DETERMINACIÓN DE LA CONCENTRACIÓN DE ACEITES Y GRASAS (A&G)

3.2.1 Deforestation in the Country as A Whole

China has a long history o f deforestation. A number of writers, Murphey (1983), Smil (1983, 1992), Pearce and W arford (1993), Liu (1993), Edmonds (1994) and Lughezzani (1995) have discussed the consequences of deforestation in China. Murphey (1983), Qu and Li (1992) and Edmonds (1994) show that the history of deforestation develops with population and economic growth. Reforestation has not kept pace with logging. The Chinese government insisted that the forest cover in 1949 amounted to 8.6 percent of surface area, or about 83 million hectares. Following a decline during the early 1950s, Chinese sources reported that forest cover expanded in an irregular manner to about 13 percent of the surface cover area from the 1984-1988 survey.

Unfortunately, these figures seem to exaggerate the success that had been achieved. This point can be shown by subtracting newly afforested area. From 1949 to 1984, over 131 million hectares were afforested but only about 25 percent were successful. It is reported that during 1984-1988 there were 124 million hectares of forests. It seems that forest land cannot have been

less than 91 million hectares, or 9.7 percent of surface in 1949 (Ross 1988).

Forest distribution is geographically unbalanced in China. Most of the forest areas are in the Provinces of Heilongjiang (13.3%), Inner M ongolia (11.9%), Jilin (5.3%), Sichuan (5.9%), Yunnan (8.0%) and Tibet (5.5%). These areas account for nearly 50% of forest lands and 71.9% of timber stocks. However, in the west part of China, where the area is more than one half of the territory, the forest area is less than 1/30 of the total area and the forest cover is below 5%.

Table 3.3 Changes of Forest Volume in 5 M ain Forest Provinces (million hectares, million cubic metres)

province 1973-1976 1977-1981 1984-1988

area volume area volume area volume

Heilongjiang 16.6 1468 15.3 1437 15.6 1317

Inner M ongolia 10.4 717 13.7 848 11.8 775

Jilin 6.5 684 6.1 657 5.1 590

Yunnan 9.2 911 9.1 1097 6.0 698

Sichuan 7.1 1241 6.8 1049 6.3 713

Sources: the Academy of Sciences of China and the State Planning Commission

Data Volume o f Land Resources o f China, V ol.l, Beijing, 1989.

3.2.2 Northeast and Inner Mongolia

Since the end of 19th century, the forest cover in Heilongjiang province has dropped from 70 percent to 34 percent. The timber stock has dropped from 4 billion cubic metres to 140 million

cubic metres and most o f the trees there are small. The forest border has shrunk by 150 kilometres. Upstream of the Songhuajiang River, the forest cover rate has reduced by 10 percent during the last 20 years, which has led to a 25 percent decrease in water level in the river.

Daxinganling is the largest forest area in China, located between the very northern part of Heilongjiang Province and Inner Mongolia, close to Siberia. 30 years ago, Jiagedaqi was still an area of virgin forests and there were only several thousand Evenk and Elunchun people (Minorities in China) living in the forests of the area. Now the area is a city of over 200,000 inhabitants. The General Bureau of Forestry of Daxinganling is located in Jiagedaqi with 293,000 employees in total all over the forest area. There are 9 bureaus under the management of Daxinganling General Bureau of Forestry. Bureaus under management of Jiagedaqi are: Songling, Tahe, Tuqiang, Xilinji, Shibajan, Xinlin, Aermu, Huzhong and Jiagedaqi. As a rough estimation, the total population exceeds 500,000 in the Daxinganling area.

Due to its high latitude, Daxinganling has only a 90 days non-frost period. The tree growth period is short and most of the trees grow very slowly in this area. The soil layer is thin in this area, between 10-20 centimetres, with a mixed layer of yellow soil and stones underneath, the ecosystem in this area is very fragile. Once the original vegetation is destroyed, soil erosion follows easily and it is very hard to restore the original vegetation (see Appendices 1 , 2 , 3 and 4). Because of the cold climate, there are some places in the area where soil is permanently frozen. On this permanent frozen soil, a hundred years old tree is no thicker than a m an’s arm and stands shorter than a man. Given the severity and length o f the winter, trees are the only fuel for heating in this area. In Daxinganling there is a huge stackpile o f wood for heating in every courtyard of each household. In all probability these have been taken from the surrounding forests.

