Difference Of Growth,Understory Vegetation And Litter In Pure And Mixed Forests Of Larix Principis Rupprechti

In order to change the single pure forest management model in long-term,and promote the regeneration of lower larch plantations rationally,increase the diversity of under-forest plants,and strengthening the ecological benefit under the forest.Therefore,the growth of larch in pure and mixed forests,the diversity of undergrowth plants and the ability of litter layers to conserve water resources were studied and compared.The research results can provide ideas for afforestation of coniferous and broad-leaved tree species in the mountainous areas of Hebei province,and provide basis for the management of forestland and protection of biodiversity.In this study,the larch pure forest of Saihanba mechanical forest farm,the mixed forest of larch birch mixed forest and the mixed forest of larch spruce were selected as research objects,and the DBH,height and volume growth of larch,forest were studied.The comparative analysis was made on the important value,richness index of the plant,the water holding capacity of the litter under the forest,and the water absorption rate.The main conclusions are summarized as follows:1.Growth status of larch forest in different forest types:the growth of larch in different forests has significant differences,and the DBH,tree height,and volume growth have all shown in mixed forests of larch and birch.obvious advantage.From the high growth curve of larch trees,the curve patterns of the three stand types are generally similar,showing a slow-fast-slow upward trend,and the growth amount is relatively close in the young stage,but in the later growth process,larch the growth of the mixed forest with white birch shows a great advantage.However,the growth of tree height in larch and mixed forest of larch and birch was higher than that of the other two forests.The change trends of the DBH and the volume of larch in the three stand forests are also similar.The annual growth of larch in larch and birch mixed forest is stable and better than that of the other two stands.Overall,the growth of Larch species in the three stands was as follows:Larch birch mixed forest>Larch spruce mixed forest>Larch pure forest.2.Comparative analysis of understory biodiversity in different forest types:there were significant differences larch white birch and larch mixed diversity indices pure forest biological,larch spruce mixed forest with no significant difference between the other two stands.Its richness and biodiversity are highest in the mixed forest of larch and birch.The richness index of undergrowth herbaceous plants was as follows:Larch Birch mixed forest(0.7083)>Larix spruce mixed forest(0.5417)>Larch pure forest(0.3958).The understory woody plant richness index was:larch birch mixed forest(0.2291)>larch spruce mixed forest(0.1875)>larch pure forest(0.1250).It shows that the understory species in the mixed forest are more abundant and diverse.The Simpson indices of understory herbs and woody plants were:Larch birch mixed forest>Larch mixed forest>Larch pure forest.The order of Shannon-Wiener index was as follows:Larch birch mixed forest>Larch spruce mixed forest>Larch pure forest.It can be seen that the most uniform and complex distribution of undergrowth plant species is the mixed forest of larch and broad-leaved species of white birch.3.The comparative analysis of the ecological benefits of forest land in different forest types:the water holding characteristics of the litter in the three forest types have significant differences.The litter reserves show the highest in the pure larch forest,while the water holding capacity the water uptake rate and the water uptake rate were both highest in the mixed forest of larch and birch,but the correlation of the water holding capacity,water absorption rate and the inundation time of the litter of the three stands were significant.The maximum water holding capacity of the litter semi-decomposing layer was:the mixed forest of larch and birch(18t/hm~2)>Larch larch mixed forest(16.18t/hm~2)>Larix pure forest(13.08t/hm~2).The maximum water holding capacity of the undecomposed layers was ranked as follows:mixed forest of larch and birch(10.58t/hm~2)>Larch mixed forest(9.63t/hm2)>Larch pure forest(8.03t/hm~2).Comparison of the water absorption rates of the three forest types:Larch birch mixed forest>Larch spruce Mixed forest>Larch pure forest.The total litter volume of litter of Larix principis-rupprechtii was compared with that of pure larch(23.97t/hm~2)>mixed forest of larch(26.09t/hm~2)>mixed forest of larch and birch(19.84t/hm~2).Overall,the mixed forest has the best water holding capacity,and the best one is the mixture of larch and broad-leaved species,followed by pure forest.Mixed coniferous and broad-leaved species can effectively improve the ability to store and retain water under the forest and improve the ecological benefits of forest land.