| Moso bamboo(Phyllostachys edulis)is an important bamboo species with economic and ecological value in China.Fujian Province is the main distribution area of moso bamboo in China,with the largest distribution area in China.Moso bamboo forests is a typical uneven-aged forest,and there are always different age bamboo in the forest.The high cost and low efficiency of traditional manual selective cutting do not meet the requirement of modern forestry management.Therefore,it is an urgent need to explore a high efficiency and low-cost cutting method.Currently,efficient,easy to operate mechanical or semi-mechanized strip-cutting method is highly concerned.In this study,four cutting width and retention width gradients(3 m cutting strip(C1)and 3 m reserved strip(D1),6 m cutting strip(C2)and 6 m reserved strip(D2),9 m cutting strip(C3)and 9 m reserved strip(D3),12 m cutting strip(C4)and 12 m reserved strip(D4))were set up.We have systematically carried out the research on the influence of four cutting width and retention width gradients on bamboo forest growth characteristics and microclimate,aiming to explore the growth characteristics,soil properties and microclimate changes of bamboo in the forest under different cutting widths.The reasonable cutting width suitable for promotion is selected to provide a theoretical basis for the efficient cultivation and sustainable management of the moso bamboo forest.The research results have important guiding significance to realise the transformation and upgrading of the bamboo industry.The main results are as follows:1.The growth of new bamboo in the cutting zone and the reserved zone is closely related to the cutting width and the reserved width,and the change range of the narrower width of the cutting zone and the reserved zone is smaller than that of the larger width of the cutting zone and the reserved zone.(1)With the increase of cutting width,DBH in 9 m cutting zone and 12 m cutting zone decreased by 19.22% and 24.19%,respectively;The DBH of new bamboo in the reserved zone is larger than that in the cutting zone;The differences of DBH between the reserved zone and the cutting zone were 3.03%,5.89%,8.20% and 15.77%,respectively.(2)The arrangement order of per plant biomass in the cutting zone was CK > C1 > C2 > C4 > C3,the order of biomass in the reserve zone was CK > D4 > D1 > D2 > D3;the biomass of the reserved bamboo was higher than that in the cutting zone.The biomass of new bamboo in reserved zone is greater than the cutting zone,gradually increasing with the increase of the cutting width.(3)Compared with the control,the litter stock in the cutting zone decreased by8.96%,15.73%,39.62%,and 50.18%,respectively.the litter stock in the reserved zone increased by 14.49%,3.49%,6.34%,3.51%,respectively.(4)The coverage of understory vegetation in the cutting zone was 3.94 times,2.3 times,2.21 times and 1.42 times of that in the control plot,respectively;The reserved zone were 3.37 times,2.03 times,0.86 times and1.04 times of the control,respectively.The vegetation coverage of the reserved zone was14.63%,12.02%,60.8% and 26.63% lower than that of the cutting zone,respectively.2.Strip cutting can increase soil nutrient content and enzyme activity in short term,and improve the comprehensive soil quality.However,the change range of soil properties is different due to the change of width of cutting zone and reserved zone,and the comprehensive quality of soil in the reserved zone is better than that of the cutting zone.(1)Strip cutting can change the physical properties of soil,and the soil density and non capillary porosity increase in the cutting zone,which is larger than that of the reserved zone and the control stand.Among them,the increase of 3 m cutting zone is the largest.(2)The strip cutting increased the soil nutrient content and soil enzyme activity in the cutting zone and the reserved zone,and the soil nutrient content of the forest land with the cutting bandwidth of 3 m and 6m was greater than 9m and 12 m.the soil nutrient content and enzyme activity of the reserved zone were higher than that in the cutting zone.(3)The results showed that the strip cutting had a certain promotion effect on the comprehensive quality of soil in a short time.The order of arrangement was D1 > D3 > C2 > D4 > C4 > D2 > C3 > C1 > CK.The soil quality of the reserved zone was better than that of the cutting zone.3.Solar radiation intensity and surface soil temperature were significantly changed by strip cutting,but the influence on soil humidity of cutting zone and reserved zone was not consistent.(1)The solar radiation intensity and surface soil temperature were increased in the cutting operation.The solar radiation intensity and the range of daily variation in the reserved zone and cutting zone were higher than that of the control,and the cutting zone was larger than the reserved zone.(2)The effect of cutting on the soil moisture content of the surface layer of the cutting zone and the reserved zone is different.The soil water content in the cutting zone and the soil water content in the reserved zone are lower than that of the control zone,and the soil moisture content in the cutting zone is greater than that of the reserved zone.4.The leaves and fine roots of new bamboos in clearcutting forests of moso bamboo have adaptive changes,and the extent of change is closely related to the width of the cutting zone and the width of the reserved zone..(1)The SLA of new bamboo in cutting zone was significantly lower than that in reserved zone and control zone.Compared with the control,the SLA of new bamboo in 9 m and 12 m cutting zone decreased by 25.32% and 25.13%.The specific leaf area of leaves in reserved zone was less affected by strip cutting.There was no significant change in reserved zone.(2)The nutrient content of leaves of bamboo strip cutting decreased,N/P increased,and the cutting width of 9 m and 12 m was greater than 3 m and 6 m.The nutrient content of leaves with bamboo was less affected by strip cutting,and n/p was smaller than that of the leaves in the cutting zone.(3)The proportion of biomass of the surface root system increased in the strip cutting bamboo forest,and the increase of the biomass of the surface root in the reserved zone was greater than that in the cutting zone.(4)The total nitrogen and total phosphorus contents of fine root in the 3 m and 6 m cutting zones were significantly higher than those in the control zone,but the change in the reserved zone was not significant.The N/P of fine roots in the cutting zone was significantly higher than that in the control zone,and gradually increased with the increase of cutting width.The 3 m and 6 m reserved zones were significantly larger than the control zone,and gradually decreased with the increase of cutting width.The N/P ratio of fine roots in cutting zone was lager than that in reserved zone.5.The soil-vegetation contained complex internal response and adaptation mechanisms.The effect of zonal cutting on cutting zone and reserved zone is different,which changes the absorption and utilization of soil nutrients by bamboo,and has a certain impact on the biomass of Phyllostachys pubescens.In conclusion,after a growing season,strip-cutting changed the local microclimate of bamboo forest and promoted the growth ability of bamboo forest in the reserved zone.Under the suitable cutting width,the recovery of the cutting zone is rapid,which is conducive to the bamboo forest to maintain efficient and stable ecological benefits and production capacity.Too large cutting zone affects the growth and biomass accumulation of new bamboo,and reduces the quality of bamboo forest.In production,the efficient utilization and sustainable management of moso bamboo forest can be realized by setting 3～6 m cutting bandwidth and reserved 2～3 times of reserved zone. |
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