Japanese Red-maple

Natural monuments

This magnificent maple is dioecious (with separate male and female trees). In their natural environment the tree can grow to about 30 m in height. In the spring it flowers with beautiful, bright red flowers borne in tight clusters. In the autumn the leaves take on an attractive red-orange colour. Acer pycnanthum is highly integrated into the Japanese culture. Many large, and sometimes solitary, trees have been appointed ‘natural monuments’ in order to emphasize the rarity, and its importance, of the species. The tree often grows near holy place and temples, sometimes as natural populations. Acer pycnanthum appears identical to the North American species, Acer rubrum (red maple) but DNA analyses clearly indicate that Acer pycnanthum is a distinct species in its own right.

Ecology and habitat

Acer pycnantum is a very rare species in the wild and in Japan only grows in central Honshu in calcium-rich wetlands – nutrient-pool marshes on a base of serpentine and limestone rocks through which water trickles or groundwater seeps up.

Threat

Through felling for firewood and the wetlands being taken over by conifer plantations grown for their wood, the habitat of Acer pycnantum has undergone a catastrophic decline over the last few decades. The remaining population seem to be too small to sustain the species – these number only 30 small populations of a maximum of 1000 mature individuals and thus represent a very limited gene pool. The species can only be saved from extinction by strict protection measures and an expansion of the remaining habitats.