Three Kinds Of Garden Tree Light Response And Plant Configuration

To clear the relationship between the main landscape trees and light in Changsha,33 sample plots were investigated in this paper.The selection choose the most useful of the three kinds of camphor tree garden,Cinnamomum camphora,Koelreuteria bipinnata,Elaeocarpus decipiens as the research object,select 36 test plant tree in Central South Forestry University of Science and Technology,to study the photosynthetic physiological characteristics of three kinds of landscape trees and plants canopy internal rule of variation of light intensity,to guide their application in landscape architecture.The main results of the paper are as follows:(1)survey of changsha commonly used landscape tree camphor,Cinnamomum camphora、Osmanthus fragrans、Magnolia grandiflora、Ginkgo biloba、Michelia chapensis、Elaeocarpus decipiens、Platanus acerifolia、Koelreuteria bipinnata、Liquidambar formosana、Cerasus yedoensis、Acer palmatum、Prunus cerasifera f.atropurpurea、Rhododendron simsii、Ligustrum quihoui,etc.,which USES high frequency and good comprehensive benefits have Cinnamomum camphora,Koelreuteria bipinnata,Elaeocarpus decipiens,etc.(2)three kinds of major landscape trees were investigated and studied.The results showed that Koelreuteria bipinnata was a light-loving plant,which could make full use of strong light for photosynthesis.The light compensation point of Elaeocarpus decipiens is relatively low and the light saturation point is relatively large,which indicates that it can adapt to both strong light radiation and shade tolerance,and has the strongest adaptability to light intensity change.The light compensation point and light saturation point of Cinnamomum camphora are both lower,which have certain shade tolerance and can be suitable for a variety of light environments.The light compensation point and light saturation point of the three kinds of landscape trees were all Koelreuteria bipinnata>Elaeocarpus decipiens>Cinnamomum camphora.The order of maximum net photosynthetic rate was as follows:Koelreuteria bipinnata>Elaeocarpus decipiens>Cinnamomum camphora.The ability of carbon fixation and oxygen release was Cinnamomum camphora>Elaeocarpus decipiens>Koelreuteria bipinnata.There was a significant positive correlation between DBH,crown width and tree height.In addition,DBH was positively correlated with leaf area index(lai),Cinnamomum camphora:y=0.1142ln(x)+1.673,R~2=0.3475.Koelreuteria bipinnata:Y=0.7082ln(x)-0.5719,R~2=0.8228;Elaeocarpus decipiens:y=0.0009x~2+0.0422x+0.8015,R~2=0.9975,indicating that this correlation is most prominent.At the same time,the transmittance decreased with the increase of leaf area index.The correlation between leaf area and transmittance can be expressed by Cinnamomum camphora:y=-4.1463x+3.2071,R~2=0.9808,Koelreuteria bipinnata:y=-2.8562x+2.9824,R~2=0.9163.Elaeocarpus decipiens can be expressed as y=-6.7084x+4.198,R~2=0.9693.The seasonal variation trend of light transmittance in the canopy of the three kinds of landscape was generally spring<summer<autumn.At the same time,the diurnal variation trends of light transmittance in the canopy of the three landscape trees were different under different weather conditions.Cloudy day performance for morning and evening and noon are lower,during the peak value.In addition,the light transmittance in the canopy of landscape trees of different sizes decreased from the periphery of the canopy to the middle part and the inner chamber,showing a strong law,which can be expressed as Cinnamomum camphora:y=0.362x-0.273,R~2=0.9996.TheexpressionofKoelreuteriabipinnata y=0.0037x~2-0.0781x+0.5894,R~2=0.9942.Elaeocarpus decipiens can be expressed by y=0.0048x~2-0.0623x+0.2546,R~2=0.9985.(3)the application status and planting characteristics of three kinds of landscape trees in landscape greening in changsha city were investigated and analyzed,and the problems existing in their community configuration were summarized and analyzed,such as:(1)the early design did not fully consider the growth habits of plants,especially the lack of light requirements,resulting in poor plant growth,poor landscape effect;(2)poor garden management,maintenance is not timely,the emergence of plant communities messy,part of the loess bare phenomena;(3)blindly pursuit of green rate,multiple plants pile up and ignore plant growth dynamics,resulting in waste of some plant resources and poor landscape viewing effect;(4)lack of comprehensive consideration of local characteristics and other factors,resulting in the flood of certain plants.And put forward the corresponding Suggestions.(4)based on the above research results,the plant configuration patterns of three landscape trees and the appropriate plant types for undergrowth were proposed,the field cases were improved.