diff --git a/pyproject.toml b/pyproject.toml
index 7c22e90..b7d1803 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -20,8 +20,11 @@ urls.Source = "https://github.com/YosefLab/treedata"
 urls.Home-page = "https://github.com/YosefLab/treedata"
 dependencies = [
     "anndata",
+    "copy",
+    "h5py",
     "numpy",
     "pandas",
+    "pathlib",
     "pyarrow",
     "networkx",
     "session-info",
diff --git a/src/treedata/_core/read.py b/src/treedata/_core/read.py
index ad756b6..a7b7a79 100755
--- a/src/treedata/_core/read.py
+++ b/src/treedata/_core/read.py
@@ -1,5 +1,6 @@
 from __future__ import annotations
 
+import json
 from collections.abc import MutableMapping, Sequence
 from pathlib import Path
 from typing import (
@@ -7,6 +8,7 @@
 )
 
 import anndata as ad
+import h5py
 import zarr
 from scipy import sparse
 
@@ -15,16 +17,14 @@
 from treedata._utils import dict_to_digraph
 
 
-def _tdata_from_adata(tdata) -> TreeData:
+def _tdata_from_adata(tdata, treedata_attrs=None) -> TreeData:
     """Create a TreeData object parsing attribute from AnnData uns field."""
     tdata.__class__ = TreeData
-    if "treedata_attrs" in tdata.uns.keys():
-        treedata_attrs = tdata.uns["treedata_attrs"]
+    if treedata_attrs is not None:
         tdata._tree_label = treedata_attrs["label"] if "label" in treedata_attrs.keys() else None
         tdata._allow_overlap = bool(treedata_attrs["allow_overlap"])
         tdata._obst = AxisTrees(tdata, 0, vals={k: dict_to_digraph(v) for k, v in treedata_attrs["obst"].items()})
         tdata._vart = AxisTrees(tdata, 1, vals={k: dict_to_digraph(v) for k, v in treedata_attrs["vart"].items()})
-        del tdata.uns["treedata_attrs"]
     else:
         tdata._tree_label = None
         tdata._allow_overlap = False
@@ -71,7 +71,12 @@ def read_h5ad(
         as_sparse_fmt=as_sparse_fmt,
         chunk_size=chunk_size,
     )
-    return _tdata_from_adata(adata)
+    with h5py.File(filename, "r") as f:
+        if "raw.treedata_attrs" in f:
+            treedata_attrs = json.loads(f["raw.treedata_attrs"][()])
+        else:
+            treedata_attrs = None
+    return _tdata_from_adata(adata, treedata_attrs)
 
 
 def read_zarr(store: str | Path | MutableMapping | zarr.Group) -> TreeData:
@@ -83,4 +88,7 @@ def read_zarr(store: str | Path | MutableMapping | zarr.Group) -> TreeData:
         The filename, a :class:`~typing.MutableMapping`, or a Zarr storage class.
     """
     adata = ad.read_zarr(store)
-    return _tdata_from_adata(adata)
+    if "treedata_attrs" in adata.uns.keys():
+        treedata_attrs = adata.uns["treedata_attrs"]
+        del adata.uns["treedata_attrs"]
+    return _tdata_from_adata(adata, treedata_attrs)
diff --git a/src/treedata/_core/treedata.py b/src/treedata/_core/treedata.py
index 99955bb..a83b384 100755
--- a/src/treedata/_core/treedata.py
+++ b/src/treedata/_core/treedata.py
@@ -1,7 +1,9 @@
 from __future__ import annotations
 
-import warnings
+import json
 from collections.abc import Iterable, Mapping, MutableMapping, Sequence
+from copy import deepcopy
+from pathlib import Path
 from typing import (
     TYPE_CHECKING,
     Any,
@@ -9,10 +11,12 @@
 )
 
 import anndata as ad
+import h5py
 import networkx as nx
 import numpy as np
 import pandas as pd
-from anndata._core.index import Index, Index1D
+from anndata._core.index import Index, Index1D, _subset
+from anndata._io.h5ad import write_h5ad
 from scipy import sparse
 
 from treedata._utils import digraph_to_dict
@@ -282,31 +286,57 @@ def _treedata_attrs(self) -> dict:
             "allow_overlap": self.allow_overlap,
         }
 
