diff --git a/package/CHANGELOG b/package/CHANGELOG
index 08234a6cb6e..93524527cd4 100644
--- a/package/CHANGELOG
+++ b/package/CHANGELOG
@@ -20,7 +20,8 @@ The rules for this file:
 
 Enhancements
 
-
+  * Modified around selections to work with KDTree and periodic boundary
+    conditions.  Should reduce memory usage (#974 PR #2022)
   * Modified topology.guessers.guess_bonds to automatically select the
     fastest method for guessing bonds using
     lib.distance.self_capped_distance (PR # 2006)
diff --git a/package/MDAnalysis/core/selection.py b/package/MDAnalysis/core/selection.py
index bc4a256e20e..4532ac854a7 100644
--- a/package/MDAnalysis/core/selection.py
+++ b/package/MDAnalysis/core/selection.py
@@ -243,9 +243,6 @@ def __init__(self):
             self.apply = self._apply_distmat
 
         self.periodic = flags['use_periodic_selections']
-        # KDTree doesn't support periodic
-        if self.periodic:
-            self.apply = self._apply_distmat
 
     def validate_dimensions(self, dimensions):
         r"""Check if the system is periodic in all three-dimensions.
@@ -282,6 +279,9 @@ def _apply_KDTree(self, group):
         # All atoms in group that aren't in sel
         sys = group[~np.in1d(group.indices, sel.indices)]
 
+        if not sys:
+            return sys[[]]
+
         box = self.validate_dimensions(group.dimensions)
 
         cut = self.cutoff if box is not None else None
@@ -321,7 +321,8 @@ def _apply_KDTree(self, group):
         """
         sel = self.sel.apply(group)
         box = self.validate_dimensions(group.dimensions)
-        ref = sel.center_of_geometry(pbc=self.periodic)
+        periodic = box is not None
+        ref = sel.center_of_geometry(pbc=periodic)
         kdtree = PeriodicKDTree(box=box)
 
         cutoff = self.exRadius if box is not None else None
@@ -363,7 +364,8 @@ def _apply_KDTree(self, group):
         """
         sel = self.sel.apply(group)
         box = self.validate_dimensions(group.dimensions)
-        ref = sel.center_of_geometry(pbc=self.periodic)
+        periodic = box is not None
+        ref = sel.center_of_geometry(pbc=periodic)
 
         cut = self.cutoff if box is not None else None
         kdtree = PeriodicKDTree(box=box)
@@ -483,7 +485,7 @@ def __init__(self, parser, tokens):
         self.cutoff = float(tokens.popleft())
 
     def _apply_KDTree(self, group):
-        box = group.dimensions if self.periodic else None
+        box = self.validate_dimensions(group.dimensions)
         kdtree = PeriodicKDTree(box=box)
         cut = self.cutoff if box is not None else None
         kdtree.set_coords(group.positions, cutoff=cut)
@@ -496,7 +498,7 @@ def _apply_distmat(self, group):
         ref_coor = self.ref[np.newaxis, ...]
 
         ref_coor = np.asarray(ref_coor, dtype=np.float32)
-        box = group.dimensions if self.periodic else None
+        box = self.validate_dimensions(group.dimensions)
 
         dist = distances.distance_array(group.positions, ref_coor, box)
         mask = (dist <= self.cutoff).any(axis=1)