ENVI-met TreePass

The coming #envimet plant module MiPSS 3 – that will be released in spring 2021 – casts its shadows and I m delighted to share a new open Access paper on ENVI-met´s next generation plant model:

In our latest paper, published open access in Forests, we are highlighting the basics of the new fractal base L-System tree model and the redesigned radiation transfer scheme that allows a much more realistic simulation of the effect of tree cover on local microclimate.

While complex urban morphologies including different materials, wall structures, etc., are rather adequately represented in microclimate models, replication of actual plant geometry is—so far—rather crudely handled. However, plant geometry greatly differs within species and locations while strongly determining a plant’s microclimate performance. To improve the plants representation in numerical models, a new method to describe plant skeletons using the so-called Lindenmayer-System has been implemented in the microclimate model ENVI-met.

The new model allows describing much more realistic plants including the position and alignment of leaf clusters, a hierarchical description of the branching system and the calculation of the plant’s biomechanics. Additionally, a new canopy radiation transfer module is introduced that allows not only the simulation of diffuse radiation extinction but also secondary sources of diffuse radiation due to scattering of direct radiation within plant canopies.

In combination with the new radiation scheme, which now also analyses the distribution of diffuse radiation in the canopy, sophisticated patterns of sun and shade can be generated and simulated.