LAI measurements for the assessment of successional trajectories in submontane non-serotinous Pinus spp. forests

This dataset compiles field measurements obtained with a LAI-2200C Plant Canopy Analyzer (LI-COR Biosciences, Lincoln, NE, USA) to generate continuous LAI profiles and capture the structural variability of submontane Pinus spp. forests. The measurements provide detailed information on canopy gap distribution, both vertically and horizontally, allowing for the assessment of successional trajectories in non-serotinous pine stands. Measurements were carried out by comparing light transmittance above the canopy (reference readings) and below the canopy (sample readings). The difference between the two was used to estimate LAI through radiative models assuming random leaf distribution and ellipsoidal orientation, which may not be accurate for all species or canopy types. Instrument: LAI-2200C Plant Canopy Analyzer (LI-COR Biosciences, Lincoln, NE, USA). Spectral range: 320–490 nm. Measurement geometry: Five concentric rings with zenith angles of 7°, 23°, 38°, 53°, and 68°. Sampling protocol: Measurements were taken every 0.5 m during floristic inventories (~900 samples). A maximum optical coverage of 270° was used to exclude the operator from the field of view. Data processing: FV2200 software (LI-COR Biosciences, Lincoln, NE, USA). Quality control: Measurements under unstable light conditions were avoided.本数据集整合了采用LAI-2200C植物冠层分析仪（LI-COR Biosciences，美国内布拉斯加州林肯市）获取的野外实测数据，用于生成连续的叶面积指数（Leaf Area Index, LAI）剖面，并刻画山麓松属（Pinus spp.）林分的结构异质性。该实测数据详细记录了冠层间隙在垂直与水平方向上的分布特征，可用于评估非闭鳞球果松林分的演替轨迹。 本次测量通过对比冠层上方（参考读数）与冠层下方（样本读数）的透光率完成。基于叶片随机分布与椭球取向的辐射传输模型，利用两组读数的差值估算叶面积指数，但该方法对部分物种或冠层类型的适配性存在局限，可能导致精度偏差。 仪器参数如下：LAI-2200C植物冠层分析仪（LI-COR Biosciences，美国内布拉斯加州林肯市）；光谱范围：320–490 nm；测量几何设置为5个同心环，对应的天顶角分别为7°、23°、38°、53°与68°。 采样方案：在植物区系调查过程中，每间隔0.5米开展一次测量，共计获取约900份样本；采用最大270°的光学视场范围，以排除操作人员对测量视场的干扰。数据处理环节采用FV2200软件（LI-COR Biosciences，美国内布拉斯加州林肯市）完成；质量控制措施为规避光照不稳定条件下的测量数据。