SIWALIK

SYLLABICATION:	Si·wa·lik Hills
PRONUNCIATION:	s-wälk

A range of the southern Himalaya Mountains extending about 1,689 km (1,050 mi) from southwest Kashmir through northern India into southern Nepal. The hills are noted for their extensive fossil remains.

SIWALIK HILLS, a name given to the foot-hills of the Himalayas in Debra Dun district of the United Provinces of India and in Nahan state and Hoshiarpur district of the Punjab. The range runs parallel with the Himalayan system from Hardwar on the Ganges to the banks of the Beas, with a length of 200 m. and an average width of 10 m. The elevation varies from 2000 to 3500 ft. Geologically speaking the Siwaliks belong to the tertiary deposits of the outer Himalayas, and are chiefly composed of low sandstone and conglomerate hills, the solidified and upheaved detritus of the great range in their rear The intermediate valley lying between the outer hills and the Mussoorie

Bourrelet montagneux de l'Inde et du Népal, avant-monts boisés de l'Himalaya s'étirant du N.-O. au S.-E., au N. de la plaine du Gange. Hauts de 800 à 1 200 m, ils sont traversés par le Gange, la Sutlej (barrage de Bakhra) et la Beas

Altitudinalmente, los Himalayas -como también se conocen- se dividen en el Siwalik, Himalaya Inferior y Gran Himalaya. El Siwalik una zona boscosa al sur del eje principal y al norte de India, nunca superior a los 900 metros de altura que se levanta sobre las llanuras del río Ganges. El Bajo Himalaya, o Himalaya Inferior, comprende montañas calizas nunca superiores a los 4.500 m y con colinas frondosas y centros como Darjeeling y Simla. En tercer lugar, el Gran Himalaya, una combinación de granito y gneis resultado del plegamiento tectónico que dio lugar al océano Índico y al mar de Bengala. Algunos autores subdividen del Gran Himalaya al Himalaya de Tetis o Tibetano. Todos los puertos del Himalaya cercanos a los 5.000 m entre noviembre y mayo permanecen cerrados por los hielos.

TEMPLE TIGER

RAMAPITHECUS, SIVAPITHECUS, GIGANTOPITHECUS

La palabra Ramapithecus procede etimológicamente de Rama, el héroe legendario de la cultura hindú. Es el antepasado de los Homínidos más antiguo que se conoce. No tenemos un ejemplar completo, sino sólo fragmentos de mandíbulas y dientes. Se le atribuye una antigüedad de 12 a 14 millones de años, y fueron hallados en el Mioceno Superior y Plioceno Inferior de la India (Montes Siwalik) y Africa. El primer ejemplar, una porción de maxilar derecho con cuatro dientes, fué encontrado por Lewis en 1933. En estos dientes se han creído reconocer caracteres hominoideos, tales como arco dentario parabólico igual que en el Hombre, ausencia de diastema, caninos pequeños, cara levemente prógnata. Hrdlicka no estaba de acuerdo con esta interpretación, creyendo que se trataba más bien de un Póngido con caracteres pitecoides. No sería extraño que un buen día aparezca otro resto fósil anterior a Ramapithecus y se convierta en un antepasado mejor para los Homínidos. En Africa, Leakey encontró un pariente próximo a Ramapithecus el año 1961 en Fort Ternan (Kenia), al que dió una antigüedad de 14 millones de años por medio de la técnica del Potasio/Argón, es decir del periodo Plioceno. Ramapithecus estaba mejor adaptado a los bosques con claros, en los que encontró una comida más dura que la de los Driopithecus por lo que desarrollaron unos dientes incisivos menores y unos molares más anchos y planos. Se difundieron por Asia, Europa y Africa.

David Pilbeam, excavando en los Montes Siwalik (Paquistán) ha encontrado tres tamaños de Hominoideos: Ramapithecus que debió pesar 20 Kg y vivía alternando árboles y suelo, Sivapithecus, muy parecido al anterior, tanto arbóreo como terrestre y Giganthopithecus, que era muy grande (la leyenda del Yeti o Abominable Hombre de las Nieves se ha relacionado con él). Vivieron hace 14 millones de años, pero hace 8 millones, debido probablemente a un cambio climático, desaparecen de Siwalik marchando a otras latitudes.

Article about Siwalik Hills

GEO-ECOLOGY OF THE TRANS SATLUJ PUNJAB-HARYANA SIWALIK HILLS, NW INDIA

INTRODUCTION

Ever since the start of construction work on Chandigarh as Capital City of Punjab in 1950 and its subsequent conversion into the seat of three governments of Punjab, Haryana as well as Union Territory of Chandigarh on reorganization of the erstwhile Punjab on linguistic basis in 1966, the trans-Satluj Punjab-Haryana Siwalik region alongwith the adjoining hill-foot rolling plains, experienced a great thrust of activity in and around Chandigarh and its satellite towns of SAS Nagar (Punjab) and Panchkula (Haryana). This resulted in great changes in the Siwalik landscape accompanied by ecological degradation in the region (Chandigarh and the adjoining region covering an area of 5,391.50 km² and known as Inter-State Chandigarh Region (ISCR) lying between 30^o17' to 30^o11' N latitude and 76^o16' to 76^o29' E longitude). The main objective of the present article is to project the changes in the forest cover and its geo-ecological implications in the trans Satluj Punjab-Haryana Siwaliks.

