Forestry and Environment Sympoisum 1998, Sri Lanka

Fourth Annual Symposium organized by Department of Forestry and Environment Science, University of Sri Jayewardenapura, Sri Lanka.

Sunday, October 08, 2006

SCREENING OF WOODY AND SHRUB LEGUMES FOR AGRO-FORESTRY SYSTEMS BASED ON BIOMASS PRODUCTION, N YIELD AND BIOLOGICAL N2 FIXING CAPACITY

W D L Gunaratne, A P Heenkenda, K V S Premakumara and W M S Bandara
Department of Export Agriculture, Research Station, Matale

A field study was carried out to identify the suitable tree species for agroforestry systems based on their biomass production. N yield and N2 fixing capacity at the Export Agriculture research Station, Matale for a period of 9 months. 15N isotope dilution method was used for the assessment of the proportion of N2 derived through fixation (Pfix). Gliricidia sepium (gliricidia), Calliandra calothyrsus (calliandra), Leucaena leucocephala (leucaena), Erythrina subumbrance (Erythrina), Albizzia falcataria (Albicia) and Acacia mangium (Acacia) were used as N2-fixing species and Senna siamea (siamea), Senna spectabilis (Spectabilis), both are non-nodulating legumes, and Michaelia champaca (michelia) were used as non N2 fixing reference species.

Total dry matter yield of non N2-fixing reference crop spectabilis was significantly (p0.05) higher than all the species. Among the fixing species, Calliandra produced the highest biomass though the value is not significantly (p≥0.05) different from gliricidia, leucaena and siamea. Acacia and michaelia recorded the lowest yields.

Highest leaf, twigs and root N% was found in erythrina and the highest trunk N% was associated with gliricidia. Leaf N% of spectabilis was less than that of gliricidia and erythrina but total N yield of spectabilis was the highest due to high biomass production. Among the six fixing species highest N yield was found with calliandra and the value is over two fold higher than that for gliricidia. Acacia and michaelia recorded the lowest in yields.

Highest Pfix values for whole plant was found with albizia followed by gliricidia, calliandra, erythrina, leucaena and acacia. The trend is common for the values based on all the three reference crops. Total N2- fixing capacity of calliandra recorded the highest value followed by leucaena, gliricidia, albizia, erythrina and acacia. N2 fixing values calculated based on siamea and spectabilis revealed N-fixing species calliandra, leucaena and gliricidia have the capacity to fix 19.51-23.11, 15.77-19.79 and 13.10-14.42g N plant-1. The values equivalent to 195-231, 158-198 and 131-144kg of N ha-1).

S. spectabilis, C. calothyrsus, L. leucocephala and G. sepium produced higher biomass and higher N yields over the others. Total N fixing capacity of C. calothyrsus, L. leucocephala and G. sepium were superior to the other species. However, where maintenance of soil N status is considered further studies are recommended to evaluate the litter quality and N transferring ability before a firm recommendation is made.

DISTRIBUTION OF Zanthium indicum AROUND GIRITALE TANK

S Maithripala and G I Seneviratne
Department of Botany
University of Colombo.

The area around Giritale tank is the main grazing ground of wild and domestic animals within the nature reserve and there has been an increase in the population of XaniOinm. irulicone (Agada) in this ,area. In the Flora of Ceylon Trimen recorded this as a rare plant probably introduced from India. Today, it is reported to be present in more than 7 districts of the country, mostly in moist areas periodically inundated. lf reduces the grazing capacity and (be hooked involucres are reported to cause damage to the internal organs of the grazers. Studies arc kin- carried out to find the distribution and suitable control measures.

Area around the tank was sampled at 100m intervals. The plant is capable of producing flowers and fruits irrespective of the time of the year and the size of the plant. When less than 50% of the area was covered by the plant the abundance was taken, as low and when it was more than 50%, as high. 53% of the total area has been identified as high abundance and only 9% as free.

The species has already spread from the edge of water towards the forest. Although the fruits are found, the plant has not established in the forest. Soil moisture, texture and the light intensity determine the growth of this plant. Fruits get embedded in the mud and after decomposition two achenes are released which germinate later. There are reports of Xanthium sp. producing two types of achenes, germinating in consecutive years. Studies are being carried out to investigate this.

To improve the grazing capacity of the area it is necessary to control the growth of this plant. Controlled burning seems to be the best. Ten other species have been recorded growing with Agada. Crotalaria pallida competes with X. indicum, reducing its population. The possibility of use of Cuscuta chinensis in the control of Xanthium indicum is being tested.

REGENERATION OF TREE SPECIES IN AREAS DISTURBED BY TWO HIGH TENSION LINES AT SEETHA ELIYA PROPOSED FOREST RESERVE

D K Angammana 1, G I Seneviratne 1 and K Nanayakkara 2
1 Department of Botany, University of Colombo
2 Botanical Garden, Hakgala

Seven years ago, to erect a high tension line a strip of forest (10 to 15 m broad) from tile Seetha Eliya reserve was cut leaving stumps of about one meter height. This was abandoned and a similar strip close to the above has been cut three years ago. This project was carried out to find the plant species which can survive after such disturbance and to see the change in the free species composition with time. Seetha Eliya is a montane forest patch with undulating terrain and the altitude of the affected area ranges from 5000 to 6000 feet. After a reconnaissance survey, 36 plots of 8x25 has been demarcated at three altitudinal ranges (low, mid and high) to include three year, seven year and the adjacent natural forest (four at each site).

The percentage of trees surviving after cutting in the three year old stand from high, mid and low altitudes were 43% 51% and 52% respectively. Survival after cutting in the seven year-old stand is riot obtainable accurately due to the decomposition of stumps.

A total of 37 tree species including 26 endemic species were recorded in the areas examined. Out of this only 27 species including 16 endemic species showed the ability to produce new shoots. Higher number of such individuals were recorded from, Neolitsea fuscata, Syzygium revolutum, Actinodaphne glaauca and Cinnamomum ovalifolium. Species like Callophyllum walkeri, Vaccinium symplocifolium, Cnthium montanum did not show regeneration after cutting. Actinodaphne speciosa was found both in the natural forest and the three-year-old stand but was absent in the seven-year-old clearing, probably removed due to competition.

Higher number of seedlings and saplings were found from Symplocus cochinchinensis, Neolitsea fuscata and Actinodaphne speciosa in all the areas examined.

Further monitoring of these areas will help to identify the native species those can be used in restoration work of montane forests.

STUDY OF GROWTH PATTERN AND PHENOLOGY OF Dipterocarpus zeylanicus FROM TWO FOREST RESERVES OF SRI LANKA

M P de Silva
Department of Botany,
University of Ruhuna.

Dipterocarpus zeylanicus is an endemic emergent tree which grows in the wet evergreen forests of Sri Lanka. Usually it grows up to height of about 45 m, A study of the growth pattern and phenology was carried out at two forests reserves viz. Kottawa Forest Reserve located in the wet zone and Ellakanda forest reserve located in the intermediate zone of Sri Lanka. Both zones receive rain through the year but the intensities of rainfall received during the North Eastern (NE) and South Western (SW) monsoons in the two zones are different, SW being the most prominent in the wet zone of Sri Lanka and NW monsoon is equally intense as SW in the intermediate zone. Monthly growth increments were studied using dendrometer bands and phenological events were observed monthly. The growth intensity varied during the year, though there was a least some growth throughout the year. There was higher growth with an average diameter increment of about 3 mm/ month in the trees growing in the intermediate zone while in the wet zone, the average was around 1 mm. In the wet zone higher growth was recorded during the SW monsoonal period (i.e. From May to July) whereas growth of equal intensities was recorded during SW and NE (i.e. From October to December) monsoons in the intermediate zone. For phenological observations, period of leaf growth / greening, leaf fall, flowering, seed ripening / fruiting, and number of growth periods were recorded.

