火炬松种源建筑材抗弯性质的变异及与树龄、晚材率、木材密度的关系

Variation in Wood Bending Properties of Exotic Loblolly Pine Provenances for Building Lumber and Their Relationships to Tree Age, Tree Growth and Wood Density

福建南屿15年生火炬松31个种源间木材抗弯弹性模量(MOE)的群体平均值为6702.6MPa,变化范围为5042.5～8610.2MPa;抗弯强度(MOR)群体平均数为99.11MPa,变化幅度为77.32～119.79MPa。种源间木材抗弯弹性模量(MOE)、抗弯强度(MOR)存在显著差异,二者广义遗传力大于0.441、0.422,方差分析中遗传方差分量在43.07%～60.79%范围内,环境方差分量范围为39.21%～56.93%,说明MOE、MOR除在遗传上受中等程度控制外,还显著受到环境条件影响。种源内MOE、MOR变异系数远大于种源间变异,说明火炬松材质改良在种源选择的基础上进行个体改良效果较好。树龄、晚材率和木材密度与MOE、MOR在0.01水平上呈显著正相关,木材基本密度估测MOE、MOR优于晚材率。火炬松种源木材MOE、MOR值与引种栽培地点有关。南屿靠近海岸线,并且纬度低于所有种源原产地纬度。火炬松种源原产地地理气象因子中,纬度对木材抗弯性能没有影响,经度与MOE、MOR呈较大的负相关,经度对抗弯性能的影响最大,6—9月降水/年降水次之,其他因素影响不显著。

93 15-year-old trees from the 31 provenances trial stand in Nanyu Forest Farm of Fujian Province were collected to deal with variations in bending properties of wood （ modulus of elasticity and modulus of rupture） for exotic Loblolly Pine （ Pinus teada） and their relationships to trees age, latewood percent and wood density in this paper. The range of rings for all test samples in radial direction within trees were marked. MOE for these provenances was from 5 042.5 to 8 610.2 MPa and their average value was 6 702.6 MPa. And MOR was 77.32 to 119.79 MPa and 99.11 MPa in order. It was found that MOE and MOR varied markedly among 31 Loblolly Pine provenances. Their broad sense heritabilities were greater than 0.441 and 0.422 respectively according to variance analyses. And genetic factor accounted of 43.07% - 60.79% in different periods of tree growth and environment factor 39.21% - 56.93 %. Consequently, apart from a medium level of genetic control, MOE and MOR were also affected by growing environment. Variation coefficients of MOE and MOR within a given provenance were greater than those among provenances. This indicated that single tree selection within a provenance on the basis of selection among provenances is beneficial to wood quality. MOE and MOR were significant positively related to tree age, latewood percent and wood density. Wood density could be a best factor used for predicting MOE and MOR in wood improvement. Values of MOE and MOR for Loblolly Pine provenance were distinct related to its culturing environment. In this trial stand, MOE and MOR for Loblolly Pine provenance were not related to altitude of its provenances in its indigenous districts in USA and were markedly affected by their latitude. Among eight factors of latitude, longitude, the lowest temperature of January, annual mean temperature, total summer rainfall from June to September, annual rainfall,the proportion of total summer rainfall to annual rainfall and frosffree season of local geography and meteorology in USA, longitude is the most important factor in effeeting bending properties of wood （ MOE and MOR）. Next is the proportion of total summer rainfall to annual rainfall. Other factors had no any effects on MOE and MOR.