ARTIFICIAL REGENERATION

 
BY
RAFIQUE AHMED
B.Sc. FORESTRY (1999-2001)
(The paper has been published without making any changes to it)
TABLE OF CONTENTS

ACKNOWLEDGEMENT
 
All glory be to Allah, the most beneficient and the merciful, who gives us the power to do, the sight to observe and the mind to think and judge.
Thanks are also due to his blessing which enabled me to complete this work, in the required time. Sincere and deepest sense of gratitudes extended to my programme officer as well as advisor Mr. Siraj-ud-Din, Lecturer-in-Forestry Pakistan Forest Institute, Peshawar. Whose patience, guidance, encouragement, friendly attitude and scholarly supervision helped me a lot in the course of this study.
I wish to express my sincere gratitude to all my well wisher and friends.
 
Rafique Ahmed
                                                                                          B.Sc. Forestry

CHAPTER – I

ARTIFICIAL REGENERATION

Before going to artificial regeneration, let us write something about regeneration.
REGENERATION
The time ultimately comes in the life of every stand, when it must be reproduced. Intermediate cuttings may greatly enhance the value of trees, but they are not absolutely necessary, on the other hand continuity of forest production is simply not possible without periodic replacement of stands.
ARTIFICIAL REGENERATION
Artificial reproduction is that obtained by planting young trees or applying seeds, which is termed seeding or direct seeding (serving). Artificial regeneration is obtained by two methods.

• From seeds
• Vegetatively

1. Seeds:

Either by direct sowing as in acacia arabica in Riverain forests of Sindh, or planting the raised stock in nursery as in Eucalyptus spp.

2. Vegetativley:

Artificial regeneration is also obtained by planting vegetative parts (other than seeds) as cutting of poplar, salix and Ficus spp. etc.
The relative importance of artificial regeneration  as compared with natural regeneration, depends on a large number of factors which determine weather reliance to be placed on the latter or how far to go with its replacement by plantation methods. In the plains of Pakistan plantation work has always been predominant owing to the changes brought about by irrigation. In the hills natural regeneration has been almost solely relied on but some sowing and planting is now being done if only as supplementations

OBJECTIVE OF ARTIFICIAL REGENERATION

Artificial regeneration by sowing or the various forms of planting is done under a variety of conditions for seasons which also vary from case to case. The main objectives are:
SUPPLEMENTING NATURAL REGENERATION
Where reliance is main placed on natural regeneration, experiences has proved that it is rarely possible to obtain adequate stocking over the whole of the regeneration area, within a reasonable time, a varying proportions of it proving difficult, slow, or even impossible to regenerate naturally. It is accordingly common, especially in the more intensively managed forests, to complete the natural regeneration by filling in the failed or backward patches by artificial methods. There are also in most regenerations areas places, where regenerate originally present has been destroyed by felling conversion and extractions.
REPLACING NATURAL REGENERATION
Artificial regeneration is also being undertaken in some types of forests instead of natural regeneration, where the latter is too scanty, slow or uncertain to be relied on, at least with present knowledge. Artificial regeneration is also done at places where labour supply are such that the artificial regeneration is economical than natural regeneration. Incase of (twisted) Chir trees the crop is replaced by artificial methods mostly in Hazara Pine forests.
In case of Irrigated Plantations of Shisham of Pakistan, the natural regeneration from root suckors is replaced by artificial stump planting, but the resulting crop is mixture of stem, or root suckors.
IMPROVING DENSITY OF MORE VALUABLE SPP.
Artificial regeneration is carried out (adopted) for increasing the proportion of valuable spp e.g. walnut in temperate forests of Galies and Kaghan areas. In other forest types and in specially dry tropical thorn forests of plains the vegetation is so depleted by grazing, felling and burning etc. that natural regeneration is not possible and the recovery and improvement can  only be done by artificial methods (stocking).
AFFORESTATION
In case of areas which have sparse vegetation or bare soil, the natural regeneration is out of question there and the only method of covering the area with vegetation is through artificial methods. The degraded and bare areas of private people when handed over to the government for improvement can only be improved by artificial methods of regeneration.

INTRODUCTION OF VALUABLE EXOTIC SPECIES

By exotic species we mean that spp. Which is grown out of its natural range of occurance. As we grow eucalyptus in Pakistan. This is only possible through artificial methods of restocking.