The original conifer and other trees in this area are larch, Zhangzisong (a kind of Chinese fir) forests with a small proportion o f oaks and birches. In the past thirty years, almost all virgin forests have either been selectively logged, partially logged or completely logged. There is

virtually no virgin forest left except in some remote areas. Most of these areas consist of secondary woods of birch arising after the original conifer trees were logged. There are also young larch in some areas. Forest density is very low and all trees are very young. These trees are rarely thicker than a m an’s leg. Plantation is not very successful in this area due to the cold weather and poor soil quality. The local people consider that the forest resources in the area can at most last only seven to eight years for logging. As the need for workers has declined, the populace has been forced to rely increasingly on herb gathering and other means o f earning a living from the forest^ (Liang 1994) and this is also the case in the Changbaishan Mountain forest area (the second largest forest area in China), where ginseng plantations are everywhere to be seen.

In the Xiaoxinganling forest area, the virgin forests have all been replaced by large areas of secondary woods and jungle; the forest resources have been greatly deforested over the past forty years. W ith 6 million hectares of forest areas, the forest cover rate was less than 50 percent and there were no timber resources suitable for logging. In the Yichun forest area, there were 1.4 million hectares of trees suitable for logging in 1949. In 1983 only 765,000 hectares of trees remained, more than half of the area of trees having been cut down. As Zhang (1993) reports, of the remaining trees, less than 10% were o f high quality.

In the west area o f the Sonhuaj iang-Nunjiang plain, because deforestation is greater than reforestation, the forest cover is too low to prevent aggravation by wind and sand damage, and as a result the grassland has degraded. Owing to destruction of the forest, the environment for animals has also changed and deteriorated. Tiger and deer are virtually extinct. Bear and wild pig are rarely sighted in the area. The unbalanced ecosystem here has resulted in the frequent occurrence of droughts and floods. It was recorded that in 1854-1874, forest cover was more than 70 percent in the area, and the probability of there being a drought or flood only 10%. From 1925 to 1974, the forest cover rate fell to 37 percent while the frequency of drought and

^ Planting ginseng and fostering mushroom and edible fungus are the main means of making a living in these areas.

flood disasters increased to 38 percent, including 5 severe droughts in the period. From 1984 to 1988, the forest cover rate reduced to an all time low of 34 percent. In summer of 1994, Harbin was hit by the Songhuajiang River’s most heavy flood.

In the Changbaishan M ountain area, there were 5.2 million hectares of forest area in the 1950s, with the forest cover 63 percent. In the mid-1970s, the forest area was reduced to 34 percent, and the area of trees dropped by more than 16 percent. In the 1980s, the forested area was reduced by more than 18 percent compared with that o f the 1950s. The timber trees area dropped by 19 percent (Ren and Bao 1992). Many precious species of tree have vanished. For example, the percentage of Korean pine is less than 3 percent in the natural forest, whereas most artificial plantations are larches, and the timber quality o f the latter is comparatively low. The decreased percentage of coniferous trees has led to an increase in insect damage and an enlargement in the scale o f soil erosion in these areas.

3.2.3 Central China

Most of the forests in the central part of China were logged in the past several thousand years and there is a very low forest cover in the area. A few remnants of natural forests exit either in the high mountain areas or in remote places. However, even these forests have not escaped deforestation or reclamation for agricultural production.

The following are illustrations of deforestation in the central part of China. In the Qinling- Banshan mountain area of Shaanxi Province, 22 out o f 30 counties have a timber consumption which is higher than the rate of growth of trees. Consumption is 87% higher than the annual growth rate of trees. The forest border has shrunk 10-20 kilometres compared with that in the 1950s. Denudation of forest, clear felling trees for agricultural cultivation, and planting crops on the steep slopes o f mountains have all led to large areas of soil erosion. In Ankang of Shaanxi Province, 23% o f the cultivated land was on a slope greater than 35 degrees. In Zhenba County in Hangzhong Prefecture 60% of cultivated land was on a slope greater than 25 degrees,

and 41.3% land was on a slope greater than 30 degrees. In the low mountain areas o f Zhenba County, the annual soil erosion quantity has reportedly reached 6000 tons per square kilometre. (Ren and Bao 1992).

3.2.4 South and Southwest China

Deforestation was serious in the south part of China. In Hainan Province historically there used to be a vast area of tropical forest. The area was 867,000 hectares in the 1950s and forest cover was 25.7 percent. Because of denudation and reclamation for agricultural land, the forest area is now less than 400,000 hectares and forest cover is only 10%. Destruction of forest vegetation led to an increase in frequency of droughts and floods, and sedimentation of river and port areas. Sand content in the water flow of Nandujiang River, Changhuajiang River and Wanquan River has increased owing to the reduction of forest areas. In the 1960s the sand content of the three rivers was on average 0.10 kilograms per cubic metre; in the 1970s, the sand content was 0.15 kilograms per cubic metre, an increase of 39 percent.