CIRCUMVENTION OF STUDY AREA OF SIWALIKS

The trans Satluj Siwaliks of the ISCR are bounded by the hills of Himachal Pradesh in the NE and E and the plains of Punjab - Haryana in NW, W and S, within this region lie the Siwalik Hills in the N, NE and E and Punjab Plains in the W and SW and Haryana Plains in S and SE. The Siwalik hills comprise the Natural Hilly Ecosystem (NHE) which lies in the northern and eastern part of the ISCR and mainly consists of a chain of low lying hills. This hilly tract forms 74 km long and 20-25 km wide foothill belt with a total area of 684.75 km² as constituted by two major ranges- the Chandigarh Siwalik Hills and the Morni Hills separated by Ghaggar river and with an area of 302 km² and 325.25 km² respectively. Additionally, the NHE of ISCR as delimited presently, includes 12 km² of Kalesar Hill lying SE of Morni Hills and 18.5 km² of hillocks abutting Satluj in the west lying separated from the main Chandigarh Siwaliks yet constituting part of the range (Figure 1).

METHODOLOGY

The geomorphology and vegetation reconnaissance of the trans-Satluj Punjab-Haryana Siwaliks was attempted from three main sources: the topographical sheets of Survey of India (SOI) on the 1:50:000 scale, the relevant satellite imageries and through field work.

Primarily, the SOI toposheets (nos. 53A, 53B and 53F) were joined together in order to demarcate the Inter-State Chandigarh Region constituting the present area (Figures 1, 2). It helped to understand the nature of the terrain, both absolute and relative relief; and identification of geomorphic features and drainage lines. Identifying them on the toposheets, geomorphic features were studied more minutely on satellite imageries together with related vegetation cover. This helped to bring out, on general relief map, the suitable surveillance areas for field-work. In field surveys, data were gathered through field observations and field photography. Field observations were made to study different geomorphic features and plant species, these two components were recorded on rough sketch of the area surveyed. Simultaneously, field photography of the same was also done by focusing for both panoramic view and close-ups.

CLIMATE

The Siwalik Hills experience Koeppen's Cwg category climate based on annual and monthly means of temperature and rainfall (Koeppen, 1936). This is characterized by humid tropical weather and dry winter (Spate, 1967), while the climatic data of Chandigarh (30^o44' N lat., 76^o56' E longitude and an elevation of 346.86 m above ms1) suggests that the Chandigarh Siwalik Hills have BSh category climatic regime. For general vegetation there are two major growth periods-February to March (Spring) and rainy months of July and August. Leaf fall for non-evergreen vegetation is experienced during October to November (Autumn).

PHYSIOGRAPHY AND PHYSIOGNOMY

Trans Satluj Siwaliks run parallel to the NW Himalayan range on southern side and generally dip to the S and SW. These are flanked by the Rolling Plains on the southern slopping side with conspicuous longitudinal valley, Pinjaur-Nalagarh dun on the north-eastern side (Figure 2).

These Hills present a highly dissected badland topography created by ephemeral streams of various genetic types. Weathering and erosion in this semi-arid region (consequential to uncontrolled deforestation) has produced a variety of erosional land-form features as rills, gulleys, scarps, cuestas, spurs, hogbacks and variously shaped ridges and amphitheatrical basins (Singh, 1990a). Depositional features like choe terraces and flood plain scrolls are formed subsequent to erosion of the surrounding landforms (Singh, 1990a).

Structurally, the study area is characterised by broad open folds both longitudinal and transverse. The longitudinal folds run parallel to the duns from NW to SE. They constitute the water divide as a result of higher crests which run along their entire length. The transverse folds running from hillfoot plains to water-divides form a ridge and valley topography of low relative relief through the entire length of these Siwalik Hills. The seasonal steams commonly called choes running from NE to SW descend into the valleys. Here they broaden and form choe terraces and flood plain scroll of fertile alluvium. The surrounding relatively higher relief gradually gets flattened due to high rate of erosion The descent of the general relief of the region such as slope is from NE to SW.

The Rolling Plains of the region primarily lie in Punjab and Haryana and are comprised of piedmont plain, the upland plain and the flood plain corresponding to descent in gradient of Siwalik foothills (Figure 2).

Now the Siwaliks are found to be sparsely forested (Figures 3 a, b) but according to Puri (1949) they probably bore a very luxuriant vegetation in the preglacial times in view of rich and varied flora and fauna discovered from wide and distant localities in them (Randhawa, 1945). The account of the present day flora and fauna that follows shows that much has been lost more so in the last 150 years.

Present day physiographic features of Chandigarh Siwalik Hills as reflected by landform and vegetation characteristics have been described and illustrated by Singh (1990 a, b). According to him both the processes of denudation and deposition operate simultaneously to sculpture landform features in the drainage basins of Kansal Choe, Jainti Devi Ki Rao and Patiali Rao. The active gradational processes due to sparse vegetation predominantly on SW aspect of Chandigarh Siwalik Hills result in extremely degraded badland topography prominently marked by scarps and gulleys (Figures 3-4). Further, vegetation in the catchment area of Patiali Rao, Sukhna Choe and Jainti Devi Ki Rao in relation to landform features studied by Singh (1990 a, c) revealed that by and large, there is no sound relation between landform and vegetation types. The main reasons for this being (i) the recent geological formation of these hills and (ii) the ecological degradation due to biotic interference spread over the past about two hundred years. Still certain features of landforms-soil structure and vegetation relationships emerge out as these lend characteristic physiognomy to the specific features of these Siwalik Hills as supported by following correlative points:

1. Cuestas, Hogbacks, Hills crests, Spurs, Serrated Knife-Edged Hills and Amphitheatrical Basins usually support Carissa spinaurm, Dodonaea viscosa, Capparis sepiaria and Adhatoda vasica. While Carrisa is abundant from base to top, Adhatoda and Dodonaea flourish more on basal and middle parts of these hills. On dun side these are mixed with Acacia catechu and spiny-non spiny dry deciduous species growing in the form of thick forests.

