A、They provide subjects for scientific research. B、They produce large amount of wood. C、They offer shelters for rare animals and

A major study has looked at efforts to save the tropical forests that remain in the world. Researchers found that less than 5 percent of the forest land is being protected.
    The study examined the use of sustainable management plans by forest operators.[26]Such a plan seeks a continuous flow of forest products, without damage to the future of the forest or its environment.
    The International Tropical Timber Organization did the study. The researchers studied the supervision of more than 800 million hectares of forests in 33 countries. This land represents two-thirds of all the natural tropical forests in the world.
    Tropical forests are divided into two major kinds: production and protection.
    Production forests are harvested for wood. These forests can be natural or planted. The study found that only 7 percent of production forests are managed sustain-ably.
    Yet four times as much land is supposed to be managed under plans developed by forest operators. The researchers say it is much easier to develop a plan than to follow it, even if the operators truly want to.
    Protection forests are recognized as valuable not for harvested wood, but as shelters for animal and plant life, a lot of which are rare.
    Protected areas represent more than 460 million hectares of forests. Yet management plans have been developed for just 4 percent of that land. And the study found that the plans are being followed on only 2 percent.
    From Asia to Africa to America, progress is uneven in efforts to save tropical forests. Good management requires law enforcement and money. It also requires interest and ability.
    Yet there is good news. The report says sustainably managed forests now cover at least 36 million hectares, an area the size of Germany.
26. What is the purpose of the sustainable management plans according to the passage?
27.Why are protection forests considered valuable?
28.What is mentioned in the passage as good news about forest protection?