Friday, July 20, 2018

Gangetic Dolphin

Scientific name: Plantanista gangetica

aquatic black and white dolphin fun

Zoologist have divided the Dolphin into two parts as Gangetic Dolphin and Indus Dolphin. There are 10 species of Dolphin found in India, Nepal ,China,USA and Brazil. Among the 10 species of Dolphin the Gangetic Dolphin, Chinese River Dolphin, Indus River Dolphin and Amazon Dolphin are fresh water living ones. Gangetic Dolphins are found in rivers of India, Nepal and Bangladesh.

Brown Bear

Scientific name: Ursus arctos

zoo bear
There are 8 different species  of Bear in the world one is this Brown Bear which is found to be  distributed in Nepal, India, Bhutan, Pakistan, Afghanistan, Tibet, Europe and North America.The male Brown Bear is 210cms-245cms long and female is a bit short than male. They weighs about 100-200 kgs and have a height of 1.5m-1.7m. It is listed in CITES Appendix-I and IUCN Red Data Book.

Black Buck

Scientific name- Antelope cervicapra

At present Black Buck is confined only to India and Nepal. There are 4 species of Black Buck present in this two countries. The male have two rounded horns and the horn does not shed every year and is not hollow also. They are usually 45 cms-50 cms long and have a height of 80cms -90cms. it is listed in CITES Annex-III and Red Data Book IUCN due to its low number and distribution.

Wednesday, July 18, 2018

Bengal Tiger

Scientific name: Panthera tigris
orange and black bengal tiger walking on green grass field during daytime
Bengal tiger is found only on 5 countries Nepal, India, Bangladesh, Myanmar and Bhutan. The male tiger weighs about 180 Kgs  to 280 Kgs  with the length of 150 cms to 300 cms and tail 60 cms  to 110 cms, the female tiger weighs 115 kgs to 185 kgs.  The tiger is yellow- golden colored.The life span of the Bengal tiger is recorded to  be 15 to 20 years. The number of the Bengal  tiger is very low than couple of decades ago but the recent records has shown increasing trend in Nepal and India.

Assamese Monkey

Scientific name: Macaca assamensis
gray monkeys
Assamese monkey have light red color in their body and their body length ranges from 55 to 60 cms and their tail from 15 to 20 cms.  Unlike other species of monkey Assamese monkey are less active and mostly prefer dense forest and cliffs. They mainly eat insects and other plant foods. They are also found to destroy agricultural crops like other species of monkeys.

South East Asian Wild Buffalo

Nepali Name : Arna

English Name: Bubalus bubalis arnee
photo of water buffalo on grass fields
There are 5 species of Arna all over  south east Asia  in Nepal, India, Bhutan, Cambodia, SriLanka, Thailand and Philippines. It is found on the areas with abundant water, grass and riverside forest. Wetlands are also its important habitat areas. They can be active for grazing twice a day morning and evening and sometimes night also. They can attack agricultural field also. They like to live on herds. They are found to have a lifespan of about 8 years. They are distinguished from the domestic buffalo by its larger size, larger horns. But the obvious feature determining the wild from domestic is its horn which can be up to 198 cms.

Wednesday, July 11, 2018

Seed Certification

aroma aromatic beans brown
The seeds after being collected and before being stored or used has to accompany a certificate giving the information like the species, date of collection of the seed, locality factors like the elevation, aspects, climatic and soil conditions, characteristics of the mother trees, method of collection, processing, method of storage, name of the collecting person, quantity of seed, date of dispatch, condition of seed at the time of dispatch, etc.


It ensures the germination percentage which help to estimate the quantity of seeds required to produce the desired number of seedlings of given species.

It is useful for provenance test as the observation of growth pattern and availability of seedlings and trees grown from seeds of various provenances will provide the knowledge of fitness of the provenance for the plantation of given site of certain species.

It helps to achieve the objective of plantation by predicting the quality and form of the products of the trees.

Besides it also helps in knowing the quality of the   mother trees, vigorous of the growth and the degree of suitability to the site of plantation.

Storage of seeds

bunch of nuts served on bowls
Storage of seeds is essential to meet the demands of seeds having right physiological and genetic characteristics during all the time.The objective of the proper storage is to maintain the viability of seeds for longer period. It helps to maintain the longevity as well. Several Species  Leguminosae and Malvaceae families have high longevity.

