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FORESTS. -Moderate climate. -Improve air quality. -Regulate water flow. -Protect aquatic. ecosystems. -Promote biodiversity. Timber for construction. Pulp and Paper Mill. Vancouver Island. Forest management.
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FORESTS -Moderate climate -Improve air quality -Regulate water flow -Protect aquatic ecosystems -Promote biodiversity
Timber for construction
Pulp and Paper Mill Vancouver Island
Forest management • Forests provide us timber, and this has helped our society achieve the standard of living we enjoy today. • Forests are also natural ecosystems that are severely altered by timber harvesting. • The practice of forestry has had to balance these two identities in trying to manage forest resources.
Soil-plant-atmosphere system p = ET + r + S Photosynthesis: 6CO2 + 6H2O + sunlight C6H12O6 + 6O2 Respiration: C6H12O6 + 6O2 6CO2 + 6H2O + energy Regulation of moisture regime Photosynthesis and Evaporation
Leaf Photosynthesis Maximum photosynthetic capacity Photosynthesis (mol C m-2 s-1) Light compensation point Varies with QUE, R Respiration rate, R PAR (molm-2 s-1)
Leaf-level net photosynthesis modelling Thornley and Johnson (1990) (Just one example)
NEE and Net Canopy Photosynthesis Determined by: Photosynthetically active radiation Temperature Vapour pressure deficit Light extinction and canopy structure Leaf area distribution Canopy vs. understorey photosynthetic capacity Soil Moisture Soil and leaf nutrient status Interspecies competition Ultraviolet radiation Diffuse vs. spectral radiation
Matt's Cloud Forest Site • 1000m 20 de Julio Field Station, Parque Nacional Munchique CAUCA 1500m El Tambo PALO VERDE CATCHMENT • 2000m Bosque Station Home • 2500m Campo Station • TAMBITO CATCHMENT 3000m · Cartagena · Cúcuta · Medellin · Bogotá Buenaventura · · Cali COLOMBIA 1 kilometre · Popayán · Pasto CEAT - CENTRO DE ESTUDIOS AMBIENTALES TAMBITO · 100 km Leticia
Photosynthetically active radiation molm-2 s-1
Temperature Average Daily Maximum Temperature 23°C (1100m) - 11°C (3000m)
Humidity & Vapour Pressure Deficit Relative Humidity (Per-cent) Solar Hour
Precipitation Rainfall in mm Month
Soil nutrient concentration Spatial distribution is also important
Plant Canopies and Carbon Dioxide Flux in the middle latitudes At night: - canopy to atmosphere - respiration from leaves, plant roots, soil Daytime: - CO2 assimilation exceeds respiration Seasonal Variation in Temperate Environments Spring: Uptake increases with leaf area index and solar radiation availability/day length Midsummer: Fc drops despite sun, due to soil moisture depletion – flux higher in morning Winter: Small, negative flux in temperate climates
Internal Carbon Allocation Foliage Rooting networks Woody biomass
High Biodiversity Old-growth Forest
Importance of Old Growth Forest Habitat: Mosses, lichen, insects, squirrels, birds Temperature regulation New nutrient rich material (dead biomass) Fungi and insect habitat Prevention of erosion *** Biodiversity *** Carbon uptake?
Monocultural Rubber Plantation Myanmar
Rubber - tea agroforestry in China
'Reforestation' of Degraded Land
Main Forest Types Tropical Forests Temperate Forests Boreal Forests 40% of the Earth's land surface in forested biomes
Tropical Forests 1.7 billion ha -15 million ha/y
Cocoa Banana Sugar
Mahogany Teak Sandalwood Rosewood Balsa
REVIEW Temperate Forests 1.7 billion ha
Temperate Rain Forest
Tall Coniferous Species of Canada's Temperate Rainforest Western Red Cedar Sitka Spruce Douglas Fir Western Hemlock Yellow Cedar
Temperate Broadleaf Forest Source:atlas.gc.ca
Temperate Mixed Forest Central Ontario Photo: L. Kissau
Boreal Forest Spruce, Fir, Pine, Larch, Aspen, Willow 920 million ha
Canadian Forestry Facts • Forestry products are largest contributor to • Canada’s trade surplus (energy sector next) • Almost 0.5% of Canada’s productive forest • is harvested every year • A 1m x 1m stack of one year’s wood harvest • would circle the globe more than 4 times • (twice for B.C. alone) • BC’s share is falling, New Brunswick’s share • is rising (private ownership – no U.S. penalty)
Provincial governments have opened public • lands to multinationals (for pulp and paper • mills, sawmills, plywood plants etc.) • Nearly 100% of Canada’s most productive • boreal forest, including several provincial • parks and wildlife reserves… is available for • logging • Timber harvesting conflicts with indigenous • people’s traditional uses of forest land • Total forested area expanding in the US, • but not yet in Canada
Demand for wood products, and for open land for agriculture, has led to deforestation, the clearing and loss of forests, throughout the world. Africa and Latin America are losing their forests most quickly. Forests are starting to grow back in North America and Europe after centuries of deforestation. Forests and Deforestation Figure 16.7
CLEARCUTTING Most cost-effective and environmentally-deleterious method 85% of Canadian logging operations
Coniferous Forest Clearcutting Whitecourt, AB (Patch clearcutting) Visible imagery Radar imagery Source: NRCAN