Soil Compaction by Trampling and its Effect on Growth Condition of Trees

Abstract

The influence of trampling on some physical properties of surface soil and tree growth condition was investigated in Kyoto Imperial Garden. The results are as follows.
1) Trampling increases volume weight of surface soil, and reduces its porosity. In the initial stage of compaction minimum air capacity decreases remarkably, and afterward, maximum water holding capacity decreases.
2) Compaction strongly reduces infiltration capacity, and increases soil hardness sounded by cornpenetrometer (corn: 25°3cm³, rammer: 1.17kg 20cm dropping)
3) “Health Index” (estimated index of living branch rate determined by observation assessment of withered branches which are classified into three groups: primary scaffold branch, intermediate branch, fine branch) has a close relationship with physical properties of soil.“Health Index” is great in a area where the infiltration capacity exeeds 100mm/hr and where hardness, shown by penetrating depth (cm) per 100 drops of rammer, exeeds 20cm. On the contrary, it is obviously small in a area where each value is below 20mm/hr and below 13cm/100 drops.