Tree Planting & Maintenance

Trees either grow because they are planted by man, or they grow from a trees seeds which have germinated.

Self-seeded trees or woodlands are where the older trees have shed seeds which germinated to become seedlings, then saplings, and then trees. This is referred to as “Natural Regeneration”. Whilst young trees can often grow successfully without any help from man, a little management can encourage favoured species to survive the dangers of nutrient and light competition from other species damage by vermin, especially in the early stages of growth.

Encouraging the growth of trees by natural regeneration is not always a good thing, especially if the original provenance of the mature trees that are producing the seeds is poor. A genetically poor tree will more than likely produce substandard seedlings. On the other hand, a good tree (with a straight, single trunk, well formed branches and in good health) will produce good seedlings. Whatsmore, these trees are more genetically adapted to their environment than, say, a tree that has been imported from elsewhere in the country or abroad.

Planting trees by hand is laborious but it (generally!) means that the forester ends up with a wood comprising of the species that he intended to grow there, and they are of the same age. Depending on species, trees are often planted at spacings of as little as 1 to 2 metres (2,500 to 10,000 trees per hectare). The whole wood is managed in the same way at the same time, whereas a self-seeded wood will require different management regimes for different trees, depending on their stage of growth.

Seedlings are sown at nurseries (from seed taken from mature trees), and grown there for a year or two before being sold to foresters for planting in woodlands. Sometimes, these seedlings or saplings are “undercut” to improve the growth of the roots and give the tree a better start in life after being planted. Plants are usually sold with a Certificate of Provenance which identifies the original seed source.

For the first few years, it is important to control the weed growth around the young trees. Plants such as willow herb, briars, bracken, nettles, grass and so on will take advantage where they can and, if left uncontrolled, the young trees will face dangerous competition for nutrients and light from the weeds. Whole plantations have been lost in this way, and we have weather conditions in Ireland that are particularly suitable to for encouraging vigorous growth.

Rabbits, hares, grey squirrels, livestock, deer and other animals also need to be controlled – either by fencing the wood or using tree tubes. Unfortunately grey squirrels are a serious problem. These creatures are not native to Ireland. (Most or all grey squirrels in Ireland are said to be descended from squirrels released at Castleforbes in Co Longford in about 1911). The grey squirrel does not fit well into an Irish woodlands ecosystem (it has forced the red squirrel away from many areas, including here at Lisnavagh) and as a result causes a lot of damage by stripping bark off trees, etc. Deer populations are also increasing rapidly (partly due to a lack of control in some of Ireland’s larger forests). Deer graze the young trees (causing the stem to bifurcate, or split in two) or they use trees to rub the velvet off antlers when the trees are about 2″ in diameter (say, 5 years old). This also rubs the bark off and the tree can die as a result. Six foot fences and tree tubes can help, though they are both expensive options. Culling of deer and grey squirrels is sometimes necessary.

So, growing trees can be quite challenging! After a few years, pruning of trees is advisable, in order to reduce the number of knots in the timber in later years. This also means that the wood is more accessible.

By the time the trees are about 20 years old (depending on species, rates of growth, etc.) some of the lesser trees are “thinned” out of the wood, leaving the better trees to grow on in a less crowded environment. Ideally, thinnings are then carried out every few years until the final crop of trees is left to grow on until maturity.