Misplaced Pages

#186813

31-563: Many of the peninsula's hardwoods were cut down for use in the charcoal -fired iron furnaces operated by the Jackson Iron Company in 1867–1891 at what is now Fayette State Park , on the peninsula's western shore. With its access to Great Lakes shipping, the remaining lumber of the Garden Peninsula was largely logged by the 1890s. However, the area is still home to endemic plants and disjunct populations. After

62-456: A hardwood despite the wood itself being very soft; it is the softest commercial hardwood and is widely used because of its light weight. Balsa trees grow extremely fast, often up to 27 metres in 10–15 years, and do not usually live beyond 30 to 40 years. They are often cultivated in dense patches, with Ecuador supplying 95% or more of the commercial balsa. The wood from these trees is highly valuable due to its high strength-to-weight ratio, which

93-518: A coarse, open grain . The density of dry balsa wood ranges from 40 to 475 kg/m , with a typical density around 160 kg/m . Balsa is the softest wood ever measured using the Janka hardness test (22 to 167 lbf ). The wood of the living tree has large cells that are filled with water. This gives the wood a spongy texture. It also makes the wood of the living tree not much lighter than water and barely able to float . For commercial production,

124-420: A more complex structure than softwoods and are often much slower growing as a result. The dominant feature separating "hardwoods" from softwoods is the presence of pores, or vessels . The vessels may show considerable variation in size, shape of perforation plates (simple, scalariform, reticulate, foraminate), and structure of cell wall, such as spiral thickenings. As the name suggests, the wood from these trees

155-404: Is a pioneer plant , which establishes itself in clearings in forests, either man-made or where trees have fallen, or in abandoned agricultural fields. It grows extremely rapidly, up to 27 metres (89 ft) in 10–15 years. The speed of growth accounts for the lightness of the wood, which has a lower density than cork . Trees generally do not live beyond 30 to 40 years. Flowers are produced from

186-408: Is achieved through a kiln-drying process that leaves the wood's cells hollow and empty. Balsa wood is popular for light, stiff structures in model bridge tests, model buildings, and construction of model aircraft. It is also used in the manufacturing of wooden crankbaits for fishing, makeshift pens for calligraphy, composites, surfboards, boats, "breakaway" props for theatre and television, and even in

217-411: Is also used in laminates together with glass-reinforced plastic ( fiberglass ) for making high-quality balsa surfboards and for the decks and topsides of many types of boats , especially pleasure craft less than 30 m in length. On a boat, the balsa core is usually end-grain balsa, which is much more resistant to compression than if the soft balsa wood were laid lengthwise. More than 90% of

248-542: Is also valued as a component of full-sized light wooden aeroplanes , most notably the World War II de Havilland Mosquito . Balsa is used to make wooden crankbaits for fishing, especially Rapala lures. Sticks of dried balsa are useful as makeshift pens for calligraphy when commercial metal nibs of the desired width are not available. Balsa wood is often selected as a core material in composites . Because O. pyramidale grows quickly and tolerates poor soils it

279-450: Is due to the variety of characteristics apparent in different timbers, including density, grain, pore size, growth and fibre pattern, flexibility and ability to be steam bent. For example, the interlocked grain of elm wood ( Ulmus spp.) makes it suitable for the making of chair seats where the driving in of legs and other components can cause splitting in other woods. There is a correlation between density and calories/volume. This makes

310-529: Is from gymnosperm trees). Hardwoods are produced by angiosperm trees that reproduce by flowers, and have broad leaves. Many species are deciduous. Those of temperate regions lose their leaves every autumn as temperatures fall and are dormant in the winter, but those of tropical regions may shed their leaves in response to seasonal or sporadic periods of drought. Hardwood from deciduous species, such as oak, normally shows annual growth rings , but these may be absent in some tropical hardwoods . Hardwoods have

341-554: Is generally harder than that of softwoods, but there are significant exceptions. In both groups there is an enormous variation in actual wood hardness, with the range in density in hardwoods completely including that of softwoods; some hardwoods ( e.g. , balsa ) are softer than most softwoods, while yew is an example of a hard softwood. The structural polymers of hardwoods are cellulose , hemicellulose , and lignin . The constituents of hardwood lignin differs from those included in softwood. Sinapyl alcohol and coniferyl alcohol are

