scholarly journals Coordination of leaf area, sapwood area and canopy conductance leads to species convergence of tree water use in a remnant evergreen woodland

2008 ◽  
Vol 56 (2) ◽  
pp. 97 ◽  
Author(s):  
Melanie Zeppel ◽  
Derek Eamus
Keyword(s):  
Leaf Area ◽  
Water Use ◽  
Canopy Conductance ◽  
Evaporative Demand ◽  
Sapwood Area ◽  
Huber Value ◽  
Tree Water Use ◽  
Decoupling Coefficient ◽  
The Relationship ◽  
Daily Total

This paper compares rates of tree water use, Huber value, canopy conductance and canopy decoupling of two disparate, co-occurring tree species, in a stand of remnant native vegetation in temperate Australia in order to compare their relative behaviour seasonally and during and after a drought. The study site was an open woodland dominated by Eucalyptus crebra F.Muell. (a broad-leaved species) and Callitris glaucophylla J.Thompson & L.A.S. Johnson (a needle-leaved tree species). Tree water use was measured with sapflow sensors and leaf area and sapwood area were measured destructively on felled trees. The Huber value was calculated as the ratio of sapwood area to leaf area. Diameter at breast height (DBH) of the stem was used as a measure of tree size. Canopy conductance was calculated with an inversion of the Penman–Monteith equation, whereas canopy decoupling) was calculated as described by Lu et al. (2003). The relationship between DBH and daily total water use varied during the four measurement periods, with largest rates of water use observed in summer 2003–2004, following a large rainfall event and the smallest maximum water use observed in winter 2003 when monthly rainfall was much less than the long-term mean for those months. Despite differences in the relationship between sapwood area and DBH for the two species, the relationship between daily total water use and DBH did not differ between species at any time. The same rates of water use for the two species across sampling periods arose through different mechanisms; the eucalypt underwent significant changes in leaf area whereas the Callitris displayed large changes in canopy conductance, such that tree water use remained the same for both species during the 2-year period. Canopy conductance and the decoupling coefficient were both significantly larger in winter than summer in both years. The generally low decoupling coefficient (0.05–0.34) reflects the low leaf area index of the site. When evaporative demand was small (winter), the degree of stomatal control was small and the decoupling coefficient was large. There was no relationship between tree size and either canopy conductance or the decoupling coefficient. Transpiration rates generally showed little variation between seasons and between species because of the balance between changes in leaf area, canopy conductance and evaporative demand. The occurrence of a significant drought did not appear to prevent these coordinated changes from occurring, with the result that convergence in water use was observed for these two disparate species.

A comparison of tree water use in two contiguous vegetation communities of the seasonally dry tropics of northern Australia: the importance of site water budget to tree hydraulics

2007 ◽  
Vol 55 (7) ◽  
pp. 700 ◽  
Author(s):  
G. Kelley ◽  
A. P. O'Grady ◽  
L. B. Hutley ◽  
D. Eamus
Keyword(s):  
Leaf Area ◽  
Water Use ◽  
Area Index ◽  
Sapwood Area ◽  
Vegetation Communities ◽  
Tree Water Use ◽  
Eucalypt Forest ◽  
Significant Difference ◽  
Site Water ◽  
Annual Water

Tree water use in two contiguous communities (eucalypt open-forest and Melaleuca paperbark forest) was measured in tropical Australia, over a 2-year period. The aims of the study were to (1) quantify daily and seasonal patterns of water use in each community, (2) compare patterns of water use among the communities and (3) compare relationships among tree size, sapwood area and water use within the two contrasting vegetation communities. Access to deep soil water stores and the effect of run-on from the eucalypt forest resulted in a relatively high pre-dawn water potential throughout the year, particularly for Melaleuca forest. There were no differences in daily rates of water use, expressed on a sapwood area (Q s) basis, between the two eucalypt species examined (Eucalyptus miniata Cunn. Ex Schauer and E. tetrodonta F.Muell) at any time in the eucalypt forest. For both the eucalypt and Melaleuca forests, there was less seasonal variation in water use expressed on a leaf area (Q l) basis than on a Q s basis, and neither year nor season were significant factors in Q l. In the mono-specific Melaleuca forest, Q s was not significantly different between years or seasons. Water use on a Q l basis was similarly not significantly different between years or seasons in the Melaleuca forest. Leaf area index (LAI) of the eucalypt forest was about half of that of the Melaleuca forest throughout the year but sapwood area per hectare was 33% larger in the eucalypt than the Melaleuca forest, despite the basal area of the Melaeuca forest being almost double that of the eucalypt forest. There was no significant difference in stand water use (mm day–1) between eucalypt and Melaleuca forests during 1998; however, in 1999 Melaleuca stand water use was larger than that of the eucalypt forest. Because of the enhanced dry-season availability of water in the Melaleuca forest and its larger LAI, average annual water use of the Melaleuca forest was almost 60% larger than that of the eucalypt forest. Despite differences in Q l, Q s and annual water use between forests, the ratio of LAI to stand water use was similar for all seasons in both forests. The applicability of ‘universal rules’ linking tree water use and tree hydraulics and the importance of ecosystem location on site water budgets and plant adaptations are discussed.

