Age‐related decline in stand productivity: the role of structural acclimation under hydraulic constraints

By Federico Magnani, Maurizio Mencuccini, John Grace. 2000

284 citations recorded by the source corpus.

The decline in above-ground net primary productivity (Pa) that is usually observed in forest stands has been variously attributed to respiration, nutrient or hydraulic limitations. A novel model is proposed to explain the phenomenon and the co-occurring changes in the balance between foliage, conducting sapwood and fine roots. The model is based on the hypothesis that a functional homeostasis in water transport is maintained irrespective of age: hydraulic resistances through the plant must be finely tuned to transpiration rates so as to avoid extremely negative water potentials that could result in diffuse xylem embolism and foliage dieback, in agreement with experimental evidence. As the plant grows taller, allocation is predicted to shift from foliage to transport tissues, most notably to fine roots. Higher respiration and fine root turnover would result in the observed decline in Pa. The predictions of the model have been compared with experimental data from a chronosequence of Pinus sylvestris stands. The observed reduction in Pa is conveniently explained by concurrent modifications in leaf area index and plant structure. Changes in allometry and shoot hydraulic conductance with age are successfully predicted by the principle of functional homeostasis.

Subfields: Atmospheric Science, Global and Planetary Change, Nature and Landscape Conservation

View Paper: https://www.semanticscholar.org/paper/1d7d959a008d6289f5bdbaa690530c0c54806188

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Citations in the corpus

A test of the hydraulic limitation hypothesis in fast‐growing Eucalyptus saligna (2003, background): “Increased below-ground allocation could also compensate for increased height (Magnani et al. 2000), but there is no evidence of it doing so (Smith & Resh 1999; Giardina & Ryan 2002; Litton 2002).”
The hydraulic limitation hypothesis revisited. (2006, background): “The Eucalyptus study also found no support for the hypothesis that an increased allocation to fine roots will offset any decrease in leaf-specific hydraulic conductivity (Magnani et al. 2000).”
Effects of stand age and tree species on canopy transpiration and average stomatal conductance of boreal forests (2005, background): “A hypothesis put forward by Magnani et al. (2000) suggests that low AS : AL species may produce juvenile wood to a much later age; compare 70 years in Abies balsamea (Coyea & Margolis 1992) with 15 years in Pinus sylvestris (Mencuccini, Grace & Fioravanti 1997).”
The ecological significance of long-distance water transport: short-term regulation, long-term acclimation and the hydraulic costs of stature across plant life forms (2003, unknown): “allocation to transport tissues may come to the detriment of decreased allocation to leaf area and subsequent reductions in productivity (Magnani et al. 2000).”
Will a 385 million year‐struggle for light become a struggle for water and for carbon? – How trees may cope with more frequent climate change‐type drought events (2011, background): “On the other hand, large trees have more root volume (Magnani et al., 2000) which may allow them to exploit more profound water pools during drought.”
Biomass expansion factors and root: shoot ratios for coniferous tree species in Great britain (2004, background): “Because of limitations imposed by light or hydraulics, large trees have proportionally less leaf area (and associated branch mass) than small trees (Magnani et al., 2000).”
Perpetuating old ponderosa pine (2007, background): “Examples include changes in carbon allocation that increase the ratio of root absorbing area to leaf area (Ewers et al., 2000; Hacke et al., 2000; Magnani et al., 2000), and increase the ratio of sapwood area to leaf area (Mencuccini and Bonosi, 2001; Fischer et al.”
AN EXPERIMENTAL TEST OF THE CAUSES OF FOREST GROWTH DECLINE WITH STAND AGE (2004, methodology): “It was also supported by a model analysis incorporating fine-root biomass data from Scots pine (Pinus sylvestris) chronosequences (Magnani et al. 2000).”
Forest Growth and Yield Modeling (2011, background): “The difficulty lies in determining what trees are actually optimally partitioning, since growth, water transport (Magnani et al., 2000), and uniform bending stress along the stem (Dean, 2001) have all been suggested.”
Leaf/sapwood area ratios in Scots pine show acclimation across Europe (2001, result): “Consequently, an increase in transpiration rate dictated by a higher ∆ω will result in smaller changes in S than predicted by the model (Magnani et al. 2000).”
Sensitivity and uncertainty analysis from a coupled 3-PG and soil organic matter decomposition model (2008, methodology): “The first three parameters were fitted to match age-related decline of productivity observed by Magnani et al. (2000), whereas values used for the specific area were 6 m 2 kg −1 and 4 m 2 kg −1 for mature leaves (Mencuccini and Bonosi, 2001), Landsberg et al. (2005) used 9 m 2 kg −1 and 6 m 2 kg −1…”
Adjustment of tree structure in response to the environment under hydraulic constraints (2002, methodology): “…12 eqn 13 The allometric balance between Wf and As, Wr can be seen to depend on tree height, less carbon being allocated to foliage as the stand ages, as discussed in detail by Magnani et al. (2000) who give a more detailed description of the mathematical development of equations 9–13.”
Mechanisms of plant survival and mortality during drought: why do some plants survive while others succumb to drought? (2008, background): “…Hacke et al., 2000; Lloret et al., 2004; West et al., 2007b); (vi) ratio of root absorbing area to leaf area (Ewers et al., 2000; Hacke et al., 2000; Magnani et al., 2000); (vii) ratio of sapwood area to leaf area (Mencuccini & Bonosi, 2001; McDowell et al., 2002b, 2006; Barnard & Ryan, 2003);…”
Does turgor limit growth in tall trees (2004, background): “A great deal of attention has recently been focused on the tnechanistrts responsible for reduced growth in trees as they age and increase in height (Friend 199:1; Yoder el al. 1994; Ryan & Yoder 1997; Magnani, Mencuccini & Grace 2000; McDowell et al. 2002).”
Picea abies sapwood width: Variations within and between trees (2006, result): “The authors took the results to support the idea that increased conducting sapwood area per unit foliage was required when the trees grew taller (Magnani et al., 2000).”