2. Spurs and Serrated Knife-edged Ridges, due to sheet and rill erosion, show very scanty vegetation of mostly Carissa species.

3. Hill Scarps and Terrace Scarps do not support major vegetation except occasionally Carrisa in the niches. However, grasses make their appearance in due course of time.

4. Middle level terraces support plenty of Zizyphus, Acacia, Carissa, Adhatoda and Dodonaea.

5. Lower level terraces and flood plain scrolls primarily show extreme growth of Saccharum while flood valley flood plain supports only Saccharum spontaneum.

6. In riverain tracts at the edge of Siwalik Hills grow Dalbergia sissoo and Acacia catechu.

7. Major features of soil structure and vegetation relationship (see Singh, 1990c) are (a) On Sand -Clay (generally 2:1) mixture grow Saccharum benghalense and Zizyphus numularia in dry-zones and S. spontaneum in wet zones; (b) On Sand Clay Conglomerates with lot of moisture, grows Saccharum spontaneum; (c) On Shingle Bars grow S. spontaneum, Z. numularia, sedges and grasses; (d) On Clay-Sand (generally 2:1) mixture grow species of Carrisa, Adhatoda, Zizphyus, Acacia, (e) On Clay and Clay-Sand (Dry) grows Butea monosperma; (f) On Sand Gravel-Clay mixture (without much of moisture) grow Dalbergia sissoo and Acacia catechu; (g) On shallow clay and boulders grow species of Zizyphus, Carrisa, Adhatoda, Ehretria, Adina, Mallotus, Flacourtia; and (h) On Boulder Beds grow A. catechu and Adhatoda.

GEOLOGY

The Siwaliks of trans Satluj Punjab – Haryana region are soft and friable. The composition of deposits shows that they are nothing else than alluvial deteritus derived from subaerial wastes of the inner mountainous ranges, swept down by their numerous rivers and streams and deposited at the foot (Wadia, 1949). These hills composed mainly of clay sand, sand rocks, poorly bedded sandstones and conglomerates (see figures 5 a, b) are more or less homogeneous along their entire length and are believed to be deposited contemporaneously (Puri, 1949). The hills conform in characters to recent alluvial deposits except that they are more compact, having undergone immense folding and faulting by Post-Tertiary orogenic movements (Puri, 1949). According to Krishnan (1943) "it is almost certain that Siwaliks extend down for several miles underneath the alluvial cover of the Indus and Ganges Valley".

GENERAL ASPECT OF VEGETATION

The history of vegetation of Chandigarh-Morni Siwalik Hills clearly shows that during the present century the tree canopy all around has been severely broken by human activities (for details see Singh 1990 b, c). There is no trace of chil (Pinus roxburghii) and sal (Shorea robusta) in the Chandigarh Siwalik Hills, however, some patches of these trees do exist in the Morni Siwalik Hills. Scattered trees of the other species grow in small groups except for the closed forests where the tress are in abundance. Now these hills are characterised by tropical dry deciduous forests with abundance of thorny species. The trees are low with xerophytes predominating. Tree canopy is more or less broken and tree heights never exceed 10 metres. The least disturbed patches of vegetation are on the northern flanks (Figure 7). Throughout the range thorny and spiny species dominate. The common ones are Capparis sepiaria, Flacourtia indica, Rhamnus persicus, Z. numularia, A. nilotia, A. catechu, A. leucophloea, A. modesta, Prosopis spicigera and Diospyros cordifolia. Of course, scruby thorny Carissa spinarum is abundant all through hill sides.

C. sepiaria, Z. numularia, and C. spinarum at places form impenetrable scrub vegetation. In the hill-foot plain areas occasionally highly lopped trees of Butea monosperma are seen.

Species such as Anogeissus latifolia, Bauhinia racemosa, Cassia fistula, Lannea coromandalica, Woodfordia floribunda, Nyctanthes arbortristis (Harshingar) are not rare. On dry exposed slopes Dodonaea viscosa and Adhatoda vasica form conspicuous shrubby elements. In the valleys of choes may be found occasionally B. monosperma, Aegle marmelos, Dalbergia sissoo and Wandlandica excerta. Where the vegetation is thick and protected Bauhinia vahlii and Puerraria tuberosa grow as conspicuous climbers and few clumps of Dendrocalamus strictus may be seen. Plantation of Eucalyptus in these hills is not scarce.

Near inhabitation in valleys, Melia azadirach and Ficus religiosa are often planted. Common perennial grasses are Eulaliopsis binnata, Heteropogon cortorus and Arundinella nepalensis. Cyperus niveus is the common sedge. Information about Life-form/Habit categorization of the common plants of Punjab Haryana-Siwalik Hills is as follows (Sharma and Sharma, 1966, 1967).

A. TREES :

Acacia catechu (katha), A. leucophloea, A. modesta, A. nilotica (kikar), Adina cordifolia, Aagle marmelos (beal), Anogeissus lalifolia, Azadiracta indica (neem) Bauhinia variegata (kachnar), B. purpurea, Bombax malabaricum syn. Salmalia malabarica (simbal), Butea monosperma (dhak), Cassia fistula (amaltas), Cedrella toona (toon), Dalbergia sissoo (sisham or tahli), Diospyros cordifolia, Ehretia aspera, Eucalyptus tereticornis (safeda), Eugenia jambolana (jaman), Ficus benghalense (borh), F. glomerata (Gular), F. religiosa (peepal), Flacourtia indica, Grewia oppositifolia Lagerstroemia parviflora, Mallouts philippense, Mangifera indica (amb), Melia azadirach, Morus alba (toot), Nyctanthes arbortristis (harshingar), Prosopis juliflora, P. spicigera, Pinus roxburghii (chil), Shorea robusta (sal), Sizygyium cuminii, Termilia arjuna, Trewia nudiflora, Vitis negundo, Zizyphus mauritiana (ber), Z. numularia (jungli ber), Z. oenoplia, etc.

