diff --git a/include/dbidef.h b/include/dbidef.h
index ecf0cecf39..20979b6e25 100644
--- a/include/dbidef.h
+++ b/include/dbidef.h
@@ -9,24 +9,21 @@
  Item list codes for TreeGetDbi
 **********************************/
 
-#define DbiEND_OF_LIST 0 /* End of list */
-#define DbiNAME 1        /* Experiment name used for open - text string */
-#define DbiSHOTID 2      /* Shot identification - longword */
-#define DbiMODIFIED                                                                \
-  3                        /* True if tree has been modified during edit - boolean \
-                            */
-#define DbiOPEN_FOR_EDIT 4 /* True if tree is open for edit - boolean */
-#define DbiINDEX \
-  5                             /* Index of tree to use for subsequent information requests */
-#define DbiNUMBER_OPENED 6      /* Number of trees currently open */
-#define DbiMAX_OPEN 7           /* Maximum number of tree allowed open at one time */
-#define DbiDEFAULT 8            /* NID of default node */
-#define DbiOPEN_READONLY 9      /* True if tree has been opened readonly */
-#define DbiVERSIONS_IN_MODEL 10 /* True if using versioning in model */
-#define DbiVERSIONS_IN_PULSE 11 /* True if using versioning in pulse files */
-#define DbiREADONLY 12          /* True if making tree readonly */
-#define DbiDISPATCH_TABLE 13    /* Tree dispatch table */
-
+#define DbiEND_OF_LIST 0           /* End of list */
+#define DbiNAME 1                  /* Experiment name used for open - text string */
+#define DbiSHOTID 2                /* Shot identification - longword */
+#define DbiMODIFIED 3              /* True if tree has been modified during edit - boolean */
+#define DbiOPEN_FOR_EDIT 4         /* True if tree is open for edit - boolean */
+#define DbiINDEX  5                /* Index of tree to use for subsequent information requests */
+#define DbiNUMBER_OPENED 6         /* Number of trees currently open */
+#define DbiMAX_OPEN 7              /* Maximum number of tree allowed open at one time */
+#define DbiDEFAULT 8               /* NID of default node */
+#define DbiOPEN_READONLY 9         /* True if tree has been opened readonly */
+#define DbiVERSIONS_IN_MODEL 10    /* True if using versioning in model */
+#define DbiVERSIONS_IN_PULSE 11    /* True if using versioning in pulse files */
+#define DbiREADONLY 12             /* True if making tree readonly */
+#define DbiDISPATCH_TABLE 13       /* Tree dispatch table */
+#define DbiALTERNATE_COMPRESSION 14 /* Set to true to enable extended compression methods */
 typedef struct dbi_itm
 {
   short int buffer_length;
diff --git a/include/mdsobjects.h b/include/mdsobjects.h
index f393295958..f44af2f12f 100644
--- a/include/mdsobjects.h
+++ b/include/mdsobjects.h
@@ -4142,6 +4142,16 @@ namespace MDSplus
     ///
     void setVersionsInPulse(bool enable);
 
+    /// This function returns true if the tree allows for alternate compression
+    /// methods (gzip).  \note this can only be changed in edit mode.
+    /// 
+    bool alternateCompressionEnabled();
+
+    /// Activates alternate compression methods. See treeshr function \ref
+    /// TreeGetDbi() called with code DbiALTERNATE_COMPRESSION.
+    ///
+    void setAlternateCompression(bool enable);
+
     /// View data stored in tree from given start date when version control is
     /// enabled.
     ///
diff --git a/mdsobjects/cpp/mdstreeobjects.cpp b/mdsobjects/cpp/mdstreeobjects.cpp
index 7c07ae597d..c30e6565d3 100644
--- a/mdsobjects/cpp/mdstreeobjects.cpp
+++ b/mdsobjects/cpp/mdstreeobjects.cpp
@@ -570,6 +570,11 @@ bool Tree::versionsInModelEnabled()
   return dbiTest(getCtx(), DbiVERSIONS_IN_MODEL);
 }
 