SECTION 10

#1732764663187

372-433: Is low in density but high in specific strength (strength per weight), balsa is a very popular material for light, stiff structures in model bridge tests , model buildings, and construction of model aircraft ; all grades are usable for airworthy control line and radio-controlled aircraft varieties of the aeromodeling sports, with the lightest "contest grades" especially valuable for free-flight model aircraft . However, it

403-435: Is lower in cost per performance compared to polymer foams like EPS while having better tensile strength than typical foams. For example, the blades of wind turbines are commonly constructed of many balsa plywood cores and internal spars covered with resin infused cloth on both sides. In table tennis rackets, a balsa layer is typically sandwiched between two pieces of thin plywood made from other species of wood. Balsa wood

434-453: Is rich in phenolic compounds, such as stilbenes , lignans , norlignans, tannins , flavonoids . Hardwoods are employed in a large range of applications, including fuel , tools , construction , boat building , furniture making, musical instruments , flooring , cooking , barrels , and manufacture of charcoal . Solid hardwood joinery tends to be expensive compared to softwood. In the past, tropical hardwoods were easily available, but

465-662: The Chevrolet Corvette had floor pans composed of balsa sandwiched between sheets of carbon-fiber-reinforced plastic . Norwegian scientist and adventurer Thor Heyerdahl , convinced that early contact between the peoples of South America and Polynesia was possible, built the raft Kon Tiki from balsa logs, and upon it his crew and he sailed the Pacific Ocean from Peru to the Polynesian Tuamotu Archipelago in 1947. However,

496-473: The Kon Tiki logs were not seasoned and owed much of their (rather slight) buoyancy to the fact that their sap was of lower density than sea water. This serendipitously may have saved the expedition, because it prevented the seawater from waterlogging the wood and sinking the raft. Balsa wood is also a popular wood type used in the arts of whittling , and surfing . In the making of picture frames, balsa

527-513: The balsa tree , is a large, fast-growing tree native to the Americas. It is the sole member of the genus Ochroma . The tree is famous for its wide usage in woodworking , due to its softness and its high strength compared to its low density. The name balsa is the Spanish word for "raft." A deciduous angiosperm , Ochroma pyramidale can grow up to 30 m tall, and is classified as

558-431: The kinkajou and the olingo , may be the primary pollinators. It is evergreen or dry-season deciduous , with large 30 to 40 centimetres (12 to 16 in), weakly palmately lobed leaves. Being a deciduous angiosperm , balsa is classified as a hardwood despite the wood itself being very soft; it is the softest commercial hardwood. Ecuador supplies 70% or more of commercial balsa. In recent years, about 60% of

589-545: The balsa has been plantation -grown in densely packed patches of around 1000 trees per hectare (compared to about two to three per hectare in nature). The trees are harvested after six to ten years of growth in Ecuador. The remaining volume of balsa is harvested from plantations in Papua New Guinea; the climate is different, therefore harvesting occurs at 4-5 years of age. Balsa lumber is very soft and light, with

620-491: The conclusion of the old-growth logging era, homesteaders tried to develop an agricultural economy on the cleared land; but these efforts largely failed in the 20th century, the main exceptions being fruit such as strawberries . Much of the peninsula reverted to second-growth woodland within the Lake Superior State Forest . Most of the peninsula is part of Delta County , although a small portion in

651-553: The denser hardwoods like oak , cherry , and apple more suited for camp fires, cooking fires, and smoking meat, as they tend to burn hotter and longer than softwoods like pine or cedar whose low-density construction and highly-flammable pitch make them burn quickly and without producing quite as much heat. Ochroma pyramidale Bombax pyramidale Cav. ex Lam. Ochroma bicolor Rowlee Ochroma concolor Rowlee Ochroma lagopus Sw. Ochroma obtusum Rowlee Ochroma pyramidale , commonly known as

SECTION 20

#1732764663187

682-527: The east is part of Schoolcraft County . The Garden Peninsula is part of the western sill of limestone bedrock of the Niagara Escarpment . The other surviving portion of the sill is now Wisconsin's Door Peninsula . Parts of the limestone sill between the Door and Garden peninsulas have been eroded away by glaciers . An archipelago of islands south of the Garden Peninsula spans the gap between

