透過免費衛星影像偵測銀合歡入侵之研究－以高雄市燕巢區、田寮區、內門區為例

Detecting Leucaena leucocephala (Lam.) de Wit. Invasion Area Distribution by Free Satellite Images Classification-Based on Yanchao District, Tianliao District, Neimen District of Kaohsiung City

黃上權(Shang-Chuan Huang) ； 張起華(Chi-Hua Chang) ； 魏浚紘(Chun-Hung Wei) ； 陳建璋(Jan-Chang Chen)

《華岡農科學報》 46期 (2020/12) Pp. 62-74

摘要

早期銀合歡被引進至國內作為製漿造紙原料之需而種植，而後續因時空的演變，使其需求不再，造成多數銀合歡造林地被棄置，任其在山坡地滋生並入侵成林。銀合歡為偏好開放地的雜木，長在半自然地區、干擾地，退化的生育地等，近年正逐漸入侵擴張，並危害本土物種，使林地之生物多樣性下降。本研究針對高雄市3處行政區域，包含燕巢區、田寮區、內門區，利用Sentinel-2衛星影像進行銀合歡分布偵測之研究，期望透過影像分類的方式快速獲得銀合歡分布位置，供相關單位經營管理之應用。研究結果顯示，本次之分類總體精度為83.3%，經影像分類與細部編修後，針對研究範圍有銀合歡生長之區域，總面積約為887.81 ha，其中銀合歡最多的區域為田寮區約583.81 ha；其次為內門區約151.28 ha與燕巢區約152.72 ha。相關研究結果資料之總結，提供未來在銀合歡之移除區之設置上，建議優先選擇之區域，以本研究結果顯示應優先移除燕巢區北部之丘陵地，以及田寮區南側之內安、中埔子、菜堂一帶之銀合歡純林林地，因其屬於國有林班地，在實際操作上可較為簡易，又其屬於銀合歡集中之場所，可有效降低其種子庫，且其環境或立地條件也可讓移除後的再造林有較高的成功機率。

關鍵字

入侵種 ； 影像分類 ； 精度評估 ； 林相改良

並列摘要

Leucaena leucocephala (Lam.) de Wit. was imported to plant to make pulp as material in early Taiwan. However, the profits are fewer than importing pulp. Because of the different circumstances, the demand no longer exist. Lots of the species plantation are deserted in mountain area and let the trees grows recklessly to become invasive forest. Leucaena leucocephala (Lam.) de Wit. prefer open space and commonly seen in half-nature area, degenerated habitats and abandoned places. Recently, it expand rapidly and endanger native species so it decrease the biodiversity severely. In this study, we focus on three different administrative districts. Using Sentinel-2 satellite images to classify and detect the distribution of the invasive species. We assume that we can use the classification to retrieve rapidly the distribution area of the species to provide the figure information for management to Kaohsiung City government. The results display that the overall accuracy of our classification is 83.3%. After we adjust the classification result, we know the area of Leucaena leucocephala (Lam.) de Wit. is 887.81 ha. Tianliao district contain the massive quantity for the species distribution as 583.81 ha. Neimen district and Yanchao district contain 151.28 ha and 152.72 ha. These results and information will be important for the city government to manage the priority of removing procedure. As the results shows that we suggest removing priority should be in the northern hillside of Yanchao district and southern side of Tianliao district due to the competent authority is Forest Bureau. They are more easily to remove trees and afforestation. Also they contain intense invasive forest. Removing the forest can decrease the seed bank significantly. The environment and the habitat condition will improve success rate for afforestation after removing invasive forest.

並列關鍵字

Leucaena leucocephala (Lam.) de Wit. ； Image Classification ； Accuracy Assessment ； Forest Improvement