Impacts of Afforestation, Deforestation, and Reforestation on Forest Cover in China from 1949 to 2003

gauge instrument or prism was introduced, which significantly expedited the process. There was no national forest resource information in China during 1963–1972. The first NFI was performed during 1973–1976, in which a stratified systematic sampling technique was used to locate NFI sample plots. Each province, autonomous region, or municipal city designed one or more sampling populations according to the physiographic conditions and forest resource distributions. The size of the sample plots varied from 0.06, 0.08, and up to 1.0 ha in circular, square, or rectangle shapes. The sampling grid varied from 1 2 km up to 8 8 km. The second NFI took place during 1977–1981. A total of 160,000 sampling plots were measured, of which 140,000 were permanent plots. An NFI system began to emerge. The third, fourth, and fifth NFIs took place during 1984–1988, 1989–1993, and 1994–1998, respectively. These subsequent inventories were performed with additional standardized techniques and provided more information than the earlier NFIs. Starting from the fourth NFI, remote sensing sample plots were established. The most recent one, the sixth NFI, took place during 1999–2003, covering the entire country for the first time. This NFI established 415,000 permanent sample plots and 2,844,400 remote sensing sample plots. Data from the sixth NFI were released in August 2005. Data from the initial forest resources survey and the subsequent six NFIs are the most comprehensive data set available for forest resources in China. Because of the fact that NFIs were an evolving process, data inconsistencies were inevitable. However, the data set reflects the overall trajectory of change of forests in China. We have extracted the total new forested areas from afforestation, deforestation, and reforestation from this data set. Consequently, we were able to assess the impact of these activities on China’s forest cover from 1949 to 2003. Analysis and Results Overall Forest Cover Dynamics. China’s forest cover increased dramatically from 8.6 to 18.21% from 1949 to 2003 (Table 1). It is the result of the combined effects of afforestation, deforestation, and reforestation. From 1949 to 2003, the cumulative planted areas in China were 241 million ha, equivalent to 25 percentage points in forest cover (Table 1). However, the actual contribution from afforestation was equivalent to an increase of 9.4 percentage points in forest cover or 90 million ha in forest areas. The majority of the afforested areas failed to reach minimum canopy cover required to be classified as forests. Only 37% of the afforested areas eventually established as plantation forests. The most recent NFI in 2003 found that plantation forests covered 53 million ha of the country’s land area, suggesting 37 of the 90 million ha of the established plantation forests were harvested. The total timber volume harvested from both plantation and natural forests during 1949– 2003 was 13.0 billion m, equivalent to 16 percentage points in forest cover at a stocking volume of 85 m/ha. In reality, timber harvesting had affected much larger areas because of selective and staged cutting, implying almost all forests suitable for harvesting might have been harvested at least once, and many areas may have been harvested multiple times. From 1962 to 2003 China’s forest cover increased 6.4 percentage points, of which 5.0 percentage points was contributed by afforestation. Impacts of Afforestation, Deforestation, and Reforestation. Table 2 shows the changes in China’s forest cover caused by afforestation, deforestation, and reforestation from 1949 to 2003. The impacts are assessed for plantation and natural forests, respectively. The net change in forest cover of plantation forests is the decrease caused by deforestation of plantation forests after compensation of the increase in plantation forest areas from afforestation. The net change in forest cover of natural forests is the decrease caused by deforestation of natural forests after compensation of the increase in natural forest areas via reforestation. The net change in overall forest cover is the sum of the net changes from plantation and natural forests. Because of World War II and the subsequent Civil War in China before the establishment of China, data were scarce for accurate estimates of China’s forest cover in 1949. The former Ministry of Forestry estimated China’s forest cover was 8.6% in 1949. The initial forest resource survey during 1950–1962 found that natural forests decreased 1.20 percentage points in forest cover, and plantation forests increased 0.53 percentage points in forest cover. However, overall forest cover was estimated to be 11.81% in 1962. This increase in forest cover can not be explained by the contribution from afforestation, deforestation, and Table 1. Forest cover and areas from natural resources survey and NFIs from 1949–2003. Years Plantation forest areas ( 10ha) Total forest areas ( 10ha) Total forest cover (%) Plantation forest cover (%) New planted areas ( 10ha) 1949 — — 8.60 — — 1950–1962 5.11 113.36 11.81 0.53 34.12 1963–1972 — — — — — 1973–1976 (I) 23.69 121.86 12.70 2.47 56.13 1977–1981 (II) 22.19 115.28 12.00 2.31 22.44 1984–1988 (III) 31.01 124.65 12.98 3.23 43.63 1989–1993 (IV) 34.25 133.70 13.92 3.57 27.76 1994–1998 (V) 46.67 158.94 16.55 4.86 25.29 1999–2003 (VI) 53.26 174.91 18.21 5.55 31.85 Forest cover is calculated based on the country area of 960 million ha (i.e., 9.6 million km) for China, including Taiwan, Hong Kong, and Macao. Forests in Taiwan, Hong Kong, and Macao are not separated into plantation and natural forests in the NFIs. New planted areas are the areas planted during the inventory period. These areas are not forests until the canopy cover reaches 30 and 20% before and after the fifth NFI, respectively. There are numerous reports for forest areas in China in the literature. However, existing reports are inconsistent. Discretion should be given to the definition of forests in various reports. For example, the Global FRA 2000 and 2005 of the United Nations FAO reported larger forest areas for China than we reported here because of the difference in forest definitions (FAO 2001, Su et al. 2005). Data in this table are direct results from NFI (Chinese Government Documents 1977–2005). The roman numbers indicate sequence of NFI. There was no forest resource information during 1963–1972. a This figure includes new planted areas during 1963–1972. b This figure includes new planted areas during 1982–1988. 384 Journal of Forestry • October/November 2006 reforestation, indicating China’s forest cover might have been underestimated in 1949. Timber harvesting during the first NFI from 1973 to 1976 was primarily natural forests, most of which were recovered through reforestation. The overall forest cover increased during 1973–1976 as a result of the increase in plantation forests (Table 2). Plantation forests established earlier began reaching harvesting status during the second NFI from 1977 to 1981, leading to a sharp increase in harvesting of plantation forests. Consequently, harvesting of natural forests decreased. However, there was a net loss of forest cover for both plantation and natural forests. The overall forest cover decreased 0.7 percentage points during 1977– 1981. The area of natural forests harvested continued to decrease during the third NFI from 1984 to 1988 because of compensation from plantation forests harvested. The overall natural forest cover managed to increase marginally. Another important reason for the decrease in areas of natural forests harvested was the changes in timber harvesting methods and concurrent efforts to protect natural forests. Timber harvesting shifted from earlier clearcutting to include selective and staged cuttings, which did not change overall forest cover. In fact, the total volume harvested during 1984–1988 increased significantly from 1977 to 1981 (Table 3). Thus, the actual areas affected by harvesting were much larger than the areas deforested. Because of earlier intensive harvesting of the natural forests, most of the deforested areas were plantation forests during 1984–1988, indicating plantation forests were becoming a major source for timber production (Table 2). The rapid increase in forest cover from afforestation was partly caused by a higher standard for afforestation adopted in 1985, raising the survival rates from 40 to 85% in the south and to 70% in the north to pass afforestation inspection (Chinese Ministry of Forestry 1989). The new standard for afforestation should improve the contribution rate from afforested areas to national forest cover in the years to come. Natural forest cover increased sharply during the fourth NFI from 1989 to 1993, exceeding that of plantation forests for the first time because of continued intensive harvesting of plantation forests. Plantation forests continued to be a major source of timber production. The overall forest cover increased 0.94 percentage points during 1989–1993 (Table 2). Overall forest cover in China sharply increased 2.63 percentage points during the 1994–1998 NFI (Table 2). One major reason for the dramatic increase was a change in the definition of forest. Forest definition by former Ministry of Forestry in China was different from that of other developing countries. In the FRA 1980 and 1990 of FAO of the United Nations (FAO 2001), the minimum canopy cover required to be classified as a forest is 10% for developing countries and 20% for the developed countries. The same definition of a minimum 10% canopy cover was used for all countries FAO definition of forest also included temporarily unstocked forest areas that were not included as forested areas in China’s NFI. Table 2. Change in forest cover caused by afforestation, deforestation, and reforestation in China from 1949 to 2003. Years New plantation forests Plantation forests harvested Natural forests regenerated Natural forests harvested Planted net change Natural net change Net forest change 1949 — — — — — — — 1950–1962 0.53 0.0 1.18 2.38 0.53 1.2 3.21 1963–1972 — — — — — — — 1973–1976 1.94 0.0 2.58 3.63 1.94 1.05 0.89 1977–1981 0.45 0.61 0.69 1.23 0.16 0.54 0.7