THE ECOLOGY OF Dipterocarpus zeylanicus PLANTATION AT INGIRIYA, SRI LANKA

P R Attygalle and B M P Singhakumara
Department of Forestry and Environmental Science,
University of Sri Jayewardenepura.

The plantation forestry in Sri Lanka began in the late 19th century. The forest cover prevailed at that time did not warrant a rapid expansion of plantations. Later, the depletion of the forest resources compelled the Forest Department to embark on establishing plantations. A rapid increase in plantation development was noted during the 2nd half of the 20th century. The species selected for plantation establishment were mostly exotics with few indigenous tree species.

Holmes as a silviculturist in the Forest Department initialed the studies on the growth performance of indigenous tree species. The present Dipterocarpus zeylanicus plantation at lngiriya was one such location established by him in 1940. At present there are other indigenous tree species also growing in association with D. zeylanicus.

A systematic sampling design was adopted for the study. The total sample area was 1.9375 ha. The diameter at breast height and height of all the trees above 10 cm were recorded in 25mx25m plots numbering thirty-one. Seedlings and saplings in 2mx2m and 5mx5m plots were also recorded. The number of plots in each case was 124. Important value indices for species, genera and families were calculated. Rank abundance curves were plotted. Endemic species in this plantation were recorded. Mean dbh, mean height, mean basal area, and mean top height for D. zeylanicus were calculated. The diameter class distribution of D. zeylanicus was plotted. Regression analysis was performed to observe whether any correlation exists between the dbh of D. zeylanicus against basal area of the same and other species.

The plantation recorded 82 species, 70 genera and 37 families. Among the 916 individual stems recorded 52% was D. zeylanicus. There were 248 individuals of D. zeylanicus per ha.

The paper highlights the floristic, status of principal species, stand parameters and suggest interventions for plantation management.

PRODUCTION OF IMPROVED QUALITY REPRODUCTIVE MATERIALS AND THE ROLE OF SEED QUALITY CONTROL IN FORESTRY

S A A Sathurusinghe and A A Paliwal
Forest Department, Battaramulla.

The quality of productivity of established forests is greatly influenced by the quality of reproductive materials used for planting. Hence, production of improved reproductive materials such as seeds, cutting and other plant parts is increasingly challenging in today’s productivity-driven forestry programs. As more improved reproductive materials become available for forestry use, the need for assurance on their genetic purity and physiological quality becomes equally important particularly in forest species where it takes many years to mature.

Short term production of quality seeds is achievable by proper selection of seed sources such as geographic and parental sources and the application of appropriate seed technology. To ensure the quality of seed being produced and utilized, certain standards have to be followed. These standards are embodied in a certification scheme and seed testing rules will be discussed in the paper.

This paper presents some approaches and challenges in producing improved quality reproductive materials such as seeds. It also discusses aspects of seed quality control which comprises of seed certification and seed testing in forestry.

EFFECT OF LIGHT AND SOIL NUTRIENT ON SEEDLING MORPHOLOGY OF Syzygium SPECIES OF A LOWLAND RAIN FOREST IN SRI LANKA

H K Gamage 1, B M P Singhakumara 1, P M S Ashton 2
1 University of Sri Jayewardenepura, Nugegoda.
2 School of Forestry and Environmental Studies, Yale University, USA

Knowledge of how light and nutrient availability affect seedling morphology in relation to seedling growth is critical for understanding the regeneration establishment of seedlings beneath rain forest canopies. This study measured changes in seedling morphology of four related tree species in family Myrtaceae in relation to differing combinations of light and soil nutrients. Species selected were canopy and sub canopy trees of rain forest in southwest Sri Lanka.

Shelters were constructed in the full open that created light treatments representing a range of photosynthetic Photon Flux Densities (PFD) and red: far red ratios found in the rain forest. Within each shelter seedlings were fertilized with phosphorous, potassium and magnesium nutrients. Newly germinated seedlings of each four species (S. firmum, S. makul, S. operculatum, S. rubicundum) were grown for one and half years after which they were dug up and measured for, shoot length, root length, root collar diameter, leaf number, leaf area, and dry masses of roots, stems and leaves.

Shoot length and leaf area attained maxima in shelters simulating large forest openings(400m2). Root length, root collar diameter and dry masses gain were highest in full sun treatment. Compared with nutrient treatments phosphorus promoted greatest morphological measurements for all species. The results suggest that these species exhibit greater morphological responsiveness to increase in irradiance and to addition of phosphorous fertilizer.

PHYSIOGNOMY AND NATURAL REGENERATION OF DRY DECIDUOUS FORESTS AT SIGIRIYA, SRI LANKA

G A D Perera
University of Peradeniya, Peradeniya.

Although, poor natural regeneration of tropical dry forest has been observed in Sri Lanka, India, Africa and in Latin America, the factors affecting this have not been well studied. In this paper, the physiognomy of dry deciduous forests at Sigiriya in the northern dry zone of Sri Lanka and some major factors which affect their natural regeneration were estimated.

The vegetation was enumerated in six 20x20m experimental plots. The diameter of trees 25cm at breast height (dbh) was measured. Seed rain was detected by collecting seeds using wooden trays, allowing them to be germinated and enumerating the germinants over a period of eleven months. The seed bank was examined by collecting ten soil samples from each plot three times within a year. Seedlings were recorded in 2x2m quadrates in each plot and their growth and survival was recorded throughout an year. Soil temperature, soil moisture and the canopy openness were also detected.

The species composition and dominant species were identified for dry deciduous forest in the area. The beta diversity of forests is high implying the importance of conserving large areas of dry forests. Seasonality of seed production, seed predation, lack of a persistent seed bank, unfavorable environmental factors are found to be affecting the regeneration of dry deciduous forest. Possibilities of sustainable timber production in dry deciduous forest and the participation of local people in forest management are also discussed.

AN INVESTIGATION OF SOME PHENOLOGICAL EVENTS IN THREE MANGROVE GENERA WITH REFERENCE TO SELECTED CLIMATIC FACTORS IN NEGOMBO LAGOON

P L Hettiarachchi and G W N T Kumara
University of Sri Jayewardenepura, Nugegoda.

Mangroves consist of few tree species which are adapted to grow under tidal conditions. Studies on the phenology of mangroves is scarce. The main objective of this research was to study major phenological cycles of some overexploited species and to compare these with previous observations on the same species samples from three other lagoons.

Phenological cycles of leafing, flowering and fruiting of Rhizophora apiculata, R. mucronata, Bruguiera gymnorhiza, B. Sexangula and Ceriops tagal were studies for a period of 24 months at selected sites in Negombo lagoon which is located in the wet zone of Sri Lanka. Phenological cycles were followed and phenological indices were calculated. These data were compared with monthly variations in rain fall, temperature and humidity of the study area.

