We consider representing tree structured features of structured data which are represented by rooted trees with ordered children. As representations of tree structured features, we use ordered tree patterns, called ordered wildcard tree patterns, which have structures of rooted ordered trees, structured variables and wildcards for edge labels. A structured variable can be replaced with an arbitrary rooted ordered tree. First we show that it is hard to compute two types of optimum frequent ordered wildcard tree patterns. Then we present an algorithm for enumerating all maximally frequent ordered wildcard tree patterns. Finally we consider extended ordered wildcard tree patterns, called ordered tag tree patterns, which have structured variables, wildcards, tags and keywords, and present an algorithm for enumerating all maximally frequent ordered tag tree patterns.We consider representing tree structured features of structured data which are represented by rooted trees with ordered children. As representations of tree structured features, we use ordered tree patterns, called ordered wildcard tree patterns, which have structures of rooted ordered trees, structured variables and wildcards for edge labels. A structured variable can be replaced with an arbitrary rooted ordered tree. First we show that it is hard to compute two types of optimum frequent ordered wildcard tree patterns. Then we present an algorithm for enumerating all maximally frequent ordered wildcard tree patterns. Finally we consider extended ordered wildcard tree patterns, called ordered tag tree patterns, which have structured variables, wildcards, tags and keywords, and present an algorithm for enumerating all maximally frequent ordered tag tree patterns.