**3. Results and Discussion**

#### **3.1. Detection of changes in natural forest, and rubber and pulp plantations**

#### *3.1.1. Spatial distribution of natural forest, and rubber and pulp plantations*

Combining DEM with remote sensing monitoring results in 1988, 1998, and 2008 (**Figure 8(1)**–**(3)**), the natural forests are mainly distributed in Wuzhishan mountain, Jianfengling mountain, Bawangling mountain, Diaoluoshan mountain, Limushan mountain of central Hainan Island areas above 600 m above sea level, while the central mountain valleys are invaded by other ecosystem types. There is relatively little natural forest distribution between 100 and 600 m above sea level, and below 100 m above sea level are mostly sparse grasslands.

**Figure 9.** Spatial distribution of pulp plantation in Hainan Island. (1) 1998; (2) 2008.

**Figure 8.** Spatial distribution of natural forest in Hainan Island. (1) 1988; (2) 1998; (3) 2008.

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**Figure 10.** Spatial distribution of rubber plantation in Hainan Island. (1) 1988; (2) 1998; (3) 2008.

As can be seen from **Figure 9(1)** and **(2)**, the planting scale of pulp plantation was relatively small in 1998, mainly scattered distribution in Qiongzhong Li and Miao Autonomous County, Tunchang County, Baisha Li Autonomous County, Danzhou city, and Lingao County. From **Figure 9(2)**, the pulp plantation planting area of 2008 has significantly increased compared with 1998. The spatial distribution of 2008 is relatively wide and evenness. The eastern of the northwest, Changjiang Li Autonomous County, Danzhou city, Lingao County offshore area and northern Chengmai County, Anding County formed strip-shaped shelterbelts, accounting for 29% of the total area of pulp plantations (194,000 hectares). These shelterbelts are responsible for windbreak, sand retention, and storm surge prevention. There is a sparse distribution of in the northern, southern, and southeastern coastal areas of Haikou. From the terrain view, there is wide distribution of pulp plantations between the coastal plains to the platform below 25 degrees slope. Part of the pulp forest distribution in the mountains above 25 degrees occupied the central mountainous areas of natural forests and even nature reserves. The spatial distribution of rubber plantation in Hainan Island showed in (**Figure 10**).

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**Figure 8.** Spatial distribution of natural forest in Hainan Island. (1) 1988; (2) 1998; (3) 2008.

transportation corridors, and the elevation and slope of each site. The data of nature protection areas were derived from the map of national nature protection area; the data of farms and transportation were extracted from Landsat TM images; the data of elevation and slope were extracted from DEM. The study area was divided into grid cells, and the information for each grid cell was extracted by the spatial analysis model of the GIS software. By using random permutation tests [16] to choose grid cells in each year, the association of different forest types with the abovementioned factors was examined. We used the average Euclidean distance between the multiple forest patches and these driving factors to capture differences in conservation value and human activity. For multiple forest conversions, the following method was used to identify the key factors: the patch of the different forest area serves as the basic unit; then, adjacent patches with the same change trends were classified into a uniform block. The average value of a factor in each block with the same trend was used to serve as a sample, and the value of the factor served as a collective value. The ratio of the area covered by a particular land use type in 2008 was compared with the corresponding blocks of the two previous periods (1988 and 1998) to detect changes using the overlay. Then, we took the altitude, slope, and the minimum distance from the farmland and road to the area where transformation occurred as variable and took the transformation of forest types as dependent variable. General regression analyses between them were conducted by collectively analyzing the blocks with the same trends.

**3.1. Detection of changes in natural forest, and rubber and pulp plantations**

above sea level, and below 100 m above sea level are mostly sparse grasslands.

Combining DEM with remote sensing monitoring results in 1988, 1998, and 2008 (**Figure 8(1)**–**(3)**), the natural forests are mainly distributed in Wuzhishan mountain, Jianfengling mountain, Bawangling mountain, Diaoluoshan mountain, Limushan mountain of central Hainan Island areas above 600 m above sea level, while the central mountain valleys are invaded by other ecosystem types. There is relatively little natural forest distribution between 100 and 600 m

As can be seen from **Figure 9(1)** and **(2)**, the planting scale of pulp plantation was relatively small in 1998, mainly scattered distribution in Qiongzhong Li and Miao Autonomous County, Tunchang County, Baisha Li Autonomous County, Danzhou city, and Lingao County. From **Figure 9(2)**, the pulp plantation planting area of 2008 has significantly increased compared with 1998. The spatial distribution of 2008 is relatively wide and evenness. The eastern of the northwest, Changjiang Li Autonomous County, Danzhou city, Lingao County offshore area and northern Chengmai County, Anding County formed strip-shaped shelterbelts, accounting for 29% of the total area of pulp plantations (194,000 hectares). These shelterbelts are responsible for windbreak, sand retention, and storm surge prevention. There is a sparse distribution of in the northern, southern, and southeastern coastal areas of Haikou. From the terrain view, there is wide distribution of pulp plantations between the coastal plains to the platform below 25 degrees slope. Part of the pulp forest distribution in the mountains above 25 degrees occupied the central mountainous areas of natural forests and even nature reserves. The spatial distribution of rubber plantation in Hainan Island showed in (**Figure 10**).

*3.1.1. Spatial distribution of natural forest, and rubber and pulp plantations*

**3. Results and Discussion**

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**Figure 9.** Spatial distribution of pulp plantation in Hainan Island. (1) 1998; (2) 2008.

**Figure 10.** Spatial distribution of rubber plantation in Hainan Island. (1) 1988; (2) 1998; (3) 2008.


The differences in the spatial distribution of natural forests in 1988, 1998, and 2008 (**Figure 11(1)**–**(3)**) are mainly concentrated on three large areas, namely Danzhou, Qiongzhong, and Baisha, which showed the change in characteristics, for example, increasing-decreasing-increasing, and the same applied for Changjiang Li Autonomous County and Dongfang County. The boundaries of Qionghai and Wanning counties (cities) are increasing continuously, while others such as Sanya City show continuously reducing state.