Leaf production showed two distinct maxima per year in all species. Rainfall seemed to exert a great influence on leaf reflushing. Peaks of leaf reflushing coincided with lulls of flowering and fruiting. Annual bimodality was observed for flowering fruiting in all species. These species showed unimodal pattern of some of these events when they were growing in dry zone.

Phenological cycles constructed using data obtained show no intraspecific variation in the time required to complete a single flowering-fruiting cycle. Similarly, intrageneric variation was absent in the life time of leafing cycles.

In Rhizophora species, leaf bud jut emerged took 1 - 1.5 yrs to complete a single cycle where as in Bruguiera species this period was 2 - 2.5 yrs. In Ceriops tagal, it was 1.5 - 2 yrs. Similarly, a flower bud of Rhizophora species took 1.5 - 2.5 yrs, Brugeciera species 1 yr and C. tagal about 1.5 yrs to form a mature hypocotyl.

A comparison of these observations with findings of the previous study proves that phenological cycles in studies species are environmentally dependent and not species specific.

Unimodality of floral phenology in dry zone species may be due to the Seasonal variation in ground water salinity.

GLOBAL VALUES FOR LOCAL RESOURCES: A CONTINGENT VALUATION APPROACH FOR SINHARAJA RAIN FOREST RESERVE IN SRI LANKA

U A D Prasanthi Gunawardena and G Edwards-Jones
University of Sri Jayewardenepura, Nugegoda.
University of Wales, Bangor.

Tropical forests are sources of important global use and non-use values. However, these values are not often reflected in global markets, thus creating global externalities. In order to demonstrate global values of tropical rain forests, this study sought to estimate global non-use values of the Sinharaja Rain Forest Reserve in Sri Lanka.

A contingent valuation survey was carried out in the United Kingdom in order to obtain existence and bequest values for the forest. Open ended questions were asked from the selected sample of respondents to obtain their maximum willingness to pay.

The non use values elicited for the forest were related to variation in respondents' socio economic status. Multiple regression analysis showed that income and education had positive coefficients for both existence and bequest values.

The results showed that remote populations have positive values for tropical rain forest. The implications of these results to the use of contingent valuation methodology for estimating total economic values of forests in developing countries is discussed, and the particular implications of demonstrating the magnitude of external benefits that could provide insights into the correction of global economic failures highlighted.

GROUND HERBACEOUS FLORA IN UNLOGGED SITES OF SINHARAJA WORLD HERITAGE SITE

M M D J Senaratne and B M P Singhakumara
Department of Forestry and Environmental Science, University of Sri Jayewardenepura, Nugegoda.

The composition and distribution of herbaceous plants were investigated at Sinharaja World Heritage site.

Previously unlogged forest areas were selected for the present study. Several transects were marked purposively in each site from valley to ridge to study the topographical variation of herbaceous plant distribution. Circular plots, each 10 m2 were demarcated on each transect to study the herbaceous flora. In addition, 200 m2 plots surrounding the 10 m2 plot were marked to enumerate the tree species in the area. The distance between two, 200 m2 plots was 20 m.

In each plot number of plant species was recorded. Voucher specimens were prepared for identification of species found in plots as well as outside the plots. Dominance diversity curves and Shannon diversity indices were prepared for each transect.

Ninety one species belonging to 40 families were recorded. Twenty nine of 91 species are found outside plots. The estimation of individuals of herbaceous plants per hectare was 21,790. Herbs and herbaceous climbers represented 38.47% of the total herbaceous flora. Fern and fern allies represented 45.67% and grasses and sedges 15.84%, respectively.

Species rich families were Zingiberaceae (6 spp.) and Rubiaceae (5 spp.) Density dominance families were Rubiaceae (6.97%) Zingiberaceae (3.9%), Mysinaceae (3.6%), Polipodiaceae (17.3%), Dennestaediaceae (7.8%) Cyatheoceae (3.8%) and Cyperaaceae (5.5%). Diversity indices in valley and ridge were 0.2153 and 0.1754, respectively.

Results indicate the localized distribution of herbaceous species in understorey vegetation of lowland rain forest. This may he due to the differences in micro habitats from valley to ridge.

ASSESSMENT OF FAUNAL DIVERSITY OF A NATURAL FOREST AND AN ADJACENT PINUS MIXED PLANTATION FOREST IN YAGIRALA

M M A I Janaka 1 and Sriyanie Miththapala2
1 Department of Forestry and Environment science, University of Sri Jayewardenepura
2 Ladies College, Colombo.

Faunal diversity of the natural forest (Pamaragala Aranya Forest) and the University of Sri Jayewardenepura Pinus-mixed forest, in Yagirala forest reserve was assessed. The University Pinus - mixed forest has a dense undergrowth and tropical lowland tree species. The natural forest is a highly degraded forest due to past logging and prevailing illicit felling. The University Pinus forest is a mixed forest which has a dense undergrowth and tropical lowland tree species.

In this study, random line sampling method was used to enumerate fauna. Five plots of 100 m x 5 m each leaving gaps of 50 m, were used as a transect line. Fifteen survey lines having 60 plots in the Pinus – mixed forest and 11 survey lines having 51 plots in the natural forest were assigned. The study was restricted to some selected faunal groups such as birds, mammals, reptiles, fishes and some invertebrates (butterflies, land snails etc.). Pitfall trapping was used to assess the diversity of selected ,round active invertebrate groups such as ants, beetles and spiders. For each forest, 10 survey lines were selected and 2 pitfall sampling points were located in each sampling plot for the location of pitfall traps. Two independent samples t -Test and the Wilcoxon Signed Rank Test were used to compare the faunal diversity between the two forests.

The results showed that there is no significant difference in the diversity of birds, mammals, butterflies, and around active invertebrates such as ants, beetles and spiders between two forests. The diversity of land snails in the natural forest is significantly higher than the diversity of land snails in the Pinus - mixed forest. The diversity of invertebrates of the Pinus - mixed forest is significantly higher than the natural forest.

According to the results of the present study, the Pinus - mixed forest also has a rich faunal diversity. Therefore, it can be assumed that one or more reasons such as food, nesting places, protection for fauna in the Pinus - mixed forest, edge effects of the surrounding home gardens, and tile effect of the rich faunal diversity in the natural have been affected considerably to increase the diversity of some fauna in the Pinus - mixed forest.

CONSERVATION OF BIODIVERSITY IN MANGROVE ECOSYSTEM IN SRI LANKA

Sunil Liyanage
Department of Wild Life Conservation

Mangrove ecosystem is one of tile most threatened natural systems in Sri Lanka and total extent of mangrove in this country is about 12,500 ha according to recent studies. The biodiversity assessments of mangrove habitats in Sri Lanka have proved that though the extent of mangrove is small, it has greater diversity compared to Asia-pacific region. However. lack of awareness and management as well as poor protection status have paved the way for destruction of this valuable natural system.

The studies shows that there are about 30 mangrove species in Sri Lanka and these species are distributed in many isolated habitats along the inter-tidal regions of coastal zone. A detail study was carried out to assess the mangrove biodiversity of Sri Lanka and the study area was confined to north western, western and southern coastal belt. The results show that the distribution pattern and range and the population size of the each species vary from one to another making conservation of total mangrove biodiversity of Sri Lanka a difficult task. Based on the population size and the distribution range, Species could be divided to groups that give a better criterion in selection of mangrove habitats for conservation. Based on distribution range, species could be divided as widely distributed, restricted to ecological regions and restricted to few habitats and based on population size as common, less common and rare.

