Monitoring Growth Performance of Naturally Regenerated Woody Species in an Enriched Pine Stand, Sri Lanka

Monitoring growth performance of newly recruited plant species after applying several silvicultural treatments in monoculture plantations is important to evaluate the success of forest restoration. This study was conducted in 2015 to determine the growth performance of the naturally regenerated woody plant species in an unrestored (UP) and a restored (RP) Pinus caribaea Morelet plantation, in lower Hantana, Sri Lanka. In RP, partial thinning of pines followed by enrichment planting of four broad-leaved tree species in 2003 and total thinning of pines was initiated in 2009. In both sites fifteen plots (5x5m) and within each of them three subplots (1x1m) were demarcated randomly. The height of seedlings (SE, <50 cm in height) in subplots and height of saplings (SA1= 50-129 and SA2=130-300 cm in height) and trees (TR, >300 cm in height) and dbh of SA2 and TR in all the plots were recorded. Collectively, 417 individuals (RP=298, UP=119) representing 28 species (RP=24, UP=12) and 22 plant families (RP=18, UP=13) survived by the end of the six months. The mean monthly increment of height (MMIH)of survived species in RP was higher for all the life forms except for SE (SE=1.35, SA1=1.61, SA2= 1.38, TR= 4.45 cmmo-1) than in UP (SE=2.06, SA1= 0.17, SA2= 0.00, TR= 1.65 cmmo-1). The MMIH of trees was significantly higher in RP than UP. The mean monthly increment of dbh (MMID) of survived individuals in RP was higher for both SA2 (0.017 cm per mo-1) and TR (0.027 cm per mo-1) than in UP (SA2= 0.0007, TR= 0.024 cmmo-1). The MMID of SA2 was significantly higher in RP than UP Of the 24 species tested in all four life form categories in RP, 19 (SE=39%, SA1=56%, SA2=69%, TR=85% of the species)had MMIH exceeding 1 cm mo-1while eight (SA2=5%, TR=26%) had dbh increment exceeding 0.05 cm mo-1. In UP, only five species (SE=60%, SA1=100%, SA2=25%, TR=77%of the species) had MMIH exceeding 1cm while one species (Alstonia macrophylla)(SA2=25%, TR=22%) had MMID exceeding0.05 cm mo-1. As the growth performance of the naturally regenerated woody species in RP was higher than UP, we conclude that restoration of pine plantation in mountainous regions of Sri Lanka, using silvicultural techniques is successful in achieving restoration goals.Keywords: Growth performance, Natural regeneration, Pinus plantation, Restoratio

Conservation Importance of Flora in the Kurulu Kele Sanctuary, Sri Lanka

Of the 3,771 flowering plant species in Sri Lanka 926 are endemic to the country. Nearly90% of the endemic flora are concentrated in the wet zone of the island. Kurulu Kele, whichis located in the lowland wet zone, was declared as a sanctuary in 1941 due to its high birdand plant diversity Due to its location in the centre of a city, this sanctuary faces lot of humanpressures. Two types of habitats identified at the Kurulu Kele Sanctuary (KKS), include thedense forest area and the rocky area. The vegetation sampling was carried out in twelverandomly selected 10 m x 10 m plots (6 quadrats in each habitat) from December 2011 toJune 2012, in order to investigate the floristic composition of the KKS.A total of 75 species of higher plants belonging to 33 families were recorded. Of the 75 plantspecies 55% were trees, 20% were tree lets and 25% were shrubs. Twenty five percent of theplant species were endemic, 63% were native and 12% were exotic. Four percent werethreatened and 9% were globally threatened. The plant density was 6,867 and 4,617individuals per ha in the dense forest area and in the rocky area, respectively. The ShannonWiener Index (H) was higher for the dense forest area (3.50) than the rocky area (3.34).The dominant families in the dense forest area were Anacardiaceae, Euphorbiaceae andMoraceae while in the rocky area the dominant families were Anacardiaceae, Euphorbiaceae,Clusiaceae and Rutaceae. Only two endemic tree species; Strychnos benthamii (Loganiaceae)and Artocarpus nobilis (Moraceae) were recorded in both habitat types.In the KKS, 65% of the individuals belonged to 10 cm - 39 cm GBH class. Densities of theother GBH classes were very low, which is a characteristic of a disturbed forest. Fourty twopercent of the individuals in the dense forest area belonged to 10 cm - 39 cm GBH class,while twenty one percent of the individuals in the rocky area belonged to 10 cm - 39 cm GBHclass.The majority of the remaining forest in the wet zone of Sri Lanka are fragmented anddegraded further due to development projects, wood extraction and over exploitation of forestproducts. Although KKS had an extent of 109 ha in 1941, due to various human impacts KKSis now left with only 11.32 ha (10.4%). Therefore, immediate action should be taken toconserve this lowland forest fragment as it provides many ecological and economicalservices. There is a great potential to develop KKS as an ecotourism destination due to itshigh biodiversity and the culture of people living in the surrounding area.