**2.** Rubber plantations-natural forest pattern changes.

As a whole, the rubber plantation converted into natural forests from 1988 to 2008 showed fragmentation character, except parts of Qionghai, Wanning, and Qiongzhong that have block area from 1988 to 1998 and from 1998 to 2008 (**Figure 12(1)**–**(3)**). Most of the changes are located in the central mountainous area and its surrounding areas, but the spatial distribution is uneven, such as Qiongzhong and Ledong County. To analysis the total changed area, the area changes of 1988–2008 (29,200 hectares) are more significant than the changes of 1988–2008 (28,000 hectares) and 1998–2008 (12,000 hectares).

As can be seen from **Figure 15**, the area of newly increased pulp plantation was relatively small (11,400 hectares) during 1988–1998, which mainly distributed at Danzhou, Qiongzhong, Baisha, Tunchang Counties. The area increased greatly to 193,800 hectares during 1998–2008. The most obvious is the formation of zonal areas along the northern coastal plains of the east, Changjiang, Danzhou, Lingao, Chengmai, the south of Haikou, and Wenchang. It contains 43.7% of the increased area. The strip-shaped forest zone also plays a role in the windbreak and sand fixation. The distribution of pulp plantation in other areas mainly showed small patches, mostly distributed in the central mountainous area and its surrounding area, with a small amount of distribution along the eastern

**Figure 12.** Spatial distribution of rubber plantation converted into natural forest: (1) 1988–1998; (2) 1998–2008; (3)

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**2.** Spatial pattern of natural forest converted into pulp plantation.

**Figure 13.** Distribution pattern of other forest converted into natural forest: (1)1988–1998; (2) 1988–1998.

coast.

1988–2008.

**3.** Distribution pattern of other forest converted into natural forest.

The total area of other forest (mainly farmland, grassland, etc.) converted into natural forests is small and shows sporadic distribution (**Figures 13** and **14**).


**Figure 11.** Newly increased natural forest distribution pattern: (1) 1988–1998; (2) 1998–2008; (3) 1988–2008.

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**Figure 12.** Spatial distribution of rubber plantation converted into natural forest: (1) 1988–1998; (2) 1998–2008; (3) 1988–2008.

As can be seen from **Figure 15**, the area of newly increased pulp plantation was relatively small (11,400 hectares) during 1988–1998, which mainly distributed at Danzhou, Qiongzhong, Baisha, Tunchang Counties. The area increased greatly to 193,800 hectares during 1998–2008. The most obvious is the formation of zonal areas along the northern coastal plains of the east, Changjiang, Danzhou, Lingao, Chengmai, the south of Haikou, and Wenchang. It contains 43.7% of the increased area. The strip-shaped forest zone also plays a role in the windbreak and sand fixation. The distribution of pulp plantation in other areas mainly showed small patches, mostly distributed in the central mountainous area and its surrounding area, with a small amount of distribution along the eastern coast.

**2.** Spatial pattern of natural forest converted into pulp plantation.

*3.1.2. Change analysis of natural forest, rubber and pulp plantations*

**1.** Newly increased natural forest distribution pattern.

as Sanya City show continuously reducing state. **2.** Rubber plantations-natural forest pattern changes.

**3.** Distribution pattern of other forest converted into natural forest.

*3.1.2.2. Spatial pattern of newly increased pulp plantation in 1988–2008*

**1.** Spatial pattern of newly increased pulp plantation.

ests is small and shows sporadic distribution (**Figures 13** and **14**).

**Figure 11.** Newly increased natural forest distribution pattern: (1) 1988–1998; (2) 1998–2008; (3) 1988–2008.

hectares).

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*3.1.2.1. Newly increased natural forest distribution pattern analysis in 1988–2008*

The differences in the spatial distribution of natural forests in 1988, 1998, and 2008 (**Figure 11(1)**–**(3)**) are mainly concentrated on three large areas, namely Danzhou, Qiongzhong, and Baisha, which showed the change in characteristics, for example, increasing-decreasing-increasing, and the same applied for Changjiang Li Autonomous County and Dongfang County. The boundaries of Qionghai and Wanning counties (cities) are increasing continuously, while others such

As a whole, the rubber plantation converted into natural forests from 1988 to 2008 showed fragmentation character, except parts of Qionghai, Wanning, and Qiongzhong that have block area from 1988 to 1998 and from 1998 to 2008 (**Figure 12(1)**–**(3)**). Most of the changes are located in the central mountainous area and its surrounding areas, but the spatial distribution is uneven, such as Qiongzhong and Ledong County. To analysis the total changed area, the area changes of 1988–2008 (29,200 hectares) are more significant than the changes of 1988–2008 (28,000 hectares) and 1998–2008 (12,000

The total area of other forest (mainly farmland, grassland, etc.) converted into natural for-

**Figure 13.** Distribution pattern of other forest converted into natural forest: (1)1988–1998; (2) 1988–1998.

The spatial distribution of other ecosystem types (farmland, tea garden, grassland, etc.) varied from 1988 to 1998, mainly in small blocks distributed in Danzhou, Qiongzhong, Baisha, Tunchang counties and cities. It increased significantly during 1998–2008, accounting for 67.5% of the total increase area (193,800 hectares), forming strip-shaped areas along the northern coastal plain of the east, Changjiang, Danzhou, Lingao, Chengmai, south of Haikou, and Wenchang County (city). Others are distributed in the central mountainous

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The newly increased rubber plantation mainly evenly distributed in the central mountainous area and its surrounding area during 1988–1998. The total area (51,400 hectares) is small. From 1998 to 2008, the area (467,300 hectares) has a great increase in the central mountainous area and its surrounding area. It extends inward and outward along the central mountainous area, especially in the northeast of Tunchang, Chengmai, Lingao, Haikou, and other counties even into sheet shape. The area during 1988–2008 changes is not

The area of newly increased natural forests converted into rubber plantations (0.37 million hectares) is small and spatially dispersed during 1988–1998, as can be seen from **Figure 17(1)**. It is mainly around the central mountainous area. From 1998 to 2008, the area of natural forest into rubber plantation changed significantly (110,900 hectares), and the increase mainly concentrated in the central mountainous area and the surrounding areas, showing the Qiongzhong, Tongshi, Baisha County as the center, the pattern of radiation to Sanya, Baoting, Ledong, Danzhou, and other counties (cities). From 1988 to 2008, the change of the total area (96,800 hectares) was not as obvious as that of 1998–2008 except for the changes in Qiongzhong, Tongshish, Baisha County (city) as the center of the region, the distribution of Sanya

**Figure 16.** The spatial pattern of newly increased rubber plantation. (1) 1988–1998; (2) 1998–2008; and (3) 1988–2008.

areas and the coastal plains.