In Xishuangbanna Prefecture of Yunnan Province, a large tropical rainforest maintained a good natural environment in the past. The change of forest cover over the years is shown below (Ren and Bao 1992):

year forest cover

1950s 55%

1959 44.7%

1963 3&19&

1973 33.9%

1980 29.8%

In the past several decades, the forest area has reduced at a rate of about 17,000 hectares per year. This has caused deterioration of the environment and has threatened the existence o f many

varieties of plants. It is recorded that since 1957, 500-800 species and varieties have become extinct or close to extinction (Ren and Bao, 1991). The situation has also endangered the existence of some animals in the forest. For instance, rhinoceros in Xishuangbanna have become extinct. The stock levels of the gibbon, the tiger, the elephant, the wild bull, and some species of bird have decreased rapidly. Xishuangbanna was called ’the home o f the peacock’, but now they are very rare. Some insects which can pass on pollens have also reduced in number, marketing it necessary to provide some plants with artificial pollen.

In the southwest area of Sichuan Province and the north area o f Yunnan Province, trees are cut down for firewood. Forest has been extensively destroyed with the result that forest cover is now just 19.5 percent. In the southeast area, forest cover is only 15.4 percent. In the northeast part of Yunnan Province the forest cover is only 18.8 percent. In Xuanwei County, forest cover was 64 percent in the 1950s, but has now fallen to only 4.6 percent. In Simao of Yunnan Province forest fires and conversion into agricultural land have reduced the forest area by 20 percent. In Honghe Prefecture, forest cover in 1958 was 48 percent, in 1962 it was 43 percent while in 1973 the rate dropped to 18 percent. Barren mountains and land have become common spectacles. Deforestation has led to an unbalanced ecosystem, an increase in the frequency of natural disasters, soil erosion, mud-rock collapse and landslides. In Yangliuxiang of Guangxi Autonomous Region, large scale denudation and reclamation has caused soil erosion, and sand and soil have inundated 300 hectares of farmlands.

Deforestation in the southwest part (Yunnan, Sichuan and Guizhou Provinces) of China is very high and has continued for some time. According to the survey in 1980-83, using the primitive slash-and-bum cultivation method, burning forest for cattle grazing and hunting led to a 700,000 m^ loss o f timber on average per annum; furthermore, denudation induced a reduction in timber o f 10 million cubic metres on average per annum; and forest fires caused loss o f forest o f about 1.3 million cubic metres on average per annum. Consequently, large amounts o f timber cutting and daily consumption have also led to a high reduction o f forest area. Because of the reasons mentioned above, the net reduction of forest resources in Yunnan Province during that period

was 10 million cubic metres on average per annum.

3.3 T he F o re st C rises in C hina

3.3.1 Decline of Natural Forests

In the previous section, the trends within the process of deforestation in China have been compiled. In this section some specific points and implications of deforestation are highlighted. There has been a striking reduction in major natural forest areas, that is, the forests without plantation. During 1984-1988 the main forest resources in the northeast part of China and Inner Mongolia decreased by 277,000 hectares compared with the figure during 1977-1981. W hile the area of overall forests increased slightly during 1984-1988, the volume and area o f timber forests decreased. During 1984-1988 the biggest reduction was 5.2 million hectares in the northeast part and Inner Mongolia. The next was Yunnan and Sichuan Provinces at 1.2 million hectares. Ten provinces in the south part of China decreased by 0.9 million hectares and other provinces decreased by 0.06 million hectares.

Table 3.2 shows the overall decline in forest resources in China over the past two decades. The decline in the timber stock is indisputable. The total tim ber stock from forests was 9571 million cubic metres over the period 1977-1981 and 9418 million cubic metres over the period 1984- 1988, of which, the stock from timber forest was 6882 million cubic metres during 1977-1981 and the volume was 6173 million cubic metres during 1984-1988, the total reduction was 709 million cubic metres. On the other hand, the stock from sparse woods was 542 million cubic metres during 1977-1981 and 546 million cubic metres during 1984-1988; the stock from individual trees was 545 cubic metres during 1977-1981 and 695 million cubic metres during 1984-1988; the stock from trees along streets and around houses was 146 million cubic metres during 1977-1981 and 191 million cubic metres during 1984-1988. In China, as we mentioned before, tim ber volume and forest cover include individual trees along streets and around houses.

