Exporting and calculating transition times for LANDFIRE reference models

[leonardo-frid]

Here is a recent question from an ST-Sim User:
I was wondering if there is a table available that lists the transition time between state classes within the LANDFIRE BpS models? This information is available in the ST-Sim transition pathways (and the LF model descriptions) but I’m not seeing a way to export out of ST-Sim for all models. I think I would want this for both the deterministic transitions as well as any alternative succession transitions where the probability is 1. If I’m understanding the alternative succession correctly, you would add the beginning age and the time since last disturbance to get a “minimum” transition time.

For example, in BpS 10451_10_19 the only way to move from Late1:OPN to Late1:CLS is with alternative succession. The probability is 1 but the time since disturbance is 40 years. Thus, the way I’m interpreting this is that the minimum time it would take to transition (assuming no disturbance) would be 155 years: Late:OPN begins at 115 and the transition requires 40 years without disturbance (in essence it’s time since last disturbance OR transition?). Is that the correct way to think about alternative succession?

Answer:
The landfirevegmodels SyncroSim package: https://apexrms.github.io/landfirevegmodels/ has a template with transitions for all LANDFIRE reference condition models. You could use the windows interface or the rsyncrosim package to export the transitions to csv or excel.

The ST-Sim Deterministic Transition table would get you the minimum and maximum age of each class as well as the destination class. For alternative succession, you want the Transition table.

However, when time since transition (TST) is involved, the minimum transition time can be a bit more complicated because TST can span other transitions between classes. This means you can’t just add the starting age of a class to Min TST to get a minimum transition time. In the example you give above, it is safer to say that the minimum transition time is 40 years without fire and the minimum age at which it can occur for that class is 115. In this example, a simulation cell that just aged and transitioned to Late1:OPN that has not experienced a fire in 40 years would transition immediately at age 115 to Late1:CLS.

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