将下列内容段落翻译成中文 There is a growing interest in the cultivation of plants exclusively for production of energy. These crops are called "energy crop", and they are lignocellulosic in nature. Such crops typically have a short growing period and high yields and require little or no fertilizer, so they provide quick return to investment. For energy production, woody crops such as miscanthus, willow, switchgrass, and poplar are widely utilized. These plants are densely planted. They have high-energy yield per unit of land area and require much less energy for cultivation.