*3.1.2.3. The pattern changes of newly increased rubber plantation*

**1.** The pattern of newly increased rubber plantation.

obvious compared with 1998–2008 (**Figure 16**).

and Ledong (city) changes is also obvious.

**2.** The pattern changes of natural forest to rubber plantation.

**Figure 14.** Mutual transformation of natural forest and rubber pulp plantation: (1)1998–2008; (2) 1988–2008.

**Figure 15.** Spatial distribution pattern of newly increasing pulp plantation. (1) 1988–1998; (2) 1998–2008; and (3) 1988–2008.

From 1988 to 1998, the conversion of natural forests into pulp plantation was mainly distributed in Qiongzhong, Danzhou, and Tunchang counties in the northern part of Zhongshan District, with a relatively small area (0.29 million hectares). From 1998 to 2008, the total area (50–200 hectares) increased obviously, which mainly distributed in the central mountainous regions. The center of the change obviously migrated to the south. Apart from the obvious increase in three counties and cities mentioned above, they were also distributed in the Dongfang, Ledong and Sanya counties, and their area diffusions were significant.

**3.** Spatial pattern of rubber plantation converted into pulp plantation.

The change from rubber plantation to pulp plantation was very small (0.02 million hectares) in 1988–1998, mainly in Tunchang County in the northern area of central mountainous. The area (90,000 hectares) increased significantly from 1998 to 2008 mainly in the junction area of northwest Danzhou and northeastern Wenchang – Haikou (city).

**4.** Spatial pattern of other ecosystem types converted into rubber plantation.

The spatial distribution of other ecosystem types (farmland, tea garden, grassland, etc.) varied from 1988 to 1998, mainly in small blocks distributed in Danzhou, Qiongzhong, Baisha, Tunchang counties and cities. It increased significantly during 1998–2008, accounting for 67.5% of the total increase area (193,800 hectares), forming strip-shaped areas along the northern coastal plain of the east, Changjiang, Danzhou, Lingao, Chengmai, south of Haikou, and Wenchang County (city). Others are distributed in the central mountainous areas and the coastal plains.

#### *3.1.2.3. The pattern changes of newly increased rubber plantation*

**1.** The pattern of newly increased rubber plantation.

The newly increased rubber plantation mainly evenly distributed in the central mountainous area and its surrounding area during 1988–1998. The total area (51,400 hectares) is small. From 1998 to 2008, the area (467,300 hectares) has a great increase in the central mountainous area and its surrounding area. It extends inward and outward along the central mountainous area, especially in the northeast of Tunchang, Chengmai, Lingao, Haikou, and other counties even into sheet shape. The area during 1988–2008 changes is not obvious compared with 1998–2008 (**Figure 16**).

**2.** The pattern changes of natural forest to rubber plantation.

From 1988 to 1998, the conversion of natural forests into pulp plantation was mainly distributed in Qiongzhong, Danzhou, and Tunchang counties in the northern part of Zhongshan District, with a relatively small area (0.29 million hectares). From 1998 to 2008, the total area (50–200 hectares) increased obviously, which mainly distributed in the central mountainous regions. The center of the change obviously migrated to the south. Apart from the obvious increase in three counties and cities mentioned above, they were also distributed in the Dongfang, Ledong and Sanya counties, and their area diffusions were

**Figure 15.** Spatial distribution pattern of newly increasing pulp plantation. (1) 1988–1998; (2) 1998–2008; and (3)

**Figure 14.** Mutual transformation of natural forest and rubber pulp plantation: (1)1998–2008; (2) 1988–2008.

The change from rubber plantation to pulp plantation was very small (0.02 million hectares) in 1988–1998, mainly in Tunchang County in the northern area of central mountainous. The area (90,000 hectares) increased significantly from 1998 to 2008 mainly in the

junction area of northwest Danzhou and northeastern Wenchang – Haikou (city).

**4.** Spatial pattern of other ecosystem types converted into rubber plantation.

**3.** Spatial pattern of rubber plantation converted into pulp plantation.

significant.

1988–2008.

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The area of newly increased natural forests converted into rubber plantations (0.37 million hectares) is small and spatially dispersed during 1988–1998, as can be seen from **Figure 17(1)**. It is mainly around the central mountainous area. From 1998 to 2008, the area of natural forest into rubber plantation changed significantly (110,900 hectares), and the increase mainly concentrated in the central mountainous area and the surrounding areas, showing the Qiongzhong, Tongshi, Baisha County as the center, the pattern of radiation to Sanya, Baoting, Ledong, Danzhou, and other counties (cities). From 1988 to 2008, the change of the total area (96,800 hectares) was not as obvious as that of 1998–2008 except for the changes in Qiongzhong, Tongshish, Baisha County (city) as the center of the region, the distribution of Sanya and Ledong (city) changes is also obvious.

**Figure 16.** The spatial pattern of newly increased rubber plantation. (1) 1988–1998; (2) 1998–2008; and (3) 1988–2008.

