Study On The Adaptive Management Of Chinese Fir Plantations To Climate Change

Climate change is one of the most important threats to the capacity of forest landscapes to provide ecological, economic and social services. Further, it has been established that healthy, well-managed forests can help to mitigate the rate of climate change by acting as sinks for atmospheric carbon. As climate regimes continue to change, it is essential that forest managers develop effective management strategies to maintain resilient forest ecosystems and communities. Chinese fir is one of the most important commercial species in China with national wide planting areas and high economic value. And in addition to its importance as a source of fiber, Chinese fir plantations also play an important role in the provision of forest ecosystem services including water and soil conservation, climate regulation, pollutant absorption and so on. Considering their large area of cultivation, and high potential for atmospheric CO2 fixation, Chinese fir plantations represent a key component of China’s greenhouse gas mitigation strategy. However, there is remarkably little evidence that science-based decision-making processes are being incorporated into forest management practices for Chinese fir. As a result, considerable uncertainty exits over sustainable management of Chinese fir aimed at enabling forest managers develop Chinese fir management strategies to adapt to climate change.In this study, we took the Chinese fir dominated area locked in Shunchang County, Fujian Province as our research object. We used the high resolution, high accuracy climate model—ClimateAP, to generate the climate data and then set 5 different climate scenarios using a direct downscale approach. We employed FORECAST Climate model to simulate the response of the growth of Chinese fir to changing climate. Then based on the collected Chinese fir current distribution data and the reference climate data generated from ClimateAP, we built a climate niche model for Chinese fir by using Random Forest Algorithm. The model was then used to simulate the climate niche shifts of Chinese fir in the study area under changing climate for the future. Also, we developed 14 analysis units to represent the landscape of the study area based on different forest productivity and forest management groups as well as 27 alternative forest management scenarios through the combination of different climate, rotation length and harvest retention scenarios. Then we developed the landscape-level trade-off analysis tool—LST model, based on the linkage of Microsoft Excel and the outputs from FORECAST Climate, to study the tradeoffs between economic benefits and ecosystem services of Chinese fir plantations. And at last, we analyzed the adaptive management strategies of Chinese fir to a changing climate. The main results of this study were listed as follows:(1) According to different climate change scenarios, the average annual temperature of the study area in the next 100 years will rise about 1.3℃ to 2.9℃. While the changing patterns of precipitation in the future is not obvious, the main differences are between GCMs instead of greenhouse gas emission scenarios, the simulation results of CNRM-CM5 model turn out as will be drier.(2) The increasing temperature will have significant influences on the geographic distribution climate nice of Chinese fir in the study area under the changing climate in the future. The simulation results showed that under RCP8.5 secnario (i.e. no measures are taken to control greenhouse gas emission), the distribution climate niche of Chinese fir will be contracted. However, when positive measures are taken to control the emission of GHG (RCP2.6 scenario), the contracted area of Chinese fir in 2050s and 2080s was only 5.4% and 12.4%, respectivity. In addition, it is important to keep in mind that the predicted results in this study are the realized climate niche for Chinese fir, additional research should focus on whether or not Chinese fir can grow outside current climate niche.(3) FORECAST Climate model validation results indicated that there was a good correlation (r=0.84, p<0.001) between the model-based output of the 8-day mean daily growth response index and the average relative 8-day composite MODIS net photosynthesis value, suggesting that FORECAST Climate model can be well applied in the study area with high and reasonable accuracy.(4) Model results suggested that Climate change is projected to have a modest positive impact on Chinese fir plantation productivity, that is,3.9% to 6.3% by the end of the first rotation (years 1-30),3.9% to 9.5% for the second rotation (years 31-60), and 5.3% to 12.9% for the third rotation (years 61-90). This is mainly due to the gradual lengthening of the growing season and an associated increase in nutrient cycling rates. While the model predicted an increase in dry-season water stress under climate change, it did not projected an increase in drought-related mortality. It is also important to note that the predicted increases in Chinese fir plantations associated with climate change may not be realized if changes in climate regime also lead to increased mortality from biotic and abiotic disturbance agents.(5) Our study illustrated that the LST model can be used as decision-support tool for managers of Chinese fir plantations. The decision matrix spreadsheet provides users with the capability to easily calculate a score to allow for a ranking of management options through the weighted sum of the indicators for each scenario based on their own determination of the importance of each indicator according to the forest management purpose.(6) To achieve the goal of adaptive forest management to address a changing climate, it is essential to improve public awareness and participation; Forest managers should actively change the mode of management and implement effective management measures; and the government should give full play to the leading position and promote the development, improvement as well as the implementation of the forest adaptation policies.