NJC JH1 Geog Notes - Tropical Rainforests

Junior High Geography Chapter 4, Issue 1: Climatics, Adaptations and Sustainable Management of Rainforests Fig. 1.1 Fig. 1.2 1.1 – Global spatial distribution of tropical rainforests, 1.2 – a climograph of a tropical rainforest, as exemplified by the Cat Tien National Park (a lowland tropical rainforest in Vietnam) The tropical rainforest is the primary natural vegetation in the tropical climate. The tropical climate is characterised by a high median temperature and high levels of precipitation , especially during the wet season of a region. The part of the earth between the Tropic of Cancer and the Tropic of Capricorn (Fig. 1.1) is classified as the ‘tropics’. The tropical rainforest consists of 4 layers: the emergent layer (top), the canopy layer (middle) and the undergrowth layer (bottom). ACTIVITY: visit the padlet link and upload snaps of the college’s prominent rain trees (canopy) and low-lying shrubs (undergrowth). what observations can you infer? Most rainforest species have broad leaves to maximize the surface area so that more chlorophyll can absorb sunlight for photosynthesis. Most rainforest species have waxy leaves which give their surface a lustrous apperance. The characteristically high temperature of tropics promotes transpiration (loss of water vapour) which may have severe effects on plants in excess. Waxy leaves help reduce this by acting as a ‘barrier’ to the stomata through which plants transpire. Due to the high precipitation in the tropics, many rainforest species – especially those in the undergrowth – have drip tips to promote surface runoff of water to deter fungal growth . (note: the characteristically high temperature of tropical environments also encourages fungi) Many rainforest trees which are taller in height to reach for as much sunlight as possile usually have buttress roots, which prevent them from toppling over. 1.3 – the ‘long, elongated tip’ of a rainforest species, 1.4 – a research study on the Buttress roots of various tropical rainforest species and their diameter and skeletal structure

Fig. 1.5 Fig. 1.6 1.5 – a distribution of the total biomass of carbon stored (more carbon correlating to a brighter colour) in highly forested areas, 1.6 – a distribution from the NASA Propulsion Jet on how the biomass carbon stock change is starting to decrease in areas like the Amazon Tropical Rainforest The Amazon are the lungs of the world. Tropical forests are simultaneously the most extensive oxygen generators and carbon sinks on earth. They release oxygen through their stomata as their chlorophyll photosynthesise, and as carbon dioxide is absorbed in photosynthesis – they can store carbon in solid form in leaves, branches, stems and roots. As plants die, the dea