The rubber plantation was partly replaced by pulp plantation. The rubber plantation was mainly distributed around the platform around the central mountainous area. The rubber and pulp plantations invaded the natural forest in central mountainous area. During 1998–2008, the natural forest decreased significantly, and the main performance was from the terrain around the hills to the central mountain, which sharply declines. The rubber plantations are mainly distributed in the vicinity of water, extending to four directions from southeast to northwest, of which northeast is the most obvious. The pulp plantation area increased greatly, forming a banded area (acting as a shelterbelt) from the northwest to the north. The pulp plantation also expanding obviously in other areas, infiltrating in nature reserves, farms, the southern Sanya area, and so forth. The north and west of pulp plantation distribution was larger than the south and east in general. Large area of natural forest was replaced by pulp

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The total area of tropical forest in the study area increased during 1988–2008. The area of tropical forest covered about 68.57% of the study area in 1988, and then covered about 71.89%

Natural tropical forest always covered the largest area of land use type within the study area, increasing slightly (6.65%) in the first decade (1988–1998), and then decreasing sharply (13.69%) in the second decade (1998–2008). Generally, the area of natural tropical forest

The area of economic forest obviously expanded from 1988 to 2008. Of the economic forest, rubber plantations covered the largest area, but decreased slightly (3.79%) during the economic recession of 1988–1998; then, it experienced a rapid increase in conjunction with the renascent market economy during 1998–2008. A few scattered pulp plantations existed before 1988. Pulp wood was planted widely after 1988, eventually covering about 0.7 × 10<sup>4</sup> hectares

Landscape-scale transformation of various forest types obviously occurred. From 1988 to 1998, natural forest in the piedmont was converted into scattered rubber plantation, ultimately covering 9.57 × 10<sup>4</sup> hectares by 1998. During the next decade (1998–2008), an additional 9.72 × 10<sup>4</sup> hectares natural forest was converted into economic forest (rubber and pulp

> **Pulp wood areas (104 hectares)**

**Total forest area (104 hectares)**

**Rubber plantation (104 hectares)**

 73.48 22.57 \* 95.91 82.66 17.28 0.70 100.64 63.29 35.91 7.09 107.29 \*Hainan Island had sporadic eucalyptus in 1988, but eucalyptus was grown for timber, not for pulp.

of the study area in 2008, with the increase approximately 8% during 1988–2008.

tended to decrease, despite obvious fluctuations during the study period.

and rubber plantation.

**Year Natural forest** 

**(104 hectares)**

**3.2. The change of different forests during 1988–2008**

by 1998 and about 7.09 × 10<sup>4</sup> hectares by 2008 (**Table 1**).

**Table 1.** Area of natural forest and economic forest during 1988–2008.

**Figure 17.** The spatial pattern of natural forest to rubber plantation. (1) 1988–1998; (2) 1998–2008; and (3) 1988–2008.

#### *3.1.2.4. Spatial pattern of newly increased other types of ecosystems*

The increased pattern changes of other types, such as orchards, farmland, grassland, and so forth, are mainly concentrated on the central region of Qiongzhong, Baisha Counties (**Figure 18**).

The major ecosystems in Hainan Island (natural forests, rubber plantation, pulp plantation, farmland, etc.) have been significantly changed in space from 1988 to 2008. Natural forests increased significantly from 1988 to 1998 and the spatial distribution expanded outward from the central mountainous areas, that is, infiltration and expansion from the central mountainous area to the surrounding land. The changes in the central mountainous area were obvious.

**Figure 18.** Spatial pattern of newly increased other types ecosystems: (1) 1998–2008 and (2) 1988–2008.

The rubber plantation was partly replaced by pulp plantation. The rubber plantation was mainly distributed around the platform around the central mountainous area. The rubber and pulp plantations invaded the natural forest in central mountainous area. During 1998–2008, the natural forest decreased significantly, and the main performance was from the terrain around the hills to the central mountain, which sharply declines. The rubber plantations are mainly distributed in the vicinity of water, extending to four directions from southeast to northwest, of which northeast is the most obvious. The pulp plantation area increased greatly, forming a banded area (acting as a shelterbelt) from the northwest to the north. The pulp plantation also expanding obviously in other areas, infiltrating in nature reserves, farms, the southern Sanya area, and so forth. The north and west of pulp plantation distribution was larger than the south and east in general. Large area of natural forest was replaced by pulp and rubber plantation.

#### **3.2. The change of different forests during 1988–2008**

*3.1.2.4. Spatial pattern of newly increased other types of ecosystems*

(**Figure 18**).

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The increased pattern changes of other types, such as orchards, farmland, grassland, and so forth, are mainly concentrated on the central region of Qiongzhong, Baisha Counties

**Figure 17.** The spatial pattern of natural forest to rubber plantation. (1) 1988–1998; (2) 1998–2008; and (3) 1988–2008.

The major ecosystems in Hainan Island (natural forests, rubber plantation, pulp plantation, farmland, etc.) have been significantly changed in space from 1988 to 2008. Natural forests increased significantly from 1988 to 1998 and the spatial distribution expanded outward from the central mountainous areas, that is, infiltration and expansion from the central mountainous area to the surrounding land. The changes in the central mountainous area were obvious.

**Figure 18.** Spatial pattern of newly increased other types ecosystems: (1) 1998–2008 and (2) 1988–2008.

The total area of tropical forest in the study area increased during 1988–2008. The area of tropical forest covered about 68.57% of the study area in 1988, and then covered about 71.89% of the study area in 2008, with the increase approximately 8% during 1988–2008.

Natural tropical forest always covered the largest area of land use type within the study area, increasing slightly (6.65%) in the first decade (1988–1998), and then decreasing sharply (13.69%) in the second decade (1998–2008). Generally, the area of natural tropical forest tended to decrease, despite obvious fluctuations during the study period.

The area of economic forest obviously expanded from 1988 to 2008. Of the economic forest, rubber plantations covered the largest area, but decreased slightly (3.79%) during the economic recession of 1988–1998; then, it experienced a rapid increase in conjunction with the renascent market economy during 1998–2008. A few scattered pulp plantations existed before 1988. Pulp wood was planted widely after 1988, eventually covering about 0.7 × 10<sup>4</sup> hectares by 1998 and about 7.09 × 10<sup>4</sup> hectares by 2008 (**Table 1**).