The methods of control of oxygen, moisture content and temperature that reduces the rate of respiration without otherwise damaging  the seed is likely to be effective in extending the longevity during storage. Seeds stored under good conditions and which have maintained higher germinative capacity can safely be used but it is not good to use seed lot in which the germinative capacity has been severely curtailed. Insects has also to be taken care of. Suitable insecticides regularly has to be used to avoid any insect damage. Cold storage facility also provide longevity. Silica gel is used to keep moisture content of 7 to 9 percent  in impermeable containers .

Seed Processing of Forest Trees

[caption id="attachment_114" align="alignnone" width="300"]batch close up cooking dry Photo by Pixabay on[/caption]

 The objective of Seed Processing is to produce good quality seeds for sowing. The Processes are Pre-cleaning, Pre-curing, Cleaning.

Pre-cleaning involves cleaning of twigs, barks, leaf litter and other impurities before they are sent for extraction. It can be done by hand and by flotation and fruits be separated by blowing and winnowing.

Pre-curing involves the deliberate storage for ripening of seeds and slow air drying of seeds/fruits.

Cleaning of sound seeds from impurities can be done by screening and sieving,sorting,winnowing,flotation. Screening and sieving remove almost all impurities which have different size than the hole in sieve or screen. Sorting according to length may remove longer and shorter impurities. Cleaning by winnowing is a common practice.Likewise, Flotation method can be used to separate out impurities having different specific gravity than that of seed.

Seed Collection of tree species

Seed collection is very important part of the plantation project or to fulfill the objective of afforestation and reforestation.
brown pistachio nut lot
The seeds should be collected from the selected tree following different guidelines. The seeds should be collected from healthy vigorous trees of reasonably good form that are making more than the average growth.The seeds produced by immature and mature trees are sometimes infertile so middle aged trees has to be chosen for collection.Poorly deformed, diseased, abnormal, insect infested trees has to be avoided. The seedlings that are produced from the isolated trees of naturally cross- pollinating species,( are likely to be self pollinated ) are weak or malformed and seeds few with low viability. Dominant and Co-dominant trees are mostly chosen and vigorous wolf-trees are also avoided.

Bamboo and Rattans

agriculture bamboo botanical bundleBAMBOOS are tall, perennial, arborescent grasses, belonging to Poaceae family. There are 50 genera and approximately 1326 species generally inhibiting the humid tropical, sub-tropical and mild temperate regions of the world. It is found  in over 18 million hectares of land, of which 75% lies only in Asia.The rhizomes of the Bamboo may be short and thick and clustered together and produce Bamboo in well defined clumps. Mature Bamboo clumps produced new shoots every year throughout the rainy season. The shoots develop then rapidly within 2-3 months and reach their full height and diameter.

abstract background bamboo close upRATTANS belong to the family Palmae/Arecaceae. 600 species of Rattans belonging to 13 genera are reported to be distributed worldwide concentrated in Africa and South East Asia.Rattan is an ideal raw material for cottage industries. Its industrial use is in furniture, walking sticks, polo sticks, umbrella handles, basket making, mats, ropes, and various other articles.

Sunday, July 8, 2018

Silviculture of indigeneous tree species in Nepal

Recommending any particular silvicultural system for a species is not a good idea. The silvicultural system for a particular forest stand should be formulated or selected on the basis of species, forest condition, forest owner's objectives and so on.

Sal ( Shorea robusta)

Silvicultural characteristics 

Strong light demander, Good coppicer , Seedling die back due to frost, drought, fire , and dense overstorey, Annual seeders but good seed years after every 2 years, Light winged seeds and seeds dispersed by winds.

Silvicultural Systems

Selection system, Irregular shelterwood system, Uniform shelterwood system, One cut shelterwood system, Clearfelling system, Coppice with standards, Coppice with reserves, Simple coppice.


Khair (Acacia catechu)

Silvicultural characteristics

Strong light demander, Seedlings are susceptible to severe frost, Drought resistant, Coppices well unless it is under shade of other species, Seeds produce in abundance, Seeds dispersed by wind and water, requires protection from grazing and browsing.

Silvicultural systems

Clearfelling and Plantation, Simple coppice, coppice with standards, Seed tree method.


Sissoo ( Dalbergia sissoo)

Silvicultural characteristics

Strong light demander, Good coppicer, Annual seeder and seeds produced abundantly, Seeds dispersed by wind and water, Older seedlings can tolerate mild frost, Should be protected against grazing and browsing.

