Temperate forests and tropical rain forests

The word forest is derived from Latin ‘Foris’ meaning outside, the reference being to village boundary fence, and must have included all uncultivated and uninhabitated land.
Today a forest is any land managed for the diverse purposes of forestry whether covered with trees, shrubs, climbers, etc.
The forest biomes include a complex assemblage of different kinds of biotic communities.
Optimum conditions of temperature and ground moisture responsible for the growth of trees contribute greatly to the establishment of forest communities.
In addition, 50 mm rainfall is a pre-requisite for the trees.
The nature of soil, wind and air currents determines the distribution (abundance or sparseness) of forest vegetation.
The temperate forest biomes are characterized by a moderate climate and broad-leaved deciduous trees, which shed their
leaves in fall, are bare over winter and grow new foliage in the spring.

1. TEMPERATE FORESTS AND TROPICAL RAIN FORESTS ALEN SHAJI P1914015 1 MSC BOTANY

2. FOREST The word forest is derived from Latin ‘ Foris ’ meaning outside , the reference being to village boundary fence, and must have included all uncultivated and uninhabitated land. Today a forest is any land managed for the diverse purposes of forestry whether covered with trees, shrubs, climbers, etc. The forest biomes include a complex assemblage of different kinds of biotic communities . Optimum conditions of temperature and ground moisture responsible for the growth of trees contribute greatly to the establishment of forest communities.

3. In addition, 50 mm rainfall is a pre-requisite for the trees. The nature of soil , wind and air currents determines the distribution (abundance or sparseness) of forest vegetation .

4. TEMPERATE DECIDUOUS FOREST The temperate forest biomes are characterized by a moderate climate and broad-leaved deciduous trees , which shed their leaves in fall, are bare over winter and grow new foliage in the spring. DISTRIBUTION These forests are the characteristics of North America, Europe, Eastern Asia, Chile , part of Australia and Japan .

5. CLIMATE C old winter and an annual rainfall of 75—150 cm and a temperature of 10—20°C . In these biomes the precipitation may be fairly uniform throughout the year .

6. VEGETATION The predominant genera of this biome are maple ( Acer ), beech ( Fagus ), oak ( Quercus ), hickory ( Carya ), basswood ( Tilia ), chestnut ( Castnea ), cottonwood ( Populas ), sycamore ( Platanus ), elm ( Ulmus ) and willow ( Salix ). In some locations, coniferous vegetation may be quite predominant and that incudes white pine ( Pinus strubos ), hemlock ( Tsuga canadensis ) and red cedar ( Juniperus virginianus ). In India , at elevations of 2743.2m-3655.6m in Himalayas occur temperate vegetation including pines, fir, yew and juniper trees with an undergrowth of scrubby rhododendrons.

7. Shrubs and herbs in the deciduous forest is typically well-developed and richly diversified , with a considerable portion of the photosynthesis and flowering attuned to the short day of the spring season , prior to the leafing out of and consequent shading by the tree canopy. Some species of mosses , algae and lichens growing on tree trunks, and a few vines , notably Vitis , the grape.

8. ANIMAL DIVERSITY The animals originally present in temperate forests are deer, bears, squirrels, gray foxes, bobcats, wild turkey and wood peckers . Other common animals of this region are invertebrates such as earthworms , snails, millipedes , Coleoptera and Orthoptera . Vertebrates like amphibians such as newts , salamanders, toads, and cricket frogs . Reptiles such as turtles, lizards and snakes . Mammals such as racoon opossum, pigs, mountain lion , etc. Birds like horned owl, hawks , etc.

9. Diversity of fauna is lower than in any of the rain forests and a few species seems clearly to be dominant.

10. ADAPTATIONS Soils of temperate forests are podozolic and fairly deep . Trees are quite tall — about 40—50m in Height and their leaves are thin and broad . There are often two separate herb assemblages . One consists of spring flowers , which bloom before the trees have expanded their leaves and are gone by summer, and the other is adapted to the low light levels of the forest floor and lasts into the fall .

11. Animals and plants show a profound seasonality . Some may even hibernate throughout the winter . The range of animal size and adaptations is wide. The largest animals include such forms as the deer and black bear . The dominant carnivores are large, including the wolf and mountain lion , although smaller carnivores such as fox and skunk are also common.

12. TEMPERATE EVERGREEN WOODLAND/CHAPARRAL CLIMATE Mediterranean- type climate with warm, dry summers and cool, moist winters . VEGETATION Commonly inhabited by low evergreen trees with small hard needles or slightly broader leaves . Trees are essentially lacking, although shrubs may range upto 3—4 m in height . Species diversity is roughly intermediate between that of a temperate deciduous forest and a drier grassland .

