These areas are usually called "ceremonial counties" or "preserved counties" in Wales. In Scotland a Statutory Instrument (rule written by a minister) defines the size of the lieutenancy. They are usually one local council area, but some council areas are too small or to large for one Lord Lieutenant.
For a list of the areas in England see Ceremonial counties of England
Meristem
A meristem is a tissue in plants made of dividing cells. They are in parts of the plant where growth can take place.
Plant cells which are differentiated generally cannot divide or produce cells of a different type. Therefore, cell division in the meristem is necessary to get new cells. This allows for the growth of tissues and new organs needed by the plant.
Meristematic cells have the same function for plants as stem cells have for animals. They are incompletely or not at all differentiated, and are capable of continued cell division.
The cells are small and protoplasm fills the cell completely. The vacuoles are extremely small. The cytoplasm does not contain plastids (such as chloroplasts, but they are there in rudimentary form ('proplastids'). Meristematic cells are packed closely together without intercellular cavities. The cell wall is a very thin primary cell wall.
The apical meristem, or growing tip, is found in the buds and growing tips of roots in plants.
It begins growth of new cells in young seedlings at the tips of roots and shoots (forming buds, among other things). Specifically, an active apical meristem lays down a growing root or shoot behind itself, pushing itself forward. Apical meristems are very small, compared to the cylinder-shaped lateral meristems.
Apical meristems may differentiate into three kinds of primary meristem:
These meristems are responsible for primary growth, or an increase in length or height.
These meristems cause secondary growth, or an increase in width. There are two types of secondary meristems:
Vascular cambium
The vascular cambium is a meristem.
It is the source of both the secondary xylem (inwards, towards the pith) and the secondary phloem (outwards), and is between these tissues in the stem and root. Only a few leaves even have a vascular cambium.
Vascular cambium is a type of meristem - a tissue consisting of embryonic (not specialized) cells which can produce other (and more differentiated) plant tissues originate. Primary meristems are the apical meristems on root tips and shoot tips. Another lateral meristem is the cork cambium, which produces cork, part of the bark.
Cork cambium
Cork cambium is a tissue in many vascular plants as part of the bark (periderm).
The cork cambium is a lateral meristem and is responsible for secondary growth that replaces the epidermis in roots and stems. It is found in woody and many herbaceous dicots, gymnosperms and some monocots, which usually have no secondary growth.
Cork cambium is one of the plant's meristems - the tissues that consist of embryonic (not specialized) cells from which the plant grows. It is one of the many layers of bark, between the cork and primary phloem. The function of cork cambium is to produce the cork, a tough protective material.
Synonyms for cork cambium are bark cambium, pericambium or phellogen.
Cork (material)
Cork is a material that is harvested for commercial use primarily from the bark of the Cork Oak tree. As the cork is harvested.
Portugal produces 50% of cork worldwide. Cork is made up of suberin, a hydrophobic substance.
In general, cork is made up of suberin (average of about 40%), lignin (22%), polysaccharides (cellulose and hemicellulose) (18%), extractables (15%) and others.
Cork's elasticity together with its near-impermeability makes it suitable as a material for bottle stoppers, especially for wine bottles. Cork stoppers represent about 60% of all cork based production. Cork's low density makes it a suitable material for fishing floats and buoys, as well as handles for fishing rods (as an alternative to neoprene). Cork is also used in the manufacture of musical instruments, particularly woodwind instruments, where it is used to fasten together different segments of the instrument and make the seams airtight.
Since cork has suberin in its cell walls, this makes the cells consist of sealed elements. And having sealed elements make it greater for acoustic insulation and even thermal insulation. Sealed elements are capable of trapping and absorbing sound. In short, suberin is mostly responsible for noise reduction! Also, lignin is another constituent of cork. It makes up about 22% of cork. One study says that it’s also associated with soundproofing and thermal insulation!
The cork industry is generally regarded as environmentally friendly. The sustainability of its production and the easy recycling of cork products and by-products are two of its most distinctive aspects.
Cork demand has increased due to a larger proportion of wine being sealed with cork rather than being sold in bulk. Top quality corks are quite expensive, so many cheaper brands have switched to lower quality cork, synthetic plastic stoppers, screwcaps, or other closures.
Cork oak
The cork oak ("Quercus suber") is a medium-sized, evergreen oak tree. It grows southwest Europe and northwest Africa.
It grows to up to 20 m, but in its native environment it is usually not that tall. The leaves are 4–7 cm long, dark green above, paler beneath, with the leaf margins often downcurved. The acorns are 2–3 cm long.
The tree forms a thick, corky bark. Over time this bark can develop considerable thickness and this is harvested every 10–12 years as cork. The harvesting of cork does not harm the tree and a new layer of cork regrows, making it a renewable resource. The tree is widely cultivated in Spain, Portugal, Algeria, Morocco, France, Italy and Tunisia. Cork oak forests cover approximately 2.5 million hectares in those countries. Portugal accounts for 50% of the world cork harvest. Cork oaks cannot legally be cut down in Portugal, except for forest management felling of old, unproductive trees.
Cork oaks live about 150–250 years. Virgin cork (or 'male' cork) is the first cork cut from generally 25-year-old trees. Another 10–12 years is required for the second harvest, and a tree can be harvested a dozen times in its lifetime. Cork harvesting is done entirely without machinery.
The European cork industry produces 340,000 tonnes of cork a year, with a value of €1.5 billion. 30,000 people work at it. Wine corks represent 15% of cork usage by weight but 66% of revenues.
Cork oaks are sometimes planted as individual trees. So they provide a small income to their owners. The tree is also sometimes cultivated for ornament. Hybrids with turkey oak ("Quercus cerris") are regular, both in the wild in southwest Europe and in cultivation; the hybrid is known as Lucombe Oak "Quercus × hispanica".
Some cork is also produced in eastern Asia from the related Chinese cork oak ("Quercus variabilis").
In many different species of trees seed predation is considered a problem for the continued growth and reproduction of trees, in this case Rabbits are affecting the cork oak tree. During the development of a plant species the seed / acorn stage in development is considered to be the most important yet most vulnerable stage. The cork oak tree encounters many challenges during its seedling stage.
Seeds are often found in the form of acorns that fall to the ground close by to the base of the tree. Those acorns become the beginning development of new trees, which develop over time. However many different species use those acorns as a source of food. When rabbits are living in the same area as the cork oak tree seed regeneration is not affected in a negative way.