+bool Tree::alternateCompressionEnabled()
+{
+  return dbiTest(getCtx(), DbiALTERNATE_COMPRESSION);
+}
+
 bool Tree::isModified() { return dbiTest(getCtx(), DbiMODIFIED); }
 
 bool Tree::isOpenForEdit() { return dbiTest(getCtx(), DbiOPEN_FOR_EDIT); }
@@ -598,6 +603,11 @@ void Tree::setVersionsInPulse(bool verEnabled)
   dbiSet(getCtx(), DbiVERSIONS_IN_PULSE, verEnabled);
 }
 
+void Tree::setAlternateCompression(bool altEnabled)
+{
+  dbiSet(getCtx(), DbiALTERNATE_COMPRESSION, altEnabled);
+}
+
 void Tree::setViewDate(char *date)
 {
   int64_t qtime;
diff --git a/mdsobjects/cpp/testing/MdsTreeTest.cpp b/mdsobjects/cpp/testing/MdsTreeTest.cpp
index f181857d5c..4abd426003 100644
--- a/mdsobjects/cpp/testing/MdsTreeTest.cpp
+++ b/mdsobjects/cpp/testing/MdsTreeTest.cpp
@@ -79,11 +79,13 @@ using namespace testing;
 //    TreeNode *getDefault();
 //    bool versionsInModelEnabled();
 //    bool versionsInPulseEnabled();
+//    bool alternateCompressionEnabled();
 //    bool isModified();
 //    bool isOpenForEdit();
 //    bool isReadOnly();
 //    void setVersionsInModel(bool enable);
 //    void setVersionsInPulse(bool enable);
+//    void setAlternateCompression(bool enable);
 //    void setViewDate(char *date);
 //    void setTimeContext(Data *start, Data *end, Data *delta);
 //    void createPulse(int shot);
@@ -425,6 +427,17 @@ int main(int argc __attribute__((unused)),
     tree = new Tree("t_tree", 1, "EDIT");
     unique_ptr<TreeNode> node = tree->addNode("versioned", "NUMERIC");
     tree->setVersionsInPulse(true);
+
+    // alternate compression - default False
+    TEST0(tree->alternateCompressionEnabled());
+
+    // alternate compression - set to True
+    tree->setAlternateCompression(true);
+    TEST1(tree->alternateCompressionEnabled());
+
+    // set alternate compression back to False
+    tree->setAlternateCompression(false);
+
     tree->write();
 
     tree = new Tree("t_tree", 1);
@@ -446,6 +459,9 @@ int main(int argc __attribute__((unused)),
 
     TEST1(node->containsVersions());
 
+    // alternate compression - should be false
+    TEST0(tree->alternateCompressionEnabled());
+
     // TODO: version in model
   }
 
diff --git a/python/MDSplus/tree.py b/python/MDSplus/tree.py
index a8a33fca96..524c42fc19 100644
--- a/python/MDSplus/tree.py
+++ b/python/MDSplus/tree.py
@@ -144,6 +144,7 @@ class Dbi(object):
     VERSIONS_IN_MODEL = (10, bool, 4)  # settable
     VERSIONS_IN_PULSE = (11, bool, 4)  # settable
     DISPATCH_TABLE = (13, bool, 4)
+    ALTERNATE_COMPRESSION = (14, bool, 4) #settable
 
     class _dbi_item(_C.Structure):
         """ Ctype structure class for making calls into _TreeGetDbi() """
@@ -652,6 +653,8 @@ def _setDbi(self, info, value):
         Dbi.VERSIONS_IN_PULSE, "Support versioning of data in pulse.", True)
     dispatch_table = Dbi._dbiProp(
         Dbi.DISPATCH_TABLE,   "True if dispatch table is built")
+    alternate_compression = Dbi._dbiProp(
+        Dbi.ALTERNATE_COMPRESSION,  "Set to True to enable alternate compression methods", False)
 
     @property
     def default(self):
@@ -1112,7 +1115,7 @@ def setVersionsInModel(self, flag):
 
     def setVersionsInPulse(self, flag):
         """Enable/Disable versions in pulse
-        @param flag: True or False. True enabled versions
+        @param flag: True or False. True enables versions
         @type flag: bool
         @rtype: None
         """
@@ -1132,6 +1135,21 @@ def versionsInPulseEnabled(self):
         """
         return self.versions_in_pulse
 