B. SHRUBS:

Adhatoda vasica (busuta), Calotropis procera (desi ak), Capparis sepiaria, Carissa spinarum, Dodonaea viscosa, Euphorbia nivulea (thor), Ipomea fistulosa (walaiti ak), Lantana indica, Mimosa aspericaulis, Murraya koengii (curry-pata), Woodfordia floribunda (fruticosa).

C. CLIMBERS :

Abrus precatorius (ratti plant), Bauhinia racemosa, B. vahlii, Cisampelos pareira, Pueraria tuberosa, Tinospora cordifolia.

D. GRASSES AND SEDGES :

Arundinella nepalensis, Cynadon dactylon (dhub, khable), Cenchrus ciliaris, Dendrocalamus strictus, Eulaliopis binnata (babbar or bagar), Heteropogon contortus, Imperata cylindrica, Saccharum benghalense (munj), S. spontaneum (kahi), Cyperus niveus, C. rotundus, Scirpus tuberosa.

GENERAL ACCOUNT OF FAUNA

The Siwalik Hills of Punjab-Haryana and the piedmont plains at the foothills were very rich in wildlife at one time. But with gradual reclamation of land and extension of agriculture to cope with increasing human population, wild animal population has been greatly reduced. Consequently, Wild Life Protection Act of 1972 was enforced in Punjab region affording protection to wild animals and birds. The Wild Life Wing of State's Forest Department is maintaining a strict vigilance on shooting of wild animals. Different zoological types of the region are as follows (cf. Sharma, 1987; Bhoria, 1984).

Figure 3a. Highly disected water shed hills at the head of Patiali Rao valley in the Chandigarh Siwalik Hills supporting entirely scrub vegetatation of xerophytic species. Gulleys are a common feature.
Figure 3b. Low Hills of the Patiali Rao and Jainti Devi Ki Rao area with scanty thomy scrub vegetation. On terraced flat land is noticed the dense growth of Dodonaea viscosa while in the foreground is the stream bed.
Figure 4. Deeply eroded clay hillock by the margin of tributary of Patiali Rao. In the fore ground are crop fields in the valley low land.

Figure 5a. Rock profile of Morni Hills nea Ghaggar river (Nade Shib, Panchkula) showing sedimentary deposites of boulder conglomerate subgroup of Upper Siwaliks.
Figure 5b. Rock profile of Chandigarh Siwalik Hills in Patiali Rao area showing sedimentary deposits of clay, sand, sandrocks, sandstones and fconglomerate.

CHANGES IN VEGETAL COVER

Forests trees almost entirely govern vegetation. Therefore, changes in forest cover are reflected through vegetal covgr and finally in the landscape. Data on forest cover in Chandigarh, Morni and Kalesar Siwalik Hills for the years 1964-1966, 1986 and 1991 has been analysed. Earlier spatio-temporal changes in forest cover of Chandigarh Siwalik Hills were assessed by Mehta and Singh (1995). Main features of changes in vegetal cover are as follows :

Spatial distribution of forest types in the NHE during 1966 to 1991 :
The relevant data are reflected in Table 1 and figures 8 and 9 for the years 1966, 1983, 1986, 1988 and 1991. Finally the Chandigarh Siwalik Hills show 85.10 per cent of the total area under forests while for Morni Hills the forested area is only 62.38 per cent but Morni Hill have 67.01 per cent area under Dense forest in strong contrast to 23.46 per cent area being under Dense forest in Chandigarh Siwaliks.

Forest Classification :
With the enforcement of Indian Forest Act of 1865 (as revised in 1878 and 1927) by the Britishers, the legal status classification was followed by Forest Departments of various states of India and SOI. The forest maps are adapted on forest use/exploitation patterns as Reserved Forests, Protected Forests and Unclassified Forests. As such no clear information is available in SOI forest maps as to the density of forest canopy or the composition or types of forests of particular region. While analyzing the data for vegetal cover in the present study the forest classification of Forest Survey of India (FSI) in terms of growth densities has been adopted. This is more meaningful index to assess the Forest Biomass i.e., gorwing stock estimation and average volume per acre/hectare in terms of cubic metres of wood. The broad categories are as follows (adopted from FSI's The State of Forest Reports).

Spatial Distribution of Forest Types in the NHE : 1966-1991:
There have been marked variations in the quality and the extent of forest cover in the NHE during the last three decades or so as is evident from the data presented in (Table 1 and Figures 8 & 9).

CHANGE IN THE FOREST COVER

A. Temporal Changes in Area under Forests
Area under forests for the NHE has experienced fluctuations during the study period (Table 2). It has been noted that area under forests declined between the years 1996 and 1988. However, there was very slight increase of only 5.75 per cent per km² due to afforestation and reforestation, starting in mid-eighties. As per Forest Survey of India, about 10 per cent of the forest area in the trans-Satluj Siwalik region of Punjab and Haryana had been deforested during 1966-1986 and diverted to other uses as agriculture and habitation. It shows that there had been encroachments on the forested area in the Trans-Satluj Punjab - Haryana Siwalik hills during the last 25 years.