+    def _mutated_copy(self, **kwargs):
+        """Creating TreeData with attributes optionally specified via kwargs."""
+        if self.isbacked:
+            if "X" not in kwargs or (self.raw is not None and "raw" not in kwargs):
+                raise NotImplementedError(
+                    "This function does not currently handle backed objects "
+                    "internally, this should be dealt with before."
+                )
+        new = {}
+        new["label"] = self.label
+        new["allow_overlap"] = self.allow_overlap
+
+        for key in ["obs", "var", "obsm", "varm", "obsp", "varp", "obst", "vart", "layers"]:
+            if key in kwargs:
+                new[key] = kwargs[key]
+            else:
+                new[key] = getattr(self, key).copy()
+        if "X" in kwargs:
+            new["X"] = kwargs["X"]
+        elif self._has_X():
+            new["X"] = self.X.copy()
+        if "uns" in kwargs:
+            new["uns"] = kwargs["uns"]
+        else:
+            new["uns"] = deepcopy(self._uns)
+        if "raw" in kwargs:
+            new["raw"] = kwargs["raw"]
+        elif self.raw is not None:
+            new["raw"] = self.raw.copy()
+
+        return TreeData(**new)
+
     def copy(self, filename: PathLike | None = None) -> TreeData:
-        """Full copy, optionally on disk"""
-        adata = super().copy(filename=filename)
+        """Full copy, optionally on disk."""
         if not self.isbacked:
-            treedata_copy = TreeData(
-                adata,
-                obst=self.obst.copy(),
-                vart=self.vart.copy(),
-                label=self.label,
-                allow_overlap=self.allow_overlap,
-            )
+            if self.is_view and self._has_X():
+                return self._mutated_copy(X=_subset(self._adata_ref.X, (self._oidx, self._vidx)).copy())
+            else:
+                return self._mutated_copy()
         else:
             from .read import read_h5ad
 
             if filename is None:
                 raise ValueError(
-                    "To copy an TreeData object in backed mode, "
+                    "To copy an AnnData object in backed mode, "
                     "pass a filename: `.copy(filename='myfilename.h5ad')`. "
                     "To load the object into memory, use `.to_memory()`."
                 )
             mode = self.file._filemode
-            adata.uns["treedata_attrs"] = self._treedata_attrs()
-            adata.write_h5ad(filename)
-            treedata_copy = read_h5ad(filename, backed=mode)
-        return treedata_copy
+            self.write_h5ad(filename)
+            return read_h5ad(filename, backed=mode)
 
     def transpose(self) -> TreeData:
         """Transpose whole object
@@ -347,13 +377,23 @@ def write_h5ad(
             Sparse arrays in TreeData object to write as dense. Currently only
             supports `X` and `raw/X`.
         """
-        with warnings.catch_warnings():
-            warnings.simplefilter("ignore")
-            self.uns["treedata_attrs"] = self._treedata_attrs()
-        super().write_h5ad(
-            filename=filename, compression=compression, compression_opts=compression_opts, as_dense=as_dense
+        if filename is None and not self.isbacked:
+            raise ValueError("Provide a filename!")
+        if filename is None:
+            filename = self.filename
+
+        write_h5ad(
+            Path(filename),
+            self,
+            compression=compression,
+            compression_opts=compression_opts,
+            as_dense=as_dense,
         )
-        self.uns.pop("treedata_attrs")
+
+        with h5py.File(filename, "a") as f:
+            if "raw.treedata_attrs" in f:
+                del f["raw.treedata_attrs"]
+            f.create_dataset("raw.treedata_attrs", data=json.dumps(self._treedata_attrs()))
 
