Oaks

An oak is a tree or shrub in the genus Quercus, of which about 600 species exist.  The genus is native to the Northern Hemisphere, and includes deciduous and evergreen species extending from cool temperate to tropical latitudes in Asia and the Americas.

Oaks have spirally arranged leaves, with lobed margins in many species; some have serrated leaves or entire leaves with smooth margins. Many deciduous species are marcescent, not dropping dead leaves until spring. The flowers are catkins, produced in spring. The fruit is a nut called an acorn, borne in a cup-like structure known as a cupule; each acorn contains one seed (rarely two or three) and takes 6–18 months to mature, depending on species.

In Ireland the most common oaks are:

Sessile - Quercus Petraea

Peduncular Oak (Irish) - Quercus robus

The oaks are one of the most valuable biodiversity plants. They can support over 300 species of wild life (insects and birds mainly).

Pines can also support a handful.

Salix - Willow

Latin plant name Salix Common plant name Willow Plant type Tree Size (meters) <5-15 m Distinguishing features Found primarily on moist soils in cold and temperate regions of the Northern Hemisphere. They came to Ireland right after the melting of the ice age thanks to their light seeds that can be blown by the wind, along with the grasses and the beerchs. Willows all have abundant watery bark sap, which is heavily charged with salicylic acid, soft usually pliant tough wood, slender branches and large fibrous often stoloniferous roots. The roots are remarkable for their toughness, size, and tenacity to life, and roots readily grow from aerial parts of the plant. The leaves are typically elongated, but may also be round to oval, frequently with a serrated margin. Most species are deciduous; semievergreen willows. Willows are dioecious, with male and female flowers appearing as catkins on different plants; the catkins are produced early in the spring, often before the leaves, or as the new leaves open. Basic crafts, such as baskets, fish traps, wattle fences and wattle and daub, house walls, were often woven from osiers. Willow wood is also used in the manufacture of boxes, brooms, cricket bats (grown from certain strains of white willow), cradle boards, chairs and other furniture, dolls, flutes, poles, sweat lodges, toys, turnery, tool handles, veneer, wands and whistles.

Alnus - Alder

Latin plant name Alnus Common plant name Alder (alisos) Plant type Tree Size (meters) <20-40 m Distinguishing features With a few exceptions, alders are deciduous, and the leaves are alternate, simple, and serrated. The flowers are catkins with elongate male catkins on the same plant as shorter female catkins, These trees differ from the birches (Betula, the other genus in the family) in that the female catkins are woody and do not disintegrate at maturity, opening to release the seeds in a similar manner to many conifer cones. Alder leaves and sometimes catkins are used as food by numerous butterflies and moths. Alder bark contains the anti-inflammatory salicin, which is metabolized into salicylic acid in the body. As a hardwood, alder is used in making furniture and cabinets and other woodworking products.

Corylus avellana - Hazel tree

Latin plant name Corylus avellana Common plant name Hazel tree Plant type Deciduous tree Size (meters) < 4m Distinguishing features They have simple, rounded leaves with double-serrate margins. The flowers are produced very early in spring before the leaves, and are monoecious, with single-sex catkins. The nuts of all hazels are edible. The Celts believed hazelnuts gave one wisdom and inspiration. There are numerous variations on an ancient tale that nine hazel trees grew around a sacred pool, dropping into the water nuts that were eaten by salmon (a fish sacred to Druids) which absorbed the wisdom. The number of spots on the salmon were said to indicate how many nuts they had eaten. A Druid teacher, in his bid to become omniscient, caught one of these special salmon and asked a student to cook the fish, but not to eat it. While he was cooking it, hot liquid from the cooking fish splashed onto the pupil's thumb, which he naturally sucked to cool, thereby absorbing the fish's wisdom. This boy was called Fionn Mac Cumhail (Fin McCool) and went on to become one of the most heroic leaders in Gaelic mythology. Hazel wood was used by the dowsers to identify sources of fresh water underground.

Popular - Cottonwood

Latin plant name Populus Common plant name Poplar or Cottonwood (chopo) Plant type Decidious tree Size (meters) < 15-50 m Distinguishing features The bark on young trees is smooth, white to greenish or dark grey, often with conspicuous lenticels; on old trees it remains smooth in some species, but becomes rough and deeply fissured in others. The flowers are mostly dioecious and appear in early spring before the leaves. They are borne in long, drooping, sessile or pedunculate catkins produced from buds formed in the axils of the leaves of the previous year. Cottonwood are ofter in wetlands. They have the advantage of growing very big, very fast. Almost all poplars take root readily from cuttings or where broken branches lie on the ground. Trees with fastigiate (erect, columnar) branching are particularly popular, and are widely grown across Europe and southwest Asia. However, like willows, poplars have very vigorous and invasive root systems stretching up to 40 m from the trees; planting close to houses or ceramic water pipes may result in damaged foundations and cracked walls and pipes due to their search for moisture.

Betula - Birch

Latin plant name Betula Common plant name Birch (abedul) Plant type Decidious tree Size (meters) <10m Distinguishing features They are typically rather short-lived pioneer species widespread in the Northern Hemisphere particularly in northern temperate and boreal climates. Birch species are generally small to medium-sized trees or shrubs, mostly of temperate climates. The simple leaves are alternate, singly or doubly serrate, feather-veined, petiolate and stipulate. They often appear in pairs, but these pairs are really borne on spur-like, two-leaved, lateral branchlets. The fruit is a small samara, although the wings may be obscure in some species. They differ from the alders in that the female catkins are not woody and disintegrate at maturity, falling apart to release the seeds, unlike the woody, cone-like female alder catkins. Birches often form even-aged stands on light, well-drained, particularly acidic soils. They are regarded as pioneer species, rapidly colonising open ground.