Silvicultural systems

Seed tree method, Clearfelling and plantation by Taungiya, Two storyed high forest system, Simple coppice, Coppice with standards, Coppice with two rotation system.


Chilaune ( Schima wallichi)

Silvicultural characteristics

Not frost hardy,Coppices very well, Good seed year are frequent , Winged light seeds dispersed by wind, Moderately shade tolerant but later it benefits from full overhead light, Capable of colonizing plantations of other species.

Silvicultural systems

Simple coppice, coppice with two rotation, Coppice with standards, Selection coppice, Selection system.

 Katus (Castanopsis indica )

Silvicultural characteristics

Moderately shade tolerant, Frost hardy, Benefits from overhead light in later stage, Young seedlings are frost tender, Coppices well.

Silvicultural systems

Simple coppice, Coppice with two rotation, Coppice with standard, Selection coppice, Selection system.

Deodar( Cedrus deodara)

Silvicultural characteristics

Shade bearer and young seedlings benefit from side shade, Winged Seeds dispersed by wind, Young seedlings don't suffer from frost, Very sensitive to fire, Good seed years after every 3 years, Most of the seeds fall close to the parent tree, Profuse regeneration in favorable sites.

Silvicultural Systems

Single tree selection, Irregular shelterwood system, Uniform shelterwood system (40-50 seed trees/ha).




Saturday, July 7, 2018

Important Fodder Tree Species Of Nepal with their Local and English Names

  1. Acacia nilotica Local name- BABUL E.N. - INDIAN ROSEWOOD

  2. Aesandra butyracea Local name-CHIURI E.N. - INDIAN BUTTER TREE

  3. Artocarpus lakoocha Local name- BADAHAR E.N.- MONKEY JACK

  4. Bauhinia purpurea Local name- TANKI

  5. Bauhinia variegata Local name- KOIRALO

  6. Choerospondias axillaris Local name-LAPSI

  7. Ficus cunia Local name-KHANYU E.N.- FIG

  8. Ficus nerifolia Local name-DUDHILO E.N.-FIG

  9. Garuga pinnnata Local name- DABDABE

  10. Litsea cubeba Local name- SILTIMUR

  11. Litsea monopetala Local name- KUTMIRO

  12. Morus alba Local name- KIMBU E.N.- WHITE MULBERRY

  13. Myrica esculanta Local name- KAPHAL

  14. Pyrus pashia Local name- MEL E.N.- WILD PEAR

  15. Sesbania grandiflora Local name- DHAINCHA

Important Exotic Tree Species of Nepal

  1. Acacia auriculiformis /Family- Mimosaceae

  2. Callistemon citrinus/ Family- Myrtaceae (Kalki phool)

  3. Cassia Siamea/ Family- Caesalpiniaceae ( Iron Wood)

  4. Casuarina equisetifolia / Family- Casuarinaceae

  5. Ceiba Pontandra / Family- Bombacaceae (Kapok- White Silk)

  6. Cinnamomum camphora/ Family- Lauraceae ( Camphor Tree-Kapur)

  7. Crypotomera japonica/ Family- Coniferae ( Dhupi salla- Cryptomeria)

  8. Delonix regia/ Family- Caesalpinaceae ( Gulmohar- Gold Mohur)

  9. Eucalyptus camaldulensis/ Family- Myrtaceae ( Red gum - Masala)

  10. Grevillea robusta / Family- Proteaceae ( Kangiyo- Silver Oak )

  11. Jacaranda mimosifolia/ Family- Bignoniaceae

  12. Leucaena leucocephala / Family- Mimosaceae ( Ipil Ipil )

  13. Pinus Patula/ Family- Pinaceae ( Patula salla)

  14. Populus ciliata/ Family- Solisaceae ( Himalayan poplar- Bangikot)

  15. Populus deltoides / Family- Saliscaceae ( Black poplar- Lahre pipal)

  16. Prosopis juliflora/ Family- Leguminosae ( Mesquite)

  17. Saraca indica/ Family- Leguminosae ( Asok)

  18. Tectona grandis / Family- Verbenaceae ( Teak- Sagawan)


Agencies involved in harvesting and distribution of Forest products in Nepal

Two agencies were involved in harvesting and distribution of  Forest Products :Timber Corporation of Nepal(TCN) and through local and national level contractors before the establishment of Community Forestry in Nepal.Now the following organizations are  involved in harvesting practices in Nepal:

  1. Government

  • District Forest Office

  • Forest Product Development Board(FPDB)

  • Timber Corporation of Nepal (TCN)

  • Herbs Production and Processing Company Ltd.