Landscape-scale transformation of various forest types obviously occurred. From 1988 to 1998, natural forest in the piedmont was converted into scattered rubber plantation, ultimately covering 9.57 × 10<sup>4</sup> hectares by 1998. During the next decade (1998–2008), an additional 9.72 × 10<sup>4</sup> hectares natural forest was converted into economic forest (rubber and pulp


**Table 1.** Area of natural forest and economic forest during 1988–2008.

wood plantations), which led directly to a corresponding decrease in the extent of natural tropical forest. At the same time, up to 6.26% of natural forest and up to 3.09% of economic forests were converted to other land uses.

The spatial conversion of forest was also seen because of the transformation of different forest types. The remaining natural tropical forests tended to occur only at higher elevations and on steeper mountain tops, that is, the average distances to farms and transportation corridors increased. This occurred because some natural tropical forests at lower elevations, and with less steep slopes that were previously closer to farms and transportation corridors, were transformed into economic forests during 1988–2008. The increasing extent of economic forests might result in a loss in the value of ecosystem services [17]. Generally, forest transition theory assumes that increasing forest cover indicates that environmental conditions are improving [18], but the increasing forest cover in our study area does not necessarily mean that biodiversity and natural ecosystems are recovering (**Figure 19**).

#### **3.3. The response of forest transformation to economic development and protection policies**

Regional market trends contribute to the conversion from natural forests to economic forests (rubber, pulp forests, etc.). Rubber and pulp plantations expanded because of new regulations and increased demand from consumers. For example, the demand for rubber kept increasing slowly, and this led to low prices between 1988 and 1998. In addition, most rubber plantations were planted on government-operated farms, typically covering large areas, whereas small landholders were not involved significantly in rubber plantations until 1995. Thus, the conversion of natural tropical forests into rubber plantations in the piedmont had been only sporadic during 1988–1998. However, the market demand for rubber increased sharply after 1999, leading to higher prices, which encouraged smaller landholders to become deeply involved in rubber plantations after 1999. Therefore, the demand for rubber in the open market might be an important factor in driving the change of different forest types during 1988–1998 (**Figure 20**).

The Chinese Government has strongly encouraged the planting of pulp plantations with the goal of developing a domestic wood pulp industry that could meet growing domestic demand. The government provided substantial capital subsidies in the form of low interest rate loans, discounted loans, and extended repayment periods for loans from state banks [19]. Thus, new plantations of economic forests greatly reduced the available space for natural tropical forests; therefore, the area of natural tropical forest decreased by 2008. Protection policies and the establishment of reserves delayed the transformation of some forests. In the early 1950s, policies encouraged the establishment of rubber plantations. Several nature reserves were established in Hainan Island starting in 1976. Currently, nine national nature reserves cover 11.20 × 10<sup>4</sup> hectares, while provincial nature reserves cover 13.84 × 10<sup>4</sup> hectares. Generally, both national nature reserves and provincial nature reserves limited the expansion of rubber plantations. The transformation of rainforests to plantation forests was suppressed by these protection policies, and especially by the existence of natural reserves during 1988–1998 (**Table 2**). Different types of reserves provide different levels of protection. The national nature reserves play important roles in protecting natural forest. During 1988–2008, in the national reserves, the area of natural forest increased steadily while the area of economic forest decreased slightly. However, provincial natural reserves play an ineffective role in protecting natural forest because local and provincial government agencies support economic growth over the conservation of natural resources. Therefore, some natural forests in provincial reserves were

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replaced by economic forests during the same period (**Table 2**).

**Table 2.** The percentage of plantation forests in different natural reserves in 1988–2008.

**Reserves type 1988 1998 2008** National reserves 16.31% 10.96% 7.22% Provincial reserves 14.24% 8.80% 16.77%

**Figure 20.** Chinese natural rubber demand and price changes.

**Figure 19.** The transformation of different forest types in 1988–1998 (left) and 1998–2008 (right).

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**Figure 20.** Chinese natural rubber demand and price changes.

wood plantations), which led directly to a corresponding decrease in the extent of natural tropical forest. At the same time, up to 6.26% of natural forest and up to 3.09% of economic

The spatial conversion of forest was also seen because of the transformation of different forest types. The remaining natural tropical forests tended to occur only at higher elevations and on steeper mountain tops, that is, the average distances to farms and transportation corridors increased. This occurred because some natural tropical forests at lower elevations, and with less steep slopes that were previously closer to farms and transportation corridors, were transformed into economic forests during 1988–2008. The increasing extent of economic forests might result in a loss in the value of ecosystem services [17]. Generally, forest transition theory assumes that increasing forest cover indicates that environmental conditions are improving [18], but the increasing forest cover in our study area does not necessarily mean

**3.3. The response of forest transformation to economic development and protection** 

factor in driving the change of different forest types during 1988–1998 (**Figure 20**).

**Figure 19.** The transformation of different forest types in 1988–1998 (left) and 1998–2008 (right).

Regional market trends contribute to the conversion from natural forests to economic forests (rubber, pulp forests, etc.). Rubber and pulp plantations expanded because of new regulations and increased demand from consumers. For example, the demand for rubber kept increasing slowly, and this led to low prices between 1988 and 1998. In addition, most rubber plantations were planted on government-operated farms, typically covering large areas, whereas small landholders were not involved significantly in rubber plantations until 1995. Thus, the conversion of natural tropical forests into rubber plantations in the piedmont had been only sporadic during 1988–1998. However, the market demand for rubber increased sharply after 1999, leading to higher prices, which encouraged smaller landholders to become deeply involved in rubber plantations after 1999. Therefore, the demand for rubber in the open market might be an important

that biodiversity and natural ecosystems are recovering (**Figure 19**).

forests were converted to other land uses.

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**policies**

The Chinese Government has strongly encouraged the planting of pulp plantations with the goal of developing a domestic wood pulp industry that could meet growing domestic demand. The government provided substantial capital subsidies in the form of low interest rate loans, discounted loans, and extended repayment periods for loans from state banks [19].

