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Stand age is a significant factor when investigating forest resource management. How to obtain age data at a sub-compartment level on a large regional scale conveniently and in real time has become an urgent scientific challenge in forestry research. In this study, we established two strategies for stand-age estimation at sub-compartment and pixel levels, specifically object-based and pixel-based approaches. First, the relationship between canopy height and stand age was established based on field measurement data, which was achieved at the Mao'er Mountain Experimental Forest Farm in 2020 and 2021. The stand age was estimated using the relationship between the canopy height, the stand age, and the canopy-height map, which was generated from multi-resource remote sensing data. The results showed that the validation accuracy of the object-based estimation results of the stand age and the canopy height was better than that of the pixel-based estimation results, with a root mean squared error (RMSE) increase of 40.17% and 33.47%, respectively. Then, the estimated stand age was divided into different age classes and compared with the forest inventory data (FID). As a comparison, the object-based estimation results had better consistency with the FID in the region of the broad-leaved forests and the coniferous forests. In addition, the pixel-based estimation results had better accuracy in the mixed forest regions. This study provided a reference for estimating stand age and met the requirements for stand-age data at the pixel and sub-compartment levels for studies involving different forestry applications. [ABSTRACT FROM AUTHOR]

Olivine-type LiMn x Fe 1- x PO 4 (LMFP) has inherited the excellent heat-stable structure of LiFePO 4 (LFP) and the high-voltage property of LiMnPO 4 (LMP), which shows great promise as a high-safety, high-energy-density cathode material. In order to combine the high energy density and excellent electrochemical performance, it is essential to consider the Mn/Fe ratio. This paper presents a theoretical investigation of the lattice structure parameters, embedded lithium voltage, local electron density, migration barrier, and lithium ion delithiation and lithiation mechanism of different LiMn x Fe 1- x PO4 (0.5 ≤ x ≤ 0.8) compounds. In situ-coated LiMn x Fe 1- x PO 4 (0.5 ≤ x ≤ 0.8) composite cathode materials with a size of 100-200 nm were prepared by a hydrothermal method to verify the theoretical study. LiMn 0.6 Fe 0.4 PO 4 /C exhibited a specific capacity of 140.2 and 97.58 mA h·g -1 at 1 and 5C, respectively, and a remarkable capacity retention rate of 88.5% after 200 cycles at 1C. When LiMn 0.6 Fe 0.4 PO 4 /C was assembled into a flexible pouch battery and subjected to long cycle tests at different rates and squeeze and extrusion tests, it demonstrated a capacity retention rate of 99.35% for 100 cycles at 0.2C and 93.2% for 200 cycles at 0.5C. Moreover, the structural evolution of LiMn 0.6 Fe 0.4 PO 4 /C were analyzed in situ XRD, indicating a high stability and the resulted as obtine electrochemical performance, paving the way for optimization of high-energy-density LMFP cathode materials.