Pinus patula var. macrocarpa Mast.

Pinus patula grows to a height of 30 m or more and attains a diameter at breast height of up to 1.2 m. Bole straight and cylindrical, sometimes forked, producing 2 or more stems. When grown at wide spacing, the crown tends to spread. The crown may also be rounded or spirelike. Young bark is characteristically a reddish-orange colour and is scaly. The mature bark is grey-brown and vertically ridged. Leaves in fascicles of 3, occasionally 4, rarely 5; slender, 15-25 cm long pendent, pale green to yellowish-green colour, the margins finely serrate; stomata present on the dorsal and ventral surfaces; resin canals 1-4, mostly 3, usually medial, occasionally with 1 or 2 internal; exterior walls of the endoderm thin to slightly thickened, fibrovascular bundles 2, contiguous but distinct; fascicle sheath pale, greyish-brown, 10-15 mm long and persistent. Cornlets purplish, mainly lateral, short, pedunculate, borne singly or in small clusters and up to 8, scales with small deciduous prickles; cones hard, strong, serotinous, generally slightly curved and reflexed, 7-10 cm long, sessile and extremely tenacious with a lustrous brown or yellowish-brown colour, persistent on the tree, borne in groups of 3-6, very variable in size and shape. Seeds dark brown to almost black, very small, about 5 mm long, with a pale brown wing about 17 mm long, slightly thickened at the base where it joins the seed; cotyledons 4-5, generally 5. ‘Pinus’ is from the Greek word ‘pinos’ (pine tree), and possibly from the Celtic word ‘pin’ or ‘pyn’ (mountain or rock), referring to the habitat of the pine.

P. patula is a monoecious plant. The female flowers are usually borne in the upper crown, and the male ones in the lower crown.

The common soil features include acidity and good moisture supply. In the east African highlands, is it found on young fertile volcanic soils and on mature leached infertile soils derived from basement complex on other sites in E. Africa and South Africa.

Often found in pure dense stands, but the occurrence is discontinuous, and now over much of its range it grows only in areas inaccessible to agriculture. Throughout its range, P. patula can be found associated with P. gregorii and P. teocote, with which it is reported to have hybridized. It also grows in association with P. montizumae and P. rudis, Abies religiosa, Taxus mexicana, and hardwood species of such genera as Acer, Cercis, Fagus, Tilia and Liquidambar.

Earliest introductions of P. patula from Mexico were made in New Zealand in 1877 and in South Africa in 1907. Introductions also took place in Congo in 1920, Malawi in 1923, Kenya in 1926 (commercial plantation scale in 1940), Sri Lanka in 1931-1934, Angola in 1942, Swaziland in 1947, and Brazil in 1957. More recent introductions have been made in Argentina, Madagascar and Tanzania in 1960 and Papua New Guinea in 1970.

Natural regeneration occurs prolifically in several places, e.g. Malawi, Madagascar, New Zealand, South Africa and Zimbabwe. However, in eastern Africa, natural regeneration is not common. No country has successfully sown seed directly in the field, as the seedlings do not produce a deep enough root system to be able to survive the 1st dry season. The common practice is to germinate the seed in nursery beds and then plant out the mature seedlings to the field. Presowing treatment is not necessary. Under ideal conditions, seeds germinate within 35-60 days. The expected germination rate of mature and healthy seed lots is between 75 and 85%.

Initial spacing for P. patula in most countries is from about 2.4 m to 2.75 m. Generally for saw logs, closer spacing is recommended for knotfree wood. Wider spacing is recommended on poorer sites. Saw log schedules in current use are designed to produce some 250 trees/ha with a mean dbh of 45 cm at a rotation of 45 years. For pulp projects, rotations vary from 15 years in Swaziland to a recommended 25 years in South Africa.

The majority of insect pests that cause damage to P. patula are defoliators, mainly of the order Lepidoptera, the notorious families being Arctiidae, Lasiocampidae, Noctuidae and Saturniidae. Damage begins from the nursery stage through cutworms, several leaf rollers and defoliators. Plantation pests include leaf-eating adult beetles, adult bark beetles (mottled pine bark weevil) and sucking insects such as pine woolly aphid. Diseases of P. patula include foliage leaf cast, tip die-back of the branches and armillaria root rot.

Seed storage behaviour is orthodox; viability is maintained for at least 3 years in open storage; a few seeds survive after 21 years of hermetic storage at 5 deg. C; viability can be maintained in hermetic storage for 6 months when seed is stored at room temperature, and for several years when stored at 3 deg. C with 7-10% mc. The number of seeds per kg depends on the provenance and the climatic conditions of the ripening year. On average, there are 143 000 seeds/kg. A purity of 98% can be achieved.

Fuel: P. patula produces excellent fuelwood. Fibre: The species is used in the commercial manufacture of pulp, for example in the Usutu Paper Mill in Swaziland and in several mills in South Africa. Timber: The wood is suitable for particle board manufacture and gives a board of good strength, does not appreciably retard the setting of cement and can be used satisfactorily for making wood-wool slabs and boards. Gum or resin: When tapped, P. patula yields an oleoresin, which is distilled to give turpentine, and rosin which is used in, for example, paint and batik industries. Medicine: Pine-leaf oil is sometimes used for medicinal baths, and the seeds may be consumed locally.