dynamic code list on plot level (dependent on single tree species)

Dear Lutz,
We don't support such a dynamic table nowadays... but... you can try to solve this issue with a workaround using the default values.
First of all, please update Collect to the latest version (3.20.18) and follow these steps:

• define a calculated numeric (integer) attribute at the same level of the tree entity to calculate the number of distinct tree species and call it for example distinct_species_count
• in the calculated value expression write this: idm:count-distinct(tree/species) (where species is the name of your Taxon attribute)
• define a multiple entity at the plot level
• define a key attribute of type Taxon inside the new multiple entity
• in the default value box, add a new default value
• in the Apply when field write: parent()/count_distinct_species >= idm:position($context)
• in the Expression field write: idm:distinct-values(parent()/tree/species)[idm:position($context)]
• in the Checks (Validation Rules) box, define a new Custom check to ensure that the inserted species is among the ones defined for the trees
• write this in the Expression: count(parent()/tree[species=$this]) > 0
• write a custom error message that indicates: Species has not been specified for any tree

Now, when you have already defined a list of trees, whenever you add a new row inside the newly defined entity, the value of the Species field will be automatically populated with the species defined in the tree table.

Please try this solution and let us know if it fits your needs.

Many thanks,
Open Foris Team