Fine Root Biomass Of Main Species And Effects Of Fire Disturbance On Great Xing’an Mountain Region

The Great Xing’an Mountain region is the most important state-owned forest zone of our country,and also the high incidence area of forest fires.The incidence of forest fire happen is high,and the affected forest fire is large.Explore the biomass status of forest underground fuel is of great significance,and the study of effect on tree roots with different intensity burning.In this research,we study the forest root biomass stock on hand of Larix gmelinii,Betula platyphylla,Pinus sylvestris var.mongolica and Populus davidiana.Then we make a comparative analysis of root biomass and its distribution in four different forest types.We set three types sample plot in forests of Larix gmelinii and Pinus sylvestris var.mongolica,the contrastive plot,low intensity sample plot and moderate intensity plot,respectively.We conduct detailed result description and analysis of root biomass in different diameter range and different soil layers,with a comparative study and significant difference analysis of each sample.Conclusions are as follows:Root biomass of different diameters within 0-20 cm was significantly different(P<0.01)of four forest types.Total root biomass were successively 703.54 g·m-2、759.53 g·m-2、763.10 g·m-2 and 341.92 g·m-2 of Larix gmelinii,Betula platyphylla,Pinus sylvestris var.mongolica and Populus davidiana.The total root biomass was significantly different(P<0.01)of different forest types.Populus davidiana was significantly different(P<0.01)with other three forest types.Total biomass of Populus davidiana forest was significantly lower than the other three forest stands.There was no significant difference between any two forest stands of the total biomass of roots in forests of Larix gmelinii,Betula platyphylla and Pinus sylvestris var.mongolica.The root biomass of four forest types had certain vertical distribution character without exception.The total root biomass between different soil layers was significantly different(P<0.01)of Betula platyphylla and Pinus sylvestris var.mongolica forest stand.The total root biomass between different soil layers was significantly different(P<0.05)of Populus davidiana forest stand.The total root biomass between different soil layers was not significantly different(P>0.05)of Larix gmelinii forest stand.The root biomass of four forest types had certain horizontal distribution character without exception.The total root biomass of Larix gmelinii,Pinus sylvestris var.mongolica and Populus davidiana forest stands were linear incremental distribution,showed increasing trend with the distance from the stem,while Betula platyphylla was to the contrary.There was no significant difference with the control(P>0.05)of total root biomass in 0-20 cm and 10-20 cm soil layer of Larix gmelinii forest stand with low intensity burning,and diameter<lmm,1-2 mm and 2-5 mm fine root was significantly different(P<0.01)from control.Within the 0-10 cm soil layer,total root biomass was significantly different from control(P＜0.05),and diameter ≤lmm,1-2 mm and 2-5 mm fine root was significantly different(P＜0.01)from control.There was significant difference with the control(P＜0.01)of total root biomass in 0-20 cm and 0-10 cm soil layer of Larix gmelinii forest stand with moderate intensity burning,and diameter ≤1mm,1-2 mm and 2-5 mm fine root was significantly different(P＜0.01)from control.Within 10-20 cm soil layer,total root biomass was no significant difference with control(P＞0.05),while diameter ≤lmm,1-2 mm and 2-5 mm fine root was significantly different(P＜0.01)from control.There was no significant difference with the control(P＞0.05)of total root biomass in 0-20 cm,0-10 cm and 10-20 cm soil layer of Pinus sylvestris var.mongolica forest stand with low intensity burning,and diameter≤1mm fine root was significantly different(P＜0.01)from control.There was not significant difference with the control(P＞0.05)of total root biomass in 0-20 cm and 0-10 cm soil layer of Pinus sylvestris var.mongolica forest stand with moderate intensity burning.Within the 0-20 cm soil layer,diameter ＜lmm fine root was significantly different(P＜0.01)from control.Within 0-10 cm soil layer,diameter<1mm fine root was significantly different(P＜0.01)from control,diameter of ＞5 mm live root was significantly different from control(P＜0.05).Within 10-20 cm soil layer,diameter－1mm fine root was significantly different(P＜0.01)from control,diameter of 2-5 mm fine root was significantly different from control(P＜0.05),the diameter of ＞ 5 mm live root and control were with significant difference(P＜0.01).