Sequoias in the cypress family occupy a special place, including several genera of truly unique trees, the only representatives of which are Sequoia sempervirens - sequoia evergreen or red (Redwood) and Sequoiadendron - giant sequoia.
Giant pine trees, as sequoias are also called, in ancient times were spread throughout the Northern Hemisphere, today in our country several copies of trees are planted in the parks of the Black Sea coast, they are also grown in greenhouses or botanical gardens. But the only place where their natural habitat has been preserved is a relatively small area of the Pacific coast of North America: Redwood National Park and the Muir Forest Reserve in California, with a length of about 800 km and a width of about 80 km, a small part of East Texas and Maryland, the east coast Of Canada.
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There was much debate about the origin of the name "sequoia" given to him by the Austrian biologist Stefan Endliger. Opinions were expressed that this was an empty set of sounds, a designation of the sequential arrangement of seeds in cones and, finally, the name of the famous leader of the Cherokee tribe. The latter option is considered the most likely.
These trees prefer a moist marine climate, due to their concentration on the ocean. They are called giants for good reason - the height of the sequoia is rarely below 60 m, more often higher specimens are found - up to 100–115 m. The width of the trunks corresponds to a gigantic size - in diameter the giants reach 18 m, and 6-meter trees are quite an average scale for sequoia. At the same time, certain species differences can be traced: the giant sequoiadendron is lower - about 70–90 m, but it has a thicker trunk, reaching a girth of 37 m, while the “thin-bore” 6-meter evergreen sequoia, or redwood, grows to 100 m and above . The weight of one plant exceeds 1000 kg. People against the background of these heroic trees look like midgets.
The genus Metasequoia glyptostroboides is a metasequoia glyptostroboid, growing in China, an evergreen coniferous tree. It is also part of the subfamily, but it does not have cyclopean sizes, being a fairly medium-sized tree belonging to endangered species.
The size of the plants is impressive, their age is striking: to rise to the height of a skyscraper and grow as thick as a house, giant pines sometimes need more than 1000 years. Some unique ones live longer - up to 2000 and 3500 years. But this is not the limit: there is information about trees of 6000 years of age. Scientists determine the weather conditions from the layers of wood of these relics - the amount of precipitation, the ambient temperature in the area, which were hundreds of years ago.
“General Sherman”, “Hyperion”, “Stratospheric Giant” and other, the most famous specimens of sequoia, are original natural monuments, thousands of tourists come to admire California national parks in the USA. Driving along the highway laid through the groves of giants can be considered a real journey through the fabulous world of grandiose giants. On the way there are tunnels for cars, punched in fallen trees, huge stumps, on the surface of which it is possible to place a whole parking lot, arrange a dance floor or an outdoor cafe.
Sequoias are monoecious trees, mostly straight-stemmed. Their bark is extremely thick and soft, from 30 to 80 cm wide, peels off quite easily. In young plants, it has a bright red color, for which they are often called American mahogany. In old-timers, the shade of the bark becomes dark. Loose as a sponge, it is able to accumulate a lot of moisture necessary for growth, and serves as a protection to the trunk from adverse external conditions and even forest fires. The root system is widely branched, located relatively shallow. Sequoia branches grow horizontally with respect to the trunk; in sequoiadendrons they often hang down like mammoth tusks, for which they are called mammoth trees. The crowns are very thick, pyramidal in shape, needles 10 to 20 mm long, scaly, flat. Cones are rounded, 3–3.5 cm in size, and consist of spirally twisted scales. Sequoia seeds are small - up to 3-4 mm, ripen in October, in one cone they are found from 3 to 7 pieces.
Pests do not damage giant pines - like any conifers, sequoias contain many volatile, destructive for insects and pathogens.
An important property of trees - the ability to quickly recover after mechanical damage - even removing the bark does not become an obstacle to further growth, and in the place of completely cut down specimens a new young shoot quickly rises.
Sequoias are relatively frost-resistant, able to withstand cold to -20 ° C, which makes it possible to plant them in the southern and temperate regions of Russia. It is propagated not only by seeds, but also by cuttings, as well as by grafting; it allows one to breed new ones, including decorative varieties of various sizes, shapes, and colors, perfectly suited for landscaping landscapes.
Wood characteristic
The wood of the evergreen sequoia and giant sequoia dendron is recognized in the world as one of the best conifers. In quality, it is similar to spruce, but with greater resistance to damage by fungus.
Red Californian tree, as they call sequoia, has earned considerable popularity. It grows 10 times faster than birch, and an array of one log can reach 2500 kg. Sequoia refers to the soft types of wood. The sapwood is thin, light, creamy, more friable compared to the central part. Kernel wood is of great value; it has a light cherry, carmine or light brown hue with uniform core rays and vertical rows of resin cells. It has a pronounced contrasting pattern formed by darker annual rings. Younger layers are less dense than older ones. The lumber fibers are straight, almost no swings.
During pre-processing, the freshly chopped material practically does not crack or warp; shrinkage due to the absence of internal stress in the sequoia is negligible, despite the high natural humidity. Dry wood hasdensity about 450 kg / cubic m, strong, well resists compression and twisting, rather light, resistant to mold damage, insect damage, rotting. Its service life is more than 40 years, in contact with the soil - about 25.
Used varieties
The so-called clean sound wood without knots and other vices, equal density, with an impeccable texture and the correct geometric pattern is recognized as the best variety. It undergoes drying under natural conditions, is not exposed to high temperatures. Such material is used exclusively for the manufacture of products and extra-class finishes.
Varieties of wood are considered to be of less quality, but quite practical and durable: simply pure and sound B. They are able to undergo preliminary drying in furnaces, include a small amount of sapwood, have knots and other defects in their composition. These types are used for the manufacture of various outdoor structures, supporting structures, flooring of terraces, installation of fences.
In addition, within less valuable varieties, there is a gradation of its own:
- building (deck) sound - includes fragments with a large number of knots, designed for beams, flooring, installation of supports;
- ordinary building - is a mixture of sapwood and core, used for various ground structures: arbors, verandas, flooring, fences;
- trading sound - a kind of clean, but cheaper wood, the composition includes various defects: cracks, knots, marriage in processing. It is used for outdoor works where decorative qualities are not important, but high strength and resistance to adverse factors are required;
- trade - the lowest grade, assuming the presence of sapwood, is used only for outdoor work: the construction of fences, formwork of supporting walls.
Sequoia is easily amenable to any type of processing: sawing, turning, cutting with mechanical and hand tools. It holds screws, nails and staples well, is pickled with stains, sanded and polished, glued and painted.
Application
High performance and beautiful appearance allow you to use this wood anywhere: for exterior and interior use, in construction, furniture, turning industry, for the manufacture of cladding and decorating. At home, it is used to make pillars and sleepers, various retaining parts, street benches, stairs, decoration panels, window frames, jambs, doors, inner lining of trailers, wagons, yacht cabins, wooden tiles, paper.
The sequoia is odorless, due to which it can be in contact with food, and in addition, it is great for making cigar cases and boxes, barrels for storing honey, boxes for spices.
Firewalls and exits from sequoias were made historically due to the high resistance of this wood to fire.