Reference : R iverine forests
Forestry Sector Master Plan Project - Pakistan-1991
The production potential of the 138,000 ha of planted riverine forests in Sindh should be 441,600 cubic meters of timber and 717,600 cubic meters firewood. However, the overall output from all types of forests in Sindh is lower than the potential of riverine forests alone. The volumes harvested in 1988-90 represent approximately 5% of the potential yield.
The riverine forests in Punjab also yield far less than their potential. The output of shisham on these bela areas is less than that in Irrigated plantations. 200 trees are planted per acre in the riverine plantations whereas, 726 per acre are planted in canal irrigated plantations. After thinnings are carried out, the canal irrigated plantations still have about 300 trees per acre. There are no intermediate yields from the riverine plantations. Since thinnings are not carried out.
Their productivity under existing conditions of flooding and mismanagement has deteriorated. In order to offset the adverse changes on one hand and to increase productivity intensive management that focuses on regeneration of appropriate trees and their tending, is necessary in order to produce more of high quality and maximum benefit that the water and land can yield.
Economic Aspects
Prolonged flooding prevents the low-lying areas to be managed as commercial forests. However, the low-lying areas have been important habitat of wild species of animals. Moreover, these forests have provided useful products and services that included livestock grazing, game animals and birds, subsistence needs of local communities and stabilisation of river banks to some extent.
The commercial species in the high-lying areas cannot survive without irrigation as they are not flooded frequently and the ground water table is low which makes its availability to plants difficult. Irrigated plantations have been established in some of these forests. Compared with the canal irrigated plantations, these high-lying areas in riverine forests have certain drawbacks;
- They do not have access to canal water, hence water has to be pumped with tube-wells or lifted from dhands and dhoras. This is a very costly operation.
- The infrastructure (e.g. roads and water channels) of the plantations in riverine forests are damaged whenever flooded. Then these require substitution or improvement.
- The expenditure on raising irrigated plantations in the high-lying areas of riverine forests is higher than the cost in a canal irrigated plantation.
The intermediate areas, which contain babul in Sindh and Shisham in Punjab, are of great interest to the Forest Department. The Internal Rate of Return (IRR) on babul plantations ranges from 5.9% to 9.7%. This, however, does not consider intangible benefits, since not computed. In fact, it is important to put a price on all intangible benefits to know the real rate of return.
From the point of view of investment, forestry has two major drawbacks:
1. Returns take a long time; and
2. Capital is difficult to release if the necessity arises.
These drawbacks are compensated to some extent with the probability that timber prices would rise. Except for the very large estates where the risk is well spread, the security of the investment may be impacted by fire, insect and fungus diseases. These risks, however, could be reduced by sound silvicultural practices.
Financial analysis, outrun figures and stock appraisal, reveal, that the extraction of forests products has exceeded production capacity, with the result the stocks and reserves have progressively depleted and forests have been degraded. Due to lack of investment and inappropriate management, the production is hardly 10% of the potential.
There is a heavy demand for wood for different commercial and industrial purposes in Pakistan. Mining needs pit props and other wooden reinforcement materials. As a result, prices of wood products from riverine forests are high.
Regeneration and Afforestation
If riverine forests are left to nature the composition of economic species of trees is going to be less desirable than when it is manipulated through artificial regeneration. Obhan , babul , lai as well as kandi grows through the normal flooding. However, if a good crop of babul is to be obtained sowing of babul seeds through broadcasting in the last flood water is required. This means collection of good seeds of babul, their timely storage at the nearby places, as well as broadcasting in the last flood are very important.
The riverine forests of Sindh have been managed on the clear felling silvicultural system, which is quite suitable. The Clear-felled areas are regenerated in the succeeding years. Babul and Kandi are regenerated by seed and coppice respectively . Kandi regenerates on arid sandy area. Restocking of blank, felled and partially regenerated areas with babul is done by broadcasting, drilling and dibbling of seeds. Even kandi could be restocked with seeds.
Workplans prescribe the first thinning at five years, second thinning at ten years of age and final felling at rotation of 30 years.
The technique for raising obhan plants in polythene bags has been developed. This can help in having a good mixture of obhan and babul in suitable areas that do not remain immersed with water for more than a week at a time.
