1、Soil and Water Conservation

Yunnan Province, located in the southwestern border of China, encompasses major river systems such as the Jinsha, Pearl, Lancang (Mekong), Red, Nu (Salween), and Irrawaddy rivers, along with numerous plateau rivers and lakes. It serves as the upstream source for the Yangtze and Pearl Rivers, as well as several international rivers flowing into Southeast Asia. In the province's total land area, only 6% is comprised of dam areas. For a long time, due to the engagement in agricultural production with outdated methods and excessive logging, the ecological environment has become extremely fragile. The province experiences soil erosion over an area of 146,000 square kilometers, accounting for 37% of its land area, with more than 500 million tons of soil lost annually. In many places, the deterioration of the ecological environment has severely impacted the livelihoods of the people, in some cases even depriving them of basic living conditions.

The production of shellac mainly involves the extensive cultivation of host plants along the banks of major rivers and in the dry and hot river valleys of Yunnan. Developing the shellac industry can establish an ecological and economic forest system in areas designated for the conversion of farmland back to forest, which is of great significance for ecological restoration and poverty alleviation in impoverished areas. China's diversity of shellac insect species, rich climatic resources, and host plants provide exceptionally favorable conditions for developing various models of shellac production in the country. In Yunnan Province, when implementing the conversion of farmland back to forest in areas with different climatic types, suitable shellac insects and host plants that match the local climate and community can be identified. This also facilitates the discovery of appropriate "insect-tree combinations" and shellac production models for the region.

Shellac Host Plants and Their Ecological Benefits

Shellac host plants are characterized by rapid growth and quick sprouting. During the shellac production process, the harvesting of lac by cutting branches of the shellac insect's host plants does not lead to the death of these plants nor does it undermine the ecological benefits of the shellac forest ecosystem. Instead, it generates economic benefits. The construction of shellac gardens employs a mix of arbor and shrub host plants in both tall and short forms, which is conducive to the sustainable economic performance of the shellac ecological forest.

Like other forest types, shellac host forests have dense canopies and a certain coverage of herbaceous plants on the ground. During rainfall, these layers can effectively block the direct impact of raindrops on the soil surface and increase the retention time of rainwater from the canopy to the ground. In experiments conducted in Green Spring, it was observed that light rain does not result in surface runoff within the forest. Surface runoff only occurs when the daily water volume exceeds 5mm. However, even during heavy rainfall, the amount of surface runoff within the forest is significantly less than that on barren hillsides, and it is comparable to that on terraced fields. Between May and September 2001, with a rainfall of 1698.6mm, the average soil erosion per hectare for shellac forest land, abandoned clear-cut land, terraced fields, and sloped farmland was 3000.0, 8570.1, 14871.0, and 21657.0kg respectively. In the same period in 2002, with 1560.1mm of rainfall, these figures were 2256.0, 7514.1, 13756.3, and 21597.2kg respectively. Over two years, the soil loss from shellac host forests was only 14% of that from sloped farmland and 30% to 40% of that from abandoned clear-cut land, demonstrating a superior effect in water conservation.