Interesting how foliage changed with increased size
.
This is a common reaction with increased health after collection. The trees selected for collection are often located in harsher environments and struggling for survival. This gives them a good portion of their character and smaller stature. Improving the environment and availability of nutrients naturally leads to an increase in foliage and foliage size. Once the tree has regained vigour the normal techniques can be applied to reduce needle size.
One other disconcerting change is rapid trunk thickening in conifers that can crack the thick aged flakey bark that is prized on some collected specimens.
One step that can be helpful is to limit fertilizer and time the application of same after the foliage has hardened off. For my collected trees I focus on small amounts of fertilizer in the late summer, early fall. The other time I tend to use smaller amounts is a month or so after repots that remove a good portion of the native soil. I also restrict my type of fertilizer to those with overall numbers below 10 in NPK. My preference is organic that breaks down very slowly and is kept in tea bags to allow for removal and limited application. The same principals could apply to liquid fertilizer application if you have a favourite. It is easy to stop and start liquid fertilizer application, particularly with inorganic substrates and low CEC ratings.