Study On The Characteristics Of Ecological Factors For The Wellness Of Common Native Tree Species In Urban Parks

As an important part of forestry,the forest healthcare industry has gradually become a hot spot in the construction of China’s health industry in recent years.Due to its accessibility and convenience,urban parks have become the main position for urban residents to enjoy recreation and communication.Native tree species are the result of long-term selection by plants in nature,and have significant advantages in creating ecological health benefits due to their good adaptability and resistance.In view of this,this article took 14 native tree species in Longzi Lake Park in Zhengzhou as the research object,measured and compared four ecological factors for the wellness,including their dust retention ability,photosynthetic characteristics,air microbial concentration,and cooling and humidifying ability in different seasons and different periods after rainfall,to explore the impact of tree species and seasonal changes on the main ecological factors for the wellness,and to conduct a comprehensive evaluation of the ecological health ability of tree species.It is expected to provide scientific basis for the selection of future tree species for the wellness and the selection of recreational periods.The main research results are as follows:(1)Comparison of dust retention ability of different tree species.The amount of dust retention per unit leaf area of 14 tree species was measured by the elution-gradient filtration method.The amount of dust retention by 14 tree species for particles of different particle sizes showed an increasing trend from 3 d to 14 d after rainfall in different seasons.Prunus cerasifera and Styphnolobium japonicum exhibited better adsorption capacity for different particle sizes at different stages after spring rainfall.Among them,Styphnolobium japonicum also showed better adsorption capacity for particles of different particle sizes at different periods after rainfall in summer and autumn.The dust retention of different particle sizes per unit leaf area of14 tree species showed a trend of spring > autumn > summer.Styphnolobium japonicum and Koelreuteria paniculata showed strong PM2.5 retention ability in three seasons;Styphnolobium japonicum and Prunus cerasifera showed strong PM10 retention ability in three seasons;Styphnolobium japonicum,Prunus cerasifera,and Photinia serrulata all showed strong TSP retention ability in three seasons.Cluster analysis of dust retention capacity of different particle sizes showed that the comprehensive ability of Styphnolobium japonicum to absorb particles of different particle sizes was the strongest,followed by Prunus cerasifera,Koelreuteria paniculata had a strong ability to absorb fine particles,and Photinia serrulata had a strong ability to absorb coarse particles.This difference might be related to leaf surface structure.(2)Comparison of photosynthetic characteristics of different tree species.The main photosynthetic indicators of tree species were measured using the Licor-6800 portable photosynthetic analyzer.The results showed that the net photosynthetic rate,stomatal conductance,and transpiration rate of 14 tree species showed a decreasing trend from 3 d to 14 d after rainfall in different seasons.In summary,Populus tomentosa showed a larger net photosynthetic rate and a smaller decrease in the three periods after spring rainfall;In the three periods after summer rainfall,Armeniaca sibirica showed a larger stomatal conductance and a smaller decline;Prunus cerasifera and Salix matsudana showed higher stomatal conductance and transpiration rate in the three periods after autumn rainfall,respectively,with a smaller degree of decline;The three main photosynthetic indicators in different seasons generally exhibited a higher trend in summer than in spring and autumn,which might be strongly related to the strong physiological activity of tree species in summer.(3)Comparison of airborne microbial concentrations in different tree species forests.Using the natural sedimentation method to measure the airborne microbial concentration,the results showed that the decline of airborne microbial concentration in the forests of Styphnolobium japonicum and Prunus cerasifera reached a significant level at different stages after spring rainfall,while the microbial concentration in the forests of Koelreuteria paniculata and Salix matsudana was relatively small at the three stages after rainfall;The decrease of airborne microbial concentrations in Photinia serrulata and Populus tomentosa forests at different stages after summer rainfall was significant,while the microbial concentrations in Koelreuteria paniculata forests were relatively small at the three stages after rainfall;After autumn rainfall,the air microbial concentration in the forests of Koelreuteria paniculata,Magnolia Grandiflora,Salix matsudana,and Styphnolobium japonicum decreased significantly at different stages,among which the average microbial concentration of Salix matsudana was lower during the three periods after rainfall.The concentration of airborne microorganisms in different seasons was shown as spring > autumn > summer.