The analysis of data shows that more than R habitats are necessary to conserve total mangrove diversity. However, few species are limited to less than fen individuals even within their habitats making in situ conservation not fully guaranteeing the total conservation of total diversity. In view of this, it is necessary to take immediate actions to conserve mangrove biodiversity of the country in a more scientific and systematic way to ensure the survival of these species.




Thursday, October 05, 2006

POLICY RELEVANT ECOSYSTEM SERVICES VALUATION; RAINFOREST NON-TIMBER PRODUCTS

B M S Batagoda
Ministry of Forestry and Environment

One recent study has estimated the current economic value of seventeen ecosystem services on a biosphere-wide basis at between US$ 16 - 54 trillion (10 12) per year, representing an average annual value some 1.8 times tile current global gross national products (Coslanza et al. 1997), Such global aggregate values, while they serve to raise awareness and stimulate dialogue between scientists, social scientists, policymakers and citizens, should not be taken too literally. The challenge will be to quantify in monetary terms and prove how valuable ecosystem services are: as well as to formulate mechanisms by which such function-based values can he realistically appropriated by society. In a much quoted paper (Peters et al 1989) the economic value (net present value) of the fruits and latex harvest. from an Amazonian forest was estimated to be US$ 6,330 ha. Even more significantly, it was also claimed that such an economic return was sawn timber extraction/production (NPV = US$ 1,000 ha-1), timber and pulpwood extraction/production (NPV = US$ 3,184 ha-1) or fully-stocked cattle pasture (NPV = US$ 2,2960 ha-1). This is a strong conclusion with obvious implications for tropical forest conservation verses development policy. The temptation then is that such findings are generalised.

This paper focuses on tropical rainforest ecosystems and the use value of their non-limber forest products (NTFPs) provisions to test whether this conclusion is universally valid? The study has rigorously applied its data collection and analysis to validity and reliability protocols in order to estimate the policy relevant NTFPs value derived from tile Sinharaja rain forest in Sri Lanka. This forest land use has then been compared with alternative land use options in a cost-benefit analysis. The results indicate that the NPV of the actual NTFPs flow from the Sinharaja is US$ 147 ha-1 which is significantly lower than the land clearance value US$ 4281 ha-1 (tea cultivation). This means that previous studies have significantly overestimated NTFPs value, and consequently that biodiversity conservation policy cannot be economically justified (economic efficiency criterion) on the basis of susluinable NTFPs collection alone. Such a strategy does, however, also have other wider social benefits for local forest village communities such as income distribution effects. Conservation of the forest ecosystem would also generate other uses and non-use values linked to other "NTFPs-compatible" forest function services. An economic case for such a conservation strategy will have to be based on the multiple services value that a given 'healthy' forest ecosystem can provide susiainably over time.

EVALUATION OF WILDLIFE HABITATS IN THE VICTORIA - RANDENIGALA - RANTAMBE SANCTUARY USING LIFE-FORM AND HABITAT MODELS

K B Ranawana, C N B Bambaradeniya and M P B Meegaskumbura
Department of Zoology,
University of Peradeniya.

A suitable habitat evaluation method is an important tool for wildlife managers to manipulate wildlife diversity, to predict how proposed habitat changes will effect different wildlife communities, as well as to determine the quantity and quality of available habitats for a particular species. A simple method of habitat evaluation is the use of life-fonn and habitat models (Anderson & Gutrzwiller, 1994). During this process, all species of animals found in a given area are placed in distinct life-form categories, based on their predominant habitat use patterns for feeding and reproduction. Once the life-form table is made, more detailed data on habitat use is presented in habitat tables for individual species under each life-form category. By adding the number of habitats used by each species for reproduction and breeding, versatility score (V) can be obtained. Species with a high versatility score are the least sensitive to habitat manipulation. This would also enable wildlife Illallaael'S to examine the impact of habitat loss/modification and list the species affected. This method was applied to evaluate the native vertebrates and their habitats in the VRR sanctuary. A total of 252 native vertebrates recorded were placed under 22 distinct life-form categories. These species were further assessed according to their major habitat utilisation patterns. Six major aquatic habitats and nine ma,jor terrestrial habitats were identified. Based on the versatility score of each species, they were grouped into three sensitivity categories for habitat manipulation; most sensitive, moderately sensitive and least sensitive. The most widely used habitat of fauna were recognised, based on the life Corms and habitat models. This simple Inethod could be adopted to evaluate the faunal habitats in all protected areas of Sri Lanka.

ON SITE EFFECTS OF SOIL EROSION IN TEA LANDS IN KANDY DISTRICT - AN ECONOMIC ASSESSMENT -

H S Premachandra
Central Environmental Authority

Soil erosion is a serious problem in many parts of Sri Lanka. It has numerous impacts on crop productivity, economic growth, income distribution, food production etc. Tea lands in Kandy district are highly susceptible to soil erosion due to several factors such as sloppy nature, unstable soils, high rainfall and improper land uses. This study focused on an economic assessment of on site effects of soil erosion in tea lands in Kandy district and based on secondary data on soil erosion. On site damage due to soil erosion was assessed using Replacement Cost Approach.

This study considered three categories of vegetatively propagated tea (VPT1, VPT2, VPT3), and another three categories of seedling tea (ST1, ST2, ST3) to assess on site damage due to tea cultivation. According to the assessment on site drainage due to tea cultivation in Kandy district is Rs. 1568 Imillion (1.5681 Rs. Billion). Per hectare replacement costs for VPTI, VPT2, VPT3 are Rs. 1919, 21016, 45654 while for STI, ST2, ST3 are 7030, 14322, 128747 respectively.

Net Present Value (NPV) criterion was used to examine the economic feasibility of soil conservation measures viz : stone walls, contour and leader drains, and biological conservation (SALT) by considering 10 percent discount rate and 5 years planning period. This study reveals that internalisation of on site cost of soil erosion is acceptable if proper soil conservation methods were used under private accounting of conservation programmes.

COMMERCIAL VIABILITY OF FOREST PLANTATIONS IN SRI LANKA

A C M Hanas and H B Kotagama
Department of Agricultural Economics,
University of Peradeniya.

The Forestry Sector Master Plan (FSMP) approved by the Government of Sri Lanka has identified the need for commercialized state owned forest plantations. This study examines commercial viability of single species forest plantations (Albizia, Eucalyptus, Mahogany Pines and Teak) for Timber (saw log and non-sow log) production and Pines plantations for resin tappinb and subsequent timber production.

Financial analysis aids planning of investment, financing and assessing business operations. Decisions on investments and financing a business primarily depends on financial profitability. In financial analysis benefits and costs realized over time are discounted using market lending interest rate to compare benefit and cost in present values. A most common decision criterion that is used is the Internal Rate of Return (IRR).

Silvicultural data were based on plantation management plans of the Forest Department and price data were based on estimates of stumpage values (base case) and past model market price of timber. The opportunity cost of capital was considered as 14% and the environmental benefits of forest plantations, which were non-financial, have been considered to determine public incentives required for forestry.

The results indicate on the base case and the sensitivity analysis for yield (10% increase yield) and cost (20% reduction of cost) that only teak plantations are financially viable. Pines resin tapping from new plantations is not financially viable. Albizia, Eucalyptus, Pines and Teak harvested for timber is financially viable, if subsidized to compensate environmental benefits. It is also found that forest plantations are not financially viable on value at site (stumpage value) but financially viable at processed timber sales.