  1. Forest User Groups (FUGs)

  2. Private Sectors in auctioning


Environmentally Important Days in Nepal

World Conservation Day- Dec 3

International Mountain Day- Dec 11

World Animal Welfare Day- Oct 4

World Nature Day- Oct 5

National Conservation Day- Asoj 7

World Wildlife Week- Oct 1-7

World Food Day- Oct 16

International Snow leopard Day- Oct 23

International Vulture Awareness Day- Sep 5

International Red Panda Day- Sep 19

World Park Day- Sep 20

World Rhino Day- Sep 22

Conservation Day- Sep 23

Ozone Layer Conservation Day - Sep 26

World Tourism Day- Sep 27

Elephant Day- Aug 12

Tiger Day- July 29

World Environment Day- Jun 5

World Biodiversity Day- May 22

Forest User Day- Jestha 19

World Heritage Day- April 18

Earth Day- April 22

World Migratory  Bird Day- April 11-12

BCN Day- April 24

World Wildlife Day- Mar 3

International Forestry Day - Mar 21

World Water Day - Mar 22

World Wetland Day- Feb 2

World Forestry Day- Feb 21





Medicinal/Aromatic plants restricted for export in crude form in Nepal

Yarsha Gumba - Cordyceps sinesis

Silajit- Rox exudate

Sarpagandha- Rauwofia serpentina

Jatamanshi- Nardostychys grandiflora

Sugandhkokila- Cinnamomum glausescens

Sugandhawal-Valeriana wallichii

Lauth Salla- Taxus baccata

Jhyau- Lichen Spps.

Talis Patra- Abies spectabilis

Monday, July 2, 2018

Manufacturing Process of Cutch and Katha and their Uses

Cutch and Katha are obtained by boiling in water, chips of heartwood of Acacia catechu (khair) as the chief constituent of heartwood are Catechin (katha) and catechu-tannic acid (cutch). The manufacturing process is essentially extraction rather than distillation as the chips are boiled in water and not treated with stream.

The manufacture of Cutch and Katha is done by Country method as well as by Factory method. But the country method is wasteful. In Factory Method, wood is chipped by disintegrators and boiled chipped in copper vessels with hot water under slight pressure. The extract is concentrated in vacuum and cooled in a refrigerator tank for about a week, when Katha crystallizes out. It is separated by filter presses cut into slabs and further sliced into square tablets which are then dried. The yield of Katha by this method is about 4 to 5 % by weight of the wood. To obtain Cutch, the liquor is further concentrated in evaporators to a consistency at which it is solidified on cooling. The Cutch yield is about 10 to 12% by weight of the wood.

Katha is mainly used in Pan but sometimes also used in medicine. Cutch is an important commercial product which is used as dyeing and preservative agent. It is used in dyeing cotton and silk and in calico-printing.


15.SUS SALVANIUS- PYGMY HOG- बाम पुड्के बदेल
18.BOS GAURUS-GAUR- गौरी गाई

How to determine the age of tree?

The age of trees is either determined by their general appearance or from existing record. The size and taper in stem, size and shape of the crown, and the color and condition of the bark. But this method requires a great practice and experience and to estimate the age of tree within responsible limits of  accuracy.

Some trees shows distinct annual rings on their cross section. So the age of the trees when standing can be determined by pressler’s borer. This instrument is used to take out a narrow cylinder of the about 2cm in length from a standing tree at both ends of the diameter. The number of the rings on the cylinders are counted. Then by ratio proportion method, the number of rings on the whole diameter are estimated.

Age of the trees which do not show annual rings is determined by measuring of trees of various sizes at fixed intervals. The measurement of a particular year are then classified by diameter classes and the average diameter of each diameter class is found. The same procedure is followed at subsequent measurements taken after a fixed interval. The difference between the two averages gives the periodic diameter  increment which is then plotted against DBH and a smooth curve drawn. The increment curve is transformed into diameter age curve. From this curve, age of any tree of known DBH can be read.

The age of felled tree can be determined if the stump shows the annual rings. The rings are counted after levelling the stump by a chisel along the diameter on which the rings are to be counted. Then age to stump height is added to determine the  age of the tree at the time it was felled.

