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

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.

2. 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.

3. 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

5. 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.