軟木橡樹 Cork oak - Quercus suber
軟木橡樹
Cork oak - Quercus suber
在數千年以前，羅馬人發現，它會漂浮，用於製作漁網浮標及涼鞋。
現今，軟木橡樹是製作葡萄酒瓶塞原料主要來源，原生於歐洲西南部和非洲西北部，海拔300至500公尺的地方，樹高約20公尺，與其它橡樹不同，軟木橡樹是常綠的，葉子是不會掉落。
為什麼軟木橡樹有這麼厚的樹皮，因為林森火災發生時，厚的樹皮可以隔熱保護樹不致於被燒死，枝條可以迅速再生，來填補空缺的樹冠。在地中海火生態系統中獲得了生存勝利。
樹齡達到25年後，每隔9至12年就可以可收穫一次，收割軟木完全依靠人工。因取樹皮而不傷害樹木需要一些技術，收割人員需要培訓。一棵軟木橡樹在200年種植過程可以收穫約12次。每年可以生產 30萬噸，產值15億歐元，3萬人以此維生。
現今，軟木橡樹是製作葡萄酒瓶塞原料主要來源，原生於歐洲西南部和非洲西北部，海拔300至500公尺的地方，樹高約20公尺，與其它橡樹不同，軟木橡樹是常綠的，葉子是不會掉落。
為什麼軟木橡樹有這麼厚的樹皮，因為林森火災發生時，厚的樹皮可以隔熱保護樹不致於被燒死，枝條可以迅速再生，來填補空缺的樹冠。在地中海火生態系統中獲得了生存勝利。
樹齡達到25年後，每隔9至12年就可以可收穫一次，收割軟木完全依靠人工。因取樹皮而不傷害樹木需要一些技術，收割人員需要培訓。一棵軟木橡樹在200年種植過程可以收穫約12次。每年可以生產 30萬噸，產值15億歐元，3萬人以此維生。
資料來源:
Quercus suber, commonly called the cork
oak, is a medium-sized, evergreen oak tree in the section Quercus sect. Cerris.
It is the primary source of cork for wine bottle stoppers and other uses, such
as cork flooring and as the cores of cricket balls. It is native to southwest
Europe and northwest Africa. In the Mediterranean basin the tree is an ancient
species with fossil remnants dating back to the Tertiary period. The cork oak
forest is one of the major plant communities of the Mediterranean woodlands and
forests eco-region. Cork oak grows best in areas with cold, moist winters and
hot summers. It is commonly found at 300-600 m, but can occur up to 1,000 m
above sea level.
Cork oak bark has been harvested for thousands of years, and
with good reason. The Romans discovered that it would float and used it for
buoys in fishing nets, as well as for making sandals. Today, the main uses of
cork are in the production of wine bottle stoppers and insulation material.
From medieval times cork has been used to insulate buildings, keeping heat in
during the winter and keeping it out during the summer. Monasteries were
sometimes built with cork oak to protect them from the heat of the summer sun
Quercus suber is slow-growing and long-lived, some individuals
surviving to 250 years of age. Cork oak landscapes are mosaics of forest
habitats, comprising cork, holm and deciduous oak species, stone and maritime
pines, wild olive trees, maquis (a type of Mediterranean shrubland), and
pasture. Cork oak is an evergreen tree with low, twisted branches and downy
twigs. It can grow up to 20 m high, but it is typically more stunted in its
native environment. It has very thick and deeply ridged bark, which is
harvested as cork. The green leaves are 4-7 cm long, with spiny-ended lobes. and
their margins are often curved downwards. The leaves fall during the second
year of growth. Once a year, the tree produces fruits, known as acorns. The
acorns are 2-3 cm long, and sit in a deep cup fringed with elongated scales.
Cork oak is wind pollinated and monoecious (having separate male and female
flowers on the same plant). As with other oaks, the seed of Quercus suber
should be collected in the autumn when green. The viability of acorns can
decline very quickly. In the glasshouse, seeds germinate after around 6-8
weeks, whilst those in the field do not germinate until the following spring.
The tree forms a thick, rugged bark containing high levels of
suberin. Over time the cork cambium layer of bark can develop considerable
thickness and can be harvested every 7 to ten years to produce cork. The
harvesting of cork does not harm the tree, in fact, no trees are cut down
during the harvesting process. Only the bark is extracted, and a new layer of
cork regrows, making it a renewable resource.
As a pyrophyte, this tree has a thick, insulating bark that
makes it well adapted to forest fires. After a fire, many tree species
regenerate from seeds (as, for example, the maritime pine) or resprout from the
base of the tree (as, for example, the holm oak). The bark of the cork oak
allows it to survive fires and then simply regrow branches to fill out the
canopy. The quick regeneration of this oak makes it successful in the
fire-adapted ecosystems of the Mediterranean biome.
Virgin cork (or 'male' cork) is the first cork cut from
generally 25-year-old trees. Another 9 to 12 years is required for the second
harvest, and a tree can be harvested about 12 times in its lifetime. It is
obtained by peeling the bark away from the trunk, leaving a thin layer of new
cork still covering the functional part (secondary phloem) of the trunk. Cork
harvesting is done entirely without machinery, being dependent solely on human
labor. Usually five people are required to harvest the tree's bark, using a
small axe. The process requires training due to the skill required to harvest
bark without harming the tree. The European cork industry produces 300,000
tonnes of cork a year, with a value of €1.5 billion and employing 30,000
people. Wine corks represent 15% of cork usage by weight but 66% of revenues.
The cork left after stoppers have been made is used to make a
wide range of products, including insulation panels, floor and wall tiles and
sound-proofing in the car industry, as well as for handicrafts and artistic
uses. This include cork paper, used in printing, book covering, clothing
manufacture, cork maroquinerie and other products. Cork is also used in making
cricket balls, badminton shuttlecocks, handles of fishing rods and special
devices for the space industry.
The habitats that support cork oak are under ever-increasing
threat, mainly due to human activity such as the intensification of agriculture
and careless causes of forest fires (too frequent fires can damage the trees,
as it makes them susceptible to fungal infection).
The increasing use of plastic wine stoppers and metal screw tops
could reduce the value of cork oak forests, leading to their conversion or
abandonment. WWF has been working to publicise the environmental and economic
value of cork stoppers, in particular with the wine industry, to show what
would be lost if cork forests disappeared, and has a major programme to promote
products derived from sustainably managed cork oak forests.
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