Effects of neighborhood interference on the radial growth of Pinus massoniana
Neighborhood interference can affect plant growth and population regeneration,thereby affecting community succession.In order to investigate the mechanism that Pinus massoniana was substituted by evergreen broadleaved trees in the succession of community,we selected P.massoniana as the study object,and analyzed the influence of neighborhood interference on growth,nutrient content and water content of P.massoniana at different diameters.The results showed that:(1)The intraspecific interference intensity of P.massoniana(540.62)was greater than that of interspecific interference intensity(245.73),among which the interference intensity of Schima superba was the highest among interspecific interference intensities(267.04).(2)Neighbor interference inhibited the radial growth of P.massoniana,and had a stronger inhibitory effect on small radial individuals.From small interference to the large,in the past 5 years the diameter growth of large-diameter P.massoniana decreased from 17.23 mm to 8.79 mm,with a decrease of 48.98%.The diameter growth of small diameter P.massoniana decreased from 22.16 mm to 5.57 mm,with a decrease of 78.46%.(3)Neighbor interference affected the water and nutrient balance of P.massoniana,significantly reduced the moisture content of the trunk and increased the total N content of the trunk and the moisture content,total N,and total P content of leaves.(4)The radial growth of P.massoniana was significantly positively correlated with crown surface area,growth space index,etc.,but not with nutrient content.Therefore,the growth and regeneration of P.massoniana are mainly influenced by interspecies competition of S.superba and P.elliottii and intraspecies self-thinning effect,and the inhibition effect on individuals at the small diameter level is stronger.This may be an important reason why P.massoniana was replaced by broad-leaved tree species during community succession.
community successioncompetition exclusiongrowth ratesubtropical zone
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