scholarly journals Airborne Tree Crown Detection for Predicting Spatial Heterogeneity of Canopy Transpiration in a Tropical Rainforest

2020 ◽  
Vol 12 (4) ◽  
pp. 651
Author(s):  
Joyson Ahongshangbam ◽  
Alexander Röll ◽  
Florian Ellsäßer ◽  
Hendrayanto ◽  
Dirk Hölscher
Keyword(s):  
Spatial Heterogeneity ◽  
Water Use ◽  
Tropical Rainforests ◽  
Sap Flux ◽  
Tree Crown ◽  
Individual Tree ◽  
Canopy Transpiration ◽  
Tree Water Use ◽  
Climate Regulation ◽  
The Relationship

Tropical rainforests comprise complex 3D structures and encompass heterogeneous site conditions; their transpiration contributes to climate regulation. The objectives of our study were to test the relationship between tree water use and crown metrics and to predict spatial variability of canopy transpiration across sites. In a lowland rainforest of Sumatra, we measured tree water use with sap flux techniques and simultaneously assessed crown metrics with drone-based photogrammetry. We observed a close linear relationship between individual tree water use and crown surface area (R2 = 0.76, n = 42 trees). Uncertainties in predicting stand-level canopy transpiration were much lower using tree crown metrics than the more conventionally used stem diameter. 3D canopy segmentation analyses in combination with the tree crown–water use relationship predict substantial spatial heterogeneity in canopy transpiration. Among our eight study plots, there was a more than two-fold difference, with lower transpiration at riparian than at upland sites. In conclusion, we regard drone-based canopy segmentation and crown metrics to be very useful tools for the scaling of transpiration from tree- to stand-level. Our results indicate substantial spatial variation in crown packing and thus canopy transpiration of tropical rainforests.

The hydraulic architecture of Eucalyptus trees growing across a gradient of depth-to-groundwater

2015 ◽  
Vol 42 (9) ◽  
pp. 888 ◽  
Author(s):  
Sepideh Zolfaghar ◽  
Randol Villalobos-Vega ◽  
Melanie Zeppel ◽  
Derek Eamus
Keyword(s):  
Hydraulic Conductivity ◽  
Leaf Area ◽  
Water Availability ◽  
Safety Margin ◽  
Hydraulic Architecture ◽  
Sapwood Area ◽  
Huber Value ◽  
Xylem Vulnerability ◽  
Safety Margins ◽  
Hydraulic Safety

Heterogeneity in water availability acts as an important driver of variation in plant structure and function. Changes in hydraulic architecture represent a key mechanism by which adaptation to changes in water availability can be expressed in plants. The aim of this study was to investigate whether differences in depth-to-groundwater influence the hydraulic architecture of Eucalyptus trees in remnant woodlands within mesic environments. Hydraulic architecture of trees was examined in winter and summer by measuring the following traits: Huber value (HV: the ratio between sapwood area and leaf area), branch hydraulic conductivity (leaf and sapwood area specific), sapwood density, xylem vulnerability (P50 and Pe) and hydraulic safety margins across four sites where depth-to-groundwater ranged from 2.4 to 37.5 m. Huber value increased significantly as depth-to-groundwater increased. Neither sapwood density nor branch hydraulic conductivity (sapwood and leaf area specific) varied significantly across sites. Xylem vulnerability to embolism (represented by P50 and Pe) in both seasons was significantly and negatively correlated with depth-to-groundwater. Hydraulic safety margins increased with increasing depth-to-groundwater and therefore trees growing at sites with deeper water tables were less sensitive to drought induced embolism. These results showed plasticity in some, but not all, hydraulic traits (as reflected in HV, P50, Pe and hydraulic safety margin) in response to increase in depth-to-groundwater in a mesic environment.