The age of trees is either determined by their general appearance or from existing record. The size and taper in stem, size and shape of the crown, and the colour and condition of the bark. But this method requires a great practice and experience and to estimate the age of tree within responsible limits of  accuracy.

Some trees shows distinct annual rings on their cross section. So the age of the trees when standing can be determined by pressler’s borer. This instrument is used to take out a narrow cylinder of the about 2cm in length from a standing tree at both ends of the diameter. The number of the rings on the cylinders are counted. Then by ratio proportion method, the number of rings on the whole diameter are estimated.

Age of the trees which do not show annual rings is determined by measuring of trees of various sizes at fixed intervals. The measurement of a particular year are then classified by diameter classes and the average diameter of each diameter class is found. The same procedure is followed at subsequent measurements taken after a fixed interval. The difference between the two averages gives the periodic diameter  increment which is then plotted against DBH and a smooth curve drawn. The increment curve is transformed into diameter age curve. From this curve, age of any tree of known DBH can be read.

The age of felled tree can be determined if the stump shows the annual rings. The rings are counted after leveling the stump by a chisel along the diameter on which the rings are to be counted. Then age to stump height is added to determine the  age of the tree at the time it was felled.

Nepali -English and Scientific Name of Some Medicinal plants in Nepal

1. Panchaule- Marsh Orchid- Dactylorhiza hatageria

2.Chirato- Felworts- Swertia Chirayita

3.Jatamasi- Spikenard- Nardostachys grandiflora

4.Kutki-Neopicrohiza scrophulariflora

5.kurilo- Wild Asparagus- Asparagus racemos

6.Sarpgandha- Serpent Wood- Rauwolfia serpentina

7.Loath Salla- Himalayan Yew- Taxus baccata

8.Sugandhawal -Valeriana spss.

9.Ghiu Kumari- Indian aloe- Aloe Vera

10.Kafal- Myrica esculenta

11. Neem- Azadirachta indica

12.Tejpat- Cinamomum spps.

13.Bel- Aegle marmelos

14.Amala- Phyllanthus emblica

15. Pipala- long pepper- Piper longum

16.Yarshagumba-Cordyceps Sinensis

17. Titepati- Mog wort- Artemisia vulgaris

18. Bojho- Acorus calamus

19.Rudarksha-Ultrasum bead- Elaeaocarpus gantrius

20.Vayakur- Dioscorea deltoidea

21.CHutro- Berbery - Berberis aristata

22.Nagbeli- Lycopodium-Lycopodium clavatum

23.Ritha-Soup nut-Spindus Mukorossi

24.Gurjo-Tinospera sinensis

25.Majitho- Indian maddar- Rubia cordifolia

Sunday, July 1, 2018

Glossary of Silviculture

Afforestation- It may be defined as the establishment of a forest by artificial means on an area from which forest vegetation has always or long been absent.

Advance Growth/Advanced Regeneration/ Advanced Reproduction- The seedlings, saplings and poles of specie of the overwood that establishes naturally in a forest before regeneration felling started.

Broad-leaved Tree- Tree with hardwood and belonging to botanical group Dicotyledons.

Budding- It is the method of vegetative reproduction in which a bud with some portion of the bark of a genetically superior plant is grafted on  an inferior plant so that it may produce shoot when the old shoot of the stock is cut off.

Clone- All cuttings and grafts derived from one tree by asexual reproduction are collectively called a clone.

Cover Crop-  The subsidiary crop of low plants introduced in a plantation to afford soil cover between or below the main crop.

 Conifer- Tree bearing cones and generally needle shaped or scale like leaves, usually evergreen and belonging to the order Coniferales of the botanical group, Gymnospermae.

Coppice- It is the method of vegetative reproduction in which the trees, plants or the seedlings of a species when cut from near the ground level, produce coppice shoots. The coppice shoots are the shoots arising from an adventitious bud at the base of a woody plant that has been cut near the ground or burnt back.

Damping off- The killing of the young seedling by certain fungi that causes the decay of the stem or roots.

Die-back- The progressive dying, usually backwards from the tip, of any portion of the plant. It is caused by the adverse climatic and edaphic factors as well as adverse weed conditions.

Frost Hardy Species- The species which possess power to withstand frost without being damaged are called frost-hardy.

Frost Tender- The species which are killed back by the frost are called Frost-tender species.

