摘要
常绿针叶树是北方地区城市森林的重要树种。在沈阳城市森林中,常绿针叶树约占公共绿地树木总量的20%。在严寒的冬季,北方城市中大部分树木落叶、休眠,惟有常绿针叶树保持着植物的生机,体现了城市的活力。然而,冬末和早春的生理干旱常常导致常绿针叶树松针失绿、枯黄甚至整株死亡,严重影响了城市绿化的景观效果。加强常绿针叶树生长季节和秋末的水、肥等管理,保持常绿针叶树旺盛的生长势,是减轻生理干旱影响的重要措施。
Despite winter dormancy, many needled evergreens, such as Abies holophylla, Picea koraiensis, Pinus armandi, P. bungeana, P. sylvestris vat. mongolica, P. tabulaeformis, P thunbergii, Sabina chinensis, and Taxus cuspidata etc. can suffer extensive damages over the winter and early spring months in northern Chinese urban forest. These damages include low temperature, winter desiccation, frost crack, salt injury, snow or ice, and early spring frost. Winter desiccation, or winter drying can make severe injury to needled evergreens,have periodically caused major damage to needled evergreens in northerly Chinese cities, from Beijing to Haerbin city. Winter desiccation symptoms on needled evergreens vary from yellowing or browning of needle tips to complete yellowing or browning of needles, several continuous years severe damage even can cause entire plant dieback. Mechanism of needled evergreens winter desiccation is that water in cool or frozen root soil is unavailable to needles transpiration, plant moisture is not adequate to maintain the proper water levels in plant tissues. Winter drying injury occurs most frequently during warm dry windy and temperature fluctuation conditions. Location is very important factor affecting the winter desiccation damage. Needled evergreens closely north to high building are severely damaged by winter desiccation. Although there is no cure for winter desiccation, we can take measures to reduce the damage, maintaining the vigor of needled evergreens through fertilization, pruning, and watering during dry periods, deep watering in fall and early spring, mulching the root soil, and application of anti-transpirants such as Wilt-Pruf, etc. are valuable practical approaches.
出处
《中国城市林业》
2010年第1期52-54,共3页
Journal of Chinese Urban Forestry
