The Vigor Assesment of Street Trees, Zelkova serrata.

Abstract

In order to develop the vigor diagnosing method, we made an extensive survey on the street trees, Zercova serrata, growing in Kyoto city in the dry summer season in 1990. Results are as follows:(1) Most trees are in the water stress, and especially the declining tree was in a severe stress.(2) A good deal of irrigation could not make them to recover in a day.(3) Properties and functions of the leaves in the upper part of the crown such as the diurnal change of photosynthetic rate and transpiration, thermal images of the crowns, NDVI image which is (Infrared-red)/(infrared + Red) by the infrared TV camera based remote sensing system, value of chlorophyll meter and the average annual increment of bole radius in recent 3 years were very effective for the vigor assessment. Xylem pressure potential and the pattern of diurnal change of the heat pulse speed were helpful to understand the vigor declining was related to the water stress.