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34-576: The Luang Prabang Range , and the Annamite Range separate the plateau from Thailand and Vietnam respectively. The ranges of the plateau are sandstone and limestone mountains between 2000 and 2800 meters high (about 6561 and 9842 feet high). These have been heavily deforested . The highest mountain of Laos , Phou Bia , is located to the south of the Xiangkhoang. Altitudes within the plateau area may reach 1000 m. Several tributaries of

68-399: A behavior known as " marcescence " whereby dead leaves are not shed in the fall and remain on the tree until being blown off by the weather. This is caused by incomplete development of the abscission layer. It is mainly seen in the seedling and sapling stage, although mature trees may have marcescence of leaves on the lower branches. A number of deciduous plants remove nitrogen and carbon from

102-602: A greater rate of transpiration (and hence CO 2 uptake as this occurs when stomata are open) during the summer growth period. The deciduous characteristic has developed repeatedly among woody plants. Trees include maple , many oaks and nothofagus , elm , beech , aspen , and birch , among others, as well as a number of coniferous genera , such as larch and Metasequoia . Deciduous shrubs include honeysuckle , viburnum , and many others. Most temperate woody vines are also deciduous, including grapes , poison ivy , Virginia creeper , wisteria , etc. The characteristic

136-606: Is a deciduous woody shrub found in Japan . Forests where a majority of the trees lose their foliage at the end of the typical growing season are called deciduous forests. These forests are found in many areas worldwide and have distinctive ecosystems, understory growth, and soil dynamics. Two distinctive types of deciduous forests are found growing around the world. Temperate deciduous forest biomes are plant communities distributed in North and South America, Asia, Southern slopes of

170-651: Is a mountain range straddling northwestern Laos and Northern Thailand . Most of the range is located in Sainyabuli Province (Laos), as well as Nan and Uttaradit Provinces (Thailand), with small parts in Phitsanulok and Loei Provinces . Several rivers such as the Nan , Pua and Wa rivers, have their sources in this range. Phu Fa waterfall , the biggest and the tallest waterfall in Nan Province,

204-663: Is allegedly a heartland for military involvement in timber trade. The Luang Prabang Range is practically devoid of vehicle roads on the Sainyabuli Province side, where there is only one north-south route extending from Sainyabuli , the provincial capital, to the Thai border opposite Thailand's Loei Province. In 1904 the Laotian area of the range was ceded from Siam to the French Indochina colony. Following

238-637: Is also located in these mountains. This range is part of the Luang Prabang montane rain forests ecoregion . Geologically its composition is similar to that of the parallel Khun Tan Range and the Phi Pan Nam Range , both located further west. The Luang Prabang mountains are the easternmost range of the Thai highlands . The range runs roughly in a North/South direction between the Mekong and

272-700: Is completed (marked by the transition from bright green spring leaves to dark green summer ones) the chlorophyll level in the leaves remains stable until cool temperatures arrive in autumn. When autumn arrives and the days are shorter or when plants are drought-stressed, the chlorophyll steadily breaks down, allowing other pigments present in the leaf to become apparent and resulting in non-green colored foliage. The brightest leaf colors are produced when days grow short and nights are cool, but remain above freezing. These other pigments include carotenoids that are yellow, brown, and orange. Anthocyanin pigments produce red and purple colors, though they are not always present in

306-400: Is formed between the leaf petiole and the stem. This layer is formed in the spring during active new growth of the leaf; it consists of layers of cells that can separate from each other. The cells are sensitive to a plant hormone called auxin that is produced by the leaf and other parts of the plant. When auxin coming from the leaf is produced at a rate consistent with that from the body of

340-498: Is one of the ultra prominent peaks of Southeast Asia . Many of the important peaks are located at the border. The vegetation is evergreen hill forest on the highest altitudes of the range height and mostly dry deciduous forest below 1,000 m, with an abundance of teak trees , which has led to heavy deforestation . Like in most ranges of the area, a great proportion of the original forest cover has disappeared owing to shifting agricultural practices and illegal logging . The area

374-551: Is one of the most heavily bombed places in the world. The plateau is also one of the most heavily contaminated areas in the world from unexploded cluster munitions also called UXO . 19°24′N 103°02′E  /  19.400°N 103.033°E  / 19.400; 103.033 This Laotian location article is a stub . You can help Misplaced Pages by expanding it . Luang Prabang Range The Luang Prabang Range ( Thai : ทิวเขาหลวงพระบาง , pronounced [tʰīw kʰǎw lǔaŋ pʰráʔ.bāːŋ] ), named after Luang Prabang ,