Thus, new plantations of economic forests greatly reduced the available space for natural tropical forests; therefore, the area of natural tropical forest decreased by 2008. Protection policies and the establishment of reserves delayed the transformation of some forests. In the early 1950s, policies encouraged the establishment of rubber plantations. Several nature reserves were established in Hainan Island starting in 1976. Currently, nine national nature reserves cover 11.20 × 10<sup>4</sup> hectares, while provincial nature reserves cover 13.84 × 10<sup>4</sup> hectares. Generally, both national nature reserves and provincial nature reserves limited the expansion of rubber plantations. The transformation of rainforests to plantation forests was suppressed by these protection policies, and especially by the existence of natural reserves during 1988–1998 (**Table 2**).

Different types of reserves provide different levels of protection. The national nature reserves play important roles in protecting natural forest. During 1988–2008, in the national reserves, the area of natural forest increased steadily while the area of economic forest decreased slightly. However, provincial natural reserves play an ineffective role in protecting natural forest because local and provincial government agencies support economic growth over the conservation of natural resources. Therefore, some natural forests in provincial reserves were replaced by economic forests during the same period (**Table 2**).


**Table 2.** The percentage of plantation forests in different natural reserves in 1988–2008.

Generally, the main forces driving the transformation of forest types seem to be protection policies and economic development. Some natural forests were protected by the established nature reserves, and protection policies suppressed the transformation process. Furthermore, the development of economic forests, such as rubber and pulp plantations, propelled the transformation between different forest types, even in provincial reserves formally under the protection policies during 1998–2008. Generally, the spatial extent of natural forests decreased significantly from 1998 to 2008. Although some protection efforts have been attempted, such as the "Natural Forest Protection Project," the establishment of nature reserves, and the closing of hillsides to facilitate afforestation, our results suggest that some of these protection measures were poorly implemented. From another viewpoint, economic development exerted an enormous influence on the tropical forests of Hainan Island and reduced the effects of these protection efforts. Extensive areas of natural tropical forest in Hainan Island have been converted into economic forest. Local politicians are evaluated strongly on their support of economic development. This encourages them to support economic development at the expense of environmental protection. Changing policies related to local government officials could increase protection for natural landscapes.

To resolve the conflict between development and protection, a balance between economic development and forest protection needs to be found based on monitoring data [20]. The establishment of ecological compensation mechanisms might contribute to providing local communities with some economic benefits in exchange for forest protection [21].

#### **3.4. Response of forest transformation to environmental factors**

The dynamics of major ecosystems are the result of the combination of economic drivers and state-related policies. The following sections will be comprehensive analysis of the relationship between the spatial patterns of main ecosystem in Hainan Island with terrain, traffic, water sources, settlements, and nature reserves.

#### *3.4.1. Relationship between distribution pattern of natural forest and topography*

The process of natural forest change in Hainan Island is a process of human disturbance. It is a process of gradually approaching to the southern of the central mountains, that is, the natural forest follows the process of approaching from plains, terraces, and hills to mountains successively. Its altitude also follows the change from low to high. With the increase of the terrain, the average patch area tends to increase. The following is an example of the relationship between natural forest distribution and topography in 1998 (**Table 3**).

From **Table 3**, natural forests were mainly distributed in the central mountainous area, closely related with the terrain. The next distribution area was the terrace, and the coastal plain was sparsely distributed. This shows that natural forests are closely related to the terrain. One thing to note is that mangroves and other natural forests distributed in coastal areas need to increase protection.

area and water system is not as obvious as the terrain. That is, the distribution of water systems

Sanya City 910.537 591.3 54 16.86180 Terrace - coastal plains

As can be seen from the distribution pattern of the farms (**Figure 22**), most of the farms are located in the hills, terraces, and coastal plains, while the central mountainous areas have relatively small densities. However, the natural forest patches in the farmland are obviously fragmented. In other words, near the farm, the destruction strength of natural forest is big, otherwise it is small. It can be seen that the distribution of farms directly affects the spatial pattern of natural forests and has obvious negative impacts on the distribution of natural forests.

is not the main reason for the distribution of natural forests in this area.

**Table 3.** Relationship between different ecosystems and topography.

**Region Natural forest** 

Baisha Li Autonomous

Qiongzhong Li and Miao Autonomous County

Ledong Li Autonomous

Lingshui Li Autonomous

Baoting Li and Miao Autonomous County

County

County

County

Changjiang Li Autonomous County **area(km2 )** **Core area patch** 

Haikou City 1.634 5 0.32671 Coastal plains, low

Lingao County 1.535 2 0.76742 Coastal plains, low

Chengmai County 151.905 19 7.99502 Coastal plains, low

Wenchang City 5.021 6 0.83677 Coastal plains, low

Anding County 61.784 15 4.11895 Northeast terraces, plains,

Pizhou City 273.933 49 5.59048 Coastal plains and terraces Tunchang County 173.980 37 4.70216 North Central Plains, hills

Qionghai City 190.571 22 8.66231 Terrace and coastal plains

Wuzhishan City 809.595 17 47.62325 Central mountainous area Dongfang City 794.933 25 31.79732 Central mountains, terraced

Wanning City 532.908 46 11.58496 Coastal plains

**numbers**

**Mean patch area(km2 )**

South China Tropical Forest Changes in Response to Economic Development and Protection…

1078.765 54 19.97714 Central mountains, terraced

1403.166 56 25.05654 Central mountainous area

487.069 50 9.74138 Terrace and coastal plains

1121.411 50 22.42821 Central mountains, terraced

549.121 431.76 12 45.76008 Central mountainous area

358.404 257.45 26 13.78476 Terraced hills

**Spatial pattern and terrain**

133

the terrain is relatively low

topography

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topography

topography

topography

hills

hills, coastal plains

hills, coastal plains

*3.4.3. Relationship between the natural forest distribution pattern and farms*

#### *3.4.2. Relationship between natural forest distribution pattern and water system*

Under the analysis of water system (**Figure 21**), the natural forest near the hilly area or in relatively low altitude, where water system developed, is gradually replaced by other types of vegetation. The relationship between the natural forest distribution in the central mountainous South China Tropical Forest Changes in Response to Economic Development and Protection… http://dx.doi.org/10.5772/intechopen.73296 133