+    def setAlternateCompression(self, flag):
+        """Enable/Disable alternate compression methods
+        @param flag: True or False. True enables alternate compression methods
+        @type flag: bool
+        @rtype: None
+        """
+        self.alternate_compression = bool(flag)
+
+    def alternateCompressionEnabled(self):
+        """Check to see if alternate compression methods are enabled
+        @return: True if alternate compression methods are enabled
+        @rtype: bool
+        """
+        return self.alternate_compression
+
     def write(self):
         """Write out edited tree.
         @rtype: None
diff --git a/tcl/tcl_setshow_alternate_compression.c b/tcl/tcl_setshow_alternate_compression.c
new file mode 100644
index 0000000000..662fcc8973
--- /dev/null
+++ b/tcl/tcl_setshow_alternate_compression.c
@@ -0,0 +1,102 @@
+/*
+Copyright (c) 2023, Massachusetts Institute of Technology All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+Redistributions of source code must retain the above copyright notice, this
+list of conditions and the following disclaimer.
+
+Redistributions in binary form must reproduce the above copyright notice, this
+list of conditions and the following disclaimer in the documentation and/or
+other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+#include <stdlib.h>
+#include <string.h>
+#include <ctype.h>
+
+#include <dbidef.h>
+#include <dcl.h>
+#include <mds_stdarg.h>
+#include <mdsdcl_messages.h>
+#include <mdsshr.h>
+#include <treeshr.h>
+
+/***************************************************************
+ * TclSetAlternateCompression:
+ **************************************************************/
+
+EXPORT int TclSetAlternateCompression(void *ctx, char **error,
+                          char **output __attribute__((unused)))
+{
+  int status = 1;
+
+  char * enabled = 0;
+  status = cli_get_value(ctx, "ENABLED", &enabled);
+  if (STATUS_OK) {
+    char * pch = enabled;
+    while (pch && (*pch) != '\0') {
+      (*pch) = toupper(*pch);
+      ++pch;
+    }
+
+    if (strcmp(enabled, "ON") == 0) {
+      status = TreeSetDbiItm(DbiALTERNATE_COMPRESSION, 1);
+    }
+    else if (strcmp(enabled, "OFF") == 0) {
+      status = TreeSetDbiItm(DbiALTERNATE_COMPRESSION, 0);
+    }
+    else {
+      status = MdsdclIVQUAL;
+    }
+  }
+
+  if (STATUS_NOT_OK)
+  {
+    char *msg = MdsGetMsg(status);
+    *error = malloc(strlen(msg) + 100);
+    sprintf(*error,
+            "Error: problem setting alternate compression.\n"
+            "Error message was: %s\n",
+            msg);
+  }
+  return status;
+}
+
+EXPORT int TclShowAlternateCompression(void *ctx __attribute__((unused)),
+                           char **error __attribute__((unused)),
+                           char **output)
+{
+  int enable, status;
+  DBI_ITM itmlst[] = {{4, DbiALTERNATE_COMPRESSION, &enable, 0},
+                      {0, 0, 0, 0}};
+  status = TreeGetDbi(itmlst);
+  if (STATUS_OK)
+  {
+    *output = malloc(500);
+    sprintf(*output,
+            "  Alternate Compression is %s.\n",
+            enable ? "enabled" : "disabled");
+  }
+  else
+  {
+    char *msg = MdsGetMsg(status);
+    *error = malloc(strlen(msg) + 100);
+    sprintf(*error,
+            "Error: problem querying alternate compression.\n"
+            "Error message was: %s\n",
+            msg);
+  }
+  return status;
+}
diff --git a/treeshr/TreeGetDbi.c b/treeshr/TreeGetDbi.c
index 506ecb509a..0476da66f2 100644
--- a/treeshr/TreeGetDbi.c
+++ b/treeshr/TreeGetDbi.c
@@ -180,6 +180,18 @@ int _TreeGetDbi(void *dbid, struct dbi_itm *itmlst)
         break;
       }
 
