1 Forests – Part 2 Extent of global forest decline 1.Extent of global forest loss. 2.Forest fragmentation. 3.Old growth forests.

2 1. Extent of global forest loss Overall, global decline in forested areas. Temperate forests – expanding slightly due to reforestation and abandonment of marginal farmlands. Tropical forests – shrinking rapidly.

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4 Original forest cover Source: Global Forest Watch

5 Current forest cover Source: Global Forest Watch

6 Remaining frontier forest Source: Global Forest Watch

7 Tropical forests Currently occupy _____% of global land surface. They are thought to contain: _____% of all higher plant biomass. _____ of all plant, animal and microbial species worldwide.

8 Decrease in forest cover in Central America, Most forests now found in small patches.

9 Loss of forest cover in Costa Rica 1983 – almost all remaining forests are in protected areas (national parks). Percentage: forest as proportion of total land area

10 Est. rate of global tropical forest decline UN-FAO estimate - 0.8% of remaining forests cleared per annum

11 Deforestation in Brazil Average deforestation rate in Brazil (1978 to 1988) was ________ km 2 per year. a square of km on each side. Systematic cutting of the forest vegetation starts along roads and then fans out to create the "feather" or "fishbone" pattern.

12 Rondonia, Brazil

13 Rondonia – June 19, 1975

14 Rondonia – Aug 1, 1986

15 Rondonia – June 22, 1992

16 Deforestation in Brazil Large-scale development of Amazonian forests as official gov’t policy began in the mid-1970’s. Resulted from agricultural expansion of both small land-holders and large-scale companies, mainly for cattle grazing. Brazilian government slogan:

17 Decline of forest cover in Vietnam, Vietnam is a region of hyperdiversity

18 Important factors influencing deforestation in the tropics Latin America

19 Important factors influencing deforestation in the tropics AfricaSE Asia

20 Important factors influencing deforestation in the tropics South Asia

21 Factors affecting deforestation in the Philippines

22 Decline of unaltered forest cover in the USA,

23 Note: this does not include changes in forest area since widescale deforestation began in the 16 th century.

24 2. Forest fragmentation

25 Habitat fragmentation Probably the greatest threat to forest ecosystems. Tree removal which decreases the size of pristine forest into smaller sized patches. Results from logging activities, roads, seismic exploration lines, right-of-ways, agricultural expansion, etc.

26 Global forest fragmentation Five categories of forest as a function of the degree of fragmentation: interior – far from forest edges. perforated – near forest edge habitat. edge – between closed forest and open area. transitional – between perforated/interior and open habitat (patch). patch – open areas within a forest.

27 Patterns of forest fragmentation for Africa

28 Patterns of forest fragmentation for North America

29 Patterns of forest fragmentation for South America

30 Forest fragmentation in the boreal region of Alberta Photo: Sue Hannon

31 Fragmentation of the Swan Hills Sept July 1964 Oct. 1991

32 Large remaining unfragmented forest areas

33 3. Old growth forests

34 What are old growth forests? Forests whose natural cycles of growth and succession have not been disturbed by natural events (eg. fires) or non-natural events (eg. logging, roads or forest clearing). Is the climax forest ecosystem. Most old growth forests are very old: Alberta – years. B.C. coast – years.

35 Ecological services of old growth

36 Importance of old growth Ecological value Ecological value: unique ecosystems, high biodiversity, endemic species, undiscovered species. Scientific value Scientific value: cannot be duplicated in any other setting, historical values. May shed some light on the cycle of atmospheric carbon. Economic values Economic values: sustainable practices such as ecotourism, plant sources (orchids).

37 Importance of old growth Aesthetic value value: is unlike any other ecosystem on earth.

38 Equatorial rain forest West coast of North America Logging of old growth trees

39 Next Class Renewable Energy Hydroelectric