Germinative Capacity- It is defined as the percentage, by number of seeds in a given sample that actually germinate irrespective of time.

Germinative Energy- It is defined as the percentage by number of seeds in a given sample that have germinated up to the time when the rate of germination reaches its peak.

Girdling- It may be defined as the cutting through the bark and  outer living layers of wood in a continuous incision all- around the bole of the tree.

Lopping- The cutting of a branch of a tree.

Mulch- Plant residues and other materials used as a covering for the soil.

Reforestation- The restocking of a felled or otherwise cleared woodland by artificial means. It is the raising of a forest artificially in an area which had forest vegetation before.

Regeneration- It may be defined as “the renewal of the forest crop by natural or artificial means.”

Seed Dormancy- It is a condition of mature viable seed in which germination is considerably delayed even though external conditions favors germination.

Shelterbelt- It is a wide belt of trees, shrubs, grasses, planted in rows which go right across the land at right angles to the direction of prevailing winds to deflect air current, to reduce wind velocity and to give general protection to cultivated areas against wind erosion and desiccating effect of hot winds.

Weeding- The tending operation done in the seedling stage in nursery or in a forest crop that involves the removal or cutting back of all the weeds.

Thinning- The felling made in an immature stand for the purpose of improving the growth and form of the trees that remain, without permanent breaking of the canopy.

Viability- It is defined as the potential capacity of a seed to germinate.


Forest Types of Nepal

Nepal has diverse climatic and topographical features which results in the contribution of different forest types in Nepal.Adapted from J.k. Jackson, here is the list of different forest types of Nepal.

  1. Tropical forest (up to 1000m)

        i.Shorea robusta Forest – The dominant species is Sal and other associates are           Terminalia alata, Anogeissus latifolia, Syzyzium cumini,etc.

ii.Acacia catechu- Dalbergia Sissoo Forest- It is mostly found along streams and rivers in deposited alluvium and often gravelly and will be eventually be succeeded by Sal or other types of forest.

iii. Other Riverain forest- This types of forest is not large and extends far from the stream banks. Jamun is dominant in western Nepal.

iv.Grassland- This type is usually found on poorly drained clays. Grass species such as Saccharam spontaneum, Eulaliopsis bipinata, Phragmites Karka.etc are found.

v.Terminalia- Anogeissus deciduous hill forest- It is confined to dry south facing slopes in the larger river valleys and up to 1200m in Western Nepal.

  1. Sub-Tropical Forest (1000m-1700m in East and 1000m 2000m in West)

i.Pinus roxburghii forest- It is found in the west of Nepal extensively. In the east, it is found in large river valleys. It is almost pure. In the far west at higher altitude, it may be associated with Olea ferruginea, Pistacia spps, etc. In transitional areas, it may be mixed with Schima wallichi or Shorea robusta.

ii.Schima-castanopsis forest – This Schima- castanopsis forest covers very large areas of the mid-hills, but much of it has been cleared for cultivation and very small passages are left.

iii.Alnus nepalensis forest- Alnus nepalensis is dominant and almost pure and associated in some places with Lyonia ovalifolia.

iv.Riverain forest with Toona and Albezia species- It is confined to narrow strips along streams and is very mixed in composition.

  1. Temperate Forest (2000m-3100m)

i.Lower temperate forest ( 2000m- 2700m)

a.Quercus leucotricophora and Quercus lanata

b.Quercus floribunda forest

c.Quercus lamellose forest

d.Lower temperate mixed broad leaved forest with abundant lauraceae

e.Pinus wallichiana forest

ii.Upper temperate forest (2700m – 3100m)

a.Quercus semecarpifolia forest

b.Upper temperate mixed broadleaved forest

c.Rhododendron Forest

d.Upper temperate coniferous forest

4. Sub- Alpine forest (3000m-4200m)

i.Abies spectabilis forest

ii.Betula utilis forest

iii.Rhododendron forest

iv.Juniperous indica steppe

v.Caragana steppe

  1. Alpine forest (up to 4500m)

It has no trees, but shrubby Rhodendrons and Junipers and some other shrubby species are found at lower elevations up to about 4500m.


What is CAI and MAI?



CAI is the increment which a tree puts on in a single year. The CAI varies from year to year being affected by seasonal conditions and treatments.

MAI is the mean volume of a tree or crop put on from origin up to the desired age i.e. the total increment up to a given age divided by that age.