scholarly journals Hydraulic architecture and water relations of several species at diverse sites around Sydney

2004 ◽  
Vol 52 (4) ◽  
pp. 509 ◽  
Author(s):  
Kate McClenahan ◽  
Catriona Macinnis-Ng ◽  
Derek Eamus
Keyword(s):  
Water Relations ◽  
Root Biomass ◽  
Woody Species ◽  
Leaf Water ◽  
Hydraulic Architecture ◽  
Evaporative Demand ◽  
Sapwood Area ◽  
Huber Value ◽  
Percentage Loss ◽  
Transverse Area

Seasonal comparisons of leaf water potential, root biomass, hydraulic architecture, xylem embolism and xylem dimensions were made for eight woody species in four diverse habitats (mangroves, coastal heathland, ridge-top woodland and river-flat woodland). In most comparisons, pre-dawn and minimum leaf water potentials were lower in winter than in summer, a result attributed to lower rainfall and a smaller root biomass in winter than in summer. Branch hydraulic conductivities (per unit transverse area, sapwood area or leaf area) were generally larger in summer than in winter across all species in all habitats. An inverse relationship between Huber value and conductivity was observed across all four habitats. Increased solar radiation and evaporative demand in the summer was associated with an increased percentage loss of xylem conductance arising from embolism, compared with winter. These results are discussed in the context of patterns and relationships among water relations, microclimate and hydraulic architecture.

Production ecology of Thuja occidentalis

2010 ◽  
Vol 40 (6) ◽  
pp. 1155-1164 ◽  
Author(s):  
Philip V. Hofmeyer ◽  
Robert S. Seymour ◽  
Laura S. Kenefic
Keyword(s):  
Leaf Area ◽  
Light Exposure ◽  
Tree Height ◽  
Growth Efficiency ◽  
Analysis Of Covariance ◽  
Stem Volume ◽  
Sapwood Area ◽  
Thuja Occidentalis ◽  
Production Ecology ◽  
The Relationship

Equations to predict branch and tree leaf area, foliar mass, and stemwood volume were developed from 25 destructively sampled northern white-cedar ( Thuja occidentalis L.) trees, a species whose production ecology has not been studied. Resulting models were applied to a large sample of 296 cored trees from 60 sites stratified across a soil gradient throughout northern Maine. Nonlinear regression analysis was used to assess alternative forms of the relationship between volume increment (VINC) and projected leaf area (PLA); analysis of covariance was used compare stemwood growth efficiency (GE) among soil-site classes, light exposure classes, and the presence of decay. Stem volume was estimated with Honer’s equation ( T.G. Honer. 1967. Forest Management Research and Services Institute ) with refitted parameters. PLA was best predicted with Maguire and Bennett’s nonlinear model ( D.A. Maguire and W.S. Bennett. 1996. Can. J. For. Res. 26: 1991–2005 ) using sapwood area or crown length and the ratio of tree height to diameter at breast height. A sigmoid model form captured the relationship between VINC and PLA more precisely and with less bias than the simple power function; this implies that the relationship between GE and PLA reaches a peak rather than decreases monotonically. At PLAs >50 m2, GE gradually declined with increasing crown size and was significantly influenced by site and light exposure. With PLA, site, and light held constant, decayed trees had a significantly lower (by 11%) GE than sound stems, a finding not previously reported for other tree species.

scholarly journals Effect of Long-Term vs. Short-Term Ambient Ozone Exposure on Radial Stem Growth, Sap Flux and Xylem Morphology of O3-Sensitive Poplar Trees

Forests ◽  
2019 ◽  
Vol 10 (5) ◽  
pp. 396 ◽  
Author(s):  
Alessio Giovannelli ◽  
Maria Laura Traversi ◽  
Monica Anichini ◽  
Yasutomo Hoshika ◽  
Silvano Fares ◽  
...  
Keyword(s):  
Water Use ◽  
Sap Flow ◽  
Stem Growth ◽  
Ozone Exposure ◽  
Compensatory Mechanisms ◽  
Planted Forests ◽  
Evaporative Demand ◽  
Huber Value ◽  
Stem Water

