城市膨胀,森林锐减,是人类社会发展到今天的两种趋势。城市是人类从自然环境中分离出来的人造环境,城市生态系统是由自然和人工两部分组成的综合体;绿色植被在这个独特的人工生态系统中占有重要位置。研究城市生态,探索城市林业,改善人类生存环境,是这两种趋势向林业工作者提出的新课题。 The expansion of cities and the sharp decline of forests are two trends in the development of human society. The city is an artificial environment separated from the natural environment by human beings. The urban ecosystem is a complex composed of natural and artificial parts; green vegetation plays an important role in this unique artificial ecosystem. Studying urban ecology, exploring urban forestry, and improving human living environment are the new topics that these two trends have brought to forestry workers.