人们常用“铁树开花”来比喻不易办到或可遇而不可求之事,说明铁树开花不易。其实,话要看怎么说了,依我看,只要同时具备三个条件,铁树就开花并不难。一是树龄必须在20年以上,树高在35厘米以上,茎径在25厘米以上。二是环境因素。苏铁原产亚热带,要求年平均气温高,日照充足,昼夜温差 People often use “Tieshu flowering” to metaphor is not easy to do or meet the event can not be found, indicating Tieshu flowering is not easy. Actually, it depends on how to say it. In my opinion, as long as the three conditions are met at the same time, it is not difficult for Tieshu to blossom. First, the age must be more than 20 years, tree height above 35 cm, stem diameter of 25 cm or more. Second, environmental factors. Cycas origin of the subtropical, requiring high average annual temperature, adequate sunshine, temperature difference between day and night