Relationship between growth rates and xylem hydraulic characteristics in young, mature and old‐growth ponderosa pine trees

Abstract

The first objective of the present study was to quantify the effects of tree age and stem position on specific conductivity ( k s ), vulnerability to embolism and water storage capacity (capacitance) in trunks of young, mature and old-growth ponderosa pine. The second objective was to determine relationships between hydraulic characteristics and radial and height growth rates to increase the understanding of possible tradeoffs. Within sapwood at all heights and in all ages of trees, outer sapwood had 25-60% higher k s than inner sapwood. The water potential at which embolism started (air entry point) was 1.3 MPa lower in inner sapwood than outer sapwood within the mature trees, but there was no difference in the other trees. There was no significant difference in capacitances between the tops of the old growth trees, the mature trees and the young trees. Taking all data together, the capacitances increased sharply with an increase in k s and an increase in vulnerability to embolism. The hydraulic characteristics of the three age classes were correlated with the height growth rate but not with the diameter growth rate. Within these age classes, high k s was associated with the slowest yearly increase in sapwood area and with a low percentage of latewood, whereas high vulnerability to embolism and high capacitance were more closely associated with high height growth rates.

Evaluating the annual nature of juvenile rings in Bolivian tropical rainforest trees

“…However, these differences were not distinct at ringboundary level. Probably, other variables such as vessel distribution, vessel number, vessel area (Heliñska-Raczkowska and Fabisiak 1999; Domec and Gartner 2003;Christensen-Dalsgaard et al 2007) or measures of the axial parenchyma (Climent et al 1998) can provide more information on variation in anatomy between juveniles and adults trees. The 14 C dating proved to be a useful tool to verify the annual nature of the rings of Clarisia and Peltogyne.…”

Tyloses and Phenolic Deposits in Xylem Vessels Impede Water Transport in Low-Lignin Transgenic Poplars: A Study by Cryo-Fluorescence Microscopy

“…The xylem must provide a sufficient and safe water supply throughout the entire pathway from roots to leaves for transpiration and photosynthesis. It is well established that enhanced water conductivity of xylem can increase total plant carbon gain (Domec and Gartner, 2003;Santiago et al, 2004;Brodribb and Holbrook, 2005a). According to the Hagen-Poiseuille equation, xylem conductivity should scale with vessel lumen diameter to the fourth power (Tyree and Zimmermann, 2002).…”

Phenotypic variation of basic wood density in Pinus ponderosa plus trees

“…This is a hypothesis that has to be confirmed due to the significant differences found for wood density among sites. It is possible to interpret that the high density values in the juvenile wood portion found in the more xeric geographic region could be related to different hydraulic properties (Alder et al 1996, Hacke et al 2001, Domec and Gartner 2003, which in turn could be related to different safety margins helping trees to prevent xylem embolism caused by the more adverse climate conditions during the growing season.…”