This study indicates that indiscreet commercialization of state owned plantations is not possible. However some forest plantations could he commercialized if a subsidy equivalent to environmentally benefit is provided.

ANTIMICROBIAL EFFECTS IN MANAGEMENT OF WASTEWATER TREATMENT PLANTS

Manisha Gunasekera, Indrika Abeygunawardana and Ajith De Alwis
Department of Chemical Engineering, University of Moratuwa.


Many wastewater treatment plants operating today in various industries have one or more biological treatment component, which could be either aerobic or anaerobic, or a combination of both. The type of biological treatment utilized will vary from one plant to another depending on the nature of the wastewater treated. Industries such as chemical process, pharmaceutical etc. have to pay more attention to their wastewater sent to tile wastewater treatment plant as these wastewaters may contain substances in quantities which can cause harmful effects to the living organisms in the biological treatment system, thus action should be taken to reduce these antimicrobial substances entering the biological treatment component of the wastewater treatment plant to levels to which the biological population is more capable of handling those in the degradation process. An action to manage this type of situation will call for the need for monitoring techniques or quantities.

In this concept paper, online and offline monitoring techniques of such substances and its management concepts are illucidated. In monitoring wastewater file use of tile parameter BOD and the inhibition characteristics of the microorganism were looked at with reference to wastewater from a pharmaceutical manufacturing industry.




CHEMISTRY OF LEAF LITTER OF SOME AGRO-FORESTRY SPECIES IN SRI LANKA

M K T K Amarasinghe and R Senaratne
Faculty of Agriculture, University of Ruhuna.


Decomposition of leaf litter is a major process in the nutrient dynamics agroecosystems, which is intrically governed by the litter chemistry. The chemistry of leaf litter determines both the time course of decomposition and the nutrient release pattern. There are many agroforcstry species in Sri Lanka, but information available on their litter chemistry is scanty. Such information proves useful in identifying appropriate agro forestry species for developing sustainable agroeosystcms. Therefore studies were carried out to determine the concentrations of nutrients (% N, P, K, Ca and Mg), lignin and cellulose of nine agroforestry species in Sri Lanka, viz., Acacia auriculiforrnis, Acacia mangium,, Gliricidia sepium, Macaranga peltata (Kande), Alstonia scholaris (Alstonia), Artocarpus inrtegrifolia (jak), Artocarpus altilis (bread fruit), Terminallia cattappa (Indian almond), and Mangifera indica (mango).

Considerable interspecific variation in the above parameters was observed in tile leaf litter. As regards the per cents of N, P, K, Ca and Mg, the values observed varied from (1.395 - 1.921, 0.025 - 0.171, 016 - 0.95, 1.76 - 2.57 and 0.22 - 0.51, respectively. The highest concentration of N was in G. sepium while A. altilis, A. integrifolia and A. schoars had the highest concentration of P, K, Ca and Mg, respectively. This underlines the importance of introducing diverse species (biological diversity) in order to establish a balanced fertility regime. M. indica and A. mangium had the highest concentration or lignin (22.99 %) and cellulose (32.76%), respectively. A salient feature in the leaf litter in M. indica was that, it had the lowest concentration of N (0.395 %) and cellulose (14.59 %) and the highest concentration of lignin (22.99%). These data prove useful in identifying a suitable combination of agroforestry species for sustainable soil fertility management.

DEVELOPMENT OF DESIGN PARAMETERS FOR AN INCLINED STEP-GRATE COMPOST VESSEL TO TREAT URBAN SOLID WASTES

B F A Basnayake, D S Fernando and A M Razmy
Faculty of Agriculture, University of Peradeniya.


There are several methods and systems of managing urban solid wastes. Aerobic systems of managing wastes are less expensive and the composition of wastes in most Sri Lankan cities is conducive to compost making since the biodegradable component is high.

The total quantity of organic matter generated in the urban centers if used as compost will still not satisfy the demand for it. These basic problems could he solved by making compost from biodegradable urban wastes, facilitating the management of these wastes and also providing organic matter for long awaited sustained and assured agricultural production in Sri Lanka.

The development of a feasible system of compost making was the challenge taken up by the Department of Agricultural Engineering. A series of studies were undertaken to determine some of the major parameters to realize the concept of an inclined step-grate compost making vessel.

The studies indicate that 65% moisture content should be maintained for optimum conditions for compost making. The bulk density increases with time and it is inversely proportional to mass. Within the first 20 days of degradation of mixed wastes, most of the volatile solids react producing largely carbon dioxide and water. The generated heat from this reaction actuates the process of evaporating excess moisture. The reduction in mass and increase in density can be expressed mathematically.

A calculation of heat and mass balances was obtained for a 3-meter pile of wastes. These calculations were based on data obtained from an Engineering Model. Several of the major parameters such as the retention time, suction, heating and cooling system for moisture control were developed to design a versatile bio-reactor to produce compost for treating wastes aerobically.

IDENTIFICATION OF A METHODOLOGY TO ESTIMATE VEHICLE EMISSIONS IN SRI LANKA

J M S J Bandara1 and N J G J Bandara2
1University of Moratuwa
2University of Sri Jayewardenepura


Estimates available to date in Sri Lanka show that the transport sector is responsible for majority share of the gaseous emissions to the environment when compared lo any other sector such as industry, agriculture, and fisheries. This pattern is applicable to most of the countries all over the world. Many countries have taken steps towards controlling vehicle emissions and Sri Lanka is seriously considering actions to control vehicle emissions.

In order to have an effective control system it is necessary to identify different emissions and the significance of their effects to tile environment and health. The main pollutant gases emitted from vehicles are Carbon dioxide, Nitrogen oxides, Carbon monoxide, volatile organic compounds and Sulfur oxides. As the effects and tile significance could change from place to place and also depend on different concentration levels, it is very important to estimate the emission to the environment to some accuracy.

Numbers of different techniques have been used for the emission estimates. They include very approximate methods such as fuel sales to very sophisticated techniques such as remote sensing measurements and simulation models. Whereas the simple techniques require little base line data and equipments, more sophisticated techniques would require considerable amount of base line information and equipment.

The technique employed today in Sri Lanka is only a simple method based on emission factors. This quantification is done taking into account the emission factors roughly estimated for each type of vehicle and on the total number of vehicles in the entire country. Only this can be used because of the difficulty faced in estimating the emission factors at a particular time and because of the lack of use of basic data on vehicle transportation. From this technique the automobile emissions at a particular location at any given time cannot be estimated.

However automobile emissions will vary according to the age of the vehicle, its travel speed and location. In order to incorporate these factors into the main estimation basic data on the number of vehicles at each place and their travel speeds have to be known.

The objective of this research is to identify a suitable methodology incorporating the available data on traffic movement patterns to estimate vehicle emissions in Sri Lanka and to identify required development in the future to improve the estimating and monitoring procedure. In this paper effects of different types of emissions, their significance and relevance to the local conditions are discussed. Methodologies available to measure and estimate selected types of emissions are also discussed. Based on this knowledge and depending on the technology and information available locally, a suitable procedure to estimate vehicle emissions that will be useful for any future control and monitoring is identified.

CONSTRUCTION OF A LOW COST AIR SAMPLER AND IT'S APPLICATION IN SAMPLING VOLATILE CARBONYL COMPOUNDS

K I A Kularatne and K R Ranjith Mahanama
University of Colombo.


