According to Hong Kong Accounting Standard 41 Agriculture (HKAS41), the Plants in the forest should be accounted as Biological Assets. At the point of harvest, the Felled Trees should be accounted as Agricultural Produce. When the Felled Trees are processed into Logs or Lumber after harvest, it should be accounted as Inventories under HKAS 2, as it is no more an agricultural activity.
Also, when you acquired a forest, you will not only acquire the Plants of the forest, but also the forest concession and plantation licenses. These license will be accounted as Land Use Rights, and would be accounted as one of the Intangible Assets under HKAS 38.