. Luskin and Potts 2011, Hardwick et al 2015, Röll et al 2015, Merten et al 2016, Hardanto et al 2017, Sabajo et al 2017 focused on limited observations from sites with different ages where topography, edaphic conditions, and microclimate heterogeneites potentially act as confounding effects, and the dynamic behaviour of a forest-OP plantation chronosequence is still poorly understood (Dislich et al 2017). Modeling efforts to simulate OP behaviour and development also exist but they are mostly focused on agronomic variables (e.g.…”

Minimum forest cover required for sustainable water flow regulation of a watershed: a case study in Jambi Province, Indonesia

“…Similarly, rubber plantations have environmental impacts such as reducing the soil infiltration capacity, accelerating soil erosion, increasing stream sediment loads (Ziegler et al, 2009;Tarigan et al, 2016b), and decreasing soil carbon stocks (Ziegler et al, 2011). Furthermore, the conversion of tropical rainforest into oil palm and rubber plantations affects the local hydrological cycle by increasing transpiration (Ziegler et al, 2009;Sterling et al, 2012;Röll et al, 2015;Hardanto et al, 2017), increasing evapotranspiration (ET) , decreasing infiltration (Banabas et al, 2008;Tarigan et al, 2016b), increasing the flooding frequency (Tarigan, 2016a), and decreasing low flow levels (Yusop et al, 2007;Adnan and Atkinson, 2011;Comte et al, 2012;Merten et al, 2016). These climatic impacts that occur due to land use change are expected to be stronger under maritime conditions, such as those in Indonesia, than under continental conditions because 40 % of the global tropical latent heating of the upper troposphere occurs over the maritime continent (Van der Molen et al, 2006).…”

Rubber tree transpiration in the lowlands of Sumatra

“…In contrast to such natural regeneration stands, rubber plantations are commonly established with relatively low stand densities at fixed distances. Aside from age and related stand structural characteristics, further factors contributing to diverging water use rates from similar ecosystems or plantation crops have been related to differences in management (e.g., Forrester, Collopy, Beadle, Warren, & Baker, 2012;Hubbard, Stape, Ryan, Almeida, & Rojas, 2010) and different site conditions including soil characteristics (e.g., Hacke et al, 2000;Sperry & Hacke, 2002), topographic position (e.g., Hardanto et al, 2017), or, at a larger scale, geographic position and related climatic conditions (e.g., Calder, 1998;Yu et al, 2008). Tree diameter as a variable strongly correlated with age has been shown to be closely related to transpiration in a variety of studies (e.g., Cienciala, Kučera, & Malmer, 2000;Meinzer, Goldstein, & Andrade, 2001).…”

“…Tree diameter as a variable strongly correlated with age has been shown to be closely related to transpiration in a variety of studies (e.g., Cienciala, Kučera, & Malmer, 2000;Meinzer, Goldstein, & Andrade, 2001). Aside from age and related stand structural characteristics, further factors contributing to diverging water use rates from similar ecosystems or plantation crops have been related to differences in management (e.g., Forrester, Collopy, Beadle, Warren, & Baker, 2012;Hubbard, Stape, Ryan, Almeida, & Rojas, 2010) and different site conditions including soil characteristics (e.g., Hacke et al, 2000;Sperry & Hacke, 2002), topographic position (e.g., Hardanto et al, 2017), or, at a larger scale, geographic position and related climatic conditions (e.g., Calder, 1998;Yu et al, 2008).…”