13. DISTRIBUTION M ost important area of tropical evergreen woodland in North America is the ‘chaparral’ of the Pacific coast, the Mediterranean ‘ maquis ’, Spanish ‘ encinar ’ and ‘ melle scrab ’ on Australia’s South coast are the same type of community. ADAPTATIONS Fire is an important factor in this ecosystem, and the adaptations of the plants enable them to regenerate quickly after being burned .

14. ANIMAL DIVERSITY C haracteristic animals of temperate evergreen woodland or chaparral are mule deer , brush rabbits, wood rats, chipmunks , lizards , wem -tits and brown towhees . Small-hooved cursorial ungulates are the dominant herbivores . Saltatorial (jumping) animals and many fast moving ungulates are also common in this fauna.

15. TEMPERATE RAINFORESTS CLIMATE Temperate rainforest is a colder ecosystem than any other rainforest. Such a forest has a definite seasonality , with both temperatures and rainfall varying throughout the year . Rainfall is high , but fog maybe very heavy and actually more important as a source of water than rainfall.

16. VEGETATION Diversity is much lower , both in plants and animals, in comparison to warmer rainforests , yet it remains still higher than other temperate forest types. Dominant trees (canopies) are coast redwood ( Sequoia sempervirens ) of the Pacific coast of North America and the alpine ash ( Eucalyptus regnans ) of Australia and Tasmania, both of which reach more than 100m in height . Epiphytes and lianas are common but are not abundant like those of other rainforest.

17. ANIMAL DIVERSITY A nimals of temperate rainforests are similar to those of deciduous forests , but show a somewhat higher diversity .

18. TROPICAL RAINFORESTS DISTRIBUTION O ccur near the equator in Central and South America , Central and Western Africa (Congo , Zambesi river), Southeast Asia (parts of India and Malaysia), Malaya, Borneo , New Guinea and Northwest Australia .

19. CLIMATE Both temperature and humidity are high and constant . The annual rainfall which exceeds 200 to 225 cm is generally evenly distributed throughout the year .

20. VEGETATION Tropical rainforests are among the most diverse communities on earth . Flora is highly diversified : a square mile may contain 300 different species of trees , a diversity unparalleled in any other biome. The extremely dense vegetation of the tropical rainforests remains vertically stratified with tall trees often covered with vines, creepers, lianas, epiphytic orchids and bromeliads . Under the tall trees is a continuous evergreen carpet , the canopy layer , some 25 to 35 meters tall .

21. Lowest layer is an understory of trees, shrubs , herbs like ferns and palms , all of which become dense where there is a break in the canopy .

22. ADAPTATIONS Leaves of most plant are of moderate size, leathery and dark green in colour . Their roots are often shallow and have swollen bases or flying buttresses . Soils of tropical rainforests are red latosols , and they may be exceedingly thick . The high rate of leaching makes these soils virtually useless for agriculture purposes , but if they are left undisturbed the extremely rapid cycling of nutrients within the litter layer (due to decomposition) can compensate for the natural poverty of the soil .

23. ANIMAL DIVERSITY Invertebrate density and abundance are very high in tropical rainforests. While vertebrates are diverse , they are not as abundant as in many other communities. Common invertebrates of these forests are worms, snails, millipedes, centipedes , scorpions , isopods , spiders, insects , planarians a nd leeches . Amount insects, heteropterans , orthopterans , blattids , mantids , phasmids , bees, termites and ants are most common.

24. C ommon vertebrates of tropical rainforests are the arboreal amphibian Rhacophorus malabaricus ; aquatic reptiles, chameleons , agamids , geckoes , and many species of snakes ; many species of birds , social birds being predominant ; and a variety of mammals . Nocturnal and arboreal habits are most common in many mammals such as insectivores, leopards, jungle cats, anteaters, giant flying squirrels, monkeys and sloths .

25. In the foot hills of the forest zone of peninsular India covered with dense tropical vegetation , we have the tiger ( Panthera tigris ), the elephant ( Elephas maximus ), samber deer ( Rusa unicolor ), muntjac ( Muntiacus muntjak ), the gaur ( Bibos gaurus ), the chital or spotted deer ( Axis axis ) , and the swamp deer ( Rucervus duraucelli ) as the major ground dwelling mammals .

26. REFERENCE Sharma PD [1997] Environmental Biology, Rastogi Publications, New Delhi. Verma PS [1974] Cell Biology, Genetics, Molecular Biology, Evolution And Ecology, S Chand Publications, New Delhi.

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