Table 1. NHE : Forest Cover by Density Classes (area in km²)
________________________________________________________________________________
Year         Location         Dense         Open         Scrub         Total Forest Cover        Non-Forest     Total Area
--------------------------------------------------------------------------------------------------------------------------------------------
1966¹     Chandigarh         24.25         231.50         32.00                 287.75                         32.75                 320.50
               Siwalik Hills        (8.43)         (80.45)       (11.12)               (89.78)                        (10.22)
               Morni Hills        158.25         95.25           48.50                302.00                         50.52                 352.25
                                           (52.40)        (31.54)       (16.06)               (85.73)                        (14.27)
               Kalesar Hill            9.00               -             2.00                   11.00                             1.00                 12.00
                                            (81.82)             -           (18.18)               (91.67)                         (8.33)
               NHE Total         191.50         326.75         82.50                 600.75                         84.00                 684.75
                                           (31.88)         (54.39)      (13.73)               (87.73)                       (12.27)
---------------------------------------------------------------------------------------------
1983²     Chandigarh         20.75         223.25           7.00                 251.00                         69.50                 320.50
               Siwalik Hills         (8.27)        (88.94)         (2.79)               (78.32)                       (21.68)
               Morni Hills          39.75         242.00         13.75                 295.50                         56.75                 352.25
                                            (13.45)       (81.90)         (4.65)               (83.89)                        (16.11)
               Kalesar Hill             -              (6.50)             -                     (6.50)                           (5.50)                 12.00
                                                -           (100.00)            -                     (54.17)                        (45.83)
               NHE Total            60.50        471.75         20.75                 553.00                         131.75               684.75
                                            (10.94)       (85.31)        (3.75)                 (80.76)                       (19.24)
---------------------------------------------------------------------------------------------
1986³     Chandigarh         10.25         192.00         29.25                 231.50                         89.00                 320.50
               Shiwalik Hills      (4.43)         (82.94)       (12.63)               (72.23)                       (27.77)
               Morni Hills          12.50         187.75         58.75                 259.00                         93.25                 352.25
                                             (4.83)         (72.49)      (22.68)                (73.53)                       (26.47)
               Kalesar Hill             -                 6.50           2.00                     8.50                           3.50                   12.00
                                                -             (76.47)       (23.53)                (70.83)                       (29.17)
               NHE Total            22.75         386.25         90.00                 499.00                       185.75                 684.75
                                             (4.56)         (77.40)      (18.04)                 (72.87)                      (27.13)
---------------------------------------------------------------------------------------------
1988⁴     Chandigarh         62.25         192.75         14.25                  269.25                         51.25                 320.50
               Siwalik Hills       (23.12)        (71.59)        (5.29)                 (84.01)                       (15.99)
               Morni Hills         126.00         35.50          57.00                 218.50                         133.75                352.25
                                            (57.67)       (16.25)       (26.08)                (62.03)                        (37.97)
               Kalesar Hill           4.25             3.00           0.25                     7.50                             4.50                   12.00
                                            (56.67)       (40.00)         (3.33)                (62.50)                        (37.50)
               NHE Total         192.50         231.25         71.50                 495.25                         189.50                 684.75
                                           (38.87)        (46.69)       (14.44)                (72.33)                        (27.67)
---------------------------------------------------------------------------------------------
1991⁵     Chandigarh         64.00         186.00          22.75                 272.75                           47.7                 320.50
               Siwalik Hills       (23.46)        (68.20)         (8.34)                (85.10)                       (14.90)
               Morni Hills         147.25         35.25           37.25                 219.75                       132.50                 252.25
                                            (67.01)       (16.04)        (16.95)                (62.38)                       (37.62)
               Kalesar Hill            4.50           3.25             0.75                     8.50                             3.50                 12.00
                                            (52.94)       (38.24)         (8.82)                 (70.83)                       (29.17)
               NHE Total             25.75        224.50         60.75                 501.00                         183.75               684.75
                                            (43.06)        (44.81)       (12.13)                (73.17)                       (26.83)
______________________________________________________________________
Figures in parentheses indicate percentages for (i) forest cover by density classes to the total forest cover and (ii) total forest cover and non forest to the total hill area.
Based on:
1. SOI topographical maps 53A, 53B and 53 F (Surveyed 1964-66);
2. Landsat MSS-FCC as on December 4, 1983;
3. Landsat TM-FCC as on November 18, 1986;
4. Landsat TM-FCC as on October 2, 1998;
5. Landsat TM-FCC as on November 16, 1991.

Figure 9. NHE : Forest types in Chandigarh Siwalik Hills (CSH), Morni Hill (MH) and Kalesar Hill (KH) during the years 1966, 1983, 1986, 1988 and 1991.

Table - 2. NHE : Temporal Changes in Area under Forests
__________________________________________________________
Year of Survey         Area Under Forests (km²)         Percentage to total Area
                                                                                                    (684.75 km²)
        1966                                 600.75                                             87.73
        1983                                 553.00                                             80.75
        1986                                 499.00                                             72.87
        1988                                 495.25                                             72.32
        1991                                 501.00                                             73.16
__________________________________________________________

B. Changes in Density Classes of forests
Marked changes took place in Forest Density Classes during the years 1966 to 1991. These are as under (Table 1) :

Monitoring of a change in the forest cover, with respect to 1966 and 1986 (Table 3; Figures 10 & 11) interestingly reveals that in the Chandigarh Siwalik Hills more than half of the forest area (53.08%) is in stable condition whereas 35.78 per cent of forest area is under deforestation due to biotic interference and 33 km² (11.13%) is under afforestation/reforestation schemes. Situation in the Morni Hills is alarminly unsatisfactory because 64.00 per cent of the forest area already stands deforested and stable forests cover only 22.75 per cent and afforested/reforested area accounts for 13.23 per cent. Kalesar Hill has 93.75 per cent of the area under deforestation while no stable forest existed. Taking an over all picture we find that now the Chandigarh Siwalik Hills supported 92.43 per cent forest area, the Morni Hills 91.69 per cent and 100 per cent of Kalesar hill area is covered with forests. But the stable forests cover only 36.55 per cent area and the rest of ;the area is either under afforestation/reforestation (12.11%) or is in the process of deforestation (51.34%), the latter category constituting more than half of the total forest area of the ISCR Siwalik Hills.

