【摘要】 通过研究不同修枝强度对杨树林内小气候和林下植被的影响,为杨树人工林合理修枝和林下间作提供理论依据。对5年生的南林3804杨(Populus deltoides ‘Nanlin 3804’)人工林进行不同强度的修枝处理,分别为1/2修枝强度(修去下部枝条,使枝下高达到树高的1/2)、1/3修枝强度(修去下部枝条,使枝下高达到树高的1/3)和CK(对照,不修枝)。修枝4个月后(7月)对不同处理的林下光照强度、气温、相对湿度等林内小气候以及林下植被状况进行调查与分析。结果表明,(1)修枝改变了林下光照强度和空气温湿度。与CK相比,1/2修枝强度下林内不同位点的日平均光照强度和气温分别提高了37.83%和5.30%,而空气相对湿度降低了9.56%;1/3修枝强度下不同位点的日平均光照强度和气温分别提高了15.03%和3.93%,空气相对湿度降低了7.72%。(2)1/2和1/3修枝强度的林分地表温度分别比CK提高了0.89℃和0.62℃;不同处理之间的5cm深土壤温度和土壤湿度差异均不显著。(3)修枝后林下植被会发生较大变化。与CK相比,1/2和1/3修枝强度下的林下植被生物量分别提高了76.24%和51.26%,Shannon-Weiner指数分别提高了43.63%和19.47%;1/3修枝强度下的Menhinick丰富度指数和Pielou均匀度指数均高于CK,但1/2修枝强度下的Menhinick丰富度指数和Pielou均匀度指数均低于CK。总体而言,修枝能增强林下光照强度,提高林内气温和地表温度,降低空气相对湿度,改变林下植被组成,提高林下植物物种多样性和生物量。更多还原

【Abstract】 The effects of pruning on microclimate and vegetation in a poplar plantation were studied to provide a theoretical basis for the plantation management. In March 2018, the plantation of poplar clone Nanlin 3804(Populus deltoides ‘Nanlin 3804’) in five years old was pruned in 1/2 treatment(height under branch was up to 1/2 of tree height after pruning), 1/3 treatment(height under branch was up to 1/3 of tree height after pruning) and CK(control treatment without pruning). Four months after pruning(in July 2018), the changes of microclimate such as light intensity, air temperature, relative humidity and understory vegetation situation were investigated. The result showed that:(1) Pruning changed the light intensity, air temperature and air humidity of plantation. Compared with the CK, the daily average light intensity and air temperature at different sites under 1/2 pruning treatment increased by 37.83% and 5.30%, respectively, but the air relative humidity decreased by 9.56%. Meanwhile, the daily average light intensity and air temperature at different sites under 1/3 pruning treatment increased by 15.03% and 3.93%, respectively, and the air relative humidity decreased by 7.72% compared to the CK.(2) Compared with the CK, ground surface temperatures in 1/2 and 1/3 pruning treatments increased by 0.89 ℃ and 0.62 ℃ respectively. There was no significant difference in soil temperature and soil moisture at 5 cm depth among different treatments. And(3) the undergrowth vegetation changed greatly after pruning. Compared with the CK, the biomass of understory vegetations under 1/2 and 1/3 pruning treatments increased by 76.24% and 51.26% respectively. Menhinick richness index and Pielou evenness index of the undergrowth vegetations under 1/3 pruning treatment were higher than that of the CK. However, the Menhinick richness index and Pielou evenness index under 1/2 pruning treatment were lower than that of the CK. On the whole, poplar pruning could enhance the light intensity, increase the soil surface temperature, while reducing the air relative humidity, changing the understory vegetation composition, and increasing the understory vegetation diversity and biomass as well.更多还原