Essential oils have insecticidal activity against several insects and are composed of numerous compounds. This study investigated the insecticidal effects of the Thuja occidentalis L. (Cupressaceae) essential oil, terpinyl acetate, and bornyl acetate against the peach aphid [Myzus persicae (Sulzer)]. The insecticidal effect of essential oils on three Cupressaceae plants was highest in T. occidentalis. The Thuja occidentalis essential oil was extracted by steam distillation, and the optimum conditions were found. The GC-MS profiling of essential oil components extracted from T. occidentalis leaves identified 16 volatile compounds. The main components were α-thujone (16.58%), β-myrcene (14.62%), bornyl acetate (9.31%), and terpinyl acetate (8.52%). As a result of the metabolite profiling of three Cupressaceae plants, terpinyl acetate and bornyl acetate were present in large amounts in all of the essential oils, and they had an acetate structure, so it was estimated that they had insecticidal activity. The insecticidal activity of these two compounds was stronger than the other individual monoterpene compounds. The addition of surfactants to the terpinyl acetate and bornyl acetate showed strong insecticidal activity. Terpinyl acetate and bornyl acetate can be used as environmentally friendly insecticidal-active compounds.

Due to climate change, heat-tolerant species have become increasingly important; however, the selection system for herbaceous plants has yet to be well established. This study aimed to establish a selection system for heat-tolerant plant species and to identify such species. Heat stress at 50 °C for 120 min was applied to 27 plant species using a heat treatment and recovery model. Among them, four herbaceous species—Hemerocallis fulva, Heliopsis longipes, Hosta plantagines, and Scilla scilloides—were selected by measuring their electrolyte leakage index (ELI). Additionally, species with high ELI values (Centaurea cyanus) and low ELI values (S. scilloide) were selected to determine the optimal temperature and time for the heat treatment using linear regression analysis. The selected heat-tolerant herbaceous plants survived under optimal heat stress conditions (120 min at 50 °C). The degree of cell death in the selected plant species was measured using Evans blue staining. The results showed that the cell death indexes of heat-tolerant species were less than 22% after heat treatment, compared to over 57% in heat-sensitive species. Furthermore, the recovery ability at room temperature after heat treatment was assessed using the DAB staining method. The selected heat-tolerant plant species recovered quickly (within 90 min), whereas the heat-sensitive species required over 480 min for recovery. The analytical method developed in this study can more accurately determine the response of various plants to heat stress and has high reproducibility. Therefore, it is considered an excellent method for establishing a heat-tolerant plant selection system.

The importance of evergreen oak species is increasing due to changes in the ecosystem caused by climate change and environmental changes such as fine dust and carbon dioxide. The Quercus myrsinifolia Blume seeds showed a recalcitrant seed property, where the germination rate decreased when the moisture content was decreased. For seedling propagation of evergreen oak, the effect of oak seed coat (pericarp and testa) removal on germination and seedling growth as well as the effect of potting soil and irrigation cycle on seedling quality were investigated. The germination rate and germination characteristics of Q. myrsinifolia evergreen oak seeds showed significant differences depending on the storage period and the presence or absence of seed coat. Seed coat removal significantly increased germination rate compared to intact seeds, accelerated mean germination time, and increased germination rate and germination value. There was no significant difference in germination rate according to the storage period. The growth of Q. myrsinifolia seedlings was much better in the seeds with the seed coat removed than the intact seeds. The root collar diameter of seedlings germinated from intact seeds was 2.44 mm, and the root collar diameter of seedlings from which the seed coat was removed was 3.38 mm. As a result of the growth characteristics according to the potting soil, 1- and 3-year-old Q. myrsinifolia seedlings showed excellent root growth in commercial potting soil and sand mixed potting soil. Consequently, seedling quality index was 0.124–0.257 according to irrigation and 0.149–0.262 according to potting soil. From observing the root growth of the seedlings according to the irrigation treatment, in the case of 3-year-old seedlings, the total root length was 432 cm when irrigated every 3 days, and the growth was the best. The above results are expected to contribute significantly to the mass propagation of Q. myrsinifolia, which is important for warming and urban greening.

Heat-tolerant species have become increasingly important because of climate change; however, a selection system for woody plants is not well established. This study was conducted to establish a selection system for heat-tolerant woody plant species and to select heat-tolerant species. After selecting heat-tolerant woody plants and applying heat stress to 27 species, the electrolyte leakage index (ELI) was measured. The ELI of the heat-tolerant species was lower than that of the non heat-tolerant species, and they survived well after heat stress treatment. For the preselected species, the degree of cell death was measured by Evans blue staining method, and the heat stress recovery ability was measured by a 3,3′-diaminobenzidine (DAB) staining method. The species showed less cell death even after heat treatment, and oxidative stress was low after recovery from heat stress. Traditional screening methods are mainly performed through field screening; however, this is difficult because it requires many samples and considerable time. The results of this study are relatively rapid, reproducible, and highly sensitive, so it is judged to be a method that can complement the existing traditional method as a heat-tolerant plant selection system. The results of this study can be widely used for the selection and breeding of heat-tolerant plants in preparation for climate change.

Sequential drought and heat stress pose a growing threat to forest ecosystems in the context of climate change, yet systematic evaluation methods for woody plants remain limited. This study aimed to develop a comprehensive screening platform for identifying woody plant species tolerant to sequential drought and heat stress among 27 native species growing in Korea. A sequential stress protocol was applied: drought stress for 2 weeks, followed by high-temperature exposure at 45 °C. Physiological indicators, including relative water content (RWC) and electrolyte leakage index (ELI), were used for preliminary screening, supported by phenotypic observations, Evans blue staining for cell death, and DAB staining to assess oxidative stress and recovery ability. The results revealed clear differences among species. Chamaecyparis obtusa, Quercus glauca, and Q. myrsinaefolia exhibited strong tolerance, maintaining high RWC and low ELI values, while Albizia julibrissin was highly susceptible, showing severe membrane damage and low survival. DAB staining successfully distinguished tolerance levels based on oxidative recovery. Additional species such as Camellia sinensis, Q. acuta, Q. phillyraeoides, Q. salicina, and Ternstroemia japonica showed varied responses: Q. phillyraeoides demonstrated high tolerance, T. japonica showed moderate tolerance, and Q. salicina was relatively sensitive. The integrated screening system effectively differentiated tolerant species through multiscale analysis—physiological, cellular, and morphological—demonstrating its robustness and applicability. This study provides a practical and reproducible framework for evaluating sequential drought and heat stress in trees and offers valuable resources for urban forestry, reforestation, and climate-resilient species selection.