Variation in canopy structure, light and soil nutrition across elevation of a Sri Lankan tropical rain forest

Ediriweera, Sisira; Singhakumara, B.M.P.; Ashton, Mark S.

doi:10.1016/j.foreco.2008.06.035

Cited by 53 publications

(29 citation statements)

References 63 publications

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“…Additionally a weak relationship was observed between average crown area with insolation in the closedcanopy BRNP study area. A similar trend for the variation in tree crowns has been reported through field investigation in dipterocarp dominated tropical rainforest in Sri Lanka (Ashton, 1992;Ediriweera et al, 2008). In this study the greatest maximum overstorey height was observed on lower slopes in both study areas and thus the variation of crown area appear be related to decrease in tree stature.…”

Section: Studying Relationships Between Vegetation Structure-environmentsupporting

confidence: 87%

“…Presumably, potential insolation or TWI was not able to describe the variation in forest structure in the hilly subtropical rainforests compared to the open-canopy eucalypt forests. This indicates that forest structure of subtropical rainforest of the BRNP can be expected to overstorey height decreased with increased elevation in the BRNP as is reported by many studies that have measured forest structure across elevation gradients elsewhere (Weaver & Murphy, 1990;Singh et al, 1994;Ediriweera et al, 2008). Due to dramatic changes in the processes causing hillslope erosion especially in areas such as the BRNP (high rainfall compared to the RRNP), soil and soil nutrients tend to accumulate to considerable depths in valleys, which have contributed to the spatial distribution of the nutrient pool and subsequently changes in vegetation structure.…”

Section: Studying Relationships Between Vegetation Structure-environmentsupporting

confidence: 57%

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The influence of topographic variation on forest structure in two woody plant communities: A remote sensing approach

Ediriweera

Danaher²,

Pathirana

2016

For. syst.

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Aim of study: The study aimed to characterise variation in structural attributes of vegetation in relation to variations in topographic position using LIDAR data over landscapes.Area of study: The study was conducted in open canopy eucalypt-dominated forest (Richmond Range National Park-RRNP) and closed canopy subtropical rainforest (Border Ranges National Park-BRNP) in north-eastern New South Wales, Australia.Material and Methods: one metre resolution digital canopy height model (CHM) was extracted from the LIDAR data and used to estimate maximum overstorey height and crown area. LIDAR fractional cover representing the photosynthetic and non-photosynthetic component of canopy was calculated using LIDAR points aggregated into 50 m spatial bins. Potential solar insolation, Topographic Wetness Index (TWI), slope and the elevation were processed using LIDAR derived digital elevation models.Main results: No relationship was found between maximum overstorey height and insolation gradient in the BRNP. Maximum overstorey height decreased with increasing insolation in the RRNP (R 2 0.45). Maximum overstorey height increased with increasing TWI in the RRNP. Average crown area decreased with increasing insolation in both study areas. LIDAR fractional cover decreased with increasing insolation (R 2 0.54), and increased with increasing TWI (R 2 0.57) in the RRNP. Research highlights:The characterization of structural parameters of vegetation in relation to the variation of the topography was possible in eucalyptus dominated open canopy forest. No reportable difference in variation of structural elements of vegetation was detected with topographic variation of subtropical rainforest.

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Section: Studying Relationships Between Vegetation Structure-environmentsupporting

confidence: 87%

Section: Studying Relationships Between Vegetation Structure-environmentsupporting

confidence: 57%

The influence of topographic variation on forest structure in two woody plant communities: A remote sensing approach

Ediriweera

Danaher²,

Pathirana

2016

For. syst.

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“…The method assumes that if topographically-induced illumination of an image has been effectively corrected, the spectral variability in each land cover class would be reduced, hence providing greater distinction between land cover classes. However, topography not only modifies the illumination of terrain, but also substantially modifies the biophysical properties of vegetation (e.g., foliage cover) on complex topography [11][12][13]. Unless very detailed land cover mapping is available, the land cover classification approach generally assesses the accuracy of topographically-corrected reflectance without separating the effects of within-class variation in biophysical properties of vegetation, due to topography.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Different Topographic Corrections for Landsat TM Data by Prediction of Foliage Projective Cover (FPC) in Topographically Complex Landscapes

