This area is approximately 45 km from Jiaohe in Jilin Province,
China, and has a monsoon climate with dry, windy springs and
warm, wet summers. The tree vegetation primarily consists of 19
tree species, among which Juglans mandshurica MAXIM., Fraxinus
mandshurica RUPR. and Phellodendron amurense Rupr. are used to
define forest stand types and are known as the ‘‘three great hardwoods’’
in north-eastern China because of their economic importance
and increasing value in forest conservation. The two
monitoring sites in this area are both 1 ha in size.