Friends of Belfast Botanic gardens

Tree of the month series - this series of short articles about trees in the Belfast Botanic Gardens is compiled by members of the Friends group and Gardens staff. The series will gradually build up to a comprehensive archive of information about the trees in Belfast Botanic gardens. Each article will illustrate the tree in Belfast together with information from a range of sources elsewhere. Click here for the rest of the trees

Tree of the Month, December 2007

Swamp cypress (Bald cypress in USA) - Taxodium distichum

by Jonathan Pilcher
There are not many conifers that are deciduous; that drop all their needles in winter. We have already featured one - the dawn redwood - and this month's tree, the swamp cypress, is superficially similar. However, the swamp cypress lacks the dramatic conical shape of the dawn redwood and has a much more graceful spreading shape. The Botanic Gardens specimen is still young, but its shape is already distinct from the dawn redwood. The leaves are also slightly different, the swamp cypress leaves tapering uniformly to a point, where the dawn redwood leaves remain parallel almost to the tip then narrow in sharply to a point. A distinctive and unique feature of the swamp cypress is the development of aerial roots in older plants. These structures, pneumatophores sometimes called 'knees', rise up from the ground around the trunk allowing the tree roots to absorb oxygen from the air and to trap sediment. This enables the tree to live in waterlogged soils and swamps. However the swamp cypress is not restricted to swamps and grows well in dry soils.

	Taxodium leaf .Metasequoia leaf

Photos taken in 2007 in Belfast Botanic Garden, except aerial roots of Taxodium which were photographed in Toulouse Botanic Garden 2007.