I understand environmental stress...and I gather that age plays a part as well, but my observations indicate that it is more variable or serendipitous than that. This year, for example, in my garden, Abies arnoldiana 'Poulsen' (two plants), which are reasonably good sized, both have hundreds of cones on them and have never had more than a few. They are situated about 25' apart. Ditto Picea omorika 'Pendula Bruns' - maybe thousands among the three of them. Very close to the Picea o. is a Picea abies pendula with three cones on it - in years past has had way more. The A. koreanas all seem to cone like crazy every year, whereas my two Abies pinsapos (one a glauca, one an aurea) have never coned, not once, even though the glauca is the second biggest/oldest conifer in my garden. I also have four C. libani var. atlantica 'Glauca Pendula', one is enormous, two have been in the ground for 7-8 years and none of them have ever coned. Thoughts? Or should I just not worry about it and enjoy them!

Sara