If when the curves of Current and Mean annual increments are plotted over tree age, the two do not coincide with each other through out the life of the tree except at two periods one at the end of first year and the other at the culmination of MAI.The CAI rises to maximum and then gradually fall off.The MAI also increases to a maximum at a later age but with much lower rate.The MAI continues to rise towards maximum even after the CAI has started falling. 

When the CAI falls to such an extent it is equal to MAI, the MAI reaches its highest points. This is the year of culmination of the MAI. At later stage, the CAI is less than the MAI, and MAI also beings to drop but not as rapid as that of CAI. THE CAI will be zero and also negative when there is rot or other damages resulting in negative CAI. But the  MAI value is never Zero and negative like CAI.


What is DBH ?

DBH is defined as the average stem diameter outside bark at the point of 1.3m or 1.37m (FAO) above the ground as measured.

  • It is a convenient height for taking measurement as it does not require bending down or stretching up to reach a lower or higher point.

  • It is a place on a tree stem, which is free from obstructions from thorny shrubs  and abnormalities like root swell, etc.

  • It gives uniform point of measurement and therefore standardizes measurement.

  • It shows strong correlation to the volume or weight of the stem for most tree species.

Rules of the DBH Measurement

  • Loose barks, mosses, lichens that are found on the tree must be removed before measuring the diameter over bark.

  • Breast Height (BH) should be measured by means of a measuring stick on standing trees at 1.3m or 1.37m (FAO)  above the ground level.

  • BH should be marked by intersecting vertical and horizontal lines 12 cm long painted with white paint.

  • On sloping land, the diameter at BH should be measured on uphill side.

  • In case of the tree is leaning, DBH is measured along the tree stem and not vertically, on the side of the lean for trees growing on flat ground and on uphill side, for trees growing on sloping ground.

  • BH should be taken at the lowest point above which the buttress formation is not likely to extend.

  • When the tree is forked above the BH, it is counted as one tree, but when it is forked below BH, each fork should be treated as though it were a separate tree.

Instruments used in Diameter measurement of trees

1. Diameter Tape

  The Diameter of a tree cross section  may be obtained with a flexible tape by measuring the circumference of the tree. A diameter tape is a measuring tape that has scale on both sides: one side is specially marked to show the diameter of a tree, and the other is a normal scale.


2. Calipers

Calipers are often used to measure tree DBHor when diameters are less than about 60cm. A Caliper may be constructed of metal, plastic or wood, consists of a graduated beam with two perpendicular arms. One arm  is fixed at the origin of the scale and the other arm slides.When the beam is pressed against the tree and the arms closed, the beam of the Caliper can be read on the scale.


3. Wooden Scale

It is generally a two feet folding scale used to measure diameters of logs at their end cross sections.


Saturday, June 30, 2018

Silviculture and Silvicultural systems

Silviculture is defined as the art an science of cultivating forest crops. In other words, Silviculture  includes both Silvics and its practical application. Silvics is defined as the study of life history and general characteristics of forest crops with particular reference to environmental factors, as the basis for practice of the silviculture. 

Objectives of the Study of Silviculture

  1. Increasing the productivity of the forest

  2. To fulfill the multifarious requirements of the people with the cultivation of more valuable and useful species of trees

  3. Improvement of deteriorating natural forest and creating new man-made forest

  4. Maintaining the good forest condition of both natural and man-made forests by proper tending

A Silvicultural System is defined as a method of silvicultural procedure worked out in accordance with accepted sets of silvicultural principles by which crops constituting forests are tended, harvested and replaced by new crops of distinctive forms.

Silvicultural systems are primarily classified on the basis of the mode of regeneration and this is further classified according to the pattern of felling.

  1. High Forest Systems- These are the systems in which the regeneration is normally of seedling origin, either natural or artificial or a combination of the both and where the rotation is generally long.

          a.Clear -felling System

   b. Shelterwood System

          c. Selection System

          d. High Forest with reserve

          e.Two Storeyed High Forest

          f .Improvement Felling

2. Coppice Systems- These are those Silvicultural Systems in which the crop originates  mainly from coppice and where the rotation of the Coppice is short. These systems are further classified into several Silvicultural systems on the pattern of felling.

a. Simple Coppice system

b.Coppice with Standards system

c. Coppice with reserve System

d. The Coppice of two Rotation system

e.The Coppice Selection system

f.The Shelter wood Coppice System

g. The pollarding