Interest is expanding in measuring, concentrations of volatile organic compounds in buildings since it is recognized that many peoples' exposure to these compounds occur in the indoor environment. However, such data are not available in Sri Lanka primarily due to lack of proper equipment for quantitation and their high maintenance cost. This paper describes the construction of a low cost air sampler (Rs. 400/=) using commonly available materials.

The air sampler contains muffler fan to pull ambient air though a filter(s) and/or a bed of sorbent material, Which are housed in a variable length PVC tube. Battery powered muffler fan and lightweight are two of the convenient features of this air sampler that minimize operational and transportation difficulties to the user.

Volatile carbonyl compounds such as formaldehyde acetaldehyde and acetone are commonly found in indoors ambient air due to the combustion sources and emissions from synthetic household products. Since formaldehyde is a known carcinogen and acetaldehyde is a suspected carcinogen compound, they were selected as the model compounds for the evaluation of constructed sampler. A filter paper spiked with 2, 4­dinitrophenylhydrazene is used to collect the airborne carbonyl compounds at a flow rate of 1.8 cm3/sec. Filters were sonicated in methanol and extracts were separated using a C18 column for quantitation at mm wavelength. Quantitation limits estimates that sampling of 10 dm3 ambient air enables minimum quantitaion of 0.5 formaldehyde, 1.0 acetaldehyde and 1.2 acetone accurately. The paper also reports quantified levels of airborne carbonyls from different indoor environments.

GIS IN SOIL EROSION - MODELLING OF VICTORIA - RANDENIGALA CATCHMENT,SRI LANKA

H G Gunawardana
Forest Department, Battaramulla.

Land and water resources are the backbones of an agricultural-based country like ours. Their role in national productivity, however, depends on how we manage them. Appropriate management alternatives are the result of technically sound decisions. With the aid of a resource-based computer program like SPANS-GIS, such decisions arc readily drawn after input variables are integrated into the program.

Victoria-Randenigala area was chosen in this work, as it is tile major catchment of the Mahaweli River which stretches tile entire central hill country. With the use of SPANS-­GIS, information on erodibility, erosion potential, catchment natural stability, strict protective areas and recommended forms of land-use were readily identified. Details of the findings show that 84% of the area lies over 1000fi. Contour and 19% at >30% slope class. About 43% of' the catchment area is at high erodibilily risk despite 39% existing forest cover, due to land degradation. Only 36%, of the catchment area is considered naturally stable. Hence protection priority should be given to 68% of the catchment area. To conserve the catchment 31% of the area must be afforested and 40% must be planted with perennial crops or forest species.

SPANS-GIS proved useful in identifying key elements necessary in managing Victoria­ - Randenigala catchment. It is a valuable tool in providing information that helps man in managing land and water resources.

Wednesday, October 04, 2006

USE OF GEO-INFORMATION FOR LAND USE PLANNING IN UPPER MAHAWELI CATCHMENT IN SRI LANKA

A Abeywickrema
Land Use Planning Division


This paper presents the results of a study which attempted to evaluate file demand for Geo information of the key decision positions involved with sub-district level plannin1g, and decision position in comparison with the existing supply of spatial information in the Upper Mahaweli Watershed Calescent in Sri Lanka.

The million of hectic of tile paper was to examine the user satisfaction will respect to the Geo information of selected mapping applications for land use und land potential and how to cater to the demand of, Key decision positions of the Sectors.

The major finding of this study shows that as far as the demand of Geo information is concerned there are a number of government institutions and donor funded projects involved in sector specific land use planning and decision making activities at sub-regional level. Also, it was found that there was in increasing demand for accurate. reliable mid more up-to-date, detailed Information specially addressed to their specific sector development.

Where the supply of Geo information was concerned there were fifteen of such applications, which cater to the user demand. Some of the products are widely used in project planning, education and all purposes while some are specially catered to the specific sector development. Where suppliers are concerned if was not only Survey Department which provide standardized maps. Seven detailed applications of maps in tile study which catered to specific sector development in relation to land use planning was found.

In terms of effectiveness and user satisfaction it was found that there were gaps in information, tile scale it has been provided, actual demand and availability for planning.", and decision making in all the sectors.

Finally, the factors or instruments for better matching the demand for Geo information with the existing supply of information was identified.

The results of this study are useful to all the users and suppliers of Geo information who arc engaged in mapping, planning, monitoring & implementation and policy formulation ill relation to sector specific land use planning and decision making.

A PRELIMINARY INVESTIGATION ON TRADITIONAL TAPPING METHODS OF `KITUL' OR THE FISH -TAIL PALM (Caryota urens L.)

K V S Premakumara, J M Senevirathne and W D L Gunaratne
Department of Export Agriculture
Kundasale.


Rural survival depends largely on the wealth of the natural environment. "Kitul" or the Fish-tail palm is one of the important species which has been exploited from the wild by the villagers from the ancient past. Tapping the inflorescence of the Kitul tree for collecting file phloem sap for producing jaggary, treacle and toddy has been generating practices, among the rural folk in some villages particularly those abutting the natural forests. The tapping process makes direct use of the transport mechanism of file tree in which the assimilates are moved to file developing organs. The method of lapping differs from place to place. Usually tappers use plant extracts for seasoning the inflorescence before tapping. The purpose of using these various plant extracts is the arresting of the maturation of the inflorescence and the increasing of the sap flow. The knowledge of these indigenous tapping practices are not being handed down file generations and therefore being gradually lost. This paper presents the results of a preliminary investigation the traditional tapping methods of Kitul by file people in villages abutting in the Sinharaja forest and the Knuckels ranges.

STATISTICAL AND COST EFFICIENCY OF SIMPLE RANDOM SAMPLING AND SYSTEMATIC SAMPLING IN ESTIMATING FOREST STAND PARAMETERS AT YAGIRALA

M C Karunaratne1 and T I Mohammed2
1University of Sri Jayewardenepura
2State Timber Co-operation.


The study was carried out at a 24 years old Pinus caribaea plantation located in lowland wet zone of Sri Lanka. Statistical and cost efficiency were compared at sampling intensities of' 11.1%, 19.4% and 32.4%, using simple random sampling design and systematic sampling design. Circular sampling units of 0.05 ha with slope correction, and boundary adjustment were also applied. Sampling units of simple random sampling were arranged in a hexagonal pattern, and selected (without replacement) after generating random numbers. Diameter at breast height and total height within each sampling unit were measured to estimate basal area per ha and volume per ha. Walking time and measuring time were recorded to calculate the variable costs of the. inventory of all species at 32.4% sampling intensity.

The pine population shows normal distribution, and simple random sampling represents it more closely than systematic sampling. Naturally regenerated tree species- under pine plantation are effecting the diameter distribution.

Simple random Sampling gives better estimates of basal area per ha and volume per ha for pine than systematic sampling. For all species, systematic sampling gives better estimates at lower sampling intensities.

In simple random sampling, the most efficient sampling intensity is 32.4%. However, 11.1% can be recommended for 25% sampling error. In all species, relative efficiency of the two sampling designs does not show a significant difference. Simple random sampling is more efficient for all species at 32.4% intensity.

The delayed silvicultural operation is found to effect the pine population and there is a need for proper management of the forest.

TEAK VOLUME MODELLING USING MEAN TREE MEASUREMENTS

D P Munaweera
Forest Department, Battaramulla.


