What kind of trees do we plant and why?
Ireland's native tree flora is not as rich as that found in Great Britain and continental Europe. Some species failed to reach these shores, before the land bridges that connected us to Britain and mainland Europe finally disappeared at the end of the last glaciation period some 10,000 years ago.
Native species to Ireland include Oak, Ash, Birch, Alder, Elm, Cherry, Whitebeam, Rowan, Willow, Hawthorn, Poplar, Holly, Crab-Apple, Yew and Juniper, of which the last two are conifers. Scots Pine is thought to have died out in Northern Ireland only in the last 2000 years, although widespread planting of this species did occur in the 1700's. Of all these species, Oak and Ash are the only two native species to have proved themselves as successful timber crops.
This tree population was enriched by many landowners as early as the 17th century, by introducing exotic species from around the world. Today, Sitka Spruce, a North American conifer, forms the backbone of commercial forestry in the British Isles. Grown extensively in Northern Ireland, due to its suitability both to high rainfall, (a feature of our climate), and the type of soils available to forestry in this country, it frequently attains high production levels exceeding 500 tonnes per hectare on relatively poor agricultural soils. It can achieve incredible growth rates (one metre per year), and reach a marketable size in a relatively short period (35-45 years).
Another vital characteristic of Sitka Spruce is its vast range of uses in the market-place. Although it has no natural durability out of doors, the sapwood takes preservative well, making suitable stake material due to its light weight, strength, nailability and non-tainting characteristics. The best quality material is used in house building, as joists, rafters and flooring. Smaller and low quality material is used to create boxes, packing cases, pallets and various types of manufactured board such as chipboard. The greatest world demand for this timber is from pulpmills for the production of paper, due to its pale colour, good fibre characteristics and low resinous content. Other conifers that play a significant role in commercial forestry in the UK include Norway Spruce, Japanese/Hybrid Larch, Lodgepole Pine, Douglas Fir and Scots Pine. Most of these species have similar characteristics to Sitka Spruce, but lack its vigour on the vast majority of sites available to forestry.
Broadleaves, such as Oak, Beech and Ash are also grown commercially, but on a much smaller scale. These species require a more fertile soil than the above conifers and their rotation age (length of time between planting and harvest) can be over three times that of the conifers.
Current regulations require private and state afforestation programs to contain a proportion of broadleaved species for conservation and/or landscape reasons. The creation or restoration of semi-natural woodland is largely dependent on native species such as Oak, Ash, Willow or Alder.
