“Amber forests,” flourished around 45 million years ago, in the territories of southern Fennoscandia (present-day northern Europe and Baltic region). The remains of these forests can be seen in numerous specimens of Baltic amber. Thus far, inclusions preserved in amber have led to the identification of over 200 species of trees, shrubs and herbaceous plants from a broad range of habitats. These include highland, lowland and marshland plants with various climatic requirements. This diversity in plant remains probably results from the varied topography of the terrain covered by the „amber forests”, and from the fact that these lands occupied an area at the junction of two climatic zones: warm temperate and subtropical. According to one of the current theories, volcanic activity (Tanet volcanism) in the North Sea in late Paleocene and the consequent considerable pollution of the atmosphere may have been responsible for the increased outflow of resin.
Translucent pieces of Baltic amber often contain numerous plant remains in various states of preservation. These became engulfed in the sticky, resin which exuded in abundance from coniferous trees over 40 million years ago. On rare occasions entire small bodies of plants, such as lichens, liverworts and mosses are found which can be identified to genus or species. It is equally rare to find larger plant fragments, such as flowers, fruit, seeds, needles, twigs or resin-saturated wood. Small fragments of plant tissue and organs are the most common form of inclusion, but attempts to identify these remains usually end in failure. Research work into pollen and spores, the smallest structures which enable the identification of a parent plant, appears very promising. The most common traces of Eocene angiosperms found in Baltic amber are stellate oak hairs from the protective outer covering of oak buds.
This Eocene ecosystem is thought to have consisted of a mixed pine-oak woodland which also featured thuja, cypress, glyptostrobus, palm, magnolia, cinnamon, laurel, and tea trees. Grasses, heaths and heathers have been identified among the plants that made up the undergrowth. Ancient amber-yielding forests are compared to today’s subtropical plant communities occupying the mountainous regions of south-east Asia. The rivers which ran through these forests carried larger and smaller dripstone forms of resin, as well as whole tree trunks, branches and roots with resin accumulations contained in numerous cracks and crevices within and beneath the bark and sapwood. This resinous material was laid down in deltaic sediments on the sea floor, where it gradually underwent a series of physical and chemical changes that resulted in the amber nodules we see today.