The temporal change in forest cover with respect to years 1966 and 1991 (Table 3; Figures 10 & 11) reveals a definite improvement in the quality of forest cover of the NHE. The stable forests constitute 41.23 per cent for the Chandigarh Siwalik Hills and 47.93 per cent for the Morni Hills. Kalesar Hill having 40.90 per cent Stable Forest area in contrast to the 1966-1986 situation when Stable Forest area was completely absent. This reveals a marked decrease (17.17%) in the Chandigarh Siwalik Hills and increase (105.8%) in the Morni Hills. Area under deforestation shows a definite decrease of 32.07 per cent for the Chandigarh Siwalik Hills, 34.94 per cent for the Morni Hills and 53.33 per cent for Kalesar Hill when compared to 1966-1986 data. Areas under afforestation/reforestation show 161. 36 per cent increase for the Chandigarh Siwalik Hills, 30.40 per cent decrease in the Morni hills and 66.66 per cent increase in Kalesar hill.

Table 3. NHE : Vegetational Changes (area km²)
_______________________________________________________________________________________
Sl. No.  Location         Stable Forest    Deforestation     Afforestation/Reforestation    Total Forest Cover    Non-Forest    Total Area
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
          A : 1966 to 1986*
1.         Chandigarh             57.25                 106.00                                 33.00                                     296.25                     24.25             320.50
            Siwalik Hills
2.         Morni Hills              73.50                 206.75                                 42.75                                     323.00                    29.25             352.25
3.         Kalesar Hills                 -                     11.25                                   0.75                                        12.00                         -                 12.00
            NHE Total             230.75                 324.00                                 76.50                                      631.25                   53.50              684.75
          B: 1986 to 1991**
1.         Chandigarh             24.00                    48.25                                 92.25                                     264.50                   56.00              320.50
            Siwalik Hills
2.         Morni Hills             60.00                     83.50                               130.00                                     273.50                   78.75              352.25
3.         Kalesar Hills             1.20                       0.70                                   7.80                                         9.70                     2.30                12.00
            NHE Total               85.20                   132.45                               230.05                                     547.70                 137.05              684.75
          C: 1966 to 1991***
1.         Chandigarh           130.25                     72.00                                 86.25                                     288.50                     32.00             320.50
            Siwalik Hills
2.         Morni Hills            151.25                   134.50                                 29.75                                     315.50                     36.75             352.25
3.         Kalesar Hill                4.50                       5.25                                   1.25                                       11.00                       1.00               12.00
            NHE Total             251.00                   244.75                                117.25                                     616.00                     68.75             684.75
_______________________________________________________________________________________
+ Area undergoing degradation of forest due to biotic interference.
* Interpreted through super imposed mapping of 1964-1966 and 1991 forest covers.
** Interpreted through super imposed mapping of 1986 and 1991 forest covers.
*** Interpreted through super imposed mapping of 1964 - 1966 and 1991 forest covers.

Comparison of overall figures for 1986 and 1991 with base period (being the same i.e. 1966) would reveal that total forest area for the Chandigarh, Morni and Kalesar Hills has decreased by 2.61 per cent, 2.32 per cent and 8.33 per cent, respectively (total forest cover for the NHE decreasing from 631.25 km² to 616.00 km²). But increase is noticeable for stable forest (10.07%) and afforestation / reforestation area (53.26%) while area under deforestation definitely decreased by 24.45 per cent. Thus, we notice a marked change for the better in the forest cover in 1991.

Tree Species Composition of the NHE Forests :
Most of the forest trees are small to medium sized with frequent stem diameter of 10-20 cm or 20-30 cm with rare occurrence of 30-40 cm or 40-50 cm stem diameter categories as determined on the basis of cross checks carried out by taking a sample survey of 100 trees of each species in five selected sites. Larger trees of 70-80 cm or more than 80 cm stem diameter are practically non-existent. List of common forest tree species in different parts of the NHE as earlier been given under life from /habitat categorization of common plants of Chandigarh-Morni Siwalik Hills.

GEOLOGICAL IMPLICATIONS:

There has been progressive desiccation of northern India in the historical times (Randhawa, 1945) and NW Indian Siwaliks are no exception. But in this region the major deterioration in vegetation and consequential environmental changes have taken place in the last 2-3 centuries. Geoecological implications of loss and deterioration of vegetal cover in the trans-Satluj Siwaliks, particularly during the post Independence period of 1950-2000, are as follows:

(a) Loss of Biodiversity in NHE :
During the last about 100 years there has been a large scale destruction of forests in the NHE with the result that one time valuable timber species namely chir pine (Pinus roxburghii) and sal (Shorea robusta) have been totally extirpated from the Chandigarh Siwalik Hills. In the Morni Hills there do exist some strands of chir pine but the forests have no extractable timber. Kalesar Hill does support some extractable sal forests. Dhak (Butea monosperma) is another tree which is almost being extirpated from the region. Only rarely stunted and highly lopped trees now grow in choe valleys although dhak forests did exist at one time; even 50 years ago dhak grew well at Siwalik foothills and in piedmont plains.

Along with the depletion of forest cover, a good amount of fauna has also disappeared from the NHE Siwalik Hills and their foothills area. Wild bear and tigers which could occasionally be seen in the foothill riverine forests of the region in the 1940s are almost extinct now. The destruction of natural ecosystem goes hand in hand with drastic reduction of biodiversity and in the long term endangers the quality of life as well as economic development (Kaiser, 1999).