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408-530: Is useful in plant identification; for instance in parts of Southern California and the American Southeast , deciduous and evergreen oak species may grow side by side. Periods of leaf fall often coincide with seasons: winter in the case of cool-climate plants or the dry-season in the case of tropical plants, however there are no deciduous species among tree-like monocotyledonous plants, e.g. palms , yuccas , and dracaenas . The hydrangea hirta

442-661: The Franco-Thai War in 1941 it was annexed by Thailand again under the name Lan Chang (Million Elephants) Province, but returned to its pre-war status in 1946 following the 1946 Washington Accord. Certain Hill tribe communities live in the range, like the Khmu and the Hmong , whose tribal villages are located on both sides of the mountain range. Since the Mekong isolated Sainyabuli from other Laotian provinces with Hmong villages,

476-660: The Mekong drain in the plateau, such as the Nam Ngum , Ngiap and the Khan River . The major town in the area is the capital of Phonsavan . The plateau gives its name to present-day Xiangkhouang Province in which Phonsavan is located. The plateau is the location of the Plain of Jars , which is a collective name for several sites with funerary archeological remains nominated for UNESCO World Heritage status. Xianghouang Province

510-900: The Nan River . Its northern end begins in the area of Hongsa District , a stretch in Laos near Luang Prabang where the Mekong River flows from west to east; its southern end is about 260 km further south, at the western end of Loei Province in Thailand where the Phetchabun Mountains begin. The highest point of the range is 2,120 m high Phu Soi Dao . Other high peaks of the Luang Prabang Range are 2,079 m high Phu Khe , 1,980 m high Doi Phu Kha , 1,837 m high Doi Phu Wae and 1,745 m high Doi Phi Pan Nam ; Phu Khe

544-503: The foliage before they are shed and store them in the form of proteins in the vacuoles of parenchyma cells in the roots and the inner bark. In the spring, these proteins are used as a nitrogen source during the growth of new leaves or flowers. Plants with deciduous foliage have advantages and disadvantages compared to plants with evergreen foliage. Since deciduous plants lose their leaves to conserve water or to better survive winter weather conditions, they must regrow new foliage during

578-844: The Himalayas, Europe and for cultivation purposes in Oceania. They have formed under climatic conditions which have great seasonable temperature variability. Growth occurs during warm summers, leaf drop in autumn, and dormancy during cold winters. These seasonally distinctive communities have diverse life forms that are impacted greatly by the seasonality of their climate, mainly temperature and precipitation rates. These varying and regionally different ecological conditions produce distinctive forest plant communities in different regions. Tropical and subtropical deciduous forest biomes have developed in response not to seasonal temperature variations but to seasonal rainfall patterns. During prolonged dry periods

612-523: The Thai side of the Luang Prabang Range. On the Lao side there is only one. The Nam Phouy National Biodiversity Conservation Area , a large protected area in Laos home to many wild elephants, is located in a forested sector close to the Thai border. The projected reservoir of Lower Nam Phoun dam , however, is partly within the Nam Phouy NBCA and a large zone of the protected area will be flooded in

646-420: The Thai side of the range. The southern part of the range saw some confrontation between December 1987 and February 1988 when Thai and Laotian forces engaged in cross-border fighting. Known as Thai–Laotian Border War , this short conflict was caused by a dispute involving the map made by French surveyors in 1907 to mark the borders between Siam and French Indochina . The Thai-Lao Joint Boundary Commission (JBC)

680-428: The earliest trees to lose their leaves in the fall. In sub-Arctic climates such as Alaska , leaves begin turning colors as early as August. However, for most temperate regions it takes place in late September through early November and in subtropical climates such as the southern US, it may be November into December. Leaf drop or abscission involves complex physiological signals and changes within plants. When leafout

714-701: The fall months and the Western United States as it has more evergreen and fewer deciduous plants, combined with the West Coast and its maritime climate. ( See also : Autumn leaf color ) Most of the Southern Hemisphere lacks deciduous plants due to its milder winters and smaller landmass, most of which is nearer the equator with only far southern South America and the southern island of New Zealand producing distinct fall colors. The beginnings of leaf drop starts when an abscission layer

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748-425: The fields of horticulture and botany , the term deciduous ( / d ɪ ˈ s ɪ dʒ u . ə s / ) means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves , usually in the autumn ; to the shedding of petals , after flowering; and to the shedding of ripe fruit . The antonym of deciduous in the botanical sense is evergreen . Generally,

782-426: The foliage is dropped to conserve water and prevent death from drought. Leaf drop is not seasonally dependent as it is in temperate climates. It can occur any time of year and varies by region of the world. Even within a small local area there can be variations in the timing and duration of leaf drop; different sides of the same mountain and areas that have high water tables or areas along streams and rivers can produce

