Causes of Decline in the Korean Fir Based on Spatial Distribution in the Mt. Halla Region in Korea: A Meta-Analysis

Abstract

Research Highlights: Technology advances have allowed for a new approach to research the decline of the Korean fir (Abies koreana E.H.Wilson). This study provides insights into the exact causes leading to this decline. Background and Objectives: Various factors could lead to the decline of fir trees around Mt. Halla, Korea, but these have not yet been verified. Here, the Korean fir across Mt. Halla were classified as dead or living and mapped using high-resolution orthorectified aerial images and three-dimensional (3D) stereoplotting. Materials and Methods: Aerial photographs were used to map spatial distribution and analyze the distribution patterns and mortality of the Korean fir. The electronic stereoplotting program (Geo3Di-PRO) enabled the creation of 3D images from aerial photographs. General, altitudinal, and topographical distribution was assessed. Results: Their accumulated percent mortality rate (APMR) showed positive correlations with altitude and tree density, a negative correlation with terrain slope, and no consistent correlation with solar radiation. The results indicate that increases in the density of Korean firs are related to decreased growth in areas at high altitude, on gentle slopes, and with high solar radiation. Consistent positive correlations between density and APMR indicate that fir mortality can be attributed to environmental deterioration and the establishment of unfavorable growth conditions. Areas with high APMR and density had gentle slopes, thus high soil moisture, or relatively high annual precipitation owing to high altitude. Conclusion: Fir mortality on Mt. Halla can be attributed to long-term persistently high rainfall and subsequent excess soil moisture.

Elevation‐related climatic factors dominate soil free‐living nematode communities and their co‐occurrence patterns on Mt. Halla, South Korea

“…Edges of co‐occurrence network reflect the interactions between the species involved in the network. While negatively correlated edges are able to reflect competitive behaviour between species, positively correlated edges mainly represent mutual symbiosis, cross‐feeding, and other cooperative behaviors between the species (Ahn & Yun, 2020 ). Our results suggest that the soil nematode population on Mt.…”

“…Halla is a volcanic mountain located in Jeju Island, South Korea. It has a wide range of climatic conditions with a subtropical maritime climate in low‐elevation areas and gradually changes to a subalpine climate as the elevation increases (Ahn & Yun, 2020 ). The mean annual temperature (MAT) is 14.7°C, with minimum temperatures in January of 5.1°C and maximum in August of 25.…”

“…Halla is 3.7°C, while it is much colder in winter (Lee et al, 1999 ; Won et al, 2006 ). The mean annual precipitation (MAP) ranges from 1130 to 2200 mm in the lower elevation sites, 1960 to 2340 mm in the middle, and 3190 to 5870 mm in the higher elevation sites (Ahn & Yun, 2020 ). Analysis of precipitation data for the 10 years from 2003 to 2012 shows the MAP of Mt.…”

Dysbiosis in the Rhizosphere Microbiome of Standing Dead Korean Fir (Abies koreana)

“…Efforts are being made to understand the tree ecosystem, the different sources of biotic or abiotic stress (such as typhoons and periods of drought), and the exact reasons behind its observed population decline to determine the most efficient protective measures to conserve this species. Although there is a consensus from previous studies regarding a link between the decline in the population of Korean fir trees and climate change-related factors, a coherent explanation and the exact reasons for this decline remain unclear [ 8 ]. A wide variation was observed in the rate of population decline in the Korean fir tree at different locations on Mt.…”

“…Researchers are exploring the reasons behind the worrying decline in Korean fir trees. Multiple contributing factors have been hypothesized; the main players, including heat stress, increased precipitation rates, reduced sunshine durations, heavy winter snow, strong winds, moisture imbalance, and vegetation changes in the area, are associated with climate change [ 5 , 6 , 7 , 8 , 9 ]. Studying tree mortality rates in relation to the degree of slope and solar radiation has shown that poor drainage networks and excess soil moisture may contribute to the observed decline [ 10 ].…”