森 林 生 態 系 經 營 模 式 之 建 構－以惠蓀林場紅檜人工林與闊葉樹次生林為例

Abstract

林業經營目標從早期的傳統木材生產，擴展至1960年代的多目標經營，而於1992年美國農部林務署更發展出生態系經營的理念，強調森林生態系的多樣性與完整性。本研究選定國立中興大學惠蓀林場第四、五林班之242、248號紅檜造林地為試區，探討如何將生態系經營之理念落實於試區內；另於248號造林地附近之闊葉樹次生林，設置二個調查樣區作為試驗研究的對照組。研究中分別於1998年四、七、十月，以及1999年一、四、七月，完成植物、動物、土壤理化性質以及微氣候因子之監測調查，此等資料可為經營和施業研究的參考與依據。 試區與林道之絕對座標透過差分全球衛星定位方式加以定位，並將造林台帳之空間與屬性資料建構於地理資訊系統。試區中之所有土樣皆屬極酸性的範圍，且紅檜人工林之淺層土壤多有灰化土分布。試區中紅檜之直徑級皆在40 cm以內，又以胸徑10－25 cm者居多；且紅檜之分叉率極高（概為50 %以上），而隨分叉數愈多，其單株平均胸徑、樹高與材積愈少，又已有如香桂等闊葉樹種入侵，故以胸高斷面積為介量，實施30、50與60 %三種疏伐度之疏伐試驗，並混植牛樟、香楠與烏心石等樹種。 研究中並發展環境、生物、群落、生態系以及經濟等生態指標，環境指標包括L-天冬醯胺活性、微生物氮生物量、pH值、有機質含量、全氮量、C/N之比值與陽離子置換能量等土壤因子，以及平均溫度與相對光度等微氣候因子；生物指標以紅檜、木荷、臺灣杉、香桂等39種植物，另紹德步行蟲、蚊科等肉食性昆蟲，屬雜食性之蟻科昆蟲，葉蟬科、癭蚋科等植食性昆蟲，埋葬蟲科、麗蠅科、偽毛蚋科和跳蟲科等腐食性昆蟲，以及初級肉食性、腐生植食性等土壤表層動物為監測候選種；此外，群落指標則為種豐富度指數與模式；而生態系歧異度指數，以及總系統傳輸量、系統優越性以及系統開銷等四種訊息指數為生態系指標；另以能值與能量價值為經濟指標。 為確實瞭解生態系之結構與功能，使所模擬之生態劇本更接近生態系的真實狀態，需以科際整合達成適切而有效的整合性森林資源監測調查；是故未來仍須加強各分類群之生物量、生產量與攝食量的基礎研究，以及蒐集有關枯枝落葉量和動物碎屑量的資料，修正所建構之生態系模式；本研究僅以林分尺度之紅檜人工林與闊葉樹次生林為例，建立森林生態系經營之理論模式，期能提供為爾後大尺度地景生態系經營之基礎。

It had long been recognized that forests provided more than timber, and should be management as multiple purpose in 1960s. For maintaining the diversity and integrity of forest ecosystem, in 1992 USDA Forest Service dropped the new perspectives label as it adopted ecosystem management as its management paradigm. To know how to carry out the conception of ecological management, experiments were executing in the Taiwan Red Cypress (Chamaecyparis formosensis) plantation. The site was located at the plantation No.242 and No.248 in 4th and 5th compartment of Hue-Sun Forest Station of National Chung Hsing University, and the broadleaf secondary forest, as control site, was neighboring the No.248 plantation. In the April, July and October 1998, and January, April and July 1999, fundamental information as baseline for ecological management and environmental monitoring was collected. Which included surveying with vegetation, animals, soil properties of physics and chemistry, