Water use of interior Douglas-fir

Water use of individual Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) trees was measured in two plots at a forest site in southern British Columbia, Canada. Average daily early summer water use by trees with diameters of 7.5-70 cm varied from 1.8 to 166 L. Sap flux density (cm3 water/cm2 sapwood per hour) was linearly related to shoot xylem pressure potential and was found to increase with increasing vapour pressure deficit (VPD) and short-wave irradiance (I), reaching maximum rates with VPD > 0.6 kPa and I > 200 W·m-2. Daily sap flux density varied among trees but was not related to tree diameter, so an average value of 1137.4 L·m-2 sapwood area was used to estimate average early summer stand transpiration for the two plots of 1.08 and 1.5 mm·d-1. A close curvilinear relationship (r2 = 0.85) was found between stem cross-sectional area increment and sapwood area. The relationship was only slightly better (r2 = 0.89) between area increment and early summer individual tree water use. Stand volume growth for 1988-1998 for the two plots was 36-47 m3·ha-1. Stem volume relative growth rate over this 10-year period is estimated at 0.027 and 0.029 m3·m-3·a-1.

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Radial variations in xylem sap flux in a temperate red pine plantation forest

Ecological Processes ◽

10.1186/s13717-021-00295-4 ◽

2021 ◽

Vol 10 (1) ◽

Author(s):

Alanna V. Bodo ◽

M. Altaf Arain

Keyword(s):

Flux Density ◽

Water Use ◽

Sap Flow ◽

Xylem Sap ◽

Red Pine ◽

Sap Flux ◽

Plantation Forest ◽

Sap Flux Density ◽

Flow Measurements ◽

Sapwood Area

Abstract Background Scaling sap flux measurements to whole-tree water use or stand-level transpiration is often done using measurements conducted at a single point in the sapwood of the tree and has the potential to cause significant errors. Previous studies have shown that much of this uncertainty is related to (i) measurement of sapwood area and (ii) variations in sap flow at different depths within the tree sapwood. Results This study measured sap flux density at three depth intervals in the sapwood of 88-year-old red pine (Pinus resinosa) trees to more accurately estimate water-use at the tree- and stand-level in a plantation forest near Lake Erie in Southern Ontario, Canada. Results showed that most of the water transport (65%) occurred in the outermost sapwood, while only 26% and 9% of water was transported in the middle and innermost depths of sapwood, respectively. Conclusions These results suggest that failing to consider radial variations in sap flux density within trees can lead to an overestimation of transpiration by as much as 81%, which may cause large uncertainties in water budgets at the ecosystem and catchment scale. This study will help to improve our understanding of water use dynamics and reduce uncertainties in sap flow measurements in the temperate pine forest ecosystems in the Great Lakes region and help in protecting these forests in the face of climate change.

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Assessing variation in the radial profile of sap flux density in Pinus species and its effect on daily water use

Tree Physiology ◽

10.1093/treephys/24.3.241 ◽

2004 ◽

Vol 24 (3) ◽

pp. 241-249 ◽

Cited By ~ 133

Author(s):

C. R. Ford ◽

M. A. McGuire ◽

R. J. Mitchell ◽

R. O. Teskey

Keyword(s):

Flux Density ◽

Water Use ◽

Radial Profile ◽

Sap Flux ◽

Sap Flux Density ◽

Pinus Species ◽

Daily Water

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Contribution of Advanced Regeneration of Pinus radiata D. Don. to Transpiration by a Fragment of Native Forest in Central Chile Is out of Proportion with the Contribution to Sapwood Area

Forests ◽

10.3390/f11020187 ◽

2020 ◽

Vol 11 (2) ◽

pp. 187

Author(s):

Don A. White ◽

Richard P. Silberstein ◽

Francisco Balocchi-Contreras ◽

Juan Jose Quiroga ◽

Pablo Ramírez de Arellano

Keyword(s):

Climate Change ◽

Leaf Area ◽

Flux Density ◽

Pinus Radiata ◽

Native Forest ◽

Sap Flux ◽

Sap Flux Density ◽

Sapwood Area ◽

Central Chile ◽

Potential Index

The transpiration of Nothofagus glauca (Phil.) Krasser and advanced Pinus radiata D. Don. regeneration was measured in a fragment of native N. glauca forest. Over the eight months of this study, P. radiata contributed approximately 60% of the total stand transpiration. This was out of proportion with the approximately 34% of the stand sapwood area contributed by P. radiata. This was due to the significantly greater sap flux density of the P. radiata compared to the N. glauca between May and October. Though the results are from a small study conducted as part of a larger experiment, it is argued that they suggest that invasion by P. radiata may substantially increase the risk from climate change to reserves of N. glauca forest in the Maule region of central Chile. In some reserves of N. glauca forest, Forestal Arauco S.A. manually removed P. radiata that regenerated after the wildfire of January 2017. This was a costly operation and there is a need for indices to assess competition. The ratio of sapwood area to leaf area is suggested as a potential index for assessing competition to identify stands at risk.

