马尾松人工林密度控制图及密度预警研究

目的密度控制图是一个集设计、展示、评价不同经营措施的有效工具，为同龄林经营提供决策依据。本研究首先是构建热林中心马尾松人工林密度控制图，并在此基础上对马尾松林分密度进行评估，进而构建密度预警图，并根据预警图提出相应的森林经营建议。方法以广西壮族自治区热林中心的马尾松人工林为研究对象，基于2011年建立的238块固定样地调查数据以及2013年和2015年的复测数据，采用Reineke自然稀疏方程，构建马尾松密度控制图，基于最优密度的上下限以及二类调查数据，构建马尾松人工林的密度预警图。结果基于最优密度上下限、优势高模型、材积模型以及地位指数模型构建了热林中心马尾松人工林的密度控制图；根据密度控制图和现有林分的密度情况，构建了热林中心密度预警图，基于此提出了相应的经营建议。结论本研究将热林中心马尾松分为高密度林分，低密度林分以及合理密度的林分，并根据林分所处的状态提出不同的经营建议。高密度的林分，采用疏伐的措施，将林分引向最优密度区间；低密度的林分，采取补植珍贵树种的方式，促使林分朝着合理密度方向发展，落入合理区间的林分，不采取任何与密度调控相关的经营措施，使林分按照原来的经营模式发展，为热林中心马尾松人工林的可持续经营提供决策支持。 

Development and application of density management diagram for Pinus massoniana plantation

ObjectiveStand density management diagram (SDMD) is an effective tool for designing, displaying and evaluating different management measures, and hence provides decision support for even-aged forest management. The objective of this study was first to construct a SDMD for Pinus massoniana plantation for the Tropical Research Center (TRC). Second, based on the SDMD, the stand density of TRC was evaluated and an early warning diagram (EWD) of stand density was further produced with relevant management suggestions.MethodThe data used in this present study consists of 238 permanent sample plots, which were established in 2011 and re-measured in 2013 and 2015. The Reineke self-thinning equation was used to develop the SDMD. Based on the SDMD, the EWD for TRC was produced using the forest management planning data.ResultBased on the optimal density upper and lower limits, dominant height model, volume model and site index model, we constructed the SDMD for Pinus massoniana plantation in TRC. According to the SDMD and the stand density, the EWD was constructed and the management suggestions were provided.ConclusionIn this study, we divided the Pinus massoniana plantation in TRC into three different stands, i.e., high-density stands, low-density stands and the optimal density stands. For the three different stands, different management strategies were proposed. For high-density stand, we can conduct the thinning operations to decrease the density and achieve optimal density stands conversion. For low-density stands, the management measures of replanting precious tree can be conducted, which could contribute to the development of reasonable density. Compared with the above two stands, the optimal density stands could not be conducted any management strategies, which can support the formulation of the Pinus massoniana plantation management strategies.