천연갱신치수 밀도조절에 따른 임분생장 변화

정상훈*, 이상태

(국립산림과학원 산림기술경영연구소)

Changes of stand growth by natural seedling density control practice

Sang Hoon Chung* and Sang Tae Lee

(Forest Technology and Management Research Center, National Institute of Forest Science)

요약: 본 연구는 수확작업 후 자연적으로 발생된 천연갱신 치수의 밀도조절작업을 위한 방법 기준 마련의 기초자료를 제공하기 위해 수행되었다. 천연갱신 치수가 ha당 30,000 그루 생육하고 있는 소나무 및 낙엽송 임분을 대상으로 2021년 밀도처리구(2천, 3천, 5천 그루/ha, 대조구)를 조성하고 처리구별 임분생장을 모니터링하였다. 밀도처리구별 생장 변화를 알아보기 위해 흉고직경, 수고, 수관폭 등을 조사하였고 Pressler식을 이용하여 4년간의 생장률을 산출하고 분산분석으로 생장을 비교하였다. 밀도처리 후 소나무 임분의 흉고직경 4년간 생장률(2천: 23.7%, 3천: 23.9%, 5천: 19.3%, 대조구: 10.5%)은 2천ㆍ3천, 5천, 대조구는 통계적으로 유의한 차이가 나는 것으로 파악되었다. 수고는 2천 처리구가 11.2%으로 가장 낮은 생장률(3천: 15.1%, 5천: 15.0%, 대조구: 14.1%)을 나타내었다. 낙엽송 임분의 경우, 흉고직경 생장률은 2천 처리구(30.2%)가 가장 높았으며 5천 처리구(26.8%), 대조구(21.5%)와 차이가 있는 것으로 나타났다(P<0.05). 수고 역시 2천 처리구(21.2%)가 양호하였으며 3천(17.5%)ㆍ5천(19.2%) 처리구, 대조구(12.9%)와 통계적으로 차이가 나는 것으로 분석되었다. 두 개의 수종 모두 5천 처리구의 생장이 상대적으로 낮은 것으로 파악되었지만, 향후 처리구별 임목형질 특성을 조사하여 생장 및 형질을 종합적으로 분석할 예정이다.

Abstract: This study was conducted to provide basic data for preparing standards of density control practice methods for natural seedling (NS) forests management. The density treatment zones (2,000, 3,000, 5,000 NS/ha, control) were established for Korea red pine (Pinus densiflora) and Japanses larch (Larix kaempferi) stands with 30,000 NS/ha in 2021. In addition, stand growth was monitored for each treatment area for the four years. In order to investigate the changes in stand growth by the density treatment plots, the diameter at breast height (DBH), tree height, and crown width were surveyed. The analysis of the growth rate over the four year period was conducted using the Pressler formula. The growth of each treatment plot was compared using analysis of variance. After density treatment, the 4-year growth rate of DBH in the pine stand (2,000 NS: 23.7%, 3,000 NS: 23.9%, 5,000 NS: 19.3%, control: 10.5%) showed statistically significant differences between the 2,000, 3,000 NS, 5,000 NS, and control plots. The height growth rate was the lowest in the 2,000 NS at 11.2%, compared to 15.1% in the 3,000 NS, 15.0% in the 5,000 NS, and 14.1% in the control. In the case of the larch stand, the DBH growth rate was the highest in the 2,000 NS (30.2%), which was significantly different from the 5,000 NS (26.8%) and control (21.5%) (P<0.05). The height growth was also the highest in the 2,000 NS (21.2%), which was statistically different from the 3,000 NS (17.5%), 5,000 NS (19.2%), and control (12.9%). For both species, the growth in the 5,000 NS was relatively lower compared to the other treatments. In the future, the study plans to investigate the shape quality in each treatment plot and conduct a comprehensive analysis of the growth and the quality.

Keywords: density control practice, growth rate, natural regeneration, seedling density