The volume of mature forests declined considerably from 3846 million cubic metres in 1976- 1981 to 2622 million cubic metres in 1984-1988, a total reduction of 1224 million cubic metres. Within only seven or eight years, one third o f mature forests was depleted, the net reduction rate being 4.4% per annum. As mentioned above, in Tibet there are 500 million cubic metres of mature forests which are still difficult to reach with present technology. The rem ainder includes a large proportion of diseased, wind-broken and withered trees. In addition to these, there are substantial forests located along the upstream of rivers that cannot be logged because o f their important function in soil conservation and ecosystem protection. Another large proportion of forests is located in high mountains and deep valleys. Transportation cannot not be extended to such places, rendering these forests very inaccessible for felling. The percentage suitable for timber felling, over all mature forests, is estimated to be only 79 percent. According to recently published figures tim ber stock from mature forests decreased by 200 million cubic metres during 1989-1993.

Between the period 1977-1981 and the period 1984-1988, total timber volumes decreased by 153 million cubic metres, the net reduction rate was 1.6%; the annual reduction was 27 million hectares and annual reduction was 0.3%. In all provinces, ten provinces in the south showed a reduction of 186 million cubic metres; Sichuan and Yunan provinces showed a reduction of 86 million cubic metres and the northeast part and Inner M ongolia showed a reduction of 83 million cubic metres. There was in fact an increase in ’Other Provinces’, the total increase was

128.8 million hectares. But the decrease was greater than the increase o f timber volume.

There was a sharp decline in timber volume throughout the whole country. The mature forests reduced most quickly; in the northeast part and Inner M ongolia the annual reduction was 109 million cubic metres by our calculations; Yunnan and Sichuan provinces had an annual average reduction of 31 million cubic metres; ’Ten Provinces’ in the south had an annual average reduction o f 22 million cubic metres and other provinces had an annual reduction o f 8.6 million cubic metres.

The shortage of forest resources has had severe consequences for industrial production and living standards (Wang 1994). Timber distributed through state channels totals over 60 million cubic metres per year'*. Besides trees used as timber, there are other timber consumptions^ as well and the total consumption of timber was 344 million cubic metres per year (the Ministry o f Forestry 1990). The shortage has affected the entire economy, and along with only two other goods steel and cement, tim er has been subject to strict pricing and distribution quota controls by the Ministry of Materials before 1992.

Table 3.4 Different Categories of Forest Areas unit:million hectares category 1973-1976 1977-1981 1984-1988 total area 257.6 261.0 261.0 forested area 105.0 113.6 119 sparse woods 15.6 17.2+5.6** 19.6+7.3+0.2** bushes 29.6 2&8 28.1 unforested area 107.4 97.8 86.6

individual trees n.a n.a. n.a.

trees along streets and around houses

n.a. n.a. n.a.

** These were areas of young trees before forming into forests

“*Data from the Statistics o f Forestry in China 1992.

^It is unclear for the composition of other consumptions. According to the statistics, timber output was 60 million cubic metres in 1992 and the total timber consumption was 344 million cubic metres.

Table 3.5 Comparison of Two Forest Surveys in China

area tim e period total timber volum e (m illion m^)

forest area (m illion ha.)

timber forest (m illion m ')

unforested land (m illion ha.)

forest density per mVha.

total 77-81 9571 113.6 6 882 101.9 84.3

8 4-88 9418 119.2 6173 86.6 7 9.0

changes -153 + 5.4 -709 -15.3 -5.3

year av. -19.1 +0.7 -88.6 -1.9

northeast and Inner 77-81 3209.1 35.1 2709.2 30.6 86

M ongolia 8 4-88 3210.2 34.8 2568.7 19.9 83.9

changes +1.1 -0.3 -140.5 -10.7 -2.7

year av. +0.13 -0.04 -17.6 -1.3

Yunnan & Sichuan 77-81 2856.6 19.4 1798.2 14.7 141

8 4-88 2759.3 20.1 1411.1 13.3 127.8

changes -97.3 +0.8 -387.1 -1.4 -13.2

year av. -12.2 +1 -48.4 -0.18

ten south provinces 77-81 1871 39.4 1336.7 3 0.2 49.6

84-88 1685.4 40.7 1138.8 2 7.2 4 3.7 changes -185.6 +1.3 -197.9 -3 -5.9 year av. -23.2 +0.2 -24.7 -0 .4 other provinces 77-81 1021 16.6 592.2 25 62.3 8 4-88 1149.8 18.6 535.6 23.9 59.8 changes + 128.8 +2 -56.6 -1.1 -2.5 year av. +16.1 +0.3 -7 -0 .1 4 no-survey 77-81 613.5 3.1 503.2 1.4 185.4 provinces 84-88 changes year av.

Source: T he M instry o f Forestry, S tatistics o f F orest R esou rces in China, Forest Press, B eijing, 1990.

3.3.2 Further Discussions

W hen the total timber volume declined from 9571.2 million cubic metres during 1977-1981 to