两种过火类型对云南松林损伤及火后自然更新的研究

The Damage and Post-fire Regeneration of Pinus yunnanensis under Two Different Fire Intensity

火是自然界广泛存在的干扰因素,过火对生境中的植物个体生存发展以及种群的动态均会产生深刻的影响。以云南省澄江县梁王山自然保护区鲁溪冲林区火烧迹地中的云南松作为研究对象,对发生地表火林冠针叶呈绿色、针叶变黄脱落和发生林冠火地段的云南松受损程度和火后自然更新,以及未过火地段林内更新进行调查。结果显示,2种过火类型地段中云南松受损呈现两极分化,林冠火地段的云南松死亡率为100%,地表火过火地段则没有全株死亡的现象。3个过火样地云南松植冠种子库种子活力均显著下降,其中林冠火样地种子萌发率最低,仅为(40±21.21)%。不同过火强度林区自然更新的幼苗数量存在显著差异(P<0.05),数量排序为地表火针叶绿>地表火针叶变黄脱落>林冠火。跟踪调查发现,过火地段云南松幼苗的地上部分高生长和地径生长明显地高于其它地段。林火后3年,林冠火区幼苗高生长达到(22.13±5.75)cm,而未过火林区幼苗高生长仅为(8.33±4.16)cm。林冠火地段云南松自然更新后幼苗生长没有出现蹲苗现象。

Fire is a widespread impact factor in the nature,and it has a profound effect on the plant individuals and population dynamics of forest.This study focused on the damage and post-fire regeneration of Pinus yunnanensis in the burned area of Luxichong Forest in Liangwang Mountain Nature Reserve,Yunnan Province.The results indicated that the damage of P.yunnanensis in different fire intensity areas showed polarization,which was 100%death rate in the crown fire area,but no death tree in the surface fire area.The burning can also reduce seed vitality of P.yunnanensis in the canopy seed bank,Most seeds in the crown fire area were affected,and the germination rate of this area was only(40±21.21)%.There were significant differences in the number of seedlings of natural regeneration in different fire intensity areas(P<0.05).The number of seedlings was ranked as low intensity surface fire >high intensity surface fire >crown fire.The tracking survey found that the growth of height and basal diameter of seedlings could be significantly promoted after fire.The height of seedlings in the crown fire area reached(22.13±5.75)cm in 3 years after fire,and the seedlings in the area without fire were only(8.33±4.16)cm.Which means seedlings in the crown fire area didn’t show the grass stage.