Study On Ecological Restoration Countermeasures Of Larix In Altai Mountain

Larix sibirica Ledeb(scientific name:Larix sibirica Ledeb)is a dominant tree species in Altai Mountain,which not only plays an important role in maintaining the structure of the cold temperate coniferous forest community,but also has an important significance for the stability of the ecosystem.At present,the forest resources of Larix sibirica in Altai Mountain are seriously damaged,and the situation of endangerment is becoming increasingly serious.In this paper,the natural community of Larix sibirica in Altai Mountain is taken as the research object,and the litter factor is determined as the research direction based on the comparison of the number of seedlings regeneration in three different interference modes(thinning,tillage,burning)and undisturbed forest land.Through the seed germination test in the laboratory and the pot planting test in the soil,combined with the analysis of the physical and chemical characteristics of the soil,This paper studied the effects of litter under Larix sibirica forest on seed germination and seedling preservation of Larix,discussed the action mode and mechanism of litter on the limitation of Larix sibirica seedling formation,and put forward countermeasures and suggestions for the protection and restoration of Larix sibirica forest in Altai Mountain.The main research results are as follows:(1)There is no seedling regeneration under the undisturbed forest,but there is seedling regeneration under three different interference modes(thinning,plowing,burning).In the fire interference forest,the best seedling regeneration is 9 plants/m~2,and the best regeneration frequency is 89.36%.Larix sibirica can not complete the regeneration succession under natural conditions,and appropriate interference is conducive to the regeneration of Larix sibirica.(2)The effect of litter on litter seed germination and seedling formation is different due to different placement positions and thicknesses.However,in general,the inhibition ability of litter on Larix sibirica seeds is shown as above leaf>in leaf>under leaf.The thickness of litter above 2 cm has a significant negative impact on Larix sibirica seed germination and seedling growth.(3)The extracts of Larix sibirica litter have allelopathy on the seed germination and seedling growth of Larix sibirica,and this allelopathy is concentration dependent.The inhibitory effect of litter extract on seed germination and seedling growth increased with the increase of concentration;The allelopathy of Larix sibirica can be eliminated by the litter after fire,and the promoting effect of the water extract of the litter after fire on seed germination and seedling growth increases with the increase of the concentration of the extract.(4)The contents of soil temperature,water,p H,hydrolytic nitrogen,available phosphorus and available potassium under fire disturbance and without fire disturbance decreased with the increase of soil depth.The soil temperature,water,p H value,hydrolytic nitrogen,available phosphorus,and available potassium content after fire were significantly different from those of unburned(CK)(P<0.05).The soil water content was CK>fire disturbance,and other indicators were fire disturbance>CK.The physical isolation and allelopathy of litter had significant effects on the seed germination and seedling growth of Larix sibirica(P<0.05),and three kinds of interference(thinning,tillage,burning)could promote the regeneration of Larix sibirica and the litter increased soil nutrients through burning.Therefore,the following ecological restoration strategies are proposed for the Larix forest ecosystem in Altai Mountain.Under the forest:the soil structure is improved by removing dead branches and fallen leaves through mowing the turf,and the seeds treated by disinfection and germination are sown manually after mowing the turf,so as to strengthen the management of water and fertilizer in the forest land and promote natural regeneration in combination with mountain closure for afforestation;In the open space≥1.5km away from the forest edge:remove dead branches and fallen leaves by burning to improve the soil structure and increase soil fertility.After burning,manually spread the treated seeds and combine with mountain closure to promote natural regeneration.