(b) Introduction of Exotic Elements :
In the NHE Eucalyptus, the all purpose quick growing timber tree, has been introduced on massive scale under afforestation/reforestation programmes in spite of its adverse effects on the ecology of the hills. Eucalyptus plantations in rainfed areas with rainfall less then 1,200 mm, can completely destroy underground water resources by stopping percolation and drainage processes (Etherington, 1976). Greater biomass productivity by Eucalyptus is at the expense of soil fertility causing heavy nutrient deficit.

It is observed that in case of the large plantations of Eucalyptus there is tremendous change in the ground vegetation of these forests. It is not only very poor but is extremely deficient in plant species composition resulting in loss of species diversity in the hills.

(c) Soil Loss in the NHE :
Although, erosion in the NW Siwaliks is nearly a century old problems (Glover, 1946) but with the development of Chandigarh, there have been more adverse and pronounced effects on the vegetation of the adjoining Punjab – Haryana Siwalik Hills because of ever increasing demand for wood, fodder and construction materials. As a result, the process of soil erosion was accelerated. In certain areas of Morni Hills soil erosion has been extremely damaging (Figures 6 a, b). Heavy siltation of the famous Sukhna Lake even within two decades of its construction in 1958, attracted the attention of a number scientists. They studied the siltation problem and indirectly worked on soil erosion in the Siwalik catchment area of the Lake (Bansal & Mishra, 1982; Grewal et al., 1990).

Now, the land degradation due to water induced soil erosion is a serious problem in Punjab-Haryana Siwalik region (Figures 3b, 6a, b). Like several other regions of India, the Siwalik Hills experience severe erosion of more than 20 tonnes per hectare per year (Singh et al., 1990). Accepted average soil loss value of 80 tonnes per year has been reported from Siwalik region, this being a very high figure due to pinnacle erosion in this region although some of the ranges of Siwalik are vegetated too.

The factors such as soil erodibility, steepness, length, aspect and shape of slope and vegetative cover have important influences on potential erosion hazard in submontane Punjab (Kukal et al., 1991). It has also been noted that slopes facing south, southwest and west have greater erosion hazard than those facing north-east because of more solar energy, greater aridity, less vegetation and dominantly concave slope. For the lower Siwalik Hills it has been found that vegetation cover is a more vital factor than slope steepness and length in determining actual erosion (Kukal et al., 1991).

According to Singh (1996) Chandigarh-Morni Siwalik Hills have experienced high vicissitudes of environment and bio-degradation because of high anthropogenic pressures from the development in the Capital City of Chandigarh and its satellite towns of SAS Nagar and Panchkula.Forest cover turns out to be the most significant factor while the geology of the hills, soil erosion and sedimentation are no less important.

According to Singh (1992), the sedimentation of seasonal streams have brought about changes in their profiles. He worked out the longitudinal profiles of Manakpur, Sughrao, Jainti Devi Ki Rao, Budhki and Siswan streams flowing from Chandigarh Siwalik Hills on to the northern piedmont of Punjab plain near Chandigarh and noted that there is high degree of resemblance in the profiles of all these streams with upper, middle and lower courses and on the whole the profiles are planar or to some degree planocovex. Due to siltation in the stream beds during rainy season the water over-flows the banks resulting in floods which cause frequent inundation of the crop fields.

It has been observed by Singh (1994), that in the areas of the high erosion intensity in Siwalik Hills, the dominant vegetation is herbaceous in character. It is composed of grasses and herbaceous elements together with crown density of stunted trees below 10 per cent. Grasses are dominant with Eulaliopsis binnata being quite frequent. Areas of moderate erosion intensity are characterised by scrub vegetation with stunted trees and afforestation plantations of Eucalyptus. In high and moderate erosion intensity classes, it is the grazing pressure and the Eucalyptus water demand aided by semi-arid conditions that accelerate erosion of loose clayey - sandy soils.

It may be pointed out that near Sukhomajri in the Siwalik Hills, about 70 per cent of rainfall of more than 1,200 mm per year (mostly received from July to September) used to be lost as run-off (working paper series No. 5 of Ford Foundation, New Delhi) till a stop to this wastage of water in Sukhomajri area in Chandigarh Siwalik Hills was ensured (Mittal et al., 1986). In Chandigarh Siwalik Hills there is alarmingly high rate of soil erosion in certain areas. According to Singh (1996) the soil loss of 367.5 tonnes/ha/year i.e. 2.45 cm of top layer per year from certain catchment areas is alarmingly high leading to voluminous depletion of organically rich soils.

LAND MANAGEMENT

Crop cultivation with traditional ploughing and irrigation mainly from streams (Kuhals) is practiced almost entirely on river teraces and choe valley low lands in the Siwalik Hills near inhabitations. Tractor cultivation and tubewell irrigation are practiced even today but over negligible acreage. The fertilizer is, however, applied and intensive cultivation is done like in the alluvial plains but very much unlike the piedmont plains where the cultivation intensity is low.

To control soil erosion and store water for irrigation, check dams under Kandi Micro-Watershed Development Project have been constructed during the last about two decades, located mainly in and around valleys at few selected sites of small and deep gulleys. Construction of check dams in streamlets has also resulted in restoration of vegetation of the hills. Commendable work has been done regarding watershed development, control of sedimentation in streams and conservation of water resources. People are raising wheat crop on terraced fields and they make use of fertilizer and pesticides to increase food production like their counterparts in plains.

