Overview
Pinus divaricata (Ait.) Dum.-Cours. var. latifolia (Engelm. ex S. Wats.) Boivin, commonly known as the Mexican mountain pine, is a coniferous tree native to Mexico and the southwestern United States. It grows at elevations ranging from 2,000 to 11,000 feet in rocky canyons and on steep slopes.
Description
The tree can reach heights of up to 30 feet and has a rounded crown. The needles are evergreen and grow in pairs, measuring between 3 and 6 inches in length. The cones are oval in shape, measuring between 2 and 4 inches long, and have a brown color. The bark is thick and dark brown, with deep ridges and furrows.
Common Names
Pinus divaricata (Ait.) Dum.-Cours. var. latifolia (Engelm. ex S. Wats.) Boivin is commonly known as the Mexican mountain pine, the western white pine, or the Arizona pine.
Uses
The Mexican mountain pine is primarily used for timber and pulpwood, as the wood is strong and durable, making it useful for construction and furniture making. The resin from the tree is also used in the production of varnishes and adhesives. In addition, the tree has ornamental value and is sometimes planted in parks and gardens.
Light Requirements
Pinus divaricata var. latifolia requires full sunlight for optimal growth and development. The species typically grows in open, sunny areas, such as meadows and savannas, where it can receive ample amounts of direct sunlight throughout the day.
Temperature Requirements
The ideal temperature range for Pinus divaricata var. latifolia is between 15 and 25 degrees Celsius. This species can tolerate a wide range of temperatures, but it prefers a cooler environment and can be damaged by extreme cold or high temperatures. In colder areas, it typically grows at elevations above 2000 feet.
Soil Requirements
Pinus divaricata var. latifolia grows well in a variety of soil types, including sandy, loamy, and well-drained soils. However, the species prefers soils that are slightly acidic and nutrient-poor. It can tolerate very acidic soils but does not do well in soils that are too alkaline or waterlogged. In general, the soil should be well-draining, as the species cannot tolerate wet roots for extended periods of time.
Cultivation methods
Pinus divaricata (Ait.) Dum.-Cours. var. latifolia (Engelm. ex S. Wats.) Boivin, commonly known as the southwestern white pine, is a native coniferous tree species in the southwestern United States and northeastern Mexico. It is well-suited for cultivation in a variety of soils, including sandy or loamy soils, as long as they are well-drained and have a neutral to slightly acidic pH. This species prefers full sun exposure and can tolerate a range of temperatures, from hot summers to chilly winter conditions.
Watering needs
Pinus divaricata var. latifolia has moderate water requirements. Newly planted trees require regular watering to establish their root system. Once established, they should be watered deeply once a week during the growing season and every two weeks during drought periods. It's essential to ensure that the soil is adequately drained to prevent waterlogging, which can result in root rot and other fungal diseases.
Fertilization
Pinus divaricata var. latifolia responds well to regular fertilization. During the growing season, apply a balanced fertilizer, such as a 10-10-10 or 12-6-6, every two to three months. An application of slow-release fertilizer in spring, combined with organic soil amendments, such as bone meal or compost, can provide essential nutrients and improve soil fertility. Be careful not to fertilize during drought conditions, as this can lead to fertilizer burn and other issues.
Pruning
Pruning is not generally necessary for Pinus divaricata var. latifolia, as it has a naturally symmetrical growth habit. However, light pruning can be performed to remove any damaged or dead branches. The best time to prune is during the dormant season, usually in late winter or early spring. Avoid pruning during the growing season, as this can slow down growth and cause stress to the tree.
Propagation Methods of Pinus divaricata var. latifolia
Pinus divaricata var. latifolia, commonly known as the southwestern white pine, is a slow-growing tree that is native to the southwestern mountains of the United States. The tree is well-adapted to high altitude environments and can be propagated through various methods.
Seed Propagation
Seeds from mature southwestern white pine cones can be collected in the fall and stratified over the winter to break seed dormancy. Stratification involves exposing the seed to a moist, cold environment for several weeks to mimic natural winter conditions. In the spring, seeds can be sown in containers or directly in the ground. Seed propagation is a cost-effective method and produces genetically diverse trees.
Cuttings Propagation
Southwestern white pine can also be propagated from cuttings taken from mature trees. Softwood cuttings taken in early summer or hardwood cuttings taken in late fall can be treated with rooting hormone and planted in rooting media in a warm and moist environment. This method produces genetically identical trees and is useful for producing large numbers of plants for reforestation or landscaping projects.
Grafting Propagation
Grafting is another method of propagating southwestern white pine. Grafting involves attaching a scion (small piece of the desired plant) onto the rootstock of a different plant to create a new, composite plant. This method is used to propagate desirable traits, such as disease resistance or faster growth, onto a rootstock that imparts favorable root characteristics. Grafting is a skilled method that requires experience and knowledge but can produce high-quality trees with desirable traits.
Disease Management
Pinus divaricata var. latifolia is usually not prone to many diseases if grown in suitable conditions. However, like any other plant, it can be susceptible to certain diseases that must be managed promptly to avoid plant losses. Some common diseases that might affect Pinus divaricata var. latifolia include:
- Dothistroma needle blight – this disease is caused by the fungal pathogen Dothistroma septosporum. The symptoms include the appearance of reddish-brown spots on needles and premature needle drop. To manage this disease, affected needles should be removed, and the area should be sprayed with a fungicide.
- Pine wilt disease – this is a lethal disease caused by nematodes called Bursaphelenchus xylophilus. Symptoms include yellowing of needles, crown thinning, and eventual death of the plant. The best management strategy is to prevent the disease by using nematode-free pine seedlings and avoiding the movement of infested wood material.
- Sphaeropsis tip blight – this fungal disease is characterized by the appearance of brown spots on needles, twig dieback, and canker formation. The best control methods include pruning affected twigs, removing fallen needles, and applying fungicides.
Pest Management
Some common pests that might affect Pinus divaricata var. latifolia include:
- Pine sawflies – these pests are common on pine trees and can cause defoliation. The larvae can be controlled by handpicking or using an insecticide.
- Pine needle scale – this pest can cause yellowing and early needle drop. The best control methods include pruning affected twigs and applying insecticidal soap or horticultural oil during the crawler stage.
- Pine shoot beetle – this pest can cause the wilting and death of new shoots. The best management strategy is to prevent the movement of infested wood material and to apply insecticides during the adult beetle emergence period.