816-400: The future. Khun Nan National Park , Doi Phu Kha National Park , Sinan National Park, Mae Charim National Park , Na Haeo National Park, Klong Tron National Park, Phu Suan Sai National Park and Phu Soi Dao National Park are located on the Thai side of the Luang Prabang Range. Phu Miang-Phu Thong Wildlife Sanctuary is another protected area on the Thai side. Deciduous In

850-417: The humid maritime climate and lower overall species diversity . It is also a factor that the continental United States and southern Canada are at a lower latitude than northern Europe, so the sun during the fall months is higher and stronger. This combination of strong sun and cool temperatures leads to more intense fall colors. The Southern United States also has poor fall colors due to warm temperatures during

884-507: The leaves are shed at the same time. Plants that are intermediate may be called semi-deciduous ; they lose old foliage as new growth begins. Other plants are semi-evergreen and lose their leaves before the next growing season, retaining some during winter or dry periods. Many deciduous plants flower during the period when they are leafless, as this increases the effectiveness of pollination . The absence of leaves improves wind transmission of pollen for wind-pollinated plants and increases

918-533: The leaves. Rather, they are produced in the foliage in late summer, when sugars are trapped in the leaves after the process of abscission begins. Parts of the world that have showy displays of bright autumn colors are limited to locations where days become short and nights are cool. The New England region of the United States and southeastern Canada tend to produce particularly good autumn colors for this reason, with Europe producing generally poorer colors due to

952-783: The next suitable growing season; this uses resources which evergreens do not need to expend. Evergreens suffer greater water loss during the winter and they also can experience greater predation pressure , especially when small. Deciduous trees experience much less branch and trunk breakage from glaze ice storms when leafless, and plants can reduce water loss due to the reduction in availability of liquid water during cold winter days. Losing leaves in winter may reduce damage from insects; repairing leaves and keeping them functional may be more costly than just losing and regrowing them. Removing leaves also reduces cavitation which can damage xylem vessels in plants. This then allows deciduous plants to have xylem vessels with larger diameters and therefore

986-469: The plant, the cells of the abscission layer remain connected; in autumn, or when under stress, the auxin flow from the leaf decreases or stops, triggering cellular elongation within the abscission layer. The elongation of these cells breaks the connection between the different cell layers, allowing the leaf to break away from the plant. It also forms a layer that seals the break, so the plant does not lose sap. Some trees, particularly oaks and beeches, exhibit

1020-591: The term "deciduous" means "the dropping of a part that is no longer needed or useful" and the "falling away after its purpose is finished". In plants, it is the result of natural processes. "Deciduous" has a similar meaning when referring to animal parts, such as deciduous antlers in deer , deciduous teeth (baby teeth) in some mammals (including humans); or decidua , the uterine lining that sheds off after birth. In botany and horticulture , deciduous plants , including trees , shrubs and herbaceous perennials, are those that lose all of their leaves for part of

1054-702: The visibility of the flowers to insects in insect-pollinated plants. This strategy is not without risks, as the flowers can be damaged by frost or, in dry season regions, result in water stress on the plant. Spring leafout and fall leaf drop are triggered by a combination of daylight and air temperatures. The exact conditions required will vary with the species, but generally more cold-tolerant genera such as Salix will leaf-out earlier and lose their leaves later, while genera such as Fraxinus and Juglans can only grow in warm, frost-free conditions so they need at least 13 hours of daylight and air temperatures of around 70 °F (21 °C) to leaf out. They will be among

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1088-640: The warfare during the Quiet War which so badly affected other Hmong communities in Laos largely did not affect the Hmong in the Luang Prabang Range. Most Hmong villages in Sainyabuli Province did not see any fighting. However, later they were persecuted all the same by the Vietnamese and the Pathet Lao soldiers, who regarded them as traitors, thus many fled across the border. There are refugee camps on

1122-501: The year. This process is called abscission . In some cases leaf loss coincides with winter—namely in temperate or polar climates . In other parts of the world, including tropical, subtropical, and arid regions, plants lose their leaves during the dry season or other seasons, depending on variations in rainfall . The converse of deciduous is evergreen , where foliage is shed on a different schedule from deciduous plants, therefore appearing to remain green year round because not all

1156-504: Was established in 1996 to clarify the 1,810-kilometre boundary and settle ownership of the disputed villages. Border demarcation is still going on. Yetis are said to have been spotted in the remote Mae Charim area of the range. Presently on the Thai side of the Luang Prabang Range some of the Hmong communities are regularly visited by organized tourist groups. River Wa is a popular river for white water rafting between July and December. There are large swathes of protected areas on

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