Objects of class semforest and semtree are very
large, which complicates downstream operations such as making partial
dependence plots, or using the model in interactive contexts (like Shiny
apps). Running strip removes all elements of the model
except for the tree structure and terminal node parameters. Note that some
methods are no longer available for the resulting object - e.g.,
varimp requires the terminal node SEM models to compute the
likelihood ratio.