Spore dispersal within a larch forest

Meindert D. de Jong VLINDERS at rcl.wau.nl
Wed Sep 4 07:25:51 EST 1991

Dear Foresters:

Herewith I send you an abstract of my latest paper dealing with a
simple simulation model for dispersal of airborne spores within a
larch forest. It was part of a research on the biological control
of a forest weed, black cherry, by the silver leaf fungus.
Besides its forestry implications, it also had a great impact on
biological control in agriculture. (I appreciate remarks.)
Larch forests have a relative simple aerodynamic structure from a
modeller's point of view. Similar models have been made for crops
as wheat and tobacco.
I have got many requests for a reprint of this paper from colleagues
in Forestry (most), Plant Pathology, Agriculture, and Meteorology.
A complete version of this paper is available on disk. So, if you
want an E-copy, I'll send it.
Hope that this topic may be a suitable contribution to your List,

Meindert D. de Jong
E-mail: Vlinders at rcl.wau.NL


Neth. J. Pl. Path. 97 (1991) 55-61

Modelling the escape of Chondrostereum purpureum
spores from a larch forest with biological control of
Prunus serotina


1: Centre for Agrobiological Research (CABO), P.O.Box 14, 6700
AA Wageningen, the Netherlands; present address: Tarthorst
195, 6708 HJ Wageningen, the Netherlands
2: Research Station for Fruit Growing, Brugstraat 51, 4475 AN
Wilhelminadorp, the Netherlands
3: Theoretical Production Ecology, Agricultural University,
P.O. Box 14, 6700 AA Wageningen, the Netherlands

Accepted 25 October 1990


Chondrostereum purpureum is being developed as a microbial
herbicide to control Prunus serotina in coniferous forests.
After biological control, the fungus produces basidiospores
that may reach and infect non-target plants. As part of a risk
analysis, spore escape from a forest was quantified. For this
purpose, a stratified model was developed for a forest of 250
m with 250 m. A turbulent diffusion equation was used to des-
cribe spore fluxes for each layer. In a simple calculation
procedure, the spore fluxes for the different layers were
calculated simultaneously. The downwind escape fraction was
found to vary from 0.19 to 0.45, and the upward escape fracti-
on from 0.07 to 0.23. These escape fractions increased with
increasing wind speed. Number of spores released from basidio-
carps, and escape fractions could be used as inputs for a
Gaussian plume model to calculate spore immision into

Additional keywords: simulation, spore dispersal, turbulent
diffusion model.

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