Studies On Water Consumption Characteristics Of The Main Sylvicultural Tree Species In Sandong

The main Sylvicultural tree species in Sandong were selected for the researches on water consumption. The study was divided into two parts. Adult trees of 15 species were selected as the specimens for research of hydraulic conductivity, water potential, and water consumption mechanism. The one year old seedlings of more than 7 species were selected as the specimens in research of water transportation and water consumption characteristics. Research materials for timber usage and water conserwation protecting tree species are Robinia pseudoacacia, Pyrus betulaefolia, Melia azedarach, Quercus acutissima, Pistacia chinensis. The non-wood usage tree species are Castanea mollissima, Amygdalus davidiana, Armeniaca sibirica, Zanthoxylum bungeanum. The landscape tree species are Acer truncatum, Gingo biloba, Sophora saponia, Platanus hispanica, Rhus typhina. And the lianas are Euonymus fortunei, Hedera hepalensis, Parthenocissus tricuspidata, Parthenocissus quinquefolia, Wisteria sinensis .Research results showed that: Xylem embolism was controlled by tree's internal water condition. Water potential of twig 50% hydrology-conductance loss and maximum of hydrology-conductance loss could be used as the index of xylem embolism vulnerability. Maximum hydrology-conductance of matured a year livings twig xylem can be taken as potential hydrology-conductance. Maximum hydrology conductance was different between seasons. Low temperature had different effect on water transportation to different tree species.Relation between twig water potential and its relative water capacitance was consisted that water capacitance regulation of different tree species was different and had a limitation for tree's water consumption. Conception of effective water potential and effective water capacitance was put forward. Certain relativity was existent in functional xylem diameter and its Huber value.Soil humidity, leaf water potential and transpiration of potted seedlings descended under a continual draught stress. Under dry condition the order of 7 tree species' autumn water transpiration was as Robinia pseudoacacia> Acer truncatum > Pistacia chinensis > Gingo biloba > Quercus acutissima > Pyrus betulaefolia > Melia azedarach. The order changed under the ample humidity environment as Melia azedarach> Quercus acutissima > Pyrus betulaefolia > Robinia pseudoacacia> Acer truncatum > Pistacia chinensis > Gingo biloba.According to twig water potential of 50% hydraulic conductance loss, the maximum xylem embolism vulnerability tree species was Melia azedarach, then Pistacia chinensis and Acer truncatum, and then was Robinia pseudoacacia. Pyrus betulaefolia, Quercus acutissima and Gingo biloba were the most unlikable xylem embolism in the 7 tree species. Order of Xylem hydraulic-conductance from maxims to minimum was Quercus acutissima, Robinia pseudoacacia, Pistacia chinensis, Melia azedarach, Gingo bilob, Pyrus betulaefolia and Acer truncatum.Acer truncatum had a stronger sensitivity and lower resistance to the extreme cold condition. Robinia pseudoacacia, Gingo biloba and Pistacia chinensis had a less sensitivity for temperature variety and had a stronger embolism-resistance to low temperature. Tree's hydraulic conductivity descended consumedly and xylem embolism vulnerability increased in the cycle of freezing and melting alternately.Relations between tree twigs water potential and its special water capacitance was studied, and the order of 6 tree species' water capacitance regulation ability was Melia azedarach> Pyrus betulaefolia> Quercus acutissima> Pistacia chinensis> Acer truncatum> Robinia pseudoacacia. Effective water potential scope and water capacitance regulation ability of most tree species descended in accordance with the season variation from spring to winter. Along with the increment of functional xylem, Huber value of Gingo biloba and Acer truncatum presented an increase trend, but Huber value of Castanea mollissima, Amygdalus davidiana, Armeniaca sibirica and Zanthoxylum bungeanum presented an i...