Volume prediction at a known precision is essential especially for planners to make decisions on forest management. Thinning planning, harvesting, timber utilization for a11 such activities Should he planned based on economical returns, to obtain maximum benefits from these man made forest plantations. Based on the dominant height growth variations, three Teak zones were identified. In each teak zone several teak trees were felled and true volumes (Total Volume and the Timber Volume) were calculated and Volume functions were developed for each Teak zone. These volume functions were developed using mean tree growth measurements of a stand. Therefore it is not to be use(] to determine volumes of individual trees but to calculate the per hector volume of a stand by measuring the mean parameter values of a stand.

The volume of a felled tree was obtained by adding volumes of its components. In the log volume calculation the "Huber's" equation was used, this equation gives reliable estimates for ally shape of logs other than "neloidic" shape. The Diameter at Breast Height (DBH) and the total height of the tree was recorded before felling the free. The models tested for better fitting were;

V = a + b * DBH2 * Height ........................................ (1)
V = a + h*DBH2 * Height + c* Height ..................... (2)
V = a * DBHb * (Height)0 ......................................... (3)
V = a + b *(DBH2) * Height + C*(DBH) .................. (4)

In all three zones the best fits obtained for volume estimation was model 3. This model has obtained high correlation in all three zones compared to other models tested.
The volume functions obtained for mean tree volume estimation in three Teak zones are;

Zone 1: V = .000013 * (DBH)2.5110 *(Height) 0.724
Zone 2: V = .000102 * (DBH)1.9063 *(Height) 0.795
Zone 3: V = .000102 * (DBH)1.8885 *(Height) 0.815

SURVIVAL AND GROWTH OF MAHOGANY SEEDLINGS UNDER A NURSE CROP WITH DIFFERENT CANOPY OPENINGS

R M Mahroof, J P Edirisinghe and Caroline Hauxswell
Department of Zoology, University of Peradeniya
Institute of Ecology & Resource Management, University of Edinburgh

Swietenia rnacrophylla King is one of the luxury class limbers of the world. The survival and growth of, S. macrophylla when planted under life nurse crop, Acacia auriculifomis with different canopy openings was determined. The study was carried out in a 9 year old Acacia plantation established by the Forest Department on a degraded, hilly land al Nattiyapana in Kegalle. Two experimental blocks (replicates) about 1km apart were selected for the study. In each block 3 plots (5x5 m) were selected on the basis of canopy openings (open, moderate, closed) by removal of trees and branches. Within each plot 18 mahogany seedlings were planted. The photosynthetically active radiation at each canopy opening was measured using a data logger with PAR light sensors. The mean Survival level of seedlings was found to be 83%, (open gap-61% PAR), 97% (moderate gap-43% PAR) and 94% (closed gap- 24 % PAR). Height of seedlings measured monthly indicated an increase in height with light intensity. Similarly, the root collar diameter measured 9 months after planting varied from 1.2 cm (open canopy), 0.98 cm (moderate canopy) to 0.71 cm (closed canopy). The mean number of leaves per plant under open canopy was 15, and 11 under moderate and closed canopy. Data obtained so far indicate that survival is low under open canopy with high light intensity, while growth is better under open canopy inferring that shade is important only during the initial establishment phase of seedlings and not thereafter. However, there are reports of high damage by the mahogany shoot borer (Hypsipyla robusta Moore) when grown in the open.

TREATABILITY OF PLANTATION TIMBER SPECIES WITH CCA (COPPER-CHROME-ARSENATE) PRESERVATIVES AND THEIR EFFECTIVENESS AGAINST INSECT AND FUNGAL ATTACK

D M T K Dissanayake and H S Amarasekera
University of Sri Jayewardenepura, Nugegoda.


This study was conducted to assess the treatability of four plantation timber species (Pinus caribaea, Hevea brasiliensis, Eucalyptus grandis and Eucalyptus microcorys) with Copper-Chrome-Arsenate (CCA) by using pressure impregnation full-cell process. The treatability of core wood and outer wood of the species were also investigated. Treatability was evaluated by measuring the preservative retention (Net Dry Salt Retention or NDSR) and depth of penetration.

According to tile results, Pinus caribaea showed the highest tretablity while treatability of Hevea brasiliensis, Eucalyptus grandis and Eucalyptus microcorys were respectively lower. A significant negative correlation was observed between density of tile timber and tile treatability. Based on depth of penetration of preservatives, Pinus caribaea and Hevea brasiliensis were classified as permeable to preservative treatment. E. grandis was resistant while E. microcorys was extremely resistant to preservative treatment.

Treatability of outer wood of all the species were higher than that of core wood indicating the higher permeability of outer sapwood area compared with the inner core wood.

Treating schedule with initial vacuum of -0.8 bar, pressure of 6.5 bar maintained for 180 minutes and final vacuum of -0.8 bar was effective treatment of Hevea brasiliensis. Even with this pressure, it was unable to achieve depth of penetration levels as specified in the Sri Lankan Standards for E. grandis and E. microcorys.

When wood samples were exposed to exterior ground contact in the grave yard test for five months, none of the treated samples were infected, but untreated control samples were attacked by fungi and termites. This indicates the effectiveness of the CCA treatment in Controlling fungal and insect attack.

DEVELOPMENT OF DRYING SCHEDULES FOR RUBBER AND PINE TIMBER FOR THE DEHUMIDIFICATION KILN DRYING

R S Sujith Rathnayake and H S Amarasekera
University of Sri Jayewardenepura,
Nugegoda.


Most of the timber in Sri Lanka is used in unseasoned state or seasoned using conventional kilns which use fuel wood boilers or open fires as a heating source. A study has been conducted to introduce dehumidification drying kiln, which is easy to fabricate and consumes less energy hence ideal for small scale timber industries.

Experiments were conducted to investigate drying behaviour, to develop kiln schedules and to evaluate the developed kiln schedules for Pine (Pinus caribaea) and Rubber (Hevea brasiliensis) timber. The dehumidification kiln used in the present study is locally fabricated and it has 25 cubic feet capacity. The temperature of the kiln can be increased to 50°C and relative humidity can be reduced to 16%.

Drying rate, percentage shrinkage and drying defects were observed for these two species by drying 21505000 mm stakes in temperature, humidity and air circulation controlled mini chamber. It was found that Pinus caribaea was relatively last drying timber compared with Hevea brasiliensis. However, H. brasiliensis showed higher percentage shrinkage and defects over P. caribaea during the early stages of drying. This indicates that H. brasiliensis should be dried slowly at the initial stages of drying.

Three kiln schedules with slow, medium and fast drying rates were developed for seasoning 25 mm planks based on the results of drying behaviour. Drying rate, drying efficiency, drying defects, drying cost and thermal efficiency of these kiln schedules were evaluated by drying 25xI50x1000 mm sample hoards in the dehumidification kiln. Compared with conventional kiln seasoning, dehumidification kiln seasoning gave higher duality dried timber with more than 90% drying efficiency and faster drying rate, while maintaining higher thermal and economical efficiency.

It is concluded that higher quality H. brasiliensis and P. caribaea dried timber can he obtained at a faster rate by drying them using these schedules in the dehumidification drying kiln compared with conventional drying.

ISOLATION OF SOME WOOD DECAYING FUNGI AND STREPTOMYCES AND THEIR EFFECTS ON SOME COMMERCIAL TIMBER SPECIES IN SRI LANKA

D T Boralessa, P Tissera and H S Amarasekera
University of Sri Jayewardenepura, Nugegoda.

