不同经营方式对华北落叶松人工林林下生态特征的影响

Effects of different management on understory ecological characteristics of Larix principis-rupprechtii plantations

以赤峰市喀喇沁旗旺业甸林场为研究区,调查华北落叶松人工林林下生态特征,探究近自然、常规和对照3种经营方式对华北落叶松幼龄林、中龄林和近成熟林林下草本层多样性和生物量、枯落物层持水特性以及土壤容重的影响。结果显示:随着林龄的增长,近自然经营方式的林下草本多样性呈上升趋势,对照区呈下降趋势,常规经营方式无明显变化;常规经营在幼龄林阶段草本生物量更高,达1.0t/hm2以上,而中龄林和近熟林则为近自然经营优于常规经营和对照经营;常规经营在中龄林阶段枯落物积累更多,达到29.07t/hm2,拦蓄量也更高,达到58.86t/hm2,近熟林阶段则为近自然经营更有利于提高枯落物的蓄积和拦蓄效果,分别达到了39.27t/hm2和81.38t/hm2;林分土壤容重为近自然经营下最小,常规经营下最大,且均随土层深度的增加而增大。综合来看,近自然经营模式更有利于林下草本植被的生长和枯落物的积累,特别是在林分趋于成熟时,对于提高林下植被多样性和增强地表保水保土能力具有一定的积极作用。

This study was conducted in Wangyedian forest farm of Kharaqin Banner,Chifeng.Ecological characteristics such as herbaceous diversity,biomass,water capacity of litters,and soil bulk density in the understory of Larix principis-rupprechtii plantations were analyzed to evaluate the effects of three management models,including close-to-nature,regular,and CK,on young,middle-aged and near-mature stands.The results showed that：With the growth of standsage,the herbaceous diversity indicies went upward gradually in close-to-nature forests,while slightly decreased in CK,and those of regular forests levelled off.Regular forests kept more herbaceous biomass with a value of more than 1.0t/hm2 when stands were young,while that of close-to-nature forests was better than that of regular forests and CK for the duration of middle-aged and near-mature stands.Regular forests kept more litters（29.07t/hm2）andcould hold more water（58.86t/hm2）in middle-aged stands,while such characteristics of closeto-nature forests were more beneficial in near-mature stands,reaching to 39.27t/hm2 and81.38t/hm2 relatively.Soil bulk density kept lowest under close-to-nature stands while peaked under regular stands,and that of each stands increased with soil depth.Overall,close-to-nature management is more effective on herbaceous growth and litters accumulation,especially when stands are approaching maturity,which is positive for enhancing ground capacity and vegetation diversity in the understory.