CHOICE OF SPECIES:
The term “choice of species” clearly implies the possibility of a selection from a number of potential candidates, with the list of possible trees being drawn from:
- Eco-physiological tests
- Field trials
FACTORS AFFECTING THE CHOICE OF SPECIES:
SELECTION OF SPECIES
The choice of species is done on the factors discussed below:
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 neighboring 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 Mastung Balochistan, we can select species from the areas having the same conditions as Quetta Quetta, etc, 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.
These factors also help in the selection of spp for the plantation. These factors include rainfall, humidity, and temperature.
For example, we can not select conifer spp for those areas where rainfall is low. Similarly, Acacia nilotica grows well in high humidity.
Objectives of Plantation
The different species have different properties a species will give more timber, other is good for firewood and the third one give good protection to the soil and so on. For this purpose the spp are classified according to their objectives which they give as:
- Production – Major and minor forest produces.
- Protection – This gives protection against wind and water erosion and has best watershed value.
- Aesthetic – The spp having good aesthetic value.
The objectives of the plantation are specified and the species are recommended.
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 an open canopy. The leaves are very hard to decompose and blown away by wind thus soil remains unfertile. If the spp. is light demander then weeds will grow in the blanks. Leaves will not decompose hence resulting in a loss of nutrients and gradually the whole site becomes unfertile. So, light demander spp should be grown with shade bearers to avoid the danger of degradation of the site. Thus the site can be utilized up to a marked extent. As Morus alba is grown with Dalbergia sissoo in irrigated plantations of Pakistan.
The spacing of Regeneration (spp)
The spacing of spp in regeneration is governed by various factors as the 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:
Method of Stocking (Regeneration)
The artificial regeneration is done by two ways as by sowing and planting.
- Sowing: In case of sowing closed spacing is required to have more chances of success.
- Planting: In case of planting the plants have 80% survival and wider spacing is recommended.
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.
The rate of Growth:
In slow-growing species, close spacing is suitable while in fast-growing spp the spacing should be wider.
Wider spacing is adopted for good quality site while closed spacing is adopted in case of poor sites.
Species having a small crown as Poplar and Eucalyptus planted at close spacing, but spacing should be wider in case of spp. Having crowns as Acacia nilotica.
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.
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 chir and 80 trees per acre in Deodar.
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.
Only those spp should be selected which requires little tending operations or which is economical one ie which give better yield with less cost.
Other factors include:
- Suitability to Soil and Moisture Conditions
- Generic Factors
- Relative Costs
PURPOSE OF PLANTATION:
- Industrial Uses
- Domestic Uses
- Environmental Uses
Tree planting as an Integral Part of Other land uses. For instance, when Changa Manga plantation was raised the main objective was to get fuel wood to overcome the demands of railway engines but now the objective has been changed to timber production.
Image: Lasbella Balochistan (Mangroves) – Image by Author
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