diff --git a/.gitignore b/.gitignore
index 6a73c32..311267d 100644
--- a/.gitignore
+++ b/.gitignore
@@ -135,3 +135,6 @@ dmypy.json
 
 # Pyre type checker
 .pyre/
+
+# uv
+uv.lock
diff --git a/asdf_pydantic/converter.py b/asdf_pydantic/converter.py
index 4be2684..d81383f 100644
--- a/asdf_pydantic/converter.py
+++ b/asdf_pydantic/converter.py
@@ -40,4 +40,4 @@ def to_yaml_tree(self, obj: AsdfPydanticModel, tag, ctx):
         return obj.asdf_yaml_tree()
 
     def from_yaml_tree(self, node, tag, ctx):
-        return self._tag_to_class[tag].parse_obj(node)
+        return self._tag_to_class[tag].model_validate(node)
diff --git a/asdf_pydantic/model.py b/asdf_pydantic/model.py
index 2d38157..20e2918 100644
--- a/asdf_pydantic/model.py
+++ b/asdf_pydantic/model.py
@@ -15,33 +15,42 @@ class AsdfPydanticModel(BaseModel):
     ASDF Serialization and Deserialization:
         Serialize to ASDF yaml tree is done with the
         py:classmethod`AsdfPydanticModel.asdf_yaml_tree()` and deserialize to an
-        AsdfPydanticModel object with py:meth`AsdfPydanticModel.parse_obj()`.
+        AsdfPydanticModel object with py:meth`AsdfPydanticModel.model_validate()`.
     """
 
     _tag: ClassVar[str | TagDefinition]
     model_config = ConfigDict(arbitrary_types_allowed=True)
 
     def asdf_yaml_tree(self) -> dict:
-        d = {}
-        for field_key, v in self.__dict__.items():
-            if field_key not in self.__fields__:
-                continue
-
+        """Converts the model to an ASDF-compatible YAML tree (dict).
+
+        .. note::
+            Any fields that are normal Pydantic `BaseModel` will be converted to
+            dict. See conversion table.
+
+        Conversion Table:
+
+            +-------------------------+-----------------------------+
+            | Value type in field     | Value type in dict          |
+            +=========================+=============================+
+            | AsdfPydanticModel       | No conversion               |
+            +-------------------------+-----------------------------+
+            | BaseModel               | Converted to dict using     |
+            |                         | BaseModel.model_dump()      |
+            +-------------------------+-----------------------------+
+            | Other types             | No conversion               |
+            +-------------------------+-----------------------------+
+        """
+        tree = {}
+        for k, v in dict(self).items():
             if isinstance(v, AsdfPydanticModel):
-                d[field_key] = v
+                tree[k] = v
+            elif isinstance(v, BaseModel):
+                tree[k] = v.model_dump()
             else:
-                d[field_key] = self._get_value(
-                    v,
-                    to_dict=True,
-                    by_alias=False,
-                    include=None,
-                    exclude=None,
-                    exclude_unset=False,
-                    exclude_defaults=False,
-                    exclude_none=False,
-                )
-
-        return d
+                tree[k] = v
+
+        return tree
 
     @model_validator(mode="before")
     @classmethod
diff --git a/tests/test_model.py b/tests/test_model.py
index 9f78227..00f1f3d 100644
--- a/tests/test_model.py
+++ b/tests/test_model.py
@@ -1,10 +1,52 @@
 import pytest
 import yaml
 from asdf.extension import TagDefinition
+from pydantic import BaseModel
 
 from asdf_pydantic import AsdfPydanticModel
 
 
+########################################################################################
+# ASDF Tree
+########################################################################################
+def test_asdf_yaml_tree_sanity():
+    class TestModel(AsdfPydanticModel):
+        foo: str
+
+    model = TestModel(foo="bar")
+    assert model.asdf_yaml_tree() == {"foo": "bar"}
+
+
+def test_asdf_yaml_tree_nested_dict():
+    class NestedTestModel(AsdfPydanticModel):
+        nested: dict
+
+    model = NestedTestModel(nested={"foo": "bar"})
+    assert model.asdf_yaml_tree() == {"nested": {"foo": "bar"}}
+
+
+def test_asdf_yaml_tree_nested_basemodel():
+    class TestModel(BaseModel):
+        foo: str
+
+    class NestedTestModel(AsdfPydanticModel):
+        nested: TestModel
+
+    model = NestedTestModel(nested=TestModel(foo="bar"))
+    assert model.asdf_yaml_tree() == {"nested": {"foo": "bar"}}
+
+
+def test_asdf_yaml_tree_nested_asdf_pydantic_model():
+    class TestModel(AsdfPydanticModel):
+        foo: str
+
+    class NestedTestModel(AsdfPydanticModel):
+        nested: TestModel
+
+    model = NestedTestModel(nested=TestModel(foo="bar"))
+    assert model.asdf_yaml_tree() == {"nested": TestModel(foo="bar")}
+
+
 ########################################################################################
 # TAGS
 ########################################################################################