| This paper investigated and analyzed the effects of five kinds of strip harvesting operations(3m?5m?8m?12m?15m)on the species diversity of undergrowth in the bamboo forest,and had important guiding significance for the restoration,tending and mechanization management of bamboo forest.By controlling the cutting width and cutting area,the canopy closed state and the characteristics of undergrowth structure were observed after one year of recovery period.The species diversity index in the strip plot was analyzed to explore the variation of cutting intensity and recovery state with bamboo forest.The research indicated that:(1)Strip harvesting reduced the quality of newborn bamboo forests,compared with samples,the number of shoots and the number of newborn bamboo increased,the competition within the species increased,the mortality rate of bamboo shoots was high,and the rate of shoots became bamboo was low.The average DBH and CH of the new bamboo decreased one grade,but the average DBH of the 3-meter-wide keeping plots was 0.15 cm and 1.23 cm larger than the sample 1 and sample 2 respectively.The average CH of the 12-meter-wide keeping plots was 0.32 cm larger than that of the Sample 2.Within the unit area,the average DBH of newbron bamboo of the 3-meter-wide keeping plots(9.86cm)and the 8-meter-wide keeping plot(9.47cm)was larger than that of the other types of strips,the average CH of the newborn bamboo of the 12-meterwide keeping plots was the highest(6.04m).The population of newborn bamboo in the 15-meterwide cutting plots was the highest(2789).The population-DBH curve and the population-CH curve of 3-meter-wide cutting plots and 15-meter-wide keeping plots could simultaneously simulate high precision,the population-DBH curve of 8-meter-wide plots,12-meter-wide keeping plots and 15-meter-wide cutting plots could simulate accuracy high,the population-CH curve of 5-meter-wide cutting plots had a high precision simulation,too.The linear equation of the structure of the newborn bamboo forest(DBH?8cm or CH?4m)with 8-meter-wide and 12-meter-wide plots was approximative to samples,and the performance showed the most reasonable.It is recommended to do deep research within the width range of 8?12 meters.(2)There were 110 species of 95 genus in 53 families of undergrowth species in the study area(76 species of shrubs of 64 genus in 37 families;and 34 species of herbs of 30 genus in 18 families),with Rosaceae,Compositae,Euphorbiaceae,Rubiaceae.Liliaceae,Labiatae,Gramineae,Verbenaceae,etc.Species richness decreased with the increase of canopy density of bamboo forest,and harvesting significantly promoted species richness(especially woody plants),with the most increased species in the 8-meter-wide and 15-meter-wide plots,but there was 5 species reduction in 12-meter-wide plots compared to sampls.The Shannon-Wiener index,Simpson index and Gleason species richness of the 8-meter-wide and 15-meter-wide plots were better than the samples,but the Pielou evenness index was not.The biomass of undergrowth in 3-meter-wide plots,5-meter-wide plots and 8-meter-wide plots collected in stems and leaves,samples,12-meter-wide plots and 15-meter-wide plots collected in roots and leaves.Harvesting operations significantly promoted the biomass of undergrowth in 8-meter-wide cutting plots and 15-meter-wide cutting plots,but had no significant effect on the keeping strip plots.(3)From January to May,soil nutrient changes drastically,soil moisture content increased but soil bulk density decreased,total N,total P,total K decomposition conversion rate increased,alkali nitrogen soluble phosphorus and available potassium content increased,soil organic matter,urease,sucrase and catalase showed a decreasing trend.Urease and invertase were significantly negative with soil p H value.Soil data analysis in May showed that there was a significant positive correlation between organic matter,total N,total P,alkali nitrogen,available phosphorus and available potassium.During early shoot period,late shoot period and the growth season of the newbron bamboo,the soil temperature conditions of the 8-meter-wide plots were better than the other type of plots.During the early shoot period(January),the soil moisture of each type of plot was not much different.After the bamboo shoots finished reproduction(May),the soil moisture of the 8-meter-wide plots and the 15-meter-wide plots were lower than the rest plots;During the growth season of the newbron bamboo forest(September),the soil moisture of 8-meter-wide plots was higher than the rest plots,and the soil moisture of the 15-meter-wide plot was the lowest.The above results showed that the bamboo forest community with bamboo as the main body interferes with the strip harvesting plots,and the above-ground part had the best structure of 8m strip-like bamboo forest.The 12-meter-wide plots bamboo forest structure was similar to the 8-meter-wide plots.However,it was more discrete;the species richness,species diversity and biomass index of the 8-meter-wide plots and 15-meter-wide plots were the best under the forest;the soil nutrient changed in the forest land was 8-meter-wide plots and 15-meter-wide plots.The most intense ground,the soil temperature and humidity changed in the 8-meter-wide plots indicated that the plot was more suitable for the growth of bamboo shoots,bamboo,and undergrowth.Therefore,the 8-meter-wide plots had the best regeneration.However,considering the structure of bamboo forest,it was recommended to conduct in-depth research in the width of 8?12m. |
PDF Full Text Request