Overview
Larix laricina (Du Roi) K. Koch var. alaskensis (W. Wight) Raup, commonly known as the Alaska larch or tamarack, is a deciduous conifer tree. It belongs to the Pinaceae family and is native to North America.
General Appearance
The Alaska larch tree can grow up to 25 meters tall and has a narrow, conical shape in its youth. The bark is thin and scaly, and its branches grow horizontally from the trunk. The dark green needles are about 2-3 cm long and grow in clusters of 12 to 20 on short shoots. In autumn, the needles turn a golden-yellow color before falling off.
Common Names
The Alaska larch tree is commonly known as the tamarack, hackmatack, eastern larch, black larch, and red larch.
Uses
The wood of the Alaska larch tree is used for various purposes such as making furniture, poles, and pulpwood. Native Americans and early European settlers used the tree for medicinal purposes, including tea made from the larch needles as a treatment for colds and coughs.
Light Requirements
Larix laricina var. alaskensis requires full sun to grow properly. It needs direct sunlight for at least six hours a day to perform photosynthesis efficiently. Trees that are grown in areas with low sunlight availability will not grow properly, and their stems will twist toward the light source.
Temperature Requirements
The plant requires a cold climate to grow properly. It is adapted to cold Canadian and Alaskan climates with minimum and maximum temperatures of -40°C and 30°C, respectively. The plant can handle occasional extreme temperatures as long as they do not occur frequently, and the area has the required moisture for growth.
Soil Requirements
Larix laricina var. alaskensis grows best in well-draining soils with a pH that is slightly acidic ranging between 4.5 and 6.5. The soil should be moist but not waterlogged, as excessive moisture can lead to root rot. The plant needs a healthy mix of organic matter to promote growth and maintain soil moisture.
Cultivation
Larix laricina var. alaskensis grows well in a wide range of soil types, from well-draining sandy soils to heavy clay soils. It prefers a moist soil but can tolerate drought conditions once established.
This plant is best grown in full sun to partial shade. When planting, select a site that receives at least six hours of direct sunlight each day.
Larix laricina var. alaskensis does not tolerate high temperatures and grows best in regions with cool summers.
Watering Needs
Water the plant deeply once a week, especially during hot and dry weather. The soil should be moist, but not soaked. Watering should be reduced during the winter months as the plant is dormant.
Fertilization
Fertilizers should not be applied during the first year of growth. In the second year, apply a balanced, slow-release fertilizer. In the following years, apply a fertilizer rich in nitrogen in the spring and a balanced fertilizer in the fall.
Pruning
Larix laricina var. alaskensis requires minimal pruning. Prune branches that are damaged or diseased during the dormant season. Pruning should be done before new growth appears in the spring.
Propagation of Larix laricina var. alaskensis
Larix laricina (Du Roi) K. Koch var. alaskensis (W. Wight) Raup, commonly known as American larch or tamarack, is a deciduous coniferous tree that provides excellent timber and is planted for ornamental purposes. There are several methods of propagating Larix laricina var. alaskensis, including:
Seed Propagation
Seed propagation involves sowing the seeds of the plant in well-aerated soil. The seeds can be collected from the cones of mature trees in the fall. They must be stored in a cool, dry place until spring, when they can be sown in seed trays or directly in the ground. The seedlings should be watered regularly and protected from low temperatures and strong winds.
Cuttings Propagation
Larix laricina var. alaskensis can be propagated from cuttings taken from healthy trees. Cuttings should be taken in late winter or early spring, before the buds start to break. They should be approximately 10-15 cm in length and taken from the middle portion of the previous year's growth. The cuttings should be treated with rooting hormones and planted in a well-draining soil mix. The soil should be kept moist, and the cuttings protected from direct sunlight and strong winds.
Suckers Propagation
Larix laricina var. alaskensis can also be propagated from suckers. Suckers are shoots that grow from the roots of the parent tree. They can be dug up in late winter or early spring and planted directly into the ground. The young plants should be watered regularly and protected from direct sunlight and strong winds.
Grafting Propagation
Grafting is another method of propagating Larix laricina var. alaskensis. The scion, a piece of the desired plant, is grafted onto a rootstock of a closely related species. The scion and rootstock are joined together and sealed with grafting tape or wax. The grafted plant should be kept in a cool, humid environment until the graft takes, and then gradually acclimatized to normal growing conditions.
Disease and Pest Management for Larix laricina var. alaskensis
Larix laricina var. alaskensis, commonly known as the Alaska larch, is a medium-sized coniferous tree that is native to northern regions of North America. While relatively resistant to disease and pests, there are still several threats that can cause damage to the plant.
Common Diseases
One of the most common diseases that affect the Alaska larch is Larch Canker, caused by the fungus Coniophora laricina. Infected trees show yellowing needles, branch dieback, and eventually, the death of the tree. Proper sanitation practices such as removing infected branches and pruning during dry weather conditions can help reduce the spread of this disease.
Larch Needle Cast, caused by the fungus Mycosphaerella laricina, is another disease that affects the Alaska larch. It results in the premature shedding of needles, reduced tree growth, and thinning of foliage. Fungicides containing chlorothalonil and propiconazole have been reported to be effective in controlling Larch Needle Cast in commercial plantations.
Common Pests
There are few pests that commonly attack the Alaska larch, but one of the most damaging is the Eastern Larch Beetle. The beetle burrows into the bark and creates galleries where it feeds and lays eggs, leading to the death of the tree. To manage the Eastern Larch Beetle, it is important to remove bark beetle-infested branches and trees and burn or bury them. Also, the use of insecticides such as permethrin, cyfluthrin, and bifenthrin can be effective.
The Larch Casebearer, a moth that lays its eggs on the needles, is another pest that can cause significant damage to the Alaska larch. The larvae wrap themselves in the needles and feed on them, leading to defoliation and stunted growth. The use of insecticides such as Bacillus thuringiensis (Bt) and spinosad is an effective way to manage this pest.
Conclusion
Proper sanitation practices, the use of fungicides and insecticides, and removal of infected branches and trees are all important aspects of managing pests and diseases that can impact the health of the Alaska larch. By implementing these strategies, growers and homeowners can help protect their trees from the most common threats identified above.
