| Taking 12 protection forest species on sandy coast in Eastern Shandong as test materials, this dissertation systematically studied their wind damage status, growth traits, photosynthetic characteristics, mechanical properties of living trees, wood physical-mechanical properties and wood fiber properties. On that basis, this study made a evaluation on the ability of wind-resistant and selection on species. The main conclusions were as follows:1.Wind damage statusThe difference of damage rate was extremely significant among different tree species. The damage rate of Quercus acutissima Carruth was 29.65%, which was the lowest, followed by Ulmus pumila L. and Robinia pseudoacacia L..The average damage rate was 57.18%. Studied on the classification of wind damage status, we found that only Pinus thunbergii Parl and Pinus densiflora Sieb. et Zucc contained all the damage grade.2.Growth traitsThe difference of annual diameter at breast height , annual tree height , crown/height ratio and average crown width was extremely significant among different tree species. Every growth traits of Quercus acutissima Carruth was higher. Annual tree height, annual diameter at breast height and average crown width was 0.59m, 0.96cm and 5.72m respectively. The average crown width of Pinus thunbergii Parl and Pinus densiflora Sieb. et Zucc was larger, which was 4.61 m and 4.55 m respectively. The taproot of Quercus acutissima Carruth and Pinus thunbergii Parl was stronger and the root of Tamarix sinensis Lour. was deepest,which was 3.8m. The average root range of Robinia pseudoacacia L. was the longest, which was 13.5 m. The root in windward side was stronger than in leeward. The total root of Pinus thunbergii Parl in windward was 1.3 times of in leeward, and Robinia pseudoacacia L. was 1.16.3.Photosynthetic characteristicsThe maximum value of Pn was found at 10:00~11:00 before and after in the morning. The first peak of Tr was greater than Pn. There had a a significant correlation or extremely significant correlation among the Pn, Tr and Gs of most of tree species. The main factors of affecting Tr is Gs. Quercus acutissima Carruth and Amorpha fruiticosa L. had the lowest light compensation point. Pinus thunbergii Parl and Tamarix sinensis Lour had higher light compensation point and a light stauration point.4. Mechanical properties of living treesThe difference of living trees mechanics parameters was extremely significant. Longitudinal elasticity modulus, wood basic density, pilodyn penetration value of Quercus acutissima Carruth was the best,which was 6.32 Gpa, 0.72g/cm~3, 8.88mm respectively. Longitudinal elasticity modulus presented a significant correlation with wood basic density, pilodyn penetration value, stress-wave velocity, which repeatability achieved moderate intensity levels. Wood basic density presented a significant correlation with pilodyn penetration value. Nine tree species were clustered into four categories. Typeâ…¢was composed by Quercus acutissima Carruth, Robinia pseudoacacia L, Pinus thunbergii Parl and Toona sinensis A.Juss, which had the highest pilodyn penetration value, stress-wave velocity and longitudinal elasticity modulus.5.Wood propertiesThe difference of wood properties was extremely significant. Air-dry density, oven-dry density, standard density of Quercus acutissima Carruth was highest, which was 0.82 g/cm~3, 0.80 g/cm~3 and 0.83g/cm~3 respectively. The correlation among all the wood physical properties reached a extremely significant level. Every mechanical properties of Robinia pseudoacacia L. was the highest, followed by Quercus acutissima Carruth. The rodial crushing strength, elastic modulus of bending, bending strength, toughness, hardness of tangential section and hardness of radial section of Robinia pseudoacacia L. was 84.61 Mpa, 15236 Mpa, 207.37 Mpa, 272.12 KJ/m2, 14.99 N, 14.36 N respectively. The correlation among all the wood mechanical properties reached a extremely significant level. Fiber length and fiber width of Pinus thunbergii Parl and Pinus densiflora Sieb. et Zucc ranked in the top two of all species. Length-width ratio of heartwood of Ulmus pumila L. and Quercus acutissima Carruth ranked in the top two. Longitudinal elasticity modulus wood basic density, pilodyn penetration value, Fiber width of heartwood presented a significant or extremely correlation with other fiber properties.Five tree species were clustered into three categories by principal component analysis. Typeâ… was composed by Robinia pseudoacacia L and Quercus acutissima Carruth, which had the highest density and mechanical properties. The oven-dry density, standard density, elastic modulus of bending, bending strength and rodial crushing strength of this type was 0.784 g/cm~3, 0.814g/cm~3, 15075Mpa, 243.537Mpa, 7.851Mpa respectively. 6.Multiple indexes evaluation system of wind resistanceIn this study, we selected six indexes which is crown/height ratio, longitudinal elastic modulus (living trees), wood basic density, standard density and rodial crushing strength to build a multiple indexes evaluation system of wind resistance, and quantified the indexes. We offered that any tree species whose crown/height ratio lower than 0.60, longitudinal elastic modulus (living trees) higher than 4.1Gpa, wood basic density higher than 0.48 g/cm~3, the standard density higher than 0.61 g/cm~3, rodial crushing strength higher than 58Mpa could be referred as wind-resistant tree species.7.The selection of wind-resistant tree speciesWe made a comprehensive selection by multiple indicators in this study and selected Quercus acutissima Carruth, Pinus thunbergii Parl, Tamarix sinensis Lour. as wind-resistant tree species on sandy coast in Eastern Shandong finally. |
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