Is this what you are looking for? Here is a fiddle demo.
The layout is based on percentage, colors are for clarity. If the content column overflows, a scrollbar should appear.
body, html, .container-fluid {
height: 100%;
}
.navbar {
width:100%;
background:yellow;
}
.article-tree {
height:100%;
width: 25%;
float:left;
background: pink;
}
.content-area {
overflow: auto;
height: 100%;
background:orange;
}
.footer {
background: red;
width:100%;
height: 20px;
}