CHAPTER – II

ARTIFICIAL VERSUS NATURAL REGENERAL

Both of the method of regeneration have their relative merits and demerits under varying conditions.

ADVANTAGES OF NATURAL REGENERATION

1. Minimizing the exposure of soil
2. Economy in labour
3. Flexibility, permitting of great extension of the regeneration area in good seed years and obtaining regeneration in advance of felling
4. Genetic improvement through survival of only the most vigorous seedlings out of large number, best adopted to the local conditions.
5. Reduced risk of damage from pests and diseases
6. Maintenance of the natural usually mixed forest type
7. Lower cost than artificial regeneration.

ADVANTAGES OF ARTIFICIAL REGENERATION

The following are demerits of natural regeneration but in favour of artificial regeneration:

1. Quicker results because every work is carried out systematically
2. Full and more even stocking
3. Facility with which species composition can be regulated
4. Concentration of forest work reducing costs and facilitating supervision
5. More rapid early growth and so less risk from weeds.
6. Better revenue even when the actual operation is not cheaper.

CHAPTER – III

EVALUATION OF SITE FOR PLANTATION PURPOSES

The most important features of the site are those which will determine whether a particular area or patch should be taken up for planting at all, and then if it is suitable for planting, then what are the chances of success what spp should be used and what special measures are required. This site can be evaluated by site factors or vegetation it carries. Two methods of site evaluation are:

1. Direct Method

Site factors are known and site value can be determined. Site factors may include climate and soil. Biotic factors are not considered separately as their effects are reflected in the soil and vegetations of the site.

1. Climate will consists of rainfall, temperature, winds, humidity etc. we will see the mean annual rainfall and its distribution. The maximum and minimum rainfall should be known. Our crop will depend upon the minimum rainfall and its distribution. About temperature mean annual temperature, winter and summer temperature should be known.

The wind movement from the dry tracts should also be known. Humidity is also important from evaporation point of view

1. The chemical and physical properties of the soil over the area, as texture, structure acidity, depth, soil profile, soil moisture, porosity and aerations etc.
2. Indirect Method

The site can be evaluated by vegetation growing over the site e.g. if Zizyphus is growing, then the site will be good for those spp having the same requirements as Zizyphus the Tamarix spp is growing then the soil is saline etc. if Prosopis specigera or Cappario apliylla are growing, conclusion can be drawn that the rainfall is 10″ per anum. Soil is drained and loamy. It will be good for irrigated plantation when Salvadora grows, soil is shallow, heavy saline and plantation is difficult.

CHAPTER – IV

SELECTION OF SPECIES

The choice of species is done on the factors discussed below:

1. Ecological Consideration

The indigenous spp. which are already growing they are selected for the plantation. The species growing in the vicinity i.e. around the area in neighbouring tracts will also succeed in the site. If no species is present then the exotic species from the areas having the same ecological conditions as the site, can be selected. As for Peshawar we can select species from the plains having the same conditions, but not from Murree and Kaghan valley. The ecological conditions of the site and the ecological requirements of the species should be compared, if these are similar, then the species are recommended for plantation in the site.

2. Objectives of Plantation

Since we have selected few species according to the ecological conditions of the site. The different species have different properties a species will give more timber, other is good for firewood and third one give good protections to the soil and so on. For this purpose the spp are classified according to their objectives which they give as:

1. Production    –         Major and minor forest produces.

2. Protection     –         Which give protections against wind and water

erosion and have best watershed value.

3. Aesthetic      –         The spp having good aesthetic value.

The objectives of the plantation are specified and the species are recommended.

3. Effect on Site

It has been found by experience that the replacement of natural forest by pure plantations of certain species leads to soil and site degradation, both directly by erosion and indirectly through changes in the biological processes in the soil. The reference is given to teak in Bangladesh as teak is light demander and have open canopy. The leaves are very hard to decompose and belown away by wind thus soil remains unfertile. If the spp. is light demander then weeds will grow in the blanks. Leaves will not decompose resulting a loss of nutrients and gradually the whole site becomes unfertile. So light demander spp. Should be grown with shade bearer together to avoid the danger of degradation of site. Thus the site can be utilized up to a marked extent. As Morusable is grown with Dalbergia sisso in irrigated plantations of Pakistan.