et al. 2013

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Abstract:The reflected radiance in topographically complex areas is severely affected by variations in topography; thus, topographic correction is considered a necessary pre-processing step when retrieving biophysical variables from these images. We assessed the performance of five topographic corrections: (i) C correction (C), (ii) Minnaert, (iii) Sun Canopy Sensor (SCS), (iv) SCS + C and (v) the Processing Scheme for Standardised Surface Reflectance (PSSSR) on the Landsat-5 Thematic Mapper (TM) reflectance in the context of prediction of Foliage Projective Cover (FPC) in hilly landscapes in north-eastern Australia. The performance of topographic corrections on the TM reflectance was assessed by (i) visual comparison and (ii) statistically comparing TM predicted FPC with ground measured FPC and LiDAR (Light Detection and Ranging)-derived FPC estimates. In the majority of cases, the PSSSR method performed best in terms of eliminating topographic effects, providing the best relationship and lowest residual error when comparing ground measured FPC and LiDAR FPC with TM predicted FPC. The Minnaert, C and SCS + C showed the poorest performance. Finally, the use of TM surface reflectance, which OPEN ACCESS Remote Sens. 2013, 5 6768 includes atmospheric correction and broad Bidirectional Reflectance Distribution Function (BRDF) effects, seemed to account for most topographic variation when predicting biophysical variables, such as FPC.

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“…The emergent species of mixed deciduous forests have closed canopies in the growing (wet) season and open canopies in the dry season; this seasonal variation influences seedling dormancy and makes establishment under the canopy difficult (Marod et al 1999). Areas with low tree stem densities have canopy breaks through which direct sunlight may reach the ground surface and promote seedling establishment (De Gouvenain et al 2007;Ediriweera et al 2008). The survival of juveniles varies by canopy openness; it is elevated in sites where more sunlight is available (Dupuy and Chazdon 2008).…”

Section: Environmental Factors Affecting Tree Regenerationmentioning

confidence: 99%

Environmental Factors Influencing Tree Species Regeneration in Different Forest Stands Growing on a Limestone Hill in Phrae Province, Northern Thailand

Asanok¹,

Marod²

2016

Journal of Forest and Environmental Science

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Improved knowledge of the environmental factors affecting the natural regeneration of tree species in limestone forest is urgently required for species conservation. We examined the environmental factors and tree species characteristics that are important for colonization in diverse forest stands growing on a limestone hill in northern Thailand. Our analysis estimated the relative influence of forest structure and environmental factors on the regeneration traits of tree species. We established sixty-four 100-m 2 plots in four forest stands on the limestone hill. We determined the species composition of canopy trees, regenerating seedlings, and saplings in relation to the physical environment. The relationships between environmental variables and tree species abundance were assessed by canonical correspondence analysis (CCA), and we used generalized linear mixed models to examine data on seedling/sapling abundances. The CCA ordination indicated that the abundance of tree species within the mixed deciduous forest was closely related to soil depth. The abundances of tree species growing within the sink-hole and hill-slope stands were positively related to the extent of rocky outcropping; light and soil moisture positively influenced the abundance of tree species in the hill-cliff stand. Physical factors had a greater effect on tree regeneration than did factors related to forest structure.Tree species, such as Ficus macleilandii, Dracaena cochinchinensis, and Phyllanthus mirabilis within the hill-cliff or sink-hole stand, colonized well on large rocky outcroppings that were well illuminated and had soft soils. These species regenerated well under conditions prevailing on the limestone hill. The colonization of several species in other stands was negatively influenced by environmental conditions at these sites. We found that natural regeneration of tree species on the limestone hill was difficult because of the prevailing combination of physical and biological factors. The influence of these factors was species dependent, and the magnitude of effects varied across forest stands.

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Variation in canopy structure, light and soil nutrition across elevation of a Sri Lankan tropical rain forest

Cited by 53 publications

References 63 publications

The influence of topographic variation on forest structure in two woody plant communities: A remote sensing approach

The influence of topographic variation on forest structure in two woody plant communities: A remote sensing approach

Evaluation of Different Topographic Corrections for Landsat TM Data by Prediction of Foliage Projective Cover (FPC) in Topographically Complex Landscapes

Environmental Factors Influencing Tree Species Regeneration in Different Forest Stands Growing on a Limestone Hill in Phrae Province, Northern Thailand

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