Plant photosynthesis and biomass production are associated with the amount of intercepted light, especially the light distribution inside the canopy. Three virtual canopies (n = 80, 3.25 plants/m2) were constructed based on average leaf size of the digitized plant structures: ‘small leaf’ (98.1 cm2), ‘medium leaf’ (163.0 cm2) and ‘big leaf’ (241.6 cm2). The ratios of diffuse light were set in three gradients (27.8%, 48.7%, 89.6%). The simulations of light interception were conducted under different ratios of diffuse light, before and after the normalization of incident radiation. With 226.1% more diffuse light, the result of light interception could increase by 34.4%. However, the 56.8% of reduced radiation caused by the increased proportion of diffuse light inhibited the advantage of diffuse light in terms of a 26.8% reduction in light interception. The big-leaf canopy had more mutual shading effects, but its larger leaf area intercepted 56.2% more light than the small-leaf canopy under the same light conditions. The small-leaf canopy showed higher efficiency in light penetration and higher light interception per unit of leaf area. The study implied the 3D structural model, an effective tool for quantitative analysis of the interaction between light and plant canopy structure.
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Peat swamp forests in Southeast Asia are under heavy pressure. Deforestation, forest degradation, wildfires, and drainage have damaged or destroyed substantial areas of the once extensive peat swamp forest formations. Several efforts are underway to rehabilitate degraded peat forests areas in order to restore some of the valuable ecosystem services these forested areas once provided. However, these efforts often result in (mixed)-plantations that only partly resemble the original peat forests. Information about these peat swamp forests' complex origin and ecology is needed to improve restoration outcomes further. Our paper analyses historical data from coastal peat swamp forests in Sarawak and Brunei and discusses the potential to use this as the reference value for intact peat forests. We describe the observed stand structure and species composition for pristine peat swamp forest, and we analyze the population structure of three dominant peat swamp forest species: Gonystylus bancanus (ramin), Dactylocladus stenostachys (jongkong) and Shorea albida (alan batu). We compare the historical data with data from recently measured, degraded peat swamp forests. We discuss our results in relation to processes of peat dome formation, nutrient availability and hydrology, and give recommendations for peat swamp forest management and restoration.
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Built environments are increasingly vulnerable to the impacts of climate change. Most European towns and cities have developed horizontally over time but are currently in the process of further densification. High-rise developments are being built within city boundaries at an unprecedented rate to accommodate a growing urban population. This densification contributes to the Urban Heat Island phenomenon and can increase the frequency and duration of extreme heat events locally. These new build-up areas, in common with historic city centres, consist mainly of solid surfaces often lacking open green urban spaces.The Intervention Catalogue is the third publication in a series produced by the Cool Towns project and has been designed as a resource for decision makers, urban planners, landscape architects, environmental consultants, elected members and anyone else considering how to mitigate heat stress and increase thermal comfort in urban areas. Technical information on the effectiveness of the full array of intervention types from trees to water features, shading sails to green walls, has been assessed for their heat stress mitigation properties, expressed in Physiological Equivalent Temperature (PET). The results shown in factsheets will help the process of making an informed, evidence based, choice so that the most appropriate intervention for the specific spatial situation can be identified.
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