Varna, Environment and Quality of varna traits
Sandalwood tree is hemiparasite. Being hemiparasite, it has dependence on host plants for nitrogen fixing roots. Hemiparasite is a parasitic plant that lacks a fully developed root system and forms connections with another plant, from which it obtains some or all of its water and minerals. Such plants have chlorophyll and produce their own food by photosynthesis, and in some cases are capable of limited growth in the absence of the host plant.
Without nitrogen fixing neighbor, Sandalwood will still grow but you will not see it full bloomed perfect Sandal. Heartwood(The aromatic trunk part) growth will be limited or none.
Similarly, each Varna seek appropriate environment for being perfect in exhibiting varna traits. But when lack of such conducive environment, you will still find Varna exist. Dormant. Not fully nurtured. (Reference post: http://prachodayat.in/varna-system-geology-farming-food-health/)