713-570: The floor pans of the Chevrolet Corvette . Balsa wood played a historical role in Thor Heyerdahl's Kon-Tiki expedition where it was used to build the raft. Balsa wood is also popular in arts such as whittling, and in the making of baroque-style picture frames due to its ease of shaping. A member of the mallow family, Ochroma pyramidale is native from southern Mexico to southern Brazil, but can now be found in many other countries (Papua New Guinea, Indonesia, Thailand, Solomon Islands). It

744-545: The hardwood significantly differs from the softwood, and mainly consists of triterpenoids , polyprenols and other higher terpenes. Triterpenoids commonly purified from hardwoods include cycloartenol , betulin and squalene . Hardwood polyterpenes are rubber , gutta percha , gutta-balatá and betulaprenols. Although in small quantities, hardwoods also contain mono- , sesqui- and diterpenes , such as α- and β-pinenes , 3-carene , β-myrcene , limonene , hinokitiol , δ-cadinene , α- and δ-cadinols , borneol . Hardwood

775-558: The main monomers of hardwood lignin. Hardwoods contain less amount of non-structural constituents, named extractives , than softwoods. These extractives are usually categorized into three broad groups: aliphatic compounds , terpenes and phenolic compounds . Aliphatic compounds found in hardwoods include fatty acids , fatty alcohols and their esters with glycerol , fatty alcohols (waxes) and sterols (steryl esters), hydrocarbons , such as alkanes , sterols , such as sitosterol , sitostanol and campesterol . The terpene content of

806-562: The peninsula's eastern shore, commemorates the gill nets used by Lake Michigan's Native American fishermen. 45°42′N 86°38′W  /  45.700°N 86.633°W  / 45.700; -86.633 Hardwood Hardwood is wood from angiosperm trees . These are usually found in broad-leaved temperate and tropical forests . In temperate and boreal latitudes they are mostly deciduous , but in tropics and subtropics mostly evergreen . Hardwood (which comes from angiosperm trees) contrasts with softwood (which

837-550: The supply of some species, such as Burma teak and mahogany , is now becoming scarce due to over-exploitation. Cheaper "hardwood" doors, for instance, now consist of a thin veneer bonded to a core of softwood, plywood or medium-density fibreboard (MDF). Hardwoods may be used in a variety of objects, but are most frequently seen in furniture or musical instruments because of their density which adds to durability, appearance, and performance. Different species of hardwood lend themselves to different end uses or construction processes. This

868-457: The third year onwards, typically at the end of the rainy season when few other trees are in flower. The large flowers open in the late afternoon and remain open overnight. Each may contain a pool of nectar up to 2.5 centimetres (0.98 in) deep. Daytime pollinators include capuchin monkeys . However, most pollination occurs at night. The main pollinators were once thought to be bats, but recent evidence suggests that two nocturnal arboreal mammals,

899-459: The two peninsulas, and hems in Green Bay , Lake Michigan's largest bay, to the west. The Garden Peninsula's line of limestone hills reaches as high as 165 feet (56 m) above the water at Burnt Bluff south of Fayette. The island-strewn waters around the Garden Peninsula continue to yield a harvest of freshwater fish . One of the peninsula's largest bays, Gillnet Haven Bay southeast of Fayette on

930-461: The wood is kiln-dried for about two weeks, leaving the cells hollow and empty. The large volume-to-surface ratio of the resulting thin-walled, empty cells gives the dried wood a large strength-to-weight ratio because the cells are mostly air. Unlike naturally rotted wood, which soon disintegrates in the rainforests where balsa trees grow, the cell walls of kiln- seasoned balsa wood retain their strong structure of cellulose and lignin . Because it

961-468: The world's Balsa wood volume is prepared into end grain panels for the composites industry, mostly used as structural cores in the wind turbine blades. Where strength, rigidity, durable and environmentally sustainable materials are sought after. Balsa is also used in the manufacture of "breakaway" wooden props such as tables and chairs that are designed to be broken as part of theatre, movie, and television productions. The fifth and sixth generations of

Garden Peninsula - Misplaced Pages Continue

#186813