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Scientia Silvae Sinicae ›› 2025, Vol. 61 ›› Issue (7): 157-169.doi: 10.11707/j.1001-7488.LYKX20240646

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Effects of Precipitation Reduction and Thinning on the Root Distribution and Physiological Characteristics of Larix kaempferi

Xin Ran1,Xiaomei Sun1,Chunyan Wu1,Dongsheng Chen1,Hongxing Wang2,Shougong Zhang1,*()   

  1. 1. National Key Laboratory of Tree Genetics and Breeding Key Laboratory of Tree Breeding and Cultivation of National Forestry and Grassland Administration Research Institute of Forestry,Chinese Academy of Forestry Beijing 100091
    2. College of Forestry and Grassland Science, Jilin Agricultural University Changchun 130118
  • Received:2024-10-31 Online:2025-07-20 Published:2025-08-19
  • Contact: Shougong Zhang E-mail:larchrif@163.com

Abstract:

Objective: The effects of thinning and precipitation reduction on soil physical and chemical properties, root distribution and physiological characteristics of Japanese larch (Larix kaempferi) plantations were analyzed by developing a combined experiment of forest cultivation and artificial simulation of climate change, so as to provide scientific basis for the rational management of larch plantations under the background of future climate change. Method: In April 2019, four experimental treatments were conducted: control (CKN), no-thinning + 30% precipitation reduction (CKR), 45% thinning intensity + natural precipitation (T45N), and 45% thinning intensity+30% precipitation reduction (T45R) on a 19-year-old Japanese larch plantations located in the mountainous region of eastern Liaoning Province. In July 2023, soil and root samples were collected from different soil layers, and the soil physicochemical properties, root distribution, and root physiological characteristics were measured. Result: 1) Four years after the implementation of thinning and continuous precipitation reduction, compared to control, a 30% precipitation reduction significantly reduced soil moisture content, porosity, field capacity, hydrolyzed nitrogen, total nitrogen, available phosphorus, total phosphorus, available potassium, and total potassium in the 0–20 cm soil layer, while significantly increasing the soil bulk density. The 45% thinning intensity and 45% thinning intensity + 30% precipitation reduction significantly improved the physicochemical properties of the 0–20 cm soil layer, indicating that the positive effects of thinning were significantly greater than the negative effects of precipitation reduction. 2) Precipitation reduction significantly decreased root characteristics (root length density, surface area density, volume density, and biomass density) at different horizontal distances in each soil layer, and promoted root distribution in the 20–60 cm soil layer and at horizontal distance of 100–200 cm. Thinning significantly enhanced root distribution and physiological characteristics across soil layers and horizontal distances. 3) The comprehensive scores of principal components were as follows: T45N (1.54) > T45R (1.00) > CKN (–0.62) > CKR (–1.92), further demonstrating that 45% thinning intensity and 45% thinning intensity + 30% precipitation reduction had positive effects on soil physicochemical properties and root characteristics. Thinning mitigated the negative impact of precipitation reduction on soil physicochemical properties, root distribution, and physiological characteristics. 4) The correlation analysis results revealed that root respiration and vitality were significantly positively correlated with root distribution and soil water content, while significantly negatively correlated with soil bulk density. Conclusion: Precipitation reduction significantly deteriorates the soil quality, root density, and physiological activity of L. kaempferi plantations, whereas thinning notably improves these attributes. Moreover, the positive effects of thinning are significantly greater than the negative effects of precipitation reduction, indicating that appropriate thinning can be an effective management strategy to counteract the impacts of future climate change.

Key words: thinning, precipitation reduction, Larix kaempferi plantations, soil properties, root distribution, physiological characteristics

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