Phytosociological Changes of Pinus densiflora Forest Induced by Insect Damage in Kyonggi-do Area

경기도지방(京畿道地方) 적송림(赤松林)의 식물사회학적(植物社會學的) 연구(硏究)

To study the changes of vegetational composition of each plant successional stage of Pinus densiflora forest caused by pine gall midge damage, Thecodiplosis japonensis, located in Kyonggi-do area, the middle part of Korea, four districts, Anseong, Yongin, Gwangju, and Gapyeong, were selected according to the length of insect damage duration. The forest in the Anseong district was the noninfested one selected as the check. And forests in Yongin, Gwangju, and Gapyeong were the recent]y damaged, severely damaged, and damage prolonged ones in sequence. It was considered that this order could be in concord with the gradual transition of plant successional stage. In view of temperature, precipitation and soil factors, these four districts were sited within the same environment. Four survey plots were selected from each district and the distance between them was 3~4 km. Then again four subplots were set within a plot. Through needle accumulation after insect infestation, light intensity, soil moisture content, and the amount of soil organic matter were increased and these conditions could create a favorable environment enabling the new species invasion and their growth. These were naturally closely related with the increase in quantity of Pinus densiflora defoliation. After considerable time lapse, the quantities of above mentioned factors decreased with the development of the new substitute tree species. It was found that Quercus mongolica was an excellently substitute tree species come first in this studied area. Species diversity increased to a degree at the early stage of the duration of pine gall midge damage and decreased thereafter. As the same manner, similarity index value between plots in the same district decreased to a degree and increased thereafter. This was linked admittedly with the increase and decrease of tree species and evenness. Synthesizing above mentioned results, the process of plant succession studied quantitatively by changes of relative density and relative importance value, it can be concluded that Pinus densiflora forest gives way to Genus Quercus forest in which Genus Lespedeza and Genus Rhododendron species become as subdominance species after removal of the Pinus densiflora trees damaged by pine gall midge.

경기도지방(京畿道地方) 적송림(赤松林)의 천이(遷移)를 연구(硏究)하기 위(爲)하여 솔잎혹파리의 피해지속기간(被害持続期間)에 따라 무피해지(無被害地)로서 안성(安城), 피해선단지(被害先端地)로서 용인(龍仁), 피해극심지(被害極甚地)로서 광주(広州) 피해지속지(被害持続地)로서 가평지역(加平地域)을 설정(設定)하고, 각조사지역별(各調査地域別) 환경요인(環境要因)과 식생상태(植生状熊)를 조사(調査)하여 (1) 환경요인(環境要因)과 식생상태(植生状熊)와의 관계(関係) (2) 삼림군집(森林群集) 구조(構造)의 비교(比較) (3) 식물상(植物相)의 변화(変化) 등(等)을 분석(分析)하였던 바 그 결과(結果)를 요약(要約)하면 다음과 같다. 1. 솔잎혹파리의 피해(被害)에 의(依)하여 소나무의 낙엽량(落葉量)이 증가(増加)하고 광조건(光條件), 토양조건(土壤條件) 등(等)의 환경요인(環境要因)에 변화(変化)가 오게 되면 다른 수종(樹種)이 집래(集來)하게 되고 대상수종(代償樹種)인 참나무류(類)의 발달(発達)에 의(依)하여 다음 천이단계(遷移段階)로 안정화(安定化)되는 경로(経路)를 밟는다. 본(本) 조사지역내(調査地域內)에서는 참나무류중(類中) 특(特)히 신갈나무 상대우점식(相状優占植)의 증가(増加)가 유의적(有意的)이었다. 2. 솔잎혹파리의 피해(被害)가 심(甚)해질수록 조사지역별(調査地別), 조사구별(調査区別) 종구성상태(種構成状態)는 점차 다양(多樣)해지며 동일지역내(同一地域內) 조사(調査) 구간(区間) 종구성상태(種構成状態)의 차이(差異)도 커지는 경향(傾向)을 보였다. 그 후(後) 피해(被害)가 지속(持続)되어 식생상태(植生状態)가 재구성(再構成)됨에 따라 종구성상태(種構成状態)는 단순화(單純化)되는 것으로 나타났다. 3 이상(以上)과 같은 결과(結果)와 상대밀도(相対密度) 및 상대우점치(相対優占値)에 의한 식생천이(植生遷移)를 종합분석(綜合分析)한 결과(結果)소나무가 우점종(優占種)을 이루는 본조사지역내(本調査地域內)에서는 솔잎혹파리의 피해(被害)가 지속(持続)됨에 따라 참나무류(類)가 우점종(優占種)으로 되며 잔달래류(類), 싸리류(類) 등(等)이 하층식생(下層植生)을 형성(形成)하는 임목군집(森林群集)으로 변화(変化)해가는 것으로 나타났다.