BDA climate extension

[Francesco Tonini]

Dear all,

I am just starting to get familiar with LANDIS-II and read some of its extension manuals. I read that Century uses monthly climate data for cohort growth and soil decomposition. However, disturbances in the form of, say, a tree pathogen/disease can only occur using a minimum of 1-year time steps. My pathogen responds, as in most cases, with climate (e.g. moisture, temperature, precipitation) and during rain season every year. Does anybody have ideas on how to tackle this modeling issue I am facing?

Finally, are there any developments out there as far as BDA dispersal component (currently missing, to the best of my knowledge)?

Thank you in advance!

Francesco

[Robert Scheller]

Francesco,

We are building a variation on the BDA that uses Palmer Ddrought Severity Index to predict when insect outbreaks will occur.  This is tied to the new climate library.  Both should be released at some time in 2014.

With the new climate library, it will be much easier to develop such monthly sub-routines for climate-related disturbances.  We are also working on a new version of Dynamic Fire that will use daily data.

[Francesco Tonini]

Thank you. I am definitely looking forward to using that new climate library for my pathogen spread. Also, a daily version of Dynamic Fire is something me and my team would be interested in using.

Francesco

[Caren Dymond]

Will that new BDA have more flexible timesteps? I seem to recall BDA only works in decades. Annual would be nice :)
thanks
Caren

[Alec Kretchun]

Hi Francesco-

  I'm currently working on both those projects Rob just mentioned. We are using BDA to represent bark beetles, which respond to drought conditions - PDSI is calculated at a monthly timestep and if this value drops low enough, it triggers an outbreak. This does not mean that the outbreaks operate at sub-annual timescales,the extension still operates the same in every other way (i.e. at an annual timestep) with the exception of the PDSI function. Would this kind of functionality help address your concerns about temporal mismatch?

   -Alec    

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Alec Kretchun

[Francesco Tonini]

Hi Alec,

In the case of my tree pathogen, the effect of drought is probably opposite, in the sense that weather conditions need to be humid and moist in order for it to establish and trigger sporulation from the infected host trees. Aside from this, precipitation play an important role in spreading it locally within sites or neighboring ones. The pathogen has previously been modeled on a weekly time step, but the model did not include any tree succession nor used LANDIS or any other FLM. So, yes, keeping the BDA at 1-year time steps (with related output maps) while triggering outbreaks using monthly climate data would make our model more realistic than using, for example, average year temperature, precip, etc.

I am also hoping that a "dispersal" component will soon be implemented in the BDA extension so that I can better account for the pathogen spread at local scales. As of now, correct me if I am mistaken, the epicenters for new outbreaks are still randomly generated within outbreak zones, so I cannot tell the model that each infected cell (site) on a landscape will generate spores to infect neighboring sites (if site vulnerability is high enough in terms of favorable food resources and climate conditions). 

Francesco

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Francesco Tonini, PhD
Post-doctorate Researcher




email: fto...@ncsu.edu
web: www.FrancescoTonini.com
phone: +1 (919) 513.0411

[Francesco Tonini]

Caren,

BDA already works at any time step, starting from 1 year and up...

Francesco

Sent from my iPad

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