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Influence of temporospatial variation in sap flux density on estimates of whole-tree water use in Avicennia marina

Trees ◽

10.1007/s00468-014-1105-z ◽

2014 ◽

Vol 29 (1) ◽

pp. 215-222 ◽

Cited By ~ 14

Author(s):

Bart A. E. Van de Wal ◽

Adrien Guyot ◽

Catherine E. Lovelock ◽

David A. Lockington ◽

Kathy Steppe

Keyword(s):

Flux Density ◽

Water Use ◽

Avicennia Marina ◽

Sap Flux ◽

Sap Flux Density ◽

Tree Water Use ◽

Whole Tree

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Variability in radial sap flux density patterns and sapwood area among seven co-occurring temperate broad-leaved tree species

Tree Physiology ◽

10.1093/treephys/28.12.1821 ◽

2008 ◽

Vol 28 (12) ◽

pp. 1821-1830 ◽

Cited By ~ 115

Author(s):

T. Gebauer ◽

V. Horna ◽

C. Leuschner

Keyword(s):

Flux Density ◽

Tree Species ◽

Sap Flux ◽

Sap Flux Density ◽

Sapwood Area

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Responses of Sap Flux Densities of Different Plant Functional Types to Environmental Variables Are Similar in Both Dry and Wet Seasons in a Subtropical Mixed Forest

Forests ◽

10.3390/f12081007 ◽

2021 ◽

Vol 12 (8) ◽

pp. 1007

Author(s):

Kechao Huang ◽

Quan Wang ◽

Dennis Otieno

Keyword(s):

Flux Density ◽

Water Use ◽

Environmental Variables ◽

Environmental Changes ◽

Mixed Forest ◽

Plant Functional Types ◽

Photon Flux ◽

Sap Flux ◽

Sap Flux Density ◽

Functional Types

Subtropical mixed forest ecosystems are experiencing dramatic changes in precipitation and different plant functional types growing here are expected to respond differently. This study aims to unravel the water use patterns of different plant functional types and their responses to environmental changes in a typical subtropical mixed forest in southern China. Diurnal and seasonal sap flux densities of evergreen broad-leaved trees (EBL), deciduous broad-leaved trees (DBL), and conifers (CON), as well as environmental variables, were recorded simultaneously from May 2016 to March 2019. The results showed that the sap flux density of EBL was significantly higher than those of CON and DBL in all seasons, irrespective of dry or wet seasons. Path analysis revealed that seasonal differences in sap flux density were mainly due to variations in photosynthetic photon flux density (PPFD). At saturating PPFD, changes in sap flux density during the day were in response to vapor pressure deficit (VPD). Regression analyses showed that sap flux density increased logarithmically with PPFD, irrespective of functional type. The hysteresis loops of sap flux density and VPD were different among different plant functional types in wet and dry seasons. Our results demonstrated converging response patterns to environmental variables among the three plant functional types considered in this study. Our findings contribute to a better understanding of the water use strategies of different plant functional types in subtropical mixed forests.

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Effects of Wood Hydraulic Properties on Water Use and Productivity of Tropical Rainforest Trees

Frontiers in Forests and Global Change ◽

10.3389/ffgc.2020.598759 ◽

2021 ◽

Vol 3 ◽

Author(s):

Martyna M. Kotowska ◽

Roman M. Link ◽

Alexander Röll ◽

Dietrich Hertel ◽

Dirk Hölscher ◽

...

Keyword(s):

Flux Density ◽

Water Use ◽

Wood Density ◽

Wood Anatomy ◽

Tree Size ◽

Plant Performance ◽

Strong Positive Correlation ◽

Sap Flux ◽

Sap Flux Density ◽

Stem Increment

The efficiency of the water transport system in trees sets physical limits to their productivity and water use. Although the coordination of carbon assimilation and hydraulic functions has long been documented, the mutual inter-relationships between wood anatomy, water use and productivity have not yet been jointly addressed in comprehensive field studies. Based on observational data from 99 Indonesian rainforest tree species from 37 families across 22 plots, we analyzed how wood anatomy and sap flux density relate to tree size and wood density, and tested their combined influence on aboveground biomass increment (ABI) and daily water use (DWU). Results from pairwise correlations were compared to the outcome of a structural equation model (SEM). Across species, we found a strong positive correlation between ABI and DWU. Wood hydraulic anatomy was more closely related to these indicators of plant performance than wood density. According to the SEM, the common effect of average tree size and sap flux density on the average stem increment and water use of a species was sufficient to fully explain the observed correlation between these variables. Notably, after controlling for average size, only a relatively small indirect effect of wood properties on stem increment and water use remained that was mediated by sap flux density, which was significantly higher for species with lighter and hydraulically more efficient wood. We conclude that wood hydraulic traits are mechanistically linked to water use and productivity via their influence on sap flow, but large parts of these commonly observed positive relationships can be attributed to confounding size effects.

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