4. System of Managment and Relative Cost

The light demander spp. Will grow uniform and even aged stand will be resulted giving more productions. But the light demander with shade bearer would result into all aged class as selection forest. If our objective is production then cvenaged stand is good but if the objective is aesthetic then we will require to have unevenaged stand or selection forest and will plant light demander with shade bearer spp. Together we will also see the relative cost of plantations and maintenance of different spp: and will recommend that spp. which has least cost or expenditure.
Spacing of Regeneration (spp)
The spacing of spp in regeneration is governed by various factors as light requirement, crown size and site fertility etc. the spacing is determined under various conditions and situations. The main points which determine the spacing may be listed as follows:

1. Method of Stocking (Regeneration)

The artificial regeneration is done by two ways as by sowing and planting.

1. Sowing: In case of sowing closed spacing is required to have

more chances of success.

1. Planting: In case of planting the plants have 80% survival and wider spacing is recommended.
2. Grazing Incidence:

By grazing , young seedlings are destroyed by animals and close spacing is necessary to face this danger, whereas wider spacing is good where grazing incidence is less.

3. Rate of Growth:

In slow growing species close spacing is suitable while in fast growing spp the spacing should be wider.

4. Site Quality:

Wider spacing is adopted for good quality site while closed spacing is adopted in case of poor sites.

5. Crown size:

species having small crown as Poplar and Eucalyptus  planted at close spacing, but spacing should be wider in case of spp. Having crowns as Acacia nilotica.

6. Wood Growth in the Area:

In the areas having wood growth, the seedlings are suppressed and killed by weeds and closer spacing is required and wider spacing is suitable for areas free of weeds because success is sure.

7. Tolerance:

If a spp is light demander then its spacing will be wider but close spacing is suggested in case shade bearing species. At the time of maturity 50 trees per acre are present in ehir and 80 trees per acre in Deodar.

8. Object:

The object may be specified and if the object is only volume production as firewood then closer spacing will be best, but in case of producing timber wider spacing is adopted to obtain good quality straight boles.

CHAPTER – V

METHODS OF SOWING IN THE FIELD

1. Broadcasting:

It is the common and simplest method of sowing in which seeds are scattered throughout the forest area. In reverain forests of Sindh seeds of Acacia nilotica are directly sown (broadcasted) and thus it is the cheapest method but the enhances of failure are also there. It is not suitable except in Acacia nilotica. This method is also adopted in Chir and Deodar area on workable soil.

2. Dibbling:

In this method seeds of bigger size are sown at equal spacing in bits with the help of dibbling rods. It is adopted in Walnut sowing. The other advantage in this method is that the seed quantity is ½ of the breadcasting method.

3. Line Sowing:

The seeds are sown in lines or rows as in coniferous forests. The soil is worked upto 1′ – 2′ depth and seeds are sown in lines. This line sowing is also adopted in for Accacia nilotica in I.Ps.

4. Strip Sowing:

It is the same as line sowing but here seeds are sown in many lines adjacent to each other and also sown in strips and seeds are broadcasted in strips in the worked soil, it is known as strip sowing.

5. Patch Sowing:

In the roughly circular patch of soil several seeds are sown. Generally only one plant is wanted in each, so any extra ones are weeded out later or used for transplanting to blank. The difficulty in this method is that the competing weed growth process on the seedlings from all sides and unless intensive weeding is continued, they are likely to be smothered, and inspection is very difficult. But with quick growing species patch sowing may be cheap and effective. For supplementing natural regeneration patches 5 x 2 ft to 5 x 5 ft are recommended for deodar with adjoining patches 6 ft aparts smaller patches are very likely to fail.

6. Ridge and Mound Sowing:

The soil is made in straight bund like structure called as ridge and simply a heap of soil is known as mound. The seeds are sown on ridges and mound in case of dry areas for condensing the moisture in the raised and loosened soil. The advantage of the ridge over the mound is the greater freedom for the seedlings from weeds. There is a risk of soil wash exposing the roots which may be minimized by not making the ridges too narrow and by firming the soil after sowing.

7. Pitch and Trench Sowing

The method which effectively concerns only the arid regions aims at securing for the young plants as merely moisture as possible. There are practical difficulties which prevent wide application. Unless special precautions are taken the top soil is lost and an inadequate depth of rootable soil is provided and often the soil surface within the pit in quickly sealed with clay particles and the seedlings drowned or the roots suffocated.

8. Combined Methods

In reclamation areas it is now common paractice to make a combine ridge and trench and sow the seeds at three levels, on the ridge, on the mound and in the trunch different conditions prevail in each of the three situations depending on the climatic and soil conditions, one or other will probably fail but the over all chances of success are improved.

