Development and validation of a simple approach to modelling tree shading in agroforestry systems

Reid, Rowan; Ferguson, Ian

doi:10.1007/bf00053142

Cited by 7 publications

(4 citation statements)

References 6 publications

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“…Microclimate research traditions provide important insights to local ways to deal with global climate change (Stigter 2007(Stigter , 2016. Shading has been represented in increasingly refined 1D, 2D and 3D models of tree canopies (Quesada et al 1989;Reid and Ferguson 1992;Charbonnier et al 2013;Rosskopf et al 2017). Simple models for light competition in discontinuous tree stands within AF shifted to a 2D representation of space (Talbot and Dupraz (2012).…”

Section: Current State Of the Artmentioning

confidence: 99%

Climate change adaptation in and through agroforestry: four decades of research initiated by Peter Huxley

Noordwijk

Coe

Sinclair

et al. 2021

Mitig Adapt Strateg Glob Change

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Agroforestry (AF)-based adaptation to global climate change can consist of (1) reversal of negative trends in diverse tree cover as generic portfolio risk management strategy; (2) targeted, strategic, shift in resource capture (e.g. light, water) to adjust to changing conditions (e.g. lower or more variable rainfall, higher temperatures); (3) vegetation-based influences on rainfall patterns; or (4) adaptive, tactical, management of tree-crop interactions based on weather forecasts for the (next) growing season. Forty years ago, a tree physiological research tradition in aboveground and belowground resource capture was established with questions and methods on climate-tree-soil-crop interactions in space and time that are still relevant for today’s challenges. After summarising early research contributions, we review recent literature to assess current levels of uncertainty in climate adaptation assessments in and through AF. Quantification of microclimate within and around tree canopies showed a gap between standard climate station data (designed to avoid tree influences) and the actual climate in which crop and tree meristems or livestock operates in real-world AF. Where global scenario modelling of ‘macroclimate’ change in mean annual rainfall and temperature extrapolates from climate station conditions in past decades, it ignores microclimate effects of trees. There still is a shortage of long-term phenology records to analyse tree biological responses across a wide range of species to climate variability, especially where flowering and pollination matter. Physiological understanding can complement farmer knowledge and help guide policy decisions that allow AF solutions to emerge and tree germplasm to be adjusted for the growing conditions expected over the lifetime of a tree.

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Section: Current State Of the Artmentioning

confidence: 99%

Climate change adaptation in and through agroforestry: four decades of research initiated by Peter Huxley

Noordwijk

Coe

Sinclair

et al. 2021

Mitig Adapt Strateg Glob Change

View full text Add to dashboard Cite

show abstract

“…The complexity of the light models varies both in terms of the geometric representation of the trees and the underlying light simulation algorithms. The simpler models rely on a small number of geometric primitives such as cylinders, cones, and ellipsoids to represent tree trunks and crowns and use simple algorithms to calculate shadows [27][28][29][30]. At the other end of the spectrum are sophisticated models that require high-resolution 3D data from trees and use complex algorithms such as ray tracing or radiative transfer models [31,32].…”

Section: Introductionmentioning

confidence: 99%

“…When modelling light availability in AFS, neither of these extremes of model complexity are desirable. Very simple models are likely to overestimate shading [27] or fail to map shading heterogeneity [29] due to the lacking inclusion of crown structure and architecture. Very complex models, on the other hand, are likely to be too costly due to the high computational and data requirements [30,33].…”

Section: Introductionmentioning

confidence: 99%

From Dawn to Dusk: High-Resolution Tree Shading Model Based on Terrestrial LiDAR Data

Schindler,

Larysch,

Frey

et al. 2024

Remote Sensing

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Light availability and distribution play an important role in every ecosystem as these affect a variety of ecosystem processes and functions. To estimate light availability and distribution, light simulations can be used. Many previous models were based on highly simplified tree models and geometrical assumptions about tree form, or were sophisticated and computationally demanding models based on 3D data which had to be acquired in every season to be simulated. The aim of this study was to model the shadow cast by individual trees at high spatial and temporal resolution without the need for repeated data collection during multiple seasons. For our approach, we captured trees under leaf-off conditions using terrestrial laser scanning and simulated leaf-on conditions for individual trees over the remainder of the year. The model was validated against light measurements (n=20,436) collected using 60 quantum sensors underneath an apple tree (Malus domestica Borkh.) on a sunny and cloudless summer day. On this day, the leaves and the shadow were simulated with a high spatial (1 cm) and temporal resolution (1 min). The simulated values were highly correlated with the measured radiation at r=0.84. Additionally, we simulated the radiation for a whole year for the sample apple tree (tree height: 6.6 m, crown width: 7.6 m) with a resolution of 10 cm and a temporal resolution of 10 min. Below the tree, an area of 49.55 m² is exposed to a radiation reduction of at least 10%, 17.74 m² to at least 20% and only 0.12 m² to at least 30%. The model could be further improved by incorporating branch growth, curved leaf surfaces, and gravity to take the weight of the foliage into account. The presented approach offers a high potential for modelling the light availability in the surroundings of trees with an unprecedented spatial and temporal resolution.

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“…The predictive model predicts system behaviour and the consequences of management actions. It models interactions such as radiation interception (Giordano et al, 1986;Kuuluvainen and Pukkala, 1989;Reid and Ferguson, 1992) and sometimes deals with the effect of these interactions on production. In this case, the model integrates several climatic and edaphic factors and provides physical (McKeon et al, 1990;Sibbald et al, 1990;Msika, 1993) or economic outputs (Doyle et al, 1986).…”

Section: Introductionmentioning

confidence: 99%

ALWAYS: a plot-based silvopastoral system model

Bergez¹,

Etienne²,

Balandier³

1999

Ecological Modelling

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Accounting for interactions is an important feature in ecological modelling when dealing with complex systems. ALWAYS is an object-oriented model which describes the biophysical functioning of a silvopastoral system at a plot and daily scale. The main processes linking the five components of the system (climate, tree, sward, soil and animal) are described. The interactions processes between the different components of the system are taken into account and resources sharing is modelled. The main biophysical equations are developed (tree and sward growth, water cycle, transmitted PAR). ALWAYS offers three ways of running it: (i) interactively by running the simulation year by year and checking results at the end of each year using graphs and output files; (ii) automatically by describing the management over the full tree rotation and (iii) in a sensitivity analysis mode to test parameters from the yearly or rotation outputs. Examples of output files, written in an ASCII format, are provided. Such a model is the first step towards a more effective decision support tool.

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Development and validation of a simple approach to modelling tree shading in agroforestry systems

Cited by 7 publications

References 6 publications

Climate change adaptation in and through agroforestry: four decades of research initiated by Peter Huxley

Climate change adaptation in and through agroforestry: four decades of research initiated by Peter Huxley

From Dawn to Dusk: High-Resolution Tree Shading Model Based on Terrestrial LiDAR Data

ALWAYS: a plot-based silvopastoral system model

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