Investigation of Death Years and Inter-annual Growth Reduction of Korean Firs (Abies Koreana) at Yeongsil in Mt. Halla

한라산 영실지역 구상나무 고사연도와 시계열적 생육쇠퇴도 조사

Abstract

With a view to developing a database of death years of Korean firs (Abies koreana) at Yeongsil in Mt. Halla and investigating their abrupt inter-annual growth reduction tree-ring analysis was employed. To this end, 10 living trees (YSL) were selected to establish a master chronology and 20 dead trees were used to date their dead years. To investigate the difference in death years by death types, 10 trees, which remained standing (YSSD) out of the 20 dead trees were selected. The rest 10 dead trees were already fallen (YSFD). Two increment cores per tree at breast height were extracted in contour direction using an increment borer. A 106-year master chronology (1911-2016) was successfully established from the 10 YSLs. Through cross-dating between individual YSSD time series and the master chronology, it was verified that 1 YSSD was dead in summer 1978, 1 YSSD between autumn 1999 and spring 2000, 2 YSSDs in summer 2007, 1 YSSD in summer 2010, 1 YSSD in summer 2012, and 1 YSSD in summer 2013. The youngest tree rings of 2 YSSDs having no bark were in 1977 and 2002. For the YSFDs, it was verified that 1 YSFD was dead between autumn 1997 and spring 1998, 1 YSFD between autumn 2001 and spring 2002, 2 YSFDs between autumn 2009 and spring 2010, 1 YSFD in summer 2010, and 2 YSFDs between autumn 2012 and spring 2013, while the youngest tree rings of 2 YSFDs having no bark were in 1989 and 2004. To note, the death years of two trees, one from each death type (YSSD and YSFD), could not be verified due to poor cross-dating with the master chronology. The inter-annual growth reductions of YSSD and YSFD occurred more frequently and intensively than YSL. Typically, the YSFD showed the most frequent and intensive inter-annual growth reduction. On comparing the inter-annual growth reductions with the corresponding records of typhoons however we could not find any reliable relationship. Finally, from prior reports and results of the current study it can be concluded that the death and abrupt growth reduction of korean fir at Yeongsil in Mt. Halla are not caused by only a certain environmental factor but various factors.

Figure 1. Sampling site (LTER: long-term ecological research) in Yeongsil area of Mt. Halla.

Figure 2. A: Estimation of distance (D) from the oldest tree ring (OTR) to the pith (P) in an increment core, B: Number (No.) of tree rings: the sum of their ring widths is just more than the estimated distance (D).

Figure 3. Master chronology and all individual tree-ring time series used to establish the master chronology.

Figure 4. Comparison of individual tree-ring time series of (A) standing dead trees and (B) fallen dead trees which are successfully cross-dated with the master chronology. The youngest tree rings in each tree, which have only earlywood (EW), were not measured (⇣: the year of the earliest dead tree ↓: the year of the latest dead tree).

Figure 5. Inter-annual growth reduction of individual trees and the accumulated diagram for each group (YSL, YSSD and YSFD).

Figure 6. April and May precipitation between 1961 and 2017 measured at Jeju and Seogwipo meteorological stations (A: raw measurement records, B: measurement records without outliner)

Table 1. Description of study trees and the number of samples

Table 2. T- and G values between individual time series and the master chronology

Table 3. Estimated tree ages of living trees (L), standing dead trees (SD), and fallen dead trees (FD)

Table 4. T- and G values between individual YSSD & YSFD time series and the master chronology

Table 5. The outmost tree-ring information for dead trees dated with the master chronology