Does Ageratina riparia Affect the Regeneration of Forest Species in Disturbed Montane Forests in the Knuckles Forest Reserve

The invasive herb Ageratina riparia (Regel) R. M. King & H. Rob. (Asteraceae) which is anoxious weed in many countries including Hawaii, New Zealand and Australia is spreadingrapidly in the forest gaps, edges and along the footpaths inside disturbed montane forests inKFR. Since A. riparia forms a thick mat in the ground layer of montane forests, its spread canhave a detrimental effect on the establishment of seedlings of forest species. Six forest gapsand four footpaths inside a disturbed montane forest were sampled to investigate the effect ofA. riparia on the regeneration of the montane forest species. Soil moisture content, soil rootdensity and canopy openness were also determined. Soil seed bank experiments were carriedout during wet and dry seasons. The percentage cover of A. riparia decreased significantlywhen moving away from the centre of the footpaths (P=0.001, F=9.78, 0 m=62.5%, 5m=6.9%, 10 m= 11.3%) and the forest gaps (P<0.001, F=25.54, centre=75%, edge=19.75%,5 m away=0.17%) into the forest interior. The mean density of seedlings of forest speciesshowed a negative relationship with percentage cover of A. riparia. The mean density (forestgaps; centre=2.8m-2, edge=7.5 m-2, 5 m=5.8 m-2, footpaths; 0 m= 2.65 m-2, 5 m=6.5 m-2, 10m=6.12m-2) and the species diversity of forest species decreased with the increased A. ripariacover. The root density and root moisture content of forest species was lower in areas wherethe root density of A. riparia is higher. The soil moisture content in all the locations wasnearly equal at all distances from the centre of the gaps and footpaths into the forest (~2). Thecanopy openness was higher in the forest gaps than the footpaths (P<0.001, F=27.48).According to the results, growth and establishment of A. riparia is determined by the qualityof light. Seedling emergence of A. riparia from soil seed bank was higher during the dryseason than the wet season. Lower number of forest seedlings emerged in the locations wherehigh emergence of A. riparia seedlings was recorded. However according to the statisticalanalysis there was no relationship between the number of A. riparia seedlings and theseedlings of tree and shrub species that emerged from the soil seed banks (forest gaps; R2=0,Footpaths R2=0.005). Since native forest species including Psychotria zeylanica andSymplocos cochinchinensis showed high seedling densities even with high A. riparia cover.They can be used to restore disturbed submontane forest patches invaded by A. riparia atKFR

Seed Germination and Dormancy of Psychotria gerdneri as a Dominant Forest Species of Tropical Montane Forest in Sri Lanka

Tropical Montane forest in Sri Lanka is rich in endemism and biodiversity. However most ofmontane forests are degraded as result of natural and anthropogenic activities. SincePsychotria gardneri is a very dominant endemic species in Sri Lankan montane forest,knowledge of seed germination and seed Dormancy is very essential in restoration activities.Fully ripen seeds of P. gardneri were collected from Hantana forest range (altitude: 1,000-1,250 m). Seed: embryo ratio was taken of ripen and germinated seeds, water imbibition ofseeds of non-scarified and manually scarified were measured and tests of standardgermination and gibberellic acid (GA) treatment were conducted to identify the dormancyclasses. Seed germination under light/ dark and dark condition were tested to identify thegermination requirement.Embryo: seed ratio of ripened seeds and germinated seeds was 0.5 and 0.7 respectively.Water Imbibition pattern was similar in both non-scarified and manually scarified seeds. Seedstarted their germination within 15 days and 50% of seeds germinated within 65 days forstanders germination. 53% of seeds germinated within 28 and 38 days respectively for 100ppm and 500 ppm of GA. Under the fully dark condition 57% seeds germinated within 56days.P. gardneri has a combination of morphological and physiological dormancy. 100 ppm GA isa suitable treatment for breaking the physiological dormancy. Although Light is not agermination requirement, dark condition has enhanced the germination of P. gardneri. If weuse bulk of seed to get seedling of P. gardneri for restoration purposes, treating of seeds with100 ppm GA is a best option. If not seeds should be sown in more than 65 days in wetmedium.

Changes in Edaphic Gradients across Forest-Land Use Margins in an Isolated Rainforest Remnant in the Knuckles Range, Sri Lanka

Forest fragmentation is been identified as one of the factors that initiate forest degradation.The size of the forest patch and its bordering landscape decide the severity of disturbances tothese forest patches. Moraella forest, a lowland rainforest remnant located in the KnucklesRange, is bordered by many landuse types. The present study was aimed at investigating theedaphic gradients across the forest edge bordered by different forest-landuse types viz., Pinus,grassland, tea plantation and a scrubland. Seven linear quadrates (3 m x 12 m) were laid in 3transects totaling 21 quadrates per forest-landuse category. The quadrates were positionedparallel to the forest-landuse edge and at different distances away from the edge (0, 10 and 30m towards the forest interior; 10, 30 and 50 m towards the bordering landuse type). Soilsamples (up to a depth of 5 cm) were collected from each quadrate and were bulked togetherto make a representative sample for each distance and per transect. The samples wereanalysed for available cations (Ca, Mg and K), available P, total C and N, pH using standardmethods. Data was analysed using General Linear Model (GLM) taking distance as a fixedfactor in Minitab 14.1.The results showed that soil Mg and available P showed significant differences betweendistances in forest-landuse transects while Ca and Mg concentrations showed significantdifferences between landuse types. Pair-wise comparisons revealed that the soil Mg in theforest interior was higher than that of the bordering landuse, irrespective of the type of thelanduse. Available soil P also showed a similar increase towards the forest interior. This ispossibly due to higher mycorrhizal-dependent tree species found in the forest than that in thebordering landuse types. Other chemical parameters did not show any significant differencesalong these transects. Soil Ca in the scrubland and small-holder tea plantation showedsignificantly higher concentrations compared to Pinus and it was evident in both in the forestinterior as well as in the open landuse. Higher Ca levels in the small-holder tea plantationmay be due to the use of lime to reduce soil acidity. The forest-scrubland soils showedsignificantly higher Mg levels than that of other three landuse categories. However, soil C, Nand pH showed no significant differences across these forest-landuse transects. The presentresults suggest that edaphic gradients do exist across forest-landuse transects, but with somesoil parameters. The bordering landuse type and its management practices may have someimpacts on creating such gradients.