Pine tree

Pinus spp.

1. Identification and origin

Pines (Pinus spp.) are evergreen conifers of the Pinaceae family, widely distributed across the Northern Hemisphere, from Mediterranean regions to boreal zones. They include species of great ecological, silvicultural and economic importance. In Portugal, Pinus pinaster Aiton (maritime pine) and Pinus pinea L. (stone pine) stand out.

2. Economic importance

Pines are of great economic relevance in the production of timber, resin, biomass and pine nuts (in the case of the stone pine). They are fundamental in national forestry, in soil protection, in dune stabilisation and in the recovery of degraded areas. They also have ornamental and landscape value.

3. Botanical characterisation

Evergreen trees of medium to tall habit, with a conical or rounded crown, depending on the species and age. The leaves are needle-like, grouped in fascicles (2, 3 or 5 needles). The cones are woody, containing winged seeds or pine nuts (in the case of P. pinea). The root system is deep in the early stages, but may become more superficial in compacted soils.

4. Soil and climate requirements

Pines adapt to a wide variety of climates, from Mediterranean to temperate. They prefer well-drained soils, of sandy to loamy texture, with a slightly acidic pH. They are tolerant of drought, but sensitive to waterlogging. In Portugal, the maritime pine is more resistant to fire, while the stone pine prefers areas less exposed to frequent fires.

5. Main pests

• Pine processionary moth (Thaumetopoea pityocampa): defoliation and health risk
• Pine weevil (Hylobius abietis): damage to the collar and roots of young plants
• Wood-boring beetles (Ips sexdentatus, Tomicus piniperda, Orthotomicus erosus): galleries in the trunk and rapid decline
• Conifer aphids (Cinara spp.): sap sucking and honeydew
• Scale insects (Diaspididae): loss of vigour and yellowing
• Insect vector of pine wilt – longhorn beetle (Monochamus galloprovincialis): transmission of the nematode and rapid decline of the trees

6. Main diseases

• Pine wilt (Bursaphelenchus xylophilus): sudden wilting and rapid death, transmitted by Monochamus galloprovincialis
• Resinous canker (Fusarium circinatum): necrosis and resin exudation
• Root rots (Armillaria spp., Heterobasidion annosum): progressive decline
• Rusts (Coleosporium spp.): leaf spots and needle drop
• Cankers and necrosis (Diplodia sapinea): death of branches and decline

7. General crop management

The management of pines includes the selection of species adapted to the climate and soil, the prevention of water stress and the reduction of the fuel load to minimise the risk of fires. Monitoring of wood-boring beetles and of the insect vector Monochamus galloprovincialis is essential, especially after periods of drought or storms. The removal of weakened trees and sanitary management are fundamental to prevent the spread of pests and diseases such as pine wilt.

Bibliographic references

• EPPO Global Database – Pinus spp.
• CABI – Crop Protection Compendium – Pinus pinaster Aiton, Pinus pinea L.
• Wingfield, M. J., et al. (2015). Diseases of conifers. Forest Pathology.
• FAO (2020). Conifer Forest Management Manual.
• Sousa, E., et al. (2015). Pine wilt disease in Europe. In: Forest Pathology. Springer.
• Seidl, R., et al. (2017). Bark beetle dynamics in pine forests. Forest Ecology and Management.