Water Use Patterns of Four Tropical Bamboo Species Assessed with Sap Flux Measurements

Abstract

Bamboos are grasses (Poaceae) that are widespread in tropical and subtropical regions. We aimed at exploring water use patterns of four tropical bamboo species (Bambusa vulgaris, Dendrocalamus asper, Gigantochloa atroviolacea, and G. apus) with sap flux measurement techniques. Our approach included three experimental steps: (1) a pot experiment with a comparison of thermal dissipation probes (TDPs), the stem heat balance (SHB) method and gravimetric readings using potted B. vulgaris culms, (2) an in situ calibration of TDPs with the SHB method for the four bamboo species, and (3) field monitoring of sap flux of the four bamboo species along with three tropical tree species (Gmelina arborea, Shorea leprosula, and Hevea brasiliensis) during a dry and a wet period. In the pot experiment, it was confirmed that the SHB method is well suited for bamboos but that TDPs need to be calibrated. In situ, species-specific parameters for such calibration formulas were derived. During field monitoring we found that some bamboo species reached high maximum sap flux densities. Across bamboo species, maximal sap flux density increased with decreasing culm diameter. In the diurnal course, sap flux densities in bamboos peaked much earlier than radiation and vapor pressure deficit (VPD), and also much earlier than sap flux densities in trees. There was a pronounced hysteresis between sap flux density and VPD in bamboos, which was less pronounced in trees. Three of the four bamboo species showed reduced sap flux densities at high VPD values during the dry period, which was associated with a decrease in soil moisture content. Possible roles of internal water storage, root pressure and stomatal sensitivity are discussed.

Drone‐based photogrammetry‐derived crown metrics for predicting tree and oil palm water use

“…In most studies, the number of plants directly analysed for water use is lower than the number of plants in the stand. In addition, recently increasingly monocot species such as bamboos and palms came into the focus of transpiration studies (Mei et al, 2016;Röll et al, 2015), in which intraspecific diameter variation may be low but nonetheless variation in water use occurs. Scaling is thus a critical issue that needs to be optimized in order to improve transpiration estimates and to reduce associated uncertainties (Hatton & Wu, 1995;Jarvis, 1995 Candidate variables for scaling include tree diameter, crown metrics, and leaf area.…”

“…Stem diameter has some limitations that include a potentially slow response to concurrent dynamics in the stand such as crown damages or crown expansions into gaps. In addition, recently increasingly monocot species such as bamboos and palms came into the focus of transpiration studies (Mei et al, 2016;Röll et al, 2015), in which intraspecific diameter variation may be low but nonetheless variation in water use occurs.…”

Environmental Controls of Diurnal and Seasonal Variations in the Stem Radius of Platycladus orientalis in Northern China

“…With increases in VPD, trees undergo severe water stress and stomatal conductance decreases to prevent excessive water loss, thereby leading to weakening of transpiration and MDS decreases. This process has been observed in some study systems [44,46] but not in many others [24,47,48] that instead observed linear and positive increases of MDS with VPD. These differences primarily depend on the level of plant water stress that is experienced [49], wherein the positive relationships between MDS and VPD were almost always observed under non-limiting soil water availability.…”

Características De Los Culmos De Guadua De Acuerdo Al Sitio Y Su Estado De Madurez

“…Esta condición podría por lo tanto ser reflejada en menor contenido de humedad en los culmos de este sitio. La relación entre la disponibilidad de agua en el suelo y su efecto en los árboles ha sido descrita por Borchert (1994) y, de acuerdo con Mei et al (2015), quienes evaluaron los patrones de uso de agua en cuatro especies de bambú, estas plantas resultan más susceptibles que los árboles a los cambios de humedad en el suelo. Aquí también se encontró una relación entre menores diámetros y mayor flujo de savia a través de los mismos, lo que implica seguramente más haces vasculares para el transporte de la misma.…”