Agriculture Reference
In-Depth Information
account for roughly five percent of forest-cover, but yield 35 percent of the world
wood supply. However plantations, which are primarily monocultural systems of
exotic species, are inferior to primary and secondary forests in supporting genetic-
and bio-diversity, ecological resilience, economic and social services to rural com-
munities, water and soil conservation, and carbon storage (Michon and de Foresta
1995; Lamb 1998; Murdiyarso et al. 2002; Roshetko et al. 2007a; van Weerd and
Snelder, Chapter 16, this volume; van Noordwijk et al., Chapter 20, this volume).
Additionally, forest plantations are frequently established by clearing primary or
secondary forests (Barr et al. 2004; Sheng and Cannon 2004), thus being a direct
cause of natural forest loss. Although tree plantations will expand, they will remain
a portion of regional forest base in South and Southeast Asia accounting for only
5.9 percent, 16.6 million hectares (FAO 2005). Overall forest-cover - the combined
area of forests and woodlands, natural exploitable natural forests, and forest planta-
tions - remains in decline. Forest-cover is projected to decrease by 2.9 percent in
the Asia-Pacific Region and by more than 10.5 percent in Southeast Asia. Forest-
cover will remain static across South Asia as a result of India's large plantation
expansion program, 3.75 million hectares between 1995 and 2010. The other coun-
tries of South Asia will each experience major forest loss (Blanchez 1997).
Projected forest area losses and gains for the Asia-Pacific Region and individual
countries in South and Southeast Asia are listed in Table 21.1.
Even if the projections above prove to be excessive, given the varied data on which
they are built, the fact remains that the regional forest base is decreasing. The declin-
ing forest base, compounded by a shift from natural forest systems to plantations, will
be accompanied by a loss of forest functions and services. The level of this environ-
mental degradation becomes evident when looking at the changes in the status of
various forest-related variables that are representative of functions such as biological
diversity, forest health and vitality, and the productive, protective and socio-economic
functions of forest resources (Table 21.4 and Photo 21.1). In the Asia region, forest
carbon storage decreased by 10.5 Gt of carbon annually between 1990 and 2005 due
to deforestation and forest degradation. The loss of primary forest at a rate of 1.5 mil-
lion hectares per year during the same period has serious consequences for regional
biodiversity. The high rate of forest loss is the result of deforestation and forest deg-
radation, the latter primarily due to selective logging which alters natural primary
forests to secondary forest (FAO 2006). Efforts to conserve forests and biological
diversity are growing, as evident by an annual increase of 1.4 percent in the area of
conservation forests (Table 21.4). Forests also suffer from fires (Photo 21.2), diseases
and insect attacks, and other disturbances, which affect up to 93,000 ha per year. Data
on forest disturbances are far from complete. The area of forests used for the produc-
tion of wood and non-wood forest products declined by an average of 683,000 ha per
year, while the area of productive forest plantations increased by 195,000 ha per year.
Official figures on total wood removals during the period 1990-2005 suggest a
regional decrease of about 3.6 million hectares per year (or two percent per year). The
actual loss is likely higher as illegal wood removals and informal fuelwood collection
are not included in the calculations (FAO 2006). Both the area of forest primarily
designated for protection and the area of protective forest plantations have increased
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