A monumental tree is considered a standalone ecosystem and serves as a habitat for many rare and endangered groups of mammals, birds, insects, fungi, and other organisms. A tree achieves the status of a monumental tree by meeting one of two criteria: circumference or height. This means that it is not just an oak, lime, maple, or pine that can become a monumental tree, but any tree from the 54 native or non-native species growing in Latvia. For example, to become a monumental tree, a white willow Salix alba must reach a circumference of 4.5 metres, while a common juniper Juniperus communis requires only a 0.8-metre circumference and a northern white-cedar Thuja occidentalis 1.5 metres.