Afforestation of high lying areas in forests has been a challenge ever since the scientific management of forests started in 1877. This concern got strengthened when the forests were depleted as a result of over fellings of the War. Consequently, innovated afforestation through agro-forestry leases was introduced and practised in high lying areas of the riverine forests. Many blank areas were granted for leases at a very low rate of Rs.8/ -per acre in 1942, as this was the year of recession in the economy. The experience in agro-forestry except in 1942 is not very positive for the reason that trees could not be planted in other cases.
For the first time, aerial seed sowing operation was undertaken in September 1974, when 2,428 ha of riverine area, that was blank, received inundation and was sown with the seed from, a specially equipped aircraft. This was a success and has been used ever since.
It is never possible to fully regenerate or plant any area in the first attempt. There are failures, the magnitude of which depends on the various factors. Whether broadcasting of seeds or planting of saplings it is important that failures are restocked. Otherwise, the productivity will be less than desired.
Grazing in new regeneration areas is very harmful. It is, therefore, important that the livestock is not allowed to graze in regeneration areas. Similarly, cleaning and weeding operations are important to get good quality and well stocked crop of trees. Most often, not much attention is paid to these essential requirements. As a result, the quality and quantity of timber and other produce from the forest is less than desirable. Unscientific cleaning of young crop by allowing the shepherds to cut young trees for their goats and sheep is also harmful.
Plantations
The high-lying areas in riverine forests, especially in the Province of Punjab that were planted, were initially irrigated by a trench system. However, this was not found feasible, especially in sandy areas as it was difficult to maintain trenches. They silted up, seepage of water took place, and mesquite invaded these areas. Mesquite is difficult and expensive to eradicate. The trench irrigation system was replaced with flood irrigation.
The Forest Department has planned to provide a cusec of water to 30ha but much less is delivered due to many factors. Since the soils in inland forests are of poor quality the yield is low. The economy of raising plantations with tube-well irrigation needs appraisal, in case the objective is purely commercial.
Exploitation of Trees
The fellings in riverine forests are either based on normal rotation of the crop which is 30 years or the felling has to be undertaken if the area is threatened by river erosion. In the latter case the felling is termed as erosion strip felling. The riverine forests are also prone to forest fires. If a crop has been damaged by forest fire it is best to exploit it in case it is harvestable. The wood produced from riverine forest comprises of timber (constructional and furniture), pit props and fuel wood. Pit props are used in the coal mines.
Timber and Non Timber Forest Products (NTFP)
The riverine forests are important both for economic and environmental reasons. The forest produce obtained from them are fuel-wood and charcoal for energy purposes, fodder for animals, and timber for furniture. The other minor produce consists of gum arabic, honey, and bark for tannin, lac for lacquer works and red dye. They also reduce the intensity of floods and damage to agricultural lands, settlements and infrastructure. Dhands and dhoras in these forest contain fish and are permanent or temporary wetlands with all their components including water mammals, water birds, amphibians and reptiles. They even provide early grazing on their banks to animals and wildlife. In the past, the riverine forests supported large herds of livestock during autumn, winter and spring providing grazing, browse and pods and leaves of babul. Harvesting of NTFP is not on scientific basis.
Biodiversity and Wildlife
There are diverse habitats in riverine forests, their important parameters being soils, topography, water regime, crop composition and age of the crop. Most of these parameters are dependant on topography and so are the habitats. The low-lying and intermediate areas have the maximum species of wild plants and animals. Dhand and dhoras are permanent or temporary water bodies which have their own faunal and floral characteristics. Fish, otters, reptiles (turtles and tortoises), amphibians (frogs) and water birds (e.g. night heron) are associated with these water bodies.
The low-lying areas mostly contain lai of different age classes. This is the preferred habitat of hog-deer and wild boar. The intermediate and high-lying areas are used by jungle cat, Indian hare, black and grey partridges, rose-ring parakeet, yellow eyed babbler, sand-lark, red munia, and coucal etc.
It is important that best examples of the various habitats in the riverine forests in Sindh and Punjab are included in the protected area system in the two provinces. |