+    case DbiALTERNATE_COMPRESSION:
+      CheckOpen(db);
+      {
+        int value = db->tree_info->header->alternate_compression;
+        memset(lst->pointer, 0, (size_t)lst->buffer_length);
+        int length = minInt(lst->buffer_length, sizeof(int));
+        memcpy(lst->pointer, &value, (size_t)length);
+        if (lst->return_length_address)
+          *lst->return_length_address = length;
+        break;
+      }
+
     default:
       status = TreeILLEGAL_ITEM;
     }
diff --git a/treeshr/TreeGetNci.c b/treeshr/TreeGetNci.c
index fb67e75834..b0becf9c77 100644
--- a/treeshr/TreeGetNci.c
+++ b/treeshr/TreeGetNci.c
@@ -290,7 +290,11 @@ int TreeGetNci(int nid_in, struct nci_itm *nci_itm)
       break_on_no_node;
       read_nci;
       set_retlen(sizeof(nci.compression_method));
-      *(unsigned char *)itm->pointer = nci.compression_method;
+      if (dblist->tree_info->header->alternate_compression) {
+        *(unsigned char *)itm->pointer = nci.compression_method;
+      } else {
+        *(unsigned char *)itm->pointer = 0;
+      } 
       break;
     case NciCLASS:
       break_on_no_node;
@@ -697,8 +701,12 @@ int TreeGetNci(int nid_in, struct nci_itm *nci_itm)
     {
       break_on_no_node;
       read_nci;
-      if (nci.compression_method >= NUM_COMPRESSION_METHODS)
-          nci.compression_method = 0;
+      if (! dblist->tree_info->header->alternate_compression) {
+        nci.compression_method = 0;
+      }
+      if (nci.compression_method >= NUM_COMPRESSION_METHODS) {
+        nci.compression_method = 0;
+      }
       string = strdup(compression_methods[nci.compression_method].name);
       break;
     }
diff --git a/treeshr/TreeSetDbi.c b/treeshr/TreeSetDbi.c
index 2a3deca3de..05b9a90b08 100644
--- a/treeshr/TreeSetDbi.c
+++ b/treeshr/TreeSetDbi.c
@@ -97,20 +97,27 @@ int _TreeSetDbi(void *dbid, DBI_ITM *dbi_itm_ptr)
     case DbiVERSIONS_IN_MODEL:
       NEED_EDIT
       dblist->tree_info->header->versions_in_model =
-          (*(unsigned int *)itm_ptr->pointer) != 0;
+          ((*(unsigned int *)itm_ptr->pointer) != 0);
       dblist->modified = 1;
       break;
     case DbiVERSIONS_IN_PULSE:
       NEED_EDIT
       dblist->tree_info->header->versions_in_pulse =
-          (*(unsigned int *)itm_ptr->pointer) != 0;
+          ((*(unsigned int *)itm_ptr->pointer) != 0);
       dblist->modified = 1;
       break;
     case DbiREADONLY:
       dblist->tree_info->header->readonly =
-          (*(unsigned int *)itm_ptr->pointer) != 0;
+          ((*(unsigned int *)itm_ptr->pointer) != 0);
       dblist->modified = 1;
       break;
+    case DbiALTERNATE_COMPRESSION:
+      NEED_EDIT
+      dblist->tree_info->header->alternate_compression = 
+          ((*(unsigned int *)itm_ptr->pointer) != 0);
+      dblist->modified = 1;
+      break;
+
     default:
       status = TreeILLEGAL_ITEM;
       break;
diff --git a/treeshr/treeshrp.h b/treeshr/treeshrp.h
index 80573017b3..44e278ac23 100644
--- a/treeshr/treeshrp.h
+++ b/treeshr/treeshrp.h
@@ -370,21 +370,13 @@ typedef struct tag_info
 typedef struct tree_header
 {
   char version; /* Version of tree file format */
-#ifdef _AIX
-  unsigned sort_children : 1;
-  unsigned sort_members : 1;
-  unsigned versions_in_model : 1;
-  unsigned versions_in_pulse : 1;
-  unsigned readonly : 1;
-  unsigned : 3;
-#else
   unsigned char sort_children : 1; /* Sort children flag */
   unsigned char sort_members : 1;  /* Sort members  flag */
   unsigned char versions_in_model : 1;
   unsigned char versions_in_pulse : 1;
   unsigned char readonly : 1;
-  unsigned char : 3;
-#endif
+  unsigned char alternate_compression : 1;
+  unsigned char : 2;
   char fill1[6];
   int free;      /* First node in free node list (connected by PARENT/CHILD indexes
              */
@@ -640,12 +632,14 @@ typedef struct pino_database
   unsigned modified : 1;      /* Flag indicating tree structure modified */
   unsigned setup_info : 1;    /* Flag indicating setup info is being added */
   unsigned remote : 1;        /* Flag indicating tree is on remote system */
+  unsigned alternate_compression : 1;
+  unsigned : 25;
   int stack_size;
+  unsigned fill;
   timecontext_t timecontext;
   int delete_list_vm;
   unsigned char *delete_list;
-  void *dispatch_table; /* pointer to dispatch table generated by dispatch/build
-                         */
+  void *dispatch_table; /* pointer to dispatch table generated by dispatch/build */
 } PINO_DATABASE;
 
