Put template:

<VegBIEN>

    <_simplifyPath id="-1">

        <next>parent_id</next>

        <path>

            <location>

                <locationevent>

                    <taxonoccurrence>

                        <aggregateoccurrence>

                            <plantobservation>

                                <sourceaccessioncode>$stemcount_id</sourceaccessioncode>

                                <stemcount>$stemcount</stemcount>

                                <stemobservation>

                                    <diameterbreastheight_m><_cm_to_m><value>$stemdiameter</value></_cm_to_m></diameterbreastheight_m>

                                    <height_m>$stemheight</height_m>

                                </stemobservation>

                            </plantobservation>

                    </taxonoccurrence>

                </locationevent>

            </location>

        </path>

    </_simplifyPath>

</VegBIEN>