Assisi Forest 2025 Updates

Below is a list of the more important Assisi Forest 2025 software updates.

Toggle for Model Scaling Factors Added

2025.4.2

Models predictions in Assisi can be scaled by entering scaling factors by species and/or species and type. Factors can be entered for crown, sawlog, merch, total and broken height models as well for DBH, crown, total and mortality growth models.

This version adds a toggle to easily apply or not apply scaling factors making it easy to compare how predictions perform with and without scaling factors.

Crown, Total and Mortality Growth Model Scaling Factors Added

2025.4.2

Scaling factors for crown height growth, total height growth and mortality models have existed at the species level. This version adds these to the species and type level and the stand a species levels. It also adds them to summary by stand and species.

Species and type allows plots and/or stands to select scaling factors by forest type and species. Stand and species allows user entered scaling factors to override defaults for specific stands and species. The summary by stand and species is where Assisi internal scaling factor calibration results are stored.

The hierarchy of scaling factors works like this. Default scaling factors set at the species level within a calibration are used if entered. If default factors at the species and type level have been entered and a plot or stand has a type entered, the species and type factors will override the species factors. If Assisi calibrations have been run, then scaling factors from the summary by stand and species will override the calibration defaults. Finally, if a user has entered their own scaling factors by stand and species, these will take precedence over either the defaults or the summaries. This hierarchy allows you to enter scale model results by species, by forest type, by calibrating measured growth and by entering your own factors for specific stands.

Young Growth Model Criteria Changed from Total Height to DBH

2025.4.1

Assisi's young growth model is used to estimate growth on small trees. Versions prior to this version used tree total height to determine if a tree was "young". This version uses DBH for that determination. This aligns the young growth model more closely with how FVS chooses trees to grow using its small tree growth model.

Calibrating Total Height Using Tarif Estimates.

2025.2.3

Assisi can estimate total height using local tarif numbers and a cubic foot vs total height equation. A difficulty one can run into is when total height is estimated using tarif while crown height is estimated using another method. The two methods can give incompatible results, for example a crown that is higher than total height. One solution is to calculate a scaling factor for total height and then apply that factor to the crown height estimate.

This version adds the ability to calibrate tarif total heights against a total height model then apply that scaling factor to crown height estimates. This should result in compatible crown heights when both the total height model and crown height model are compatible, for example when both are from the ORGANON model.

Model Tree Groupings Moved to Calibration Fields

2025.1.2

Assisi can process growth modeling with trees in separate plots, combined into one plot or as stand table data. In previous versions, the method was set in the growth model settings. With this version, the method is stored in the Calibration TreeGroupCompile, TreeGroupGrowth and TreeGroupSimulate fields.

Thinning Triggers

2025.1.2

When to process a thinning is more often triggered by conditions on the ground rather than at a scheduled interval. Assisi can do both. And with this version you can define complex thinning triggers using C# scripting.

This version exposes a Trigger class that can be coded in C# to be as complex or as simple or plan simulations, Assisi processes your code to determine if thinning actions need to take place.

For example, here is a thinning trigger that schedules triggers based on stocking, age and habitat. This type of thinning is found within the Lake States region of the US. A prescription for White Pine is suggested in the chart below. Note that the prescription involves triggering on "Habitat" types, "Featured" species, definitions of different types of thinning: "Final Cut Shelterwood, 1st Cut Shelterwood" as well as age and TPA.

White Pine Prescription

Here is the Assisi trigger for White Pine as coded in C# scripting. The Initialize() method is used to define variables. The Trigger() method carries out the thinning log. Triggers can be a complex or simple as needed.