(4)Comparison of cooling and humidifying abilities of different tree species.The temperature and humidity of the 14 tree species in the sample plots and the control plots were measured,and the results showed that the sample plots of the 14 tree species showed a certain degree of cooling and humidifying ability,among which,Magnolia Grandiflora and Populus tomentosa showed better cooling and humidifying ability in the three seasons.The cooling rate and humidifying rate of the 14 tree species in the sample plots showed a trend of summer > spring > autumn.Cluster analysis based on cooling rate and humidifying rate showed that overall Magnolia Grandiflora had the strongest cooling and humidifying ability,followed by Populus tomentosa and Ginkgo biloba.(5)The correlation analysis between ecological factors for the wellness showed that there was a significant positive correlation between the internal indicators of each factor;There was a significant negative correlation between dust retention indicators and photosynthetic indicators.Among them,there was a high correlation between stomatal conductance and dust retention indicators,indicating that the impact of dust on plant photosynthetic characteristics was mainly based on stomatal limitations,which to some extent indicates that the decline trend of photosynthetic indicators after rainfall was related to the accumulation of dust retention on leaves;There was a significant negative correlation between dust retention indicators and cooling and humidifying indicators;There was a significant weak positive correlation between photosynthetic indicators and cooling and humidifying indicators.(6)Using the entropy-weight-TOPSIS method for comprehensive evaluation,it was found that the ecological health characteristics of the 14 native tree species were ranked in the following order: Populus tomentosa > Salix matsudana > Prunus cerasifera > Styphnolobium japonicum > Photinia serrulata > Magnolia Grandiflora > Koelreuteria paniculata > Armeniaca sibirica > Amygdalus davidiana > Ginkgo biloba > Ligustrum lucidum > Platanus orientalis >Malus halliana > Osmanthus fragrans,which could be selected and utilized according to their different characteristics.The comprehensive ranking of the top five Styphnolobium japonicum,Prunus cerasifera,and Photinia serrulata had good dust retention ability;The photosynthetic indicators of Ginkgo biloba and Prunus cerasifera were less affected during the dust retention period.These tree species could be considered to be planted in areas adjacent to highways in urban parks.The air microbial concentration in Populus tomentosa and Salix matsudana forests was relatively small,while the air microbial concentration in Styphnolobium japonicum and Photinia serrulata forests had a significant decrease,which had a strong ability to reduce bacteria.It can be planted with tree species with strong dust retention ability.Populus tomentosa and Salix matsudana have strong cooling and humidifying abilities,which can mitigate the heat island effect to a greater extent in the process of urban construction.The ranking results of ecological factors for wellness in different periods were as follows: 3 days after summer rain > 14 days after spring rain > 14 days after summer rain > 7 days after summer rain > 14 days after autumn rain > 7days after spring rain > 3 days after autumn rain > 7 days after autumn rain > 3 days after spring rain.From the perspective of wellness and recreation,in terms of season selection,tree species in different periods in summer generally exhibited good ecological health characteristics,so wellness and recreation activities in the forest should be conducted in summer;For different seasons,tree species all showed a strong ecological ability for the wellness around two weeks after rainfall,so the specific travel time in different seasons is preferably around two weeks after rainfall.In terms of ornamental effects,deciduous trees are mostly planted in northern urban parks,and leaf decay has a certain impact on the beauty of the landscape.Therefore,traveling around two weeks after rainfall in spring and summer can provide a good wellness experience while obtaining a better ornamental effect.In terms of location selection,due to the significant impact of the location of tree species on their cooling and humidifying ability,it is possible to choose urban park adjacent to water when traveling in order to achieve better wellness and ecological effects.