Good Evening Ethan,
This is a very good question. I've asked around our team and hopefully the information below will point you to the correct information sources.
You mentioned the Help Center documentation, I’ll post the most relevant topic below, that is probably the one you’ve consulted already but I’ll pasted a link below to provide context to other forum readers:
For information beyond what is posted on that topic, we’d recommend reaching out to the LANDFIRE Helpdesk https://www.landfire.gov/contactus.php who can speak to the details on the use of FVS and plot data in both the Landscape products as well as their editing rules.
As I was reminded by our team, the LANDFIRE Look Up Rules (which LANDFIRE produced and uses to update their data) are used as the Default Edit rules EXCEPT in the case where the user has edited the landscape with a User Created Edit Rule first. In that case, the LANDFIRE Look Up Rules cannot be applied because they rely on stand characteristics (which the user may have changed with a user created edit rule). In those cases, rules developed specifically for IFTDSS are used which do not rely on stand characteristics. If this is the part you need more information on, let us know and I'll inquire further on our end to see if that is also a LANDFIRE reference, or if we have another point of contact or information source we can make available.
Josh
IFTDSS Support Team
Josh,
Thanks for the reply.
To simplify, I'll create a scenario: Private landowner comes to me wanting some treatments done to reduce wildfire risk. I go into IFTDSS and create a landscape that includes their 50 acre parcel. Things like EVT, EVC etc are all supplied by underlying LF data. I first run a simulation with a wildfire on existing conditions based on the EVT, EVC and other items from the underlying LF data to get a baseline for fire risk on their lands. I then add a user edit that says I'm going to do a heavy thin and masticate. How is that user rule inferring DBH because in the documentation from IFTDSS, a heavy thin is characterized by " >75% of the area affected by an understory thinning treatment that cuts 90% of all material up to an 8” diameter and leaves it on site in the form of masticated material." If it specifies DBH that implies that it is generating tree lists for this site, but let's just assume this is not one of the many parcels where there is actual real-world collected data on, as it is specifying a target DBH on which we will thin from below. How is it generating these DBH's such that the underlying data is then manipulated and eventually modeled for fire impacts/behavior metrics? Is it just pasting a general outlook based on the EVT and EVC that were there before and using a template to then model within the IFTDSS system? I get that it doesn't actually alter the underlying landfire data, but I am struggling with the fact that it is specifically targeting trees of certain sizes when EVC and EVT don't really get that that kind of detail. Forgive me if I am being dense, just trying to understand how the system works with data.
Hi Ethan,
Thank you for that additional information and scenario. Given that the rule would be applied to an unedited landscape, IFTDSS would be applying a LANDFIRE Look up rule to represent those changes. Given the level of detail you need, how DBH is address in specific EVC and EVTs, this question will have to be addressed by LANDFIRE. Their helpdesk can be reached at helpdesk@landfire.gov
I apologize we couldn't provide the level of detail you need on our end, but we can at least point you to the folks who can.
Josh
IFTDSS Support Team
Ethan Bucholz
Good Evening,
I was digging through documentation trying to find out how IFTDSS alters underlying LF data when you enter treatments and I noticed that it uses FVS to model treatment impacts on areas. What does IFTDSS do to infer DBH? I would imagine FIA data is used at some point to populate tree lists, but is this just general estimates from similar FIA plots in terms of canopy cover, species and other items? Or are these real estimates of structure that are produced in the form of tree lists that FVS then models in the background? Looking for help on this front.