A number of long-term studies on supply and demand of forestry products have been conducted in recent years (e.g., Sedjo and Lyon, 1990, 1996; FAO, 1998; Hagler, 1998; Sohngen et al., 1999, 2001). These studies project a shift in harvest from natural forests to plantations. For example, Hagler (1998) suggested the industrial wood harvest produced on plantations will increase from 20% of the total harvest in 2000 to more than 40% in 2030. Other estimates (FAO, 2004a) state that plantations produced about 34% of the total in 2001 and predict this portion may increase to 44% by 2020 (Carle et al., 2002) and 75% by 2050 (Sohngen et al., 2001). There will also be a global shift in the industrial wood supply from temperate to tropical zones and from the Northern to Southern Hemisphere. Trade in forest products will increase to balance the regional imbalances in demand and supply (Hagler, 1998).
Forecasts of industrial wood demand have tended to be consistently higher than actual demand (Sedjo and Lyon, 1990). Actual increases in demand have been relatively small (compare current demand of 1.6 billion m3 with 1.5 billion m3 in the early 1980s (FAO, 1982, 1986, 1988, 2005b)). The recent projections of the FAO (1997), Häggblom (2004), Sedjo and Lyon (1996) and Sohngen et al. (2001) forecast similar modest increases in demand to 1.8-1.9 billion m3 by 2010 to 2015, in contrast to earlier higher predictions of 2.1 billion m3 by 2015 and 2.7 billion m3 by 2030 (Hagler, 1998). Similarly, an FAO (2001) study suggests that global fuelwood use has peaked at 1.9 billion m3 and is stable or declining, but the use of charcoal continues to rise (e.g., Arnold et al., 2003). However, fuelwood use could dramatically increase in the face of rising energy prices, particularly if incentives are created to shift away from fossil fuels and towards biofuels. Many other products and services depend on forest resources; however, there are no satisfactory estimates of the future global demand for these products and services.
Finally, although climate change will impact the availability of forest resources, the anthropogenic impact, particularly land-use change and deforestation in tropical zones, is likely to be extremely important (Zhao et al., 2005). In the Amazon basin, deforestation and increased forest fragmentation may impact water availability, triggering more severe droughts. Droughts combined with deforestation increase fire danger (Laurance and Williamson, 2001): simulations show that during the 2001 ENSO period approximately one-third of Amazon forests became susceptible to fire (Nepstad et al., 2004).