Pine

Pine (lat. Pínus)- a genus of coniferous trees of the family Pinaceae. Includes about 120 species. The habit of pine is diverse – ranging from trees 40 m high with pyramidal or umbrella-shaped crowns to prostrate dwarf forms. Lives 300-500 years.

They are coniferous trees or shrubs with whorled branch arrangement. Crown shape is variable, becoming more open with age, ovate-rounded or umbrella-shaped.

Trunk in youth is covered with smooth bright bark, in old age – fissured, thick, brown or dark gray, toward the top becoming plated, brown-yellow.

Root system deep and powerful.

Shoots of two types: long and short (spur shoots). Leaves on long shoots are scale-like, brown. On short shoots leaves are 5-9 cm long, green, needle-like, in bundles of 2-5, provided with sheaths of scale-like basal leaves. Needles function for 2-11 years depending on the species. The arrangement of needles and cones, as well as their size, are distinguishing characteristics.

Pines flower from May to June. Male and female inflorescences grow on the same tree. Male flowers are strobili, gathered in catkins located at the base of young shoots; stamens are scale-like, with 2 anthers on the underside. Female cones are reddish, consisting of seed and cover scales. They grow in the upper part of the tree. Cones are pollinated before the young needles unfold. Since pollination is carried out by wind, trees produce such a vast amount of pollen that on a fine day one can observe yellowish clouds near pine plantings.

Cones are ovoid or elongated, usually pendulous, and fall when fully ripe. They consist of imbricate seed scales, leathery or woody, thickened at the end into a faceted shield. In unripe cones the scales are closed; at full maturity they open, exposing winged (rarely wingless) seeds, usually two per scale.

Seeds are enclosed in a hard nut-like coat. The embryo contains 4-15 cotyledons.

Most pine species have hardiness zone 5. Scots pine has zone 1, its ornamental forms and cultivars zones 1-3. Pinus banksiana, Siberian cedar, mountain pine, dwarf cedar (creeping cedar) – zone 4; Pinus contorta, Pinus peuce (rumelian), Pinus strobus – 5a; Pinus heldreichii, Austrian black pine, Pinus strobus «Radiata» - 5b; Pinus schwerinii, ornamental «Glauca» and Pinus mugo forms, «Negishi» - 6b.

Species: Scots pine (Pinus silvestris), Mountain pine (Pinus mugo), Siberian pine (Pinus sibiriсa), Siberian dwarf pine or creeping Siberian pine (Pinus pumila), Black pine (Pinus nigra), Korean pine or Korean cedar (Pinus koraiensis), Eastern white pine (Pinus strobus).

Location: almost all species of the genus are light-demanding, practically undemanding regarding soil and moisture. They are sensitive to air pollution and do not tolerate urban conditions well. Grow well in open sites.

Soil: undemanding to soil, but grow better on sandy and sandy loam soils. Soil mix: turf soil, sand or clay (2:1). If lime is lacking, it is recommended to add 200-300 g into the planting hole. On heavy soils drainage is mandatory (sand or gravel layer of 20 cm).

Planting: recommended distance between plants 1.5-4 m. Planting depth 0.8-1 m or more, root collar at ground level. Pines have deep roots and are therefore wind-resistant. In young age (up to 5 years) plantings tolerate transplantation well. Mature trees are recommended to be transplanted only with a prepared root system or with a frozen root ball.

Care: at planting it is necessary to add nitroammofoska or humus. During the first two seasons after planting it is recommended to fertilize in small amounts with mineral fertilizers (30-40 g/sq.m). Pines are drought-resistant and do not need additional watering. A thick mulch of needle branches helps retain moisture. If the soil becomes compacted, loosening is recommended. Some ornamental forms with delicate needles and young trees may suffer from winter burn. To protect against this it is recommended to cover with conifer branches, which can be removed in mid-April. Mature pines are winter-hardy.

Pruning: in maturity needs only sanitary pruning. In formative pruning remove no more than 1/3 of the green mass in one cut. To increase crown density, cut off one-third of the current year's growth at the end of the season while maintaining the crown shape. Formative pruning can be carried out no earlier than one year after planting or transplanting. Pruning is recommended in March-April before the start of new shoot growth. Corrective pruning is performed in July-August so that the shoots formed have time to lignify before winter. It is recommended to prune on cloudy days to avoid brown spots on the needles due to increased moisture evaporation.

Diseases and pests: Pests: pine aphid, adelgids, coniferous scale insects, pine scale, pine bark bug (under-bark bug), spider mite, red pine sawfly, pine silkmoth, pine shoot weevil, pine geometrid (pine looper), pine cutworm, pine mining moth, cone moth, cone tortrix, pine bark beetle, large and small pine bark borers, pine longhorn beetle, pine jewel beetle, pine weevil, spotted tortrix. Diseases: rusts, pine vertun (vernacular/transliterated disease name), rust canker (resin canker – "seryanka"), scleroderriosis (umbrella disease), Schütte, bark necrosis.

Propagation: Pines are propagated by sowing seeds; two-needle species are sown mainly in spring after stratifying seeds for a month; five-needle species – in autumn or spring after 4-5 months of stratification, which is more effective than autumn sowing. Pine seeds mature only in the 2nd year after pollination. Rare very decorative species can be propagated by grafting.

Uses: used to create stands in forest parks, some are valuable nut-producing plants that give edible, oil-rich seeds. Wood is widely used for making boards, logs, lumber and more. Rosin is made from resin. Pine buds, extract, resin (pitch), essential oil, needles, tar are widely used in medicine.