CHAPTER – VI

SEED SUPPLY

GENERAL
An adequate supply of good quality seed is a prerequisite for successful artificial regeneration. Seed of the main plants species such as Shisham and Babul can be collected locally any year in any desired quantity. Good seed years of conifers, however, occur comparatively infrequently, and in case of Silver Fir especially, may occur once in three or four years. It is however one of the advantages of artificial regeneration that the benefits of a good seed year can be extended over 2 or 3 years with appropriate measures of seed storage.

SEED COLLECTION

Quantity Required

The quantities required must be carefully worked out well in advance and reasonable margin be allowed not only for resowing failed areas, but also to cover the possibility of shortage of supplies in some species.
 Ripeness
Seed collectors have to be trained to distinguish ripe and good seeds at the time of collection. Ripeness of seed is most important. Both the earliest and the latest seed to ripen and fall is often suspect and best avoided. Incase of chir pine, cones may safely be collected at any time from December onwards even though still green.

Agency of Collection

There are various agencies of who collect seed through forest guards, or contractors and or import seeds. The present general low standard is partly due to lack of appreciation of its importance and the lack of responsibility of the agency. Collection of seed should never be allowed from the trees of cultivated land and grazing grounds.

Method of Collection

The seeds should as for as possible be collected off the trees immediately natural seed fall commences. There are various methods of seed collection. In one method the capsules and cones are collected by climbing up to the trees as in Eucalyptus and Chir Pine. The next method consists of clearing the ground below the tree and the branches are shaken, thus the legumes are fallen down and then collected as in case of Shisham. The 3^rd method is that from the felling coupe special steps being taken if necessary to concentrate the feeling when the seed is ripe or to lop and top the marked standing trees if feeling is not paracticable. The simplest method of improving the genetic quality of seed is to select in the neighbouring forests areas of exceptionally good quality, to an aggregate total estimated to be sufficient to meet all requirements with a reasonable margin. The ground surface may also be cleaned up to facilitate seed collection.
Extraction of Seeds
Seed extraction means the separation of seeds from dry fruits collected by any one of the above methods. Dry fruits such as cones (Pines), capsules (Eucalyptus etc) and dry legumes (Albizzia and Shisham etc) require treatments to extract the seeds. The simplest and commonest procedure is to spread the fruits in the sun on trays or a clean hard floor until they open up, and then rake, roll or beat as seems best to separate the seeds.

Cleaning of seeds

The dried seed has next to be cleaned of all foreign materials such as fragments of fruits cones, husks and empty or unsound seeds, a step usually necessary when it has been swept up off the ground. Methods will vary with spp. Water separation with redrying is a simple method with many species. Sieving is sometimes helpful. Special cleaning is unnecessary in the case of such seeds as Sal, which is sown individually after collection.

Testing of Seeds

Systematic testing for purity and germinative capacity should be a routine measure wherever seed is collected in quantity for local use, storage or dispatch to other centers.

Determinations of Purity

A  weighed sample of seeds is cleaned of all foreign matter usually by hand picking, and re-weighed. The result being expressed as a percentage. As
%  purity
Germination Test
To find out the number of seeds which can germinate as %age. After knowing the germinative capacity of seeds we can use the required quantity on the basis of this germinative capacity. As calculated in this way
%  G. Capacity
Methods of Seed Testing
The seed testing is generally conducted by three methods:

1. By sowing seeds in nursery beds
2. By sowing seeds in eartheren paths.
3. By automatic germinater

In all these cases the conditions should be favourable for germination to obtain good and connect result as our whole estimate will be based upon these tests.

Seed Certificate

No seed should be dispatched from the collection center without a certificate giving essential particulars as given below.

Particulars of Seeds of Fruit Supplied

1. Species
2. Date of collection
3. Locality
4. Elevation
5. Aspect
6. Average annual rainfall
7. Characteristics of mother tree.
8. Method of Collection
9. Method of storage
10. Signature (or name) of person furnishing above details
11. Date and place of dispatch
12. Quantity dispatched
13. Condition at time of packing for dispatch and how packed.

Seed Storage
Some seeds require storage for ripening their embryo. Storage over a whole year may be desirable as giving higher germination as in case of Cassia fistula. In rare cases the seed may either be germinate at once before the seed coat has become hard and impermeable, or it will go into dormancy for a period of a year or more.