**Table 3.** Relationship between different ecosystems and topography.

Generally, the main forces driving the transformation of forest types seem to be protection policies and economic development. Some natural forests were protected by the established nature reserves, and protection policies suppressed the transformation process. Furthermore, the development of economic forests, such as rubber and pulp plantations, propelled the transformation between different forest types, even in provincial reserves formally under the protection policies during 1998–2008. Generally, the spatial extent of natural forests decreased significantly from 1998 to 2008. Although some protection efforts have been attempted, such as the "Natural Forest Protection Project," the establishment of nature reserves, and the closing of hillsides to facilitate afforestation, our results suggest that some of these protection measures were poorly implemented. From another viewpoint, economic development exerted an enormous influence on the tropical forests of Hainan Island and reduced the effects of these protection efforts. Extensive areas of natural tropical forest in Hainan Island have been converted into economic forest. Local politicians are evaluated strongly on their support of economic development. This encourages them to support economic development at the expense of environmental protection. Changing policies related to local government officials could increase protection for natural landscapes. To resolve the conflict between development and protection, a balance between economic development and forest protection needs to be found based on monitoring data [20]. The establishment of ecological compensation mechanisms might contribute to providing local

communities with some economic benefits in exchange for forest protection [21].

The dynamics of major ecosystems are the result of the combination of economic drivers and state-related policies. The following sections will be comprehensive analysis of the relationship between the spatial patterns of main ecosystem in Hainan Island with terrain, traffic,

The process of natural forest change in Hainan Island is a process of human disturbance. It is a process of gradually approaching to the southern of the central mountains, that is, the natural forest follows the process of approaching from plains, terraces, and hills to mountains successively. Its altitude also follows the change from low to high. With the increase of the terrain, the average patch area tends to increase. The following is an example of the relationship

From **Table 3**, natural forests were mainly distributed in the central mountainous area, closely related with the terrain. The next distribution area was the terrace, and the coastal plain was sparsely distributed. This shows that natural forests are closely related to the terrain. One thing to note is that mangroves and other natural forests distributed in coastal areas need to

Under the analysis of water system (**Figure 21**), the natural forest near the hilly area or in relatively low altitude, where water system developed, is gradually replaced by other types of vegetation. The relationship between the natural forest distribution in the central mountainous

**3.4. Response of forest transformation to environmental factors**

*3.4.1. Relationship between distribution pattern of natural forest and topography*

between natural forest distribution and topography in 1998 (**Table 3**).

*3.4.2. Relationship between natural forest distribution pattern and water system*

water sources, settlements, and nature reserves.

increase protection.

132 Tropical Forests - New Edition

area and water system is not as obvious as the terrain. That is, the distribution of water systems is not the main reason for the distribution of natural forests in this area.

#### *3.4.3. Relationship between the natural forest distribution pattern and farms*

As can be seen from the distribution pattern of the farms (**Figure 22**), most of the farms are located in the hills, terraces, and coastal plains, while the central mountainous areas have relatively small densities. However, the natural forest patches in the farmland are obviously fragmented. In other words, near the farm, the destruction strength of natural forest is big, otherwise it is small. It can be seen that the distribution of farms directly affects the spatial pattern of natural forests and has obvious negative impacts on the distribution of natural forests.

**Figure 21.** Relationship between natural forest distribution and water system. (1) 1988; (2) 1998; and (3) 2008.

**Figure 22.** Relationship between natural forest distribution patterns and farms. (1) 1988; (2) 1998; (3) 2008.

#### *3.4.4. Relationship between natural forest distribution and traffic route distribution*

The traffic conditions directly affect the spatial distribution pattern of natural forests (**Figure 23**). The areas with convenient transportation are mainly distributed in plains, terraces, and hilly areas. The patches of natural forests on both sides of the traffic line showed fragmented trend. That is, the destruction of natural forests is serious where the traffic line is dense, the terrain is relatively flat, and the distribution of residents and farms is wide. Therefore, the distribution of traffic lines is closely related to the distribution of natural forests.

*3.4.6. Relationship between rubber plantations and farms, traffic lines, water distribution*

*3.4.7. Relationship between pulp plantation with farm, traffic lines, and water distribution*

The space distribution of pulp plantations shows small block-like but relatively wide distribution. There are a large number of distributions in the vicinity of farms, traffic lines, and waters, as well as widely distributed in coastal plains, central mountains, and terraces, which mostly

deforestation and rubber plantations.

**Figures 25** and **26** are the spatial distribution maps of rubber plantations and settlements in 1988, 1998, and 2008. The farms were mainly distributed in the western and northern parts of Baisha, Zhanzhou, Tunchang and southwest Sanya, Ledong and other counties and cities. Its distribution is more in northwest, north and less in southern, coastal plains in short. Most of the rubber plantations are located near 3–5 km to the farms and settlements, showing that the distribution of farms, settlements, and rubber plantations are closely related. According to the abovementioned analysis, most of the traffic lines in settlements and farms are well developed and are relatively close to the water source. Therefore, it can be considered that most of the rubber plantations were relatively close to the traffic and water source. Therefore, the distribution of water systems, traffic lines, and farm concentration is frequent areas for

**Figure 24.** Relationship between natural forest distribution and nature reserve distribution. (1) 1988; (2) 1998; (3) 2008.

**Figure 23.** Relationship between natural forest distribution and traffic route distribution. (1) 1988; (2) 1998; (3) 2008.

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#### *3.4.5. Relationship between natural forest distribution and nature reserve distribution*

In order to better protect the cherished species, there are many provincial and national nature reserves have been successively set up in recent years (**Figure 24**). In this area, 88.71% of the National Nature Reserve area is covered by natural forest in 2008, 94.03% in 1998, and 82.71% in 1988, while the surrounding area of the reserves is often replaced by other features, especially the provincial nature reserves. The natural forest has become an island, such as Hainan Jiaxin Provincial Nature Reserve, Liulianling Provincial Nature Reserve, and so forth. This shows that the establishment of nature reserves played a positive role in the protection of natural forests but also exposed hidden worries of other types of ecosystems to natural forests.

