Minimum spanning tree by hand

The Wirehouse Lumber Company will soon begin logging eight groves of trees in the same general area. Therefore, it must develop a system of dirt roads that makes each grove accessible from every other grove. The distance (in miles) between every pair of groves is as follows: Management now wishes to determine between which pairs of groves the roads should be constructed to connect all groves with a minimum total length of road. Describe how this problem fits the network description of the minimum spanning tree