Abstract:

The trial stand of 2 m×2 m spacing for slash pine was founded on yellow-red soil in 1991.Eleven sorts of fertilization treatments were designed in forms of randomized blocks in this trial.Fertilizes of nitrogen (N),potassium (K) and phosphorous (P) were successively done in this stand in 1992 and 1994.Effects of fertilization on tree growth increments and wood physical mechanic properties of young slash pine were studied in March of 1998.Variance analyses showed that there were significant effects of fertilization on tree growth of slash pine and latewood percent,wood basic density and compression parallel to the grain of wood (CP),modulus of elasticity (MOE) and modulus of rupture (MOR) for slash pine.Nitrogen fertilize made trees in the stand grow slowly and had a distinct negative effects on tree growth of slash pine.Volume of trees fertilized with K was smaller than that of unfertilized trees.Fertilize of P,fertilizes of P combined with N or K and Combined fertilizes of N-P-K were very clearly helpful to increase tree growth of slash pine.Significant differences in shrinkage percent of tangential,radial,axial (AL),volume of wood at air dried condition and ratio (T/R) of tangential to radial shrinkage were not found among eleven treatments at 0 05 level.But the AL and T/R of wood from trees fertilized with P,N-P were smaller than those from unfertilized trees and AL of wood from trees treated with only nitrogenous or potash fertilizer were than that unfertilized trees.P fertilizer,N-P fertilizers,N-K fertilizer and combined fertilizers of N-P-K enhanced distinctly latewood percent,basic density,CP,MOR and MOE compared with the physical mechanical properties of wood from unfertilized trees in trail stand of slash pine.Increasing percents of wood properties above were positively correlated with the amount of P fertilizer treated per hm². Growth increments of tree height,diameter at breast height and tree volume in stands treated with fertilizers were positively related with latewood percent,wood basic density,CP,MOR and MOE,respectively.Latewood percent and wood basic density were separately correlated with CP,MOR and MOE in all treated trees.In trial stand of slash pine,wood physical mechanic properties from dominated trees were best compared with those from suppressed trees and intermediate trees.Wood properties from intermediate trees were better than those from suppressed trees in the stand.

Key words: Slash pine, Fertilization, Growth increment, Wood physical mechanic properties, Correlation analyses