dependency tree

plugins/ui/docs/describing/your_ui_as_a_tree.md

@@ -133,4 +133,20 @@ Although render trees may differ across render passes, these trees are generally
 
 Identifying these categories of components are useful for understanding data flow and performance of your component.
 
-## The module dependency tree
+## The dependency tree
+
+Another relationship in a `deephaven.ui` query that can be modeled with a tree are an query's dependencies. Each node in a dependency tree is a module and each branch represents an import statement in that module.
+
+If we take the previous app, we can build a dependency tree.
+
+```mermaid
+flowchart TD
+    A[app] -->|imports| B[ui]
+    A -->|imports| C[random]
+```
+
+Comparing to the render tree of the same app, there are similar structures but some notable differences:
+
+- The nodes that make-up the tree represent modules, not components.
+- Non-component modules, like `random`, are also represented in this tree. The render tree only encapsulates components.
+- Dependency trees are useful to determine what modules are necessary to run your `deephaven.ui` query.