SOCIO-ECONOMIC ASPECT

With rapid growth of Chandigarh Conurbation in 1970s and 1980s the demand for timber and firewood increased tremendously. The local contractors and brick kiln owners extracted wood from the ISCR Siwaliks (NHE) unabatedly. In these deforested hills the construction of roads deviated the run off. This caused more frequent landslides and activation of gulley erosion.

The local population is confined to pockets of non-forested lands. Hill agriculture is limited to areas near inhabitations and is backward because of poor, un-irrigated, infertile soils except in certain choe valleys where a few tube wells have been installed.

Usually a large number of cattle kept by the people are burden on the forests resulting in their quick degradation. Firewood and fodder requirements of village people are almost entirely met with from government forests. Although all the forests belong to the government yet the people of hilly villages depend on forests for cattle grazing. The rural poor collect dry and fallen twigs as fuel and even cut root suckers of sisham. Often lopping of forest trees is resorted to for firewood during winter months. Fodder trees are lopped especially during winter.

Although agricultural wastes or residues do provide substantial quantities of fuel yet continuous demand for fuel-firewood is on the increase and this accounts for unauthorized cutting of forest trees. The daily needs for some timber are also met with from the forests since there are hardly any timber trees on village common lands.

Katha wood or khair (Acacia catechu) and bhabar grass (Eulaliopsis binnata) are a source of regular income to local people and the forest department. Of course, sisham (Dalbergia sissoo) that grows in riverain tracts is a prized timber.

The increasing distances of the recedidng forests, however, have made firewood procurement so difficult that ultimately cattle dung is dried for fuel. It deprives the soil of valuable manure which affects productivity.

Finally, it may be stated that the main brunt of anthropogenic pressures is exerted on the W, SW and S slopes of the trans-Satluj hills with the result these prominently exhibit dry scrub vegetation and rampant land erosion while the N, NE and E slopes are comparatively stable and support more vegetation and are less degraded (compare Figures 3 and 7). Obviously, the people inhabiting the Siwalik hills facing the Punjab - Haryana plains are leading more rigorous life for their dependence on 'badlands' since the destruction of trees, shrubs and grasses from the hills of the region that has taken place during the present century, has continuously exposed the hill lands to wind and sheet erosion to greater degrees with passage of time. Huge quantity of soil being washed into the streams constitute a great loss of soil nutrients in the arable lands in the Siwaliks. Moreover, according to Zaimeche (1994) the eroded soils, after losing their organic matter, cease to retain moisture during the rainy seasons and even after the rains
return, the affected soils fail to regain their former productivity, and the capacity of
the forest for regeneration is considerably diminished. With limited availability of per capita arable land due to increasing population and decreasing productivity of land, the economic conditions of the Siwalik Hill people, like elsewhere in NW Himalaya where deforestation is on the increase, is getting worse and worse with the passage of time.

CONCLUSIONS

In the post Independence period, due to high increase in developmental activities caused by up coming of Chandigarh and its satellite towns alongwith urbanization in the peripheral region of the City Beautiful, the basic structure of NHE has been badly altered in the detrimental direction. There have been marginal improvement in area under forest cover in the recent past but the quality of forest in Chandigarh and Morni Siwalik Hills is far from being satisfactory from view point of biomass productivity. It may be pointed out that water run-off, infiltration capacity, soil displacement, moisture retentive capacity in trans Satluj Punjab-Haryana Siwalik region, are highly dependent on the vegetal cover and leaf litter. The result is that water and soil erosion have become the major problems of today. Except for Sukhomajri area in Chandigarh Siwaliks, the economic condition of the local people is a live-cause for worry to the future environmental planners.

There is absolutely no doubt that the forests of NHE of ISCR are protective as well as productive assets of the life support environment. But Siwalik Hilly ecosystem of Punjab-Haryana has been over burdened over the past 50 years or so for biomass productivity due to active deforestation, grazing, unscientific cultivation and anthropogenic interference, except for Sukhomajri. Even today 'badland' topography due to severe erosion in the ecologically vulnerable trans-Satluj Punjab-Haryana Siwalik Hilly region is prominent. So far the intensive urban and industrial development in and all around Chandigarh Capital city has caused a great pressure on the forest areas of the adjoining hilly tract with the consequence that there has been a serious imbalance due to heavy soil loss with high runoff in the hills. The ecological results of such changes have been transformation of forests into scrubs, disorders in the availability of water, intensification in the rate of erosion, so evident in the sedimentation of Sukhna Lake and beds of streams of the region. As a matter of fact these changes are manifested in the Semi Natural Drainage Ecosystem (SNDE) of ISCR where streams frequently experience floods because of situation being aggravated by filling up of stream channels which have undergone a change to planoconvex condition due to heavy siltation.

In order to save the Chandigarh environs from getting further deteriorated it is but essential to transform 'badland' topography of the adjoining Siwaliks into forest protected landscapes within minimum possible time period. This means result oriented efforts are needed on high priority basis. To achieve it in an efficient way, the policy makers and scientist's data requirements will be massive and even continue to grow. So the need now is just not to check deforestation onslaught at national or state levels, but to generate data for forest type and biomass density on spatially disaggregated or sectional basis for the Siwalik Hills. Deforestation and reforestation or afforestation rates and consequential changes in rates of soil erosion need to be monitored on continuous basis with periodic performance assessments rather than random assessments or subjective estimates. There are no limitations for this approach. Now we have available satellite imageries data on regional basis but what is more important is data evaluation and scheme implementation with application of Geographic Information System (GIS).

ACKNOWLEDGEMENT

The author expresses his gratitude to Prof. G.S. Gosal, Prof. (Mrs.) Swarnjit Mehta, Prof. Jasbir Singh, Prof. M.S. Gill and Dr. (Mrs.) Dhian Kaur for providing inspiration, encouragement and day to day help in the compilation of the present work.

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