Březinské tisy National Nature Monument

The Březinské tisy NNM covers a section of the rocky and talus-covered slopes of Velký Chlum Hill above the Ploučnice river valley, in the northern part of the České středohoří Mountains PLA and in the Ústecký kraj – Ústí nad Labem Region. The Březiny yew trees are protected on an area of 35.7 ha at elevations of 158 – 372 metres above sea level. The slopes were declared a national nature monument to protect a rich population of yew trees (Taxus baccata) in all possible age classes. The territory is also designated to protect a significant palaeontological site where Tertiary flora and fauna can be found, one of the richest palaeontological sites in the volcanic-sedimentary complex of the České středohoří Mountains.
 
The dominant formation is the so-called Bechlejovická stěna (Bechlejovice Cliff), which is formed by a basalt flow, with a distinctive slag structure and cavities (the result of high gas content). Thick layers of boulder talus can be found at the foot of the cliffs. On the lower section of the boulder field we can find distinctively layered diatomite slate between the individual boulders or blocks. When these slates are broken open they can contain the fruits of Tertiary roses, several species of frogs which lived in lakes in the Tertiary period with preserved soft body tissue (lungs, cloaca, saliva glands, eye and skin pigments) and several- centimetre-long crayfish of the Bechleja order, which floated freely in the lakes in prehistoric times. The name of this order of crayfish comes from the nearby hamlet of Bechlejovice.
 
The flora is formed of common species and is most colourful in spring time, when the coralroot (Dentaria bulbifera) flowers at the eastern tip of the reserve. The only protected species which has been recorded here is the martagon lily (Lilium martagon).
 
Zoological research has not been carried out here, but the character of the territory indicates that a rich invertebrate fauna bound to the talus forests could be present in the protected area.
 
The yew trees at this locality are indigenous, although the tree species composition in the forest was considerably modified in the past. The proportion of spruces is much higher than it would naturally be. The yews grow individually and in small groups, with the centre of their distribution in the eastern part of the reserve, where they grow in mixed forest stands along with beech, oak, hornbeam, ash and spruce. The yews are healthy and regenerate naturally. The older examples exhibit signs of previous commercial usage (pruning). An interesting forest community of yews with limes can be found on the lower rocky terraces of the Bechlejovická stěna Cliffs.
 
The forests are not commercially used and management of the territory is focussed on modifying the current, unnatural species composition in favour of the yews. The area is occasionally targeted by amateur fossil hunters who remove palaeontological findings. The northern edge of the monument is negatively affected by the neighbouring Březina hamlet.