Wood is subject to attack by wood inhabiting fungi in a variety of environmental situations from standing tree to the wood product in service. An investigation was carried out to study the resistance of five commercial timber species namely Rubber (Hevea brasiliensis), Lunumidella(Melia dubia) Pine (Pinus caribaea), Mahogany (Swietenia macrophylla) and Teak (Tectona grandis) to fungal attack.

Four wood decaying fungal species were isolated from naturally infected Wood samples. Three species namely Tricoderma sp., Mycelia sterilia and Streptomyces sp. belonging to Deuteromycotina subdivision and Aspergillus sp. belonging to Ascomycotina subdivision were identified. These species were used to assess the initial decay of wood. Out of the four species tested ,Streptomyces sp. was the most destructive fungal species.

The weight loss of timber was taken as parameter of decay. Wood species and the fungal species had a significant effect on the weight loss. The highest weight loss due to fungal attack was caused by Streptomyces species in all the timber species except in Lunumidella where Tricoderma sp. recorded the highest weight loss.

In Rubber, Lunumidella and Pinus moisture gain was observed with fungal attack while moisture loss was observed in controls. In Mahogany and Teak moisture gain due to fun-al attack was negligible. Since these fungi caused a considerable damage at the initial stage of decay they can he grouped as primary decaying fungi in wood.

STUDY OF EFFECTIVENESS OF TWO WEED MANAGEMENT METHODS ON THE ESTABLISHMENT OF INDIGENOUS TIMBER SPECIES IN THE GRASS INFESTED WET ZONE LANDS

D Tilakaratna
Research Officer, Forest Research Centre,
Kumbalpola.


The effectiveness of two manual weed control methods were studied for the establishment of four timber species in a grass infested wet zone land. One method was the standard weeding practice used for plantation establishment by Forest Department. (Low slashing and strip weeding 3 limes during the 1st year, 2 times during the 2nd year and one low slashing and patch weeding during file third year). The other is high intensity (luxury) weeding involving complete cultivation of the topsoil. Fourteen months observations and survival and height measurements were recorded.

Results indicate that three Species, Artocarpus nobilis, Artocarpus heterophyllus and Filicium decipiens failed to successfully establish and grow under both weeding methods. Other species, Dipterocarpus zeylanicus although established showed poor growth and vigour. The slight improvement of' survival and growth under luxury weeding does not justify the cost involved.

Eucalyptus AND Acacia SPECIES AND FUTURE STRATEGIES FOR IMPROVEMENT IN THE UP COUNTRY OF SRI LANKA

K M A Bandara
Research Officer, Forest Department Passara Road, Badulla.


Most of the arable lands ill up country are used for tea and some other cash crops like vegetables. The land available for commercial reforestation is marginal and degraded. However, commercially valuable tree species like Eucalyptus and Acacia are planted ill the tea plantations as ill additional income source; to produce a significant timber and fuel wood production.

Naturally available tree species cannot he cultivated commercially due to their slow growth and poor timber quality. Furthermore, Michelia champaca, Cedrella toona and Artocarpus heterophyllus that are localized to up country show slow growth and are therefore very difficult to plant as commercial trees.

Fast growing Eucalyptus and Acacia species have been introduced to up country in the 1800s. E. grandis and E. microcorys species are planted in the up country in large-scale industrial plantations and in the farmlands, Hence they produce significant production for the, timber market. Acacia species are not planted widely in this zone but there will be a high potential for the species A. melanoxylon in the future as a furniture timber tree.

Genetic improvement of Eucalypus started ill 1990s. E. grandis, E. microcorvs, E. cloeziana and E. urophylla have shown promising growth in the species trials. Provenances of E. grandis from northern Queensland and provenances of E. miorocorys from northern New South Wales have performed well. Broad range provenances of A. melanoxylon trial have been established in the recent past.

A long tern breeding programme for E.grandis was formulated in 1994. The first generation progeny trial was established in 1995 in the upcountry intermediate zone. Hence, it is proposed to convert that to a seedling seed orchard in the future. Two seed production areas for each species were established in two different climatic zones, Up country intermediate and wet zone for immediate seed requirements.

Present activities of tree improvement in the up country and future improvement strategies and plans will be discussed.

EFFECT OF THE PERIOD OF THE YEAR WHICH EXPLANTS WERE COLLECTED ON SHOOT GROWTH AND THE CALLUS FORMATION OF THE TISSUE CULTURED JACK FRUIT

K A H K Kasthuri Arachchi and W T P S K Senarath
Department of Botany, University of Sri Jayewardenepura,
Nugegoda.


A method for rapid propagation of mature Jack fruit from apical meristem culture was developed. Apical meristems were established in Modified Campbell and Durzan medium supplemented with NAA and IBA. Cultures were sub cultured in every 4 weeks interval in order to reduce the accumulation of phenolic compounds. Reducing the accumulated phenolics at the base of the explant enhanced the growth rate. There was a significant difference in the growth performance of shoots and callus produced according to the period of the year in which explants were collected.

60% of the apical meristems cultured in modified CD medium supplemented with IBA and NAA produced shoots in November to December period. It was only 30% when the apices were cultured in April to May months and decreased to 20% in June - July months. The shoots produced in November - December period showed a higher vigour (in number of leaves per shoot, mean leaf width and mean shoot length) than those produced in other months. Since jackfruit show seasonal changes in fruit bearing and shedding of leaves, it can be suggested that the difference in growth performances of tissues cultured in artificial culture media would have been effected by endogenous rhythms. It has been observed that the callus production depends on the incubation temperature. Callus was induced at the base of the shoot by increasing the incubation temperature from 25±1"C to 30±1°C. Growth of the callus was also retarded by accumulated phenolic compounds in the medium.

DISTRIBUTION OF INVASIVE PLANT Ulex europeus IN HORTON PLAINS NATIONAL PARK

M C Devendra1, H S Amarasekera1 AND S Wahala2
1Department of Forestry and Environment Science,
University of Sri Jayewardenepura, Nugegoda.
2'Young Biologists' Association

One of the most sensitive problems facing the conservation and management of Horton Plains National Park is the spreading of Ulex europeus (gorse), an invasive plant species. To effectively manage and control this species it is necessary to have a sound knowledge of its distribution within this park.

This study was carried out to find the extent and distribution of Ulex europeus in tile park and finally to prepare a map showing the extent and distribution. The percent coverage was assessed using 2m x 2m quadrates. In each quadrate percentage cover of reproductives and non - reproductives were measured.

According to the results of this study, about 6ha of the area is covered by Ulex europeus. Total amount of the area which covers more than 80% of Ulex europeus is 2.4ha. The area which consists of less than 80% of Ulex europeus is 3.31ha. The extent of reproductives and non reproductives are also presented in the paper. Findings on the distribution pattern of the species show that tile area around the main gate and Farr Inn guest house is the most densely and continuously distributed area with more than 80% coverage of Ulex europeus. Except this there are a few isolated patches on either side of the road and trail with more than 80% coverage of Ulex europeus. The distribution of the Ulex europeus plants are mainly restricted along the stream from Black bridge to Gempit pool. The density of the species gradually decreased from up stream to down stream but it was higher in the areas where water is stagnated along the stream. It is interesting to note that there are no plants of Ulex europeus found inside the natural forest except at the margins of the forest.