  This study uses hierarchical structure methods (minimal spanning tree, (MST)
and hierarchical tree, (HT)) to examine the hierarchical structures of the
United State (US) foreign trade by using the real prices of their commodity
export and import move together over time. We obtain the topological properties
among the countries based on US foreign trade over the periods of 1985-2011. We
also perform the bootstrap techniques to investigate a value of the statistical
reliability to the links of the MSTs. Finally, we use a clustering linkage
procedure in order to observe the cluster structure much better. The results of
the topologies structural of these trees are as follows: i) We identified
different clusters of countries according to their geographical location and
economic growth. ii) Our results show that the European Union and Asian
countries are more important within the network, due to a tighter connection
with other countries. The country's most important trading partners are the
Canada, China, Mexico, Japan, Germany, United Kingdom, South Korea, France,
Taiwan, India, Singapore and Netherlands iii) We have also found that these
countries play a significance role for US foreign trade and have important
implications for the design of portfolio and investment strategies.
