Xia Zhixiang how to improve the survival rate
With the rapid development of urban construction, planting trees during the hot and dry months of July and August has become a common practice. However, in recent years, there has been an unusual phenomenon where Toona sinensis (Chinese mahogany) planted during these seasons often fails to survive. This article explores the reasons behind this issue and discusses ways to improve the survival rate of such plants.
In 2001, I was involved in the Shihuifang Landscape Project in Suzhou. In 2002 and 2003, I managed the greening projects of Shihu West Road and Shannon Apartment. During these projects, the survival rate of Toona sinensis with a diameter at breast height (DBH) of 8–10 cm (referred to as "Xiao Xiangyu") was relatively low. Given that younger seedlings typically have better survival rates than older ones, this raised some concerns. The main factors contributing to this problem include:
First, the extreme heat and drought conditions during July and August in southern regions like Suzhou are particularly harsh. The average temperature ranges from 29°C to 30°C, with daily minimums between 25°C and 27°C and maximums reaching up to 36°C or even 37°C. Moreover, while it is a rainy season, long dry spells—sometimes lasting 10 to 20 days—can occur. According to plant growth principles, when faced with unfavorable conditions, plants develop stress resistance. However, when metabolic activity is high, stress resistance tends to be weaker. And high metabolic activity is closely related to moisture content in the plant body.
Second, most Toona sinensis trees planted in summer undergo heavy pruning. The stems of mature Toona sinensis have mottled surfaces and longitudinal cracks, are highly lignified, and have low water content, making them more resistant to heat and drought. In contrast, young Toona sinensis (Xiao Xiangyu) have tender, green branches with high moisture content and strong metabolic activity, but poor tolerance to heat and drought.
Third, there's a mismatch between water supply and demand. Newly planted seedlings usually lose most of their leaves during transplanting, so they rely on water transport through the stem surface. Mature Toona sinensis can effectively protect themselves from sunburn and maintain moisture due to their thick, lignified stems. However, Xiao Xiangyu lacks this protection and must continuously lose water through evaporation to regulate temperature and sustain metabolism.
Fourth, the root systems of newly planted trees are often severely damaged. The mud balls around the roots are typically only 8–10 times the DBH, meaning most of the roots are cut off. As a result, the tree depends mainly on the limited root system within the mud ball for water absorption. Since the root system of Toona sinensis is often compromised, its ability to absorb water is barely enough to support normal metabolic functions. Under intense sunlight, the lack of protective tissue leads to rapid water loss and ultimately, a disruption of the water balance essential for plant survival.
Fifth, remedial measures taken during the hot and dry season often fail to work effectively. When new Toona sinensis show signs of leaf blackening and wilting, actions such as soil loosening, radial trench digging, and applying vitality or rooting agents may help. However, for Xiao Xiangyu, once symptoms appear, even timely interventions rarely save the plant. Within 5–7 days, the leaves, small branches, and entire seedling will turn black and die.
To address these challenges, several strategies can be implemented: First, avoid planting seedlings during the hottest and driest months, especially for species like Xiao Xiangyu. Second, apply shading and cooling techniques, such as wrapping the trunk and branches with straw rope, plastic film, and regular misting. Third, prune the above-ground parts to reduce the evaporation area and minimize water loss. Fourth, ensure that the root ball is well-formed and as large as possible during excavation to retain more effective roots. Fifth, strengthen post-planting care, including timely watering to promote root absorption. Lastly, consider using biological agents like root stimulants or vitality enhancers to accelerate root development and improve survival chances.
Frozen Squid Ring,Frozen Calamari Rings,Frozen Fried Calamari,Frozen Squid Rings
Zhejiang Fudan Tourism FOODS Co., Ltd. , https://www.fudanfood.com