Thuja

The climate of the west coast of North America favours trees that grow to enormous size, one of them being the western redcedar. In its natural range it can achieve 70m in height, a giant conifer with brown-grey fibrous bark and shiny scale-like leaves.

Western redcedar was the most important tree to many of the native peoples of the west coast, on which their whole lives were based. It was used for canoes and houses, clothes and medication. Knowing it to be the home of the thunder gods, the Haida Indians erected a redcedar as part of their houses as a kind of lightning conductor. Totems were always made from the redcedar, which lasts for decades without rotting. One sign of their respect for the tree is shown by its use without actually felling it – planks were carved from the living tree, which usually recovered and continued its life for hundreds of years.

Western redcedar has been grown in Finland for almost 100 years, but is still rare. Being adapted to a maritime climate, the species grows most successfully on the south and south-west coasts. The severe winters of inland Finland usually kill the tree, unless the provenance is suitable. The trees planted on the moist Pohjoisrinne (Northern Slope) at Mustila in the 1930s are now over 20m high, showing that with seed of suitable provenance and good growing conditions the redcedar can grow into a considerable tree even inland.

In its native habitat in the north-east of North America, the red cedar typically grows on mires and at the edges of cliffs, where competition from other species is minimal. The species is slow-growing but durable; as many as 1650 annual rings have been counted on a felled tree.

Arborvitae, or the tree of life, as it was named by European settlers, was among the first species to be brought to Europe from America. In the 1500s it was thought to have medicinal properties. It quickly achieved popularity as a garden and landscape species, and hundreds of named varieties have been produced of varied habit and colour.

Hardy throughout Finland, arborvitae is widely used in hedges and individually. In modern gardens it seems to be used mainly in various mutant forms, dense and slow-growing, pillar, spherical or conical in habit.

The species has been grown at Mustila since the 1930s, cuttings from the 2-hectare plantation providing florists with winter greenery for wreaths and bouquets.

Rarely grown in the West, the Korean thuja is native to a small mountainous area of eastern Manchuria and to northern parts of the Korean peninsula. This slow-growing conical tree can reach over 10m in its native habitat but often remains shrubby in less favourable spots. Due to excessive forest clearance for agriculture, there are few reproductive trees left and the species is on the endangered list in its native area.

Korean thuja has a beautiful regularly conical habit and flattened shoots whose scale-like needles are chalk white on their under-surface. The upper surface is usually a dull dark green but can take on silvery shades in sunny spots. The bark is fibrous, greyish brown in colour.

Korean thuja is the second hardiest of the thuja species which can be grown in Finland. It was first introduced here in the early 1930s when Mustila and the Forestry Research Department obtained seed direct from its natural range.

Two thuja species, the Korean and the Canadian redcedar (T. occidentalis), grow adjacently at Mustila and have produced a hybrid species, a combination of east and west, a rare occurrence on a world scale.