退化红壤区湿地松恢复林潜在耗水量预测及造林密度选择

POTENTIAL WATER USE FORECAST AND PLANTING DENSITY CHOOSING OF PINUS ELLIOTTII ENGLEM.IN DEGRADED RED SOIL AFTER REFORESTATION

基于植被重建的生态恢复作为退化红壤治理的重要技术在南方得到了广泛应用。采用热扩散探针法(TDP)对以千烟洲为代表的南方退化红壤区湿地松树干液流与气象因子进行同步观测,建立湿地松潜在耗水量模型,并对目前湿地松的造林合理性进行评价。结果表明:湿地松边材面积与胸径、树龄的相关关系分别可用二次函数和幂函数很好地拟合。采用多元线性回归分析建立潜在液流通量模型,潜在液流通量与冠层温度、冠层相对湿度、光合有效辐射相关性均显著。基于边材面积和潜在液流通量的潜在耗水量模型不仅可以预测林分耗水动态规律,还可以插补液流观测过程中的非正常值和缺失值。就林分耗水量方面而言,目前研究区湿地松林造林密度是比较合理的。

Ecological rehabilitation based on artificial vegetation reconstruction which was the important technique for fathering degraded red soil was widely applied in Southern China.Forest water consumption and rational planting density during afforestation were thus increasingly concerned.Pinus elliottii Englem.sapflow and meteorological factors were measured synchronously using thermal dissipation probe in Qianyanzhou representative of southern degraded red soil area.Potential water use was modeled and rationality of planting density was evaluated.A significant correlation between sapwood area（SWA）and diameter at breast height（DBH）was well fitted with conic model.A significant correlation between sapwood area（SWA）and tree age（A）was well fitted with nilpotent model.Potential sap flow density model was established by multi-linear regression equation.Significant correlation also existed between potential sap flow density（Qp）and three meteorological factors,i.e.canopy temperature（CT）,canopy relative humidity（CRH）and photosynthetically active radiation（PAR）.Potential water use model based on sapwood area and potential sap flow density could not only be used for predicting forest water consumption dynamics,but also interpolating abnormal and absent sap flow observation data.The present planting density of P.elliottii Englem.in the study area was relatively reasonable as for stand water use.