Changes in canopy structures caused by harvesting and regeneration practices can significantly alter the wind environment. Therefore, it is essential to understand the wind patterns influenced by seed tree arrangements for predicting seed dispersal by winds and ensuring the success of natural regeneration. This study aimed to identify how wind speed responds to seed tree arrangement designs with differing horizontal distances, vertical positions, and free-stream wind speeds. A wind tunnel test was conducted using pine saplings for a scale model of various seed tree arrangements, and the change in wake speed was tracked. The wake’s relative wind speed averaged 71%, ranging from 3.5% to 108.5%, depending on the seed tree arrangement, distance from saplings, and vertical position. It peaked within the patch of three seed trees compared to other arrangements and at the top canopy layer. The empirical function effectively described the wind speed reduction and recovery with distance from saplings. For instance, the minimum wind speed was reached at 0.6–2.2 times the canopy height, and a wind speed reduction of over 20% of the free-stream wind speed was maintained at a 1.6–7.6 canopy height. A negative relationship between the seed tree leaf area and the relative wind speed was observed only at the top canopy layer. This study presents empirical evidence on the patterns of wake winds induced by different types of heterogeneous canopy structures.
The ecosystem across the Democratic People’s Republic of Korea (DPRK) is threatened by deforestation. However, there is very little attention being given to government efforts for afforestation and rehabilitation plan. The most significant barriers to addressing this problem are technique limitations, availability of information, and lack of a stepwise forest management plan. This study identifies spatially suitable tree species, and establishes a stepwise restoration plan to support decision making for restoring degraded forest in the DPRK throughout a suitable restoration map. First off, target species were chosen from reference data, and spatial distribution maps for each tree species were prepared based on social needs as well as natural conditions in the DPRK. The suitable restoration map was calculated by two priorities in a weighting method; suitable priority, and distributional clustering level. Finally, the 23 afforestation species were selected for the suitable restoration map, including 11 coniferous and 12 deciduous tree species. We introduced a stepwise afforestation/restoration plan of degraded forest in the DPRK; general (long-term), detailed (medium-term), implementation (short-term) plans. Maps with different spatial resolutions were prepared for each of the plans. A restoration map with 12.5 km spatial resolution can be used for the general plan at the national level, and maps with 5 km and 1 km spatial resolutions can be used for detailed plan at the local level and implementation plan at the site level, respectively.
Rhododendron sobayakiense is an endemic and near-threatened species (Korean Red List, NT) found in the alpine regions of South Korea that requires conservation. This study investigated the species’ genetic variations and seed germination characteristics and predicted its potential habitat change according to climate change scenarios. The genetic diversity of R. sobayakiense at the species level (P = 88.6%; S.I. = 0.435; h = 0.282) was somewhat similar to that observed for the same genus. The inter-population genetic differentiation was 19% and revealed a relatively stable level of gene exchange at 1.22 in each population. The main cause of gene flow and genetic differentiation was presumed to be the Apis mellifera pollinator. Seed germination characteristics indicated non-deep physiological dormancy, with germination at ≥10 °C and the highest percent germination (PG) of ≥60% at 15–25 °C, while the PG was ≥50% at 30 °C. The PG increased at constant temperature than at variable temperatures; the mean germination time decreased as temperature increased. The climate scenarios SSP3 and SSP5 were analyzed to predict future R. sobayakiense habitat changes. The variables of the main effects were Identified as follows: elevation > temperature seasonality > mean diurnal range.
Carbon stored on land is discharged into rivers through water flow, which is an important mechanism for energy transfer from land to river ecosystems. The goal of this study was to identify the relationship between land cover and carbon flux mediated through precipitation. In order to clarify the general relationship, research was conducted on a range of national scales. Eighty-two watershed samples from an area where the urban land cover area was less than 10% and with a water-quality measurement point at an outlet were delineated. Carbon flux and soil organic carbon of the watershed was estimated using the Soil and Water Assessment Tool model, Forest Biomass and Dead Organic Matter Carbon model, and other data. Finally, the data were analyzed to determine the relationship between soil organic carbon and carbon flux. As a result, it was concluded that the carbon flux of the watershed increased with increasing area of the watershed. Under the same area condition, it was revealed that the greater the forest soil organic carbon, the less the carbon flux released from the watershed. Through this study, it was observed that as the above-ground biomass of forest increased, the carbon flux from watershed to river outlet decreased logarithmically.
Seed dispersal studies have primarily relied on prediction model methods, which limit clarity regarding how variables affect movement direction. Suggestions for improvement are limited to specific domains due to the lack of quantitative evaluation of the comprehensive scope of the basic steps, from explaining seed dispersal to its application in related fields. This study aimed to reconsider the classification of seed movement mechanisms, identify research trends from an integrated perspective, and discuss the current implications and improvement measures. The data included 240 studies related to seed dispersal across the observation, generalization, and application phases. By classifying the mechanisms based on the direction of movement, the main variables affecting movement due to gravity or wind can be clearly distinguished. Although seed dispersal models assume gravity as the core principle, only 12.91% of the studies addressed terminal velocity, and a mere 1.25% measured the diaspore area, both of which are essential for accurate prediction. In addition, attempts to utilize seed dispersal for natural regeneration were relatively frequent (14.58%), but they remained at the empirical model stage, relying on data collected in the field, and thus lacked connection with models developed in previous studies. The requirements for enhancing the field usability of seed dispersal based on the current review include (1) improving the data collection system for securing primary data, (2) collecting sufficient field data, and (3) developing a unified model that can be applied to various conditions and species.