Abstract: Green development has emerged in various fields and one of the most fundamental fields goes back to green agriculture. Under the influence of carbon emission which has become increasingly serious, the development of forestry carbon sequestration eases the pressure on corporate emissions. And it also brings the new gain points to forestry investors. The traditional evaluation of forestry investment project only considers the wood cutting benefits, which has been undervalued.
In order to assess the value of forestry investment projects with carbon sequestration benefits, the benefits of carbon sequestration are taken as endogenous variables into the classic faustmann model. On the basis of calculating the net present value of traditional wood(NPV^w), it adds the net present value of carbon (NPV^c). The land expectation value(LEV) of forest within the investment period is calculated by building timber-carbon sequestration joint management decision-making model, which is regarded as theinitial value of forestry projects. And the basic idea of compound real option is adopted, the expansion option, contracting option and abandonment option are introduced in the process of investment and the method of stochastic dynamic programming is selected to solve the maximize market value of the investment project. It is assumed that the deadline of project is 20 years and the period is divided into four stages. On the other hand, it is assumed that the value of project increases ɑ times after executing the expansion option and decreases β times after executing the contracting option. The binary tree option method is combined to analyze the portfolio and strategy problems of forestry projects. So that the compound real option pricing of the carbon sequestration benefits attached forestry investment projects can be implemented.Take a project of carbon sink afforestation in Zixing city in Hunan province as an example. The Chinese fir is selected for analyzing, and the time of project is from 2008 to 2027. There is non forest land before investment, with a total area of 2,665.3 hectares. The results show that the forestry value with carbon sequestration benefits is greater than traditional value. In the absence of carbon sinks trade, the net income present value of timber within 20 years is 172 million Chinese yuan, but it increases to 191 million Chinese yuan when existing the benefit of carbon sink. And the value of project eventually can increase to 329 million Chinese yuan after the introducing real option, which means to implement the option value as high as 138 million Chinese yuan.Therefor the value will increase significantly when we use the compound real option to assess the value of forestry investment projects. By further analysis, it is found that the price fluctuation of carbon sink and wood positively correlated with the value of forestry project. And once the other conditions is stable, the higher investment cost is, the lower option value will be.

Key words: forestry carbon sequestration, compound real options, stochastic dynamic programming method, investment strategy, value evaluation