Environmental Engineering Reference
In-Depth Information
of tropical Africa (above all in the basin of the Congo River), and slower but con-
tinuing losses of remaining old-growth forests in virtually every tropical and sub-
tropical country. In contrast, the temperate and boreal forests in the afl uent countries
have continued to expand. This reforestation has multiple beginnings, going back
to the seventeenth century and including changes in attitude (the cult of trees in
early modern England with its spacious and meticulously designed estate parks
and gardens), long-range planning (Jan Baptiste Colbert's pre-1680 planting of oak
forests to supply timber for the French navy of the nineteenth century), and advances
in forest management, particularly the German contributions to the development of
highly productive forestry based on non-native but fast-growing coniferous species,
mainly Norway spruce and Scotch pine (Bernhardt 1966).
In Europe, slow pre-World War II gains accelerated after 1950 as higher crop
yields led to the abandonment of large areas of marginal cultivated land and as
large-scale afforestation programs and stricter requirements for immediate replant-
ing of harvested forests stopped the net losses from commercial tree cutting. Some
of these gains have been small, particularly in highly forested Scandinavian nations,
but other countries have recorded substantial expansion of the tree cover: between
1950 and 1998 by 22% in Italy, between 1947 and 1988 by 30% in Germany,
and between 1947 and 1997 by 32% in France, and the relative gains have been
even higher in terms of the growing stock, 2.7-fold in Italy and threefold in France
(Gold 2003). The latest data (UNECE 2010) show continued strong gains. Between
1900 and 2005 Europe's forest cover increased by almost 13 Mha (roughly the
equivalent of Greece), annual additions to the total growing stock averaged 358 Mm3
(an equivalent of the total growing stock of Slovenia), and the total carbon stock
in aboveground phytomass increased by 2 Gt to 53 Gt C.
But no nation has planted more trees during the second half of the twentieth
century than China. Large-scale reforestation campaigns claimed to restore tree
cover on 28 Mha between 1949 and 1979, but most of those plantings failed, and
the forested area (referring to fully stocked productive forests with a canopy cover
of at least 30%) was put at 122 Mha, or 12.7% of China's territory, in 1979 (Smil
1993). More successful reforestation campaigns began during the early 1980s
(mostly in the southeast and the southwest), and the satellite-based national land
cover data set showed forested area at nearly 138 Mha in the year 2000 (Liu et al.
2005). Most of the Chinese gains have been monocultural plantings of fast-growing
trees; so it has been in India where the latest nationwide forest survey found a 5%
expansion during the preceding decade (MEF 2009) but, as noted by Puyravaud,
Davidar, and Laurance (2010), this was misleading, as the automated analysis of