South China Tropical Forest Changes in Response to Economic Development and Protection… http://dx.doi.org/10.5772/intechopen.73296 135

**Figure 23.** Relationship between natural forest distribution and traffic route distribution. (1) 1988; (2) 1998; (3) 2008.

**Figure 24.** Relationship between natural forest distribution and nature reserve distribution. (1) 1988; (2) 1998; (3) 2008.

#### *3.4.6. Relationship between rubber plantations and farms, traffic lines, water distribution*

**Figure 22.** Relationship between natural forest distribution patterns and farms. (1) 1988; (2) 1998; (3) 2008.

**Figure 21.** Relationship between natural forest distribution and water system. (1) 1988; (2) 1998; and (3) 2008.

134 Tropical Forests - New Edition

The traffic conditions directly affect the spatial distribution pattern of natural forests (**Figure 23**). The areas with convenient transportation are mainly distributed in plains, terraces, and hilly areas. The patches of natural forests on both sides of the traffic line showed fragmented trend. That is, the destruction of natural forests is serious where the traffic line is dense, the terrain is relatively flat, and the distribution of residents and farms is wide. Therefore, the distribution of

In order to better protect the cherished species, there are many provincial and national nature reserves have been successively set up in recent years (**Figure 24**). In this area, 88.71% of the National Nature Reserve area is covered by natural forest in 2008, 94.03% in 1998, and 82.71% in 1988, while the surrounding area of the reserves is often replaced by other features, especially the provincial nature reserves. The natural forest has become an island, such as Hainan Jiaxin Provincial Nature Reserve, Liulianling Provincial Nature Reserve, and so forth. This shows that the establishment of nature reserves played a positive role in the protection of natural forests but also exposed hidden worries of other types of ecosystems to natural forests.

*3.4.4. Relationship between natural forest distribution and traffic route distribution*

*3.4.5. Relationship between natural forest distribution and nature reserve distribution*

traffic lines is closely related to the distribution of natural forests.

**Figures 25** and **26** are the spatial distribution maps of rubber plantations and settlements in 1988, 1998, and 2008. The farms were mainly distributed in the western and northern parts of Baisha, Zhanzhou, Tunchang and southwest Sanya, Ledong and other counties and cities. Its distribution is more in northwest, north and less in southern, coastal plains in short. Most of the rubber plantations are located near 3–5 km to the farms and settlements, showing that the distribution of farms, settlements, and rubber plantations are closely related. According to the abovementioned analysis, most of the traffic lines in settlements and farms are well developed and are relatively close to the water source. Therefore, it can be considered that most of the rubber plantations were relatively close to the traffic and water source. Therefore, the distribution of water systems, traffic lines, and farm concentration is frequent areas for deforestation and rubber plantations.

#### *3.4.7. Relationship between pulp plantation with farm, traffic lines, and water distribution*

The space distribution of pulp plantations shows small block-like but relatively wide distribution. There are a large number of distributions in the vicinity of farms, traffic lines, and waters, as well as widely distributed in coastal plains, central mountains, and terraces, which mostly

distributed less than 25 degrees slope. It can be seen that the regularity of pulp plantation

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In recent years, natural forest reserves have been established one after another to protect natural forests and other species (**Figure 27**). In National Nature Reserve area, the area 11.29% in 2008, 5.197% in 1998, 17.29% in 1988 was covered with rubber plantation and pulp plantation. This shows that nature reserves play a protective role in natural forests. At the same time, rubber forests and pulp and paper forests gradually penetrate into nature reserves and gradually

The results emphasize that forest monitoring could incorporate remote sensing imagery of specific periods and an object-based decision tree method to identify forest change. The objectbased information extraction based on the decision tree method proved applicable and effective in identifying the main forests with complex surface features in a tropical evergreen ecosystem. Based on the results of forest information extraction, it is determined that the tropical forests of the central Hainan Island suffered a significant change during 1988–2008. Initially, the spatial extent of natural tropical forest increased slightly and then experienced a considerable decrease during 1998–2008. Larger amounts of natural tropical forest were replaced by economic forests, resulting in an expansion of economic forests (rubber and pulp plantations). Forests also shifted spatially during 1998–2008. Elimination of some natural tropical forests in the lower piedmont, due to economic development, caused the average location of the remaining tropical forest shift to higher altitudes. The transformation of forests was driven mainly by protection policies and economic development, but economic development exerted a much stronger influence and minimized the protection efforts. Transportation corridors, farmland, slope, and elevation were

also important intrinsic dynamics that affected the transformation of tropical forests.

Research grants from the National Science Foundation of China (Grant No. 41671362, 41371359), the Fundamental Research Funds for the Central Universities (Grant No. 2017B05114).

1 Institute of Remote Sensing and Digital Earth, Chinese Academy of Sciences, Beijing, China

2 School of Earth Sciences and Engineering, Hohai University, Nanjing, China

*3.4.8. Relationship between pulp and rubber plantation with nature reserves*

spatial distribution is not obvious.

replace natural forests.

**Acknowledgements**

**Author details**

Shudong Wang<sup>1</sup>

and Taixia Wu2

\*Address all correspondence to: wutx@hhu.edu.cn

\*

**4. Conclusions**

**Figure 25.** Relationship between rubber plantations and farms, traffic lines, water distribution. (1) 1988; (2) 1998; and (3) 2008.

**Figure 26.** Relationship between rubber plantation area change with other woodlands and nature reserves. (1) 1988; (2) 1998; and (3) 2008.

**Figure 27.** Relationship between pulp plantation area change with other woodlands and nature reserves. (1)1988–1998 and (2)1998–2008.

distributed less than 25 degrees slope. It can be seen that the regularity of pulp plantation spatial distribution is not obvious.

#### *3.4.8. Relationship between pulp and rubber plantation with nature reserves*

In recent years, natural forest reserves have been established one after another to protect natural forests and other species (**Figure 27**). In National Nature Reserve area, the area 11.29% in 2008, 5.197% in 1998, 17.29% in 1988 was covered with rubber plantation and pulp plantation. This shows that nature reserves play a protective role in natural forests. At the same time, rubber forests and pulp and paper forests gradually penetrate into nature reserves and gradually replace natural forests.
