本文系统地综述了树木的老化、幼年性、成年性、相互关系及其利用的各个方面.在不同老化中,以个体发育老化对林木无性繁殖关系最大,无性繁殖中的各种麻烦都与这种老化有关.从幼年期到成年期到老年期,本是树木一生中的个体发育历程,然而由于树木的特点,这三个时期可在一株树上同时并存,这是树木老化不均衡性的有趣方面.如何将这一不均衡性巧妙用于育种和无性繁殖,是本文讨论的主要内容.作者最后结合毛白杨的位置效应、成熟效应、幼化处理和幼化材料的分析作例子,阐述林木育种中深刻认识老化及幼化的重要性. In this paper, we systematically reviewed the aspects of aging, juvenile, adult, interrelationships and their utilization of trees.In the different ages, the individual developmental aging has the greatest relationship with climatic asexual reproduction of trees, and all kinds of troubles in asexual reproduction are related to this From the juvenile to adulthood to the old age, this is the tree throughout the life of the individual development history, but because of the characteristics of the trees, these three periods can co-exist in a tree, which is the aging of trees is not balanced Of the interesting aspects.How to use this imbalance cleverly for breeding and asexual reproduction, is the main content of this article.Finally, the author combined with the location effect of Populus tomentosa, maturation effect, seedling treatment and the analysis of young material as an example, Describe the importance of deep understanding of aging and seedling in tree breeding.