     write = write_h5ad  # a shortcut and backwards compat
 
diff --git a/tests/test_readwrite.py b/tests/test_readwrite.py
index f53f927..241d54b 100755
--- a/tests/test_readwrite.py
+++ b/tests/test_readwrite.py
@@ -75,7 +75,7 @@ def test_read_anndata(tdata, tmp_path):
 def test_h5ad_backing(tdata, tree, tmp_path):
     tdata_copy = tdata.copy()
     assert not tdata.isbacked
-    backing_h5ad = tmp_path / "test.h5ad"
+    backing_h5ad = tmp_path / "test_backed.h5ad"
     tdata.filename = backing_h5ad
     # backing mode
     tdata.write()
@@ -93,13 +93,10 @@ def test_h5ad_backing(tdata, tree, tmp_path):
     with pytest.warns(UserWarning):
         with pytest.raises(ValueError):
             tdata_subset.obs["foo"] = range(3)
-    # with pytest.warns(UserWarning):
-    #    with pytest.raises(ValueError):
-    #       tdata_subset.obst["foo"] = tree
     assert subset_hash == joblib.hash(tdata_subset)
     assert tdata_subset.is_view
     # copy
-    tdata_subset = tdata_subset.copy(tmp_path / "test.subset.h5ad")
+    tdata_subset = tdata_subset.copy(tmp_path / "test_subset.h5ad")
     assert not tdata_subset.is_view
     tdata_subset.obs["foo"] = range(3)
     assert not tdata_subset.is_view
@@ -110,4 +107,9 @@ def test_h5ad_backing(tdata, tree, tmp_path):
     tdata_subset = tdata_subset.to_memory()
     assert not tdata_subset.is_view
     assert not tdata_subset.isbacked
+    print(tdata_subset)
     check_graph_equality(tdata_subset.obst["tree"], tdata.obst["tree"])
+
+
+if __name__ == "__main__":
+    pytest.main(["-v", __file__])
diff --git a/tests/test_views.py b/tests/test_views.py
index bdefbcd..dff59e4 100755
--- a/tests/test_views.py
+++ b/tests/test_views.py
@@ -75,6 +75,23 @@ def test_views_subset_trees():
     assert list(tdata_subset.obst["tree2"].edges) == [("root", "2")]
 
 
+def test_views_copy():
+    # subset tdata with multiple trees
+    tree1 = nx.DiGraph([("root", "0"), ("root", "1")])
+    tree2 = nx.DiGraph([("root", "2"), ("root", "3")])
+    tdata = td.TreeData(X=np.zeros((8, 8)), allow_overlap=False, obst={"tree1": tree1, "tree2": tree2})
+    tdata_subset = tdata.copy()[["0", "1"], :].copy()
+    assert list(tdata_subset.obst["tree1"].edges) == [("root", "0"), ("root", "1")]
+    assert list(tdata_subset.obst["tree2"].edges) == []
+    print(tdata_subset)
+    tdata_subset = tdata.copy()[["2", "3"], :].copy()
+    assert list(tdata_subset.obst["tree1"].edges) == []
+    assert list(tdata_subset.obst["tree2"].edges) == [("root", "2"), ("root", "3")]
+    tdata_subset = tdata.copy()[["0", "1", "2"], :].copy()
+    assert list(tdata_subset.obst["tree1"].edges) == [("root", "0"), ("root", "1")]
+    assert list(tdata_subset.obst["tree2"].edges) == [("root", "2")]
+
+
 def test_views_mutability(tdata):
     # can mutate attributes of graph
     nx.set_node_attributes(tdata.obst["tree"], False, "in_subset")
@@ -140,3 +157,7 @@ def test_views_contains(tdata):
 def test_views_len(tdata):
     tdata_subset = tdata[[0, 1, 4], :]
     assert len(tdata_subset.obst) == 1
+
+
+if __name__ == "__main__":
+    pytest.main(["-v", __file__])