## 1 Introduction  
As the most important terrestrial ecosystem, forest ecosystems, with a large number of complex ecological processes, can continuously provide tangible or intangible benefits for human beings [1]. Serving as an integral part of the forest ecosystem/resources, non-timber forest products (NTFPs) are widely distributed in 124 countries and territories [2], and millions of households around the world rely heavily on NTFPs for material subsistence and cash income, especially in less developed countries [3; 4; 5]. Thus, NTFPs have been playing a crucial role worldwide in supporting regional economies [6; 7; 8]. The forest area of China accounts for 5.4 percent of the total forest area of the world, and about one-third of national forests are distributed in Northeast China [2; 9]. Especially the East Asian temperate forest, one of the three major temperate forests in the world and the most well-preserved temperate forest, is mainly distributed in Northeast China [10]. Because the natural forests (accounting for more than 70% of total forests) in this region have been protected under the Natural Forest Protection Project of China (NFPP) since 1998, timber harvest is prohibited for natural forests. To maintain livelihoods and raise revenue, more and more local people who used to rely on timber production are turning to utilize the abundant resources of wild NTFPs. Consequently, the disordered harvesting and unreasonable utilization of NTFP resources have led to resource unsustainability. Therefore, in recent years, local people have begun experimenting with artificial cultivation of high-value NTFPs under the forests. As an important understory economic plant with strong sprouting ability, _Aralia elata_ (Miq.) Seem., is widely distributed in the forest region of Northeast China, and only a small amount spreads in Korea, Japan, Russia, etc. _A. elata_ is considered as a perennial medicine-food woody plant, the tender new shoots and root bark of which have significant medical benefits such as immunity enhancement and antineoplastic [11; 12]. Moreover, the tender new shoots of _A. elata_ are famous for its delicious taste and rich nutrition, and are well received by the market and the public. Thus, it is one of the main NTFPs to earn foreign exchange [11; 13]. The tender new shoots of wild _A. elata_ are heavily harvested in spring due to their high medicinal and edible values, and the stems of _A. elata_ are also harvested in large quantities to meet the demands of off-season cultivation. Consequently, the over-exploitation of wild _A. elata_ has caused resource exhaustion and difficulties in its sustainable development. To sustainably utilize the _A. elata_, it is extremely urgent to conduct tending management of wild _A. elata_ resources, and, in the meantime, carry out effective artificial cultivation. Aiming to sustainably utilize _A. elata_, on the one hand, it is necessary to determine the optimum harvest methods to maximize the yield of tender new shoots during the spring harvest period while maintaining the healthy individual growth and population development [14]. On the other hand, artificial cultivation of _A. elata_ is also an effective way to meet the demand for _A. elata_ while conserving wild resources. The artificial cultivation of _A. elata_ includes field cultivation and off-season cultivation. Field cultivation can provide both tender new shoots for sale in spring and raw materials (stems) for off-season cultivation in winter. Therefore, the key to artificial cultivation of _A. elata_ in the field is to ensure the healthy growth and sustainable sprouting generation of _A. elata_ and provide more stems for off-season cultivation. Our previous study has indicated that stump diameter is positively correlated with the subsequent development of stump sprouts [15]. Thus, in this study, we chose plant basal diameter growth as the variable to measure the radial growth of _A.