<!-- candidates for the extension -->
<!-- maybe we should consider adding more general factors which do not -->
<!-- include the object. -->
<!-- <xs:enumeration value="Diversity"> -->
<!-- <xs:annotation> -->
<!-- <xs:documentation xml:lang="en"> -->
<!-- </xs:documentation> -->
<!-- NA -->
<!-- </xs:annotation> -->
<!-- </xs:enumeration> -->
<!-- <xs:enumeration value="Composition"> -->
<!-- <xs:annotation> -->
<!-- <xs:documentation xml:lang="en"> -->
<!-- NA -->
<!-- </xs:documentation> -->
<!-- </xs:annotation> -->
<!-- </xs:enumeration> -->
<!-- <xs:enumeration value="Density"> -->
<!-- <xs:annotation> -->
<!-- <xs:documentation xml:lang="en"> -->
<!-- NA -->
<!-- </xs:documentation> -->
<!-- </xs:annotation> -->
<!-- </xs:enumeration> -->
<!-- <xs:enumeration value="Structure"> -->
<!-- <xs:annotation> -->
<!-- <xs:documentation xml:lang="en"> -->
<!-- NA -->
<!-- </xs:documentation> -->
<!-- </xs:annotation> -->
<!-- </xs:enumeration> -->
<!-- candidates for the extension -->
<!-- Votes: 2 -->
<!-- maybe we should consider adding more general factors which do not -->
<!-- include the object. -->
<!-- <xs:enumeration value="Environmental Structure"> -->
<!-- <xs:annotation> -->
<!-- <xs:documentation xml:lang="en"> -->
<!-- </xs:documentation> -->
<!-- NA -->
<!-- </xs:annotation> -->
<!-- </xs:enumeration> -->
<!-- or -->
<!-- <xs:enumeration value="Abiotic Structure"> -->
<!-- <xs:annotation> -->
<!-- <xs:documentation xml:lang="en"> -->
<!-- </xs:documentation> -->
<!-- NA -->
<!-- </xs:annotation> -->
<!-- </xs:enumeration> -->
<!-- candidates for the extension -->
<!-- topography -->
<!-- <xs:enumeration value="Aspect"> -->
<!-- <xs:annotation> -->
<!-- <xs:documentation xml:lang="en"> -->
<!-- Aspect or exposition is the direction a slope is facing and tends -->
<!-- to be related to the amount of radiation and humidity a plot -->
<!-- receives. -->
<!-- </xs:documentation> -->
<!-- </xs:annotation> -->
<!-- </xs:enumeration> -->
<!-- <xs:enumeration value="Coverage"> -->
<!-- <xs:annotation> -->
<!-- <xs:documentation xml:lang="en"> -->
<!-- Compises e.g. the percentage of tree, her, shrub layer in an area -->
<!-- or the total coverage of vegetation. -->
<!-- </xs:documentation> -->
<!-- </xs:annotation> -->
<!-- </xs:enumeration> -->