 static inline NODE *nid_to_node(PINO_DATABASE *dbid, NID *nid)
diff --git a/xml/tcl_commands.xml b/xml/tcl_commands.xml
index e6198b4c5f..c66158e6c2 100644
--- a/xml/tcl_commands.xml
+++ b/xml/tcl_commands.xml
@@ -948,6 +948,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     <keyword name="TREE" syntax="set_tree"/>"
     <keyword name="VIEW" syntax="set_view"/>"
     <keyword name="VERSIONS" syntax="set_versions"/>"
+    <keyword name="ALTERNATE_COMPRESSION" syntax="set_alternate_compression"/>"
   </type>
 
   <syntax name="set_attribute">
@@ -1237,6 +1238,23 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     <qualifier name="SHOT"/>
   </syntax>
 
+  <syntax name="set_alternate_compression">
+    <help name="SET ALTERNATE_COMPRESSION">
+      Command: SET ALTERNATE_COMPRESSION
+      Purpose: Enable or disable alternate compression methods in a tree.
+      Format: SET ALTERNATE_COMPRESSION [ON|OFF]
+      Description:
+
+      The SET ALTERNATE_COMPRESSION command is used to enable or disable support
+      for alternate compression methods (stored in the NCI for a node) across
+      an entire tree.
+
+    </help>
+    <routine name="TclSetAlternateCompression"/>
+    <parameter name="p1" prompt="What" required="True" type="SET_TYPE"/>
+    <parameter name="p2" label="enabled" prompt="ON/OFF" required="True"/>
+  </syntax>
+
   <verb name="SETEVENT">
     <help name="SETEVENT">
       Command: SETEVENT
@@ -1268,6 +1286,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     <keyword name="VERSION" syntax="show_version"/>"
     <keyword name="GIT" syntax="SHOW_GIT_INFO"/>
     <keyword name="VERSIONS" syntax="show_versions"/>"
+    <keyword name="ALTERNATE_COMPRESSION" syntax="show_alternate_compression"/>"
   </type>
 
   <syntax name="show_attribute">
@@ -1462,6 +1481,28 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     <parameter name="p1" prompt="What" required="True" type="show_TYPE"/>
   </syntax>
 
+  <syntax name="show_alternate_compression">
+    <help name="SHOW ALTERNATE_COMPRESSION">
+      Command: SHOW ALTERNATE_COMPRESSION
+      Purpose: Show whether or not data alternate compression methods are enabled
+      for the current tree.
+      Format: SHOW ALTERNATE_COMPRESSION
+
+      Description:
+
+      The SHOW ALTERNATE_COMPRESSION command is used to display the current
+      alternate compression settings for the current tree.
+
+      Example:
+
+      TCL> SET TREE main
+      TCL> SHOW ALTERNATE_COMPRESSION
+        Alternate Compression is disabled.
+    </help>
+    <routine name="TclShowAlternateCompression"/>
+    <parameter name="p1" prompt="What" required="True" type="show_TYPE"/>
+  </syntax>
+
   <!--
   <verb name="start">
     <parameter name="p1" prompt="What" required="True" type="start_TYPE"/>