High ozone (O3) pollution impairs the carbon and water balance of trees, which is of special interest in planted forests. However, the effect of long-term O3 exposure on tree growth and water use, little remains known. In this study, we analysed the relationships of intra-annual stem growth pattern, seasonal sap flow dynamics and xylem morphology to assess the effect of long term O3 exposure of mature O3-sensitive hybrid poplars (‘Oxford’ clone). Rooted cuttings were planted in autumn 2007 and drip irrigated with 2 liters of water as ambient O3 treatment, or 450 ppm ethylenediurea (N-[2-(2-oxo-1-imidazolidinyl)ethyl]-N0-phenylurea, abbreviated as EDU) solution as O3 protection treatment over all growing seasons. During 2013, point dendrometers and heat pulses were installed to monitor radial growth, stem water relations and sap flow. Ambient O3 did not affect growth rates, even if the seasonal culmination point was 20 days earlier on average than that recorded in the O3 protected trees. Under ambient O3, trees showed reduced seasonal sap flow, however, the lower water use was due to a decrease of Huber value (decrease of leaf area for sapwood unit) rather than to a change in xylem morphology or due to a direct effect of sluggish stomatal responses on transpiration. Under high evaporative demand and ambient O3 concentrations, trees showed a high use of internal stem water resources modulated by stomatal sluggishness, thus predisposing them to be more sensitive water deficit during summer. The results of this study help untangle the compensatory mechanisms involved in the acclimation processes of forest species to long-term O3 exposure in a context of global change.

The effect of stand structure and stand density on the leaf area–sapwood area relationship of lodgepole pine

1989 ◽  
Vol 19 (3) ◽  
pp. 392-396 ◽  
Author(s):  
Dan C. Thompson
Keyword(s):  
Leaf Area ◽  
Stand Structure ◽  
Lodgepole Pine ◽  
Habitat Type ◽  
Ring Width ◽  
Stand Density ◽  
Habitat Types ◽  
Sapwood Area ◽  
Relationship Of ◽  
The Relationship

The relationship of sapwood area to leaf area in lodgepole pine was examined across a variety of habitat types and stand densities in northwest Montana. No statistical differences were found between plots with regard to either habitat type or stand density. A nonlinear relationship was found between leaf area and sapwood area. Increasing amounts of sapwood were associated with a decrease in the leaf area–sapwood area ratio. A large amount of within-plot variation in the sapwood area–leaf area relationship was explained by differences between dominant trees and trees of other crown classes. Leaf area (LA) was best estimated by the equation LA = 0.12 × S − 0.0003 × S2 + 0.06 × S × D, where LA is leaf area, S is sapwood area, and D is the crown class (dominant). Differences between dominant and subdominant trees appear to be related to ring width and its associated permeability. Differences in sapwood area–leaf area equations among different studies may be due in part to differences in stand structure.

scholarly journals Effects of size and microclimate on whole-tree water use and hydraulic regulation inSchima superbatrees

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5164
Author(s):  
Xiao-wei Zhao ◽  
Lei Ouyang ◽  
Ping Zhao ◽  
Chun-fang Zhang
Keyword(s):  
Water Use ◽  
Water Consumption ◽  
Large Scale ◽  
Hydraulic Conductance ◽  
Canopy Conductance ◽  
Wet Season ◽  
Sap Flux Density ◽  
Tree Water Use ◽  
Tree Transpiration ◽  
Whole Tree

BackgroundPlant-water relations have been of significant concern in forestry and ecology studies in recent years, yet studies investigating the annual differences in the characteristics of inter-class water consumption in trees are scarce.MethodsWe classified 15 trees from aSchima superbaplantation in subtropical South China into four ranks using diameter at breast height (DBH). The inter-class and whole-tree water use were compared based on three parameters: sap flux density, whole-tree transpiration and canopy transpiration over two years. Inter-class hydraulic parameters, such as leaf water potential, stomatal conductance, hydraulic conductance, and canopy conductance were also compared.Results(1) Mean water consumption of the plantation was 287.6 mm over a year, 165.9 mm in the wet season, and 121.7 mm in the dry season. Annual mean daily water use was 0.79 mm d−1, with a maximum of 1.39 mm d−1. (2) Isohydrodynamic behavior were found inS. superba. (3) Transpiration was regulated via both hydraulic conductance and stoma; however, there was an annual difference in which predominantly regulated transpiration.DiscussionThis study quantified annual and seasonal water use of aS. superbaplantation and revealed the coordinated effect of stoma and hydraulic conductance on transpiration. These results provide information for large-scale afforestation and future water management.

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