The Seed Store

It is usually worth while to build a permanent seed store in any forest division where the raising of large scale plantations is a part of normal work. Such a seed store should have a long well ventilated room with shelves in tiers, where seed can be stored in tins, sacks or containers. The floor should be cemented and damp proof. All openings should be guarded with wire netting to exclude rats, mice and squirrels. It is preferable to have another smaller room attached to the store for carrying out simple tests. A low cement platform should be built on one side for drying and extraction of seeds. Preventive measure, against insect attack are necessary. Previously carbon disulphide was recommended for fumigating infested seeds. This is now displaced by modern insecticide such as D.D.T. or B.H.C. which are equally effective, easy to handle and reasonable priced.

CHAPTER – VII
NURSERY
The production of forest planting stock in nurseries is an important item of artificial regeneration. Cheap and efficient production can be achieved only in large nurseries with an out put running into millions of trees per year. The sowing of seeds of many species as Eucalyptus, Mulbery etc is quite important because the direct sowing in the field fails and good result is impossible. These spp. require option and suitable conditions for their germination and successful survival, for which growing in nurseries is most important. (D.M. SMITH, 1962).
The key task of nursery management is to provide the required number of strong plants of the right size at the right time. (mannual for silviculture for park)by Khattak.
Nursery  may be temporary for local and small requirement at the spot of felling coupes and for the production of stock year after year continuously. The temporary nursery may be raised for one or two planting years (season) while permanent nursery is maintained continuously.
SELECTION OF SITE FOR NURSERY
                    In selecting the site for raising a nursery these points should be considered.

1. It should be located centerally in the area.
2. It should be near headquarter for intensive care.
3. It should be near the road for easy transportation.
4. Water should be available, throughout the year for irrigation.
5. Labour should be available for carrying out various nursery operations at any time.
6. Soil should be preferably loamy, deep and well drained. Pure clayey and pure sandy soil is not suitable for successful growth.
7. In hilly areas the slope of site should be less than 25^o.

KIND OF  NURSERIES

The nursery may vary at various places and with species to species. The kind of nursery also varies with the ecological condition as plain may differ from hill nursery.
The main kind of nurseries in practice are:

1.          Range Nursery

The nursery where sowing is done at the top ridge between trenches. The size of  trenches is 12 inch top width and 9 inch bottom  width. If the soil problem is there and seapage is less then the width of ridge should be reduced for easier seapage. The sowing is done by broadcasting or drill method.

2. Irrigated plantation nursery.

In irrigated plantation, the entire width of the berms on both sides of irrigation trenches may be sown by broadcast method except for about 3 inches nearest to the trench as for Shisham, Mulberry and Albizzia, or two rows of seed may be drill sown on the either side of the trench. The first about 2 inches away from the bern and the second 3 inches further away. In case of beds half feet wide irrigated by percolation from the trenches between a line of seed is sown along the length of the trenches about one and half inches away from the edge.

3. Raised bed nursery

In temperate zone the nursery is of raised bed. The beds are raised   4-6 inches from the ground level and sowing is done. The width of bed should not be more than 4 inches as if located in dry zone then watering is done through sprinkler (Fowara)

4. Flat bed Nursery

The nursery may be of flat bed at the ground level. The ground is leveled first and then beds are separated by small marking ridges and watered though flood irrigation. It is most common type as in case of poplar the cuttings are sown and irrigated. This is adopted in dry areas or sandy soils.

5. Modern Nursery

The nursery practice developed with the passage of time and the most up to date method of raising smaller seeds in nursery is as under.
In case of Eucalyptus seeds the seeds are sown in earthern pots or in the special prepared beds. The seeds are sown by broadcast method in these beds and pots. The pure sandy soil is spreaded on the bed and the seeds are sown covering by sand. The watering is done through spraying. When the seedling are enough to handle then transplanted into the polythen tubes in which soil mixture is  filled and the tubes are placed on the beds. Watering is done by spray or flood irrigation below the collor level of plants.

PREPARATION OF SOIL FOR NURSERY OR SOIL PREPARATION

Soil preparation in temporary nurseries in the plains has been confined to ploughing or digging and leveling the soil and working it to a good debth. A fallow period of few months follows the ploughing before the beds and irrigation trenches are prepared. With the recent great increase in the number of permanent nurseries. Well rotted organic manures are usually incorporated with the existing soil.
In hills a similar period of fallow between digging the soil in May and making the beds in December is recommended for deodar nurseries, where also liberal use of leaf mould is made, sometimes supplemented in the permanent nurseries by well rotted cow dungs. In permanent nurseries, good results may ensure from sterilizing the upper soil with formalin solution.

