New Base BDA extension released (v3.0)

[Brian Miranda]

A new version of the Base Biological Disturbance Agent (BDA) extension has been released on the LANDIS-II website (http://www.landis-ii.org/extensions/base-biological-disturbance-agents).  The changes to the extension are listed in the Users Guide, and copied below for reference.  Users of previous versions of Base BDA should note (1) because this bug has been present in all earlier releases (and custom versions like Budworm-BDA).  It likely had minimal impact, except in cases using a neighborhood (NeighborFlag yes) where the landscape had a lot of cells that contained no host and the non-host is meant to count as 0 resource values (not IgnoredSpecies).  The input format for v3.0 has changed slightly to accommodate current changes and future development, but the translation from the old format to the new format should be straightforward for users.  Questions regarding the new version or reports of bugs can be directed to me (brmi...@fs.fed.us).

Version 3.0:

1. Bug fix to Neighborhood Resources Dominance (NRD)

   The NRD calculation had an error in logic that required neighborhood cells to have Site Resource Dominance (SRD) > 0 to be included in the neighborhood averaging.  When non-host species are meant to decrease the susceptibility (host value = 0), sites that contain only those non-hosts should be included in the NRD calculation.

2. User-defined intensity class thresholds

   New user inputs now define the Biological Disturbance Probability (BDP) thresholds to reach the different intensity classes (1-3).  These were previously hard-coded to be 0.33, 0.66, and 1.0.

3. User-defined Site Resource Dominance

   The user can now define the Site Resource Dominance (SRD) value for each host class (Minor, Secondary, Major).  These were previously hard-coded to be 0.33, 0.66, and 1.0, respectively.

4. Stochastic mortality

   If a site is disturbed (based on biological disturbance probability [BDP], described in 2.5 below) the mortality of individual cohorts is now a probabilistic function of the mortality probability (MortProb) of the corresponding susceptibility class for the cohort.  The user defines which species and ages fall into each susceptibility class (1-3), and the probability of cohort mortality for each class.  This feature can be used to account for the advanced regeneration strategy of certain species, where small, young cohorts exist under the main canopy and are able to survive an insect/disease outbreak, but older cohorts are highly susceptible.

5. Specialty dead fuel class

   Host species can now be flagged as contributing to a specialty dead fuel class, which allows the dead cohorts of these species to be considered by fuel extensions that account for disturbance-related fuels.  For example, the Dynamic Fire and Fuel System (DFFS) extension uses the presence of dead conifers to specify certain insect-kill fuel types.

6. Variable start and end times

   Each BDA agent can have a specified start and end year. Outbreaks for the agent are constrained to occur only between the start and end years.

7. Added flexibility to Disturbance Modifiers

   Disturbance modifiers can now how different impacts based on the severity of wind and fire disturbances, and can also be applied to specific harvest prescriptions, biomass insects mortality or defoliation, and other BDA agents.

[Brian Miranda]

The original installer posted for this new version (v3.0) was missing the Metadata Library dll, which this extension now requires.  A new version of the installer has now been posted to the LANDIS-II website.  This version is denoted as v3.0.1.  There are no code changes with this version, just the inclusion of the extra dll.

-Brian Miranda