METHODS OF SOWING IN NURSERY

The seeds are sown in the nurseries by the following methods

1. Broad Casting

Smaller seeds are broadcasted on the beds and covered by a thin layer. It is adopted in Mulberry, Eucalyptus etc.

2. Drill Sowing

Large seeds are usually individually drilled running across the width of the bed. The drills are conveniently laid out by pressing down a drill board on the preparation bed. This is equal to the width of the bed and of the width necessary to mark 2 or 3 drills. A drilling roller, constructed on the same principle is more convenient.

3. Dibbing

The seeds are sown out upper spaces but not in intrenches as in case of walnut seeds. After sowing soil is compacted by roller for seapage.

METHODS OF IRRIGATION IN NURSERY

The irrigation methods are

1. Flood Irrigation

The water is allowed all over the bed of leveled ground as in case of Poplar nursery.

2. Through Perculation

The water is allowed in trenches between the beds and the water is not allowed to over flow the beds, but the beds receive water through perculation from both the sides, as in the nursery of  melia azadrach.
 
3                  Through sprinkling.
As in case of Eucalyptus nursery, the watering is through sprinkling orspraying and not over flooded but receiver water through seapage.

CHAPTER – VIII
METHODS OF PLANTING IN THE FIELD
After the stock is ready in the nursery. It is planted in regeneration area by the following methods.

1. Planting with bare roots

The plant is taken out from the nursery with bare roots and soil is not with the roots as in broad leaved species. Pits are made (dug) in the field depending upon the depth of root system. The plant is burried into the soil upto colar level. The loose soil is compacted with hand and then with heel and finally compacted. For checking pull out the plant, if comes out then, it is not perfectly compacted and this results in failure. So it should be compacted firmly for success full planting.

2. Planting with ball of Earth

The plants which are tender and cannot bear exposure of roots are taken with the soil retained with its roots called as ball. The trenches are dug  around the plants and depend upto the depth of roots system. The plant is taken along with ball of earth. It is for the tender and bigger plants. The soil should be moistened before lifting the plants. The plant should be handled with the ball of soil and not with the stem. These plants are planted in pits with the ball of earth as such this method is adopted for planting along the road sides in plains.

3. Planting with Containers

This method offers considerable advantages particularly on difficult sites and with species with a relatively poor root system. The plant will have been established in the container under optimum conditions in the nursery and can be planted out with a minimum of disturbance. As there is an intact root system to the bottom of the container the plant will not be greatly influenced by temporary dryness in the surface soil, which extends the possible growing season considerably. In the past time earthen pots were used as container now polythen tubes replaced these totally. The stumps are also raised in containers (polythen tubes) in the nursery.

4. Cutting Planting

Poplar, Willow and Tamarix etc are commonly raised through cuttings. The current year growth or the branches upto ½ diameter are used for cutting but in case of Tamarix the older parts can also be used. That part of branches having more living buds. The cuttings are 9″ – 12″ in length and planted in the area. The advantages are taken from vegetative parts of the plants in this method.

REFERENCES

1. The Practice of Silviculture by David Martyn Smith
2. Plantation Forestry in the Tropics by Julian Evans
3. Plant Propagation Principles and practices. Dale E. Kester by Hudson T. Hartmann
4. Principles of Silviculture by Theodore W. Daniel, Johan A. Helms , Fredericks, Baker

REFERENCES

1. Evan J 1986. Plantation Forestry in the Tropics by Oxford Science Publication 1986.
2. Hartman H.T, D.E. Kesro, 1975. third edition
3. Helms J.a., T.W. Deniel 1975. principles of Silviculture second edition.
4. Smith D.M. 1962. The practice of Silviculture eight edition (1962)

• Author Details

Naeem Javid Muhammad Hassani

Naeem Javid Muhammad Hassani is working as Conservator of Forests in Balochistan Forest & Wildlife Department (BFWD). He is the CEO of Tech Urdu (techurdu.net) Forestrypedia (forestrypedia.com), All Pak Notifications (allpaknotifications.com), Essayspedia, etc & their YouTube Channels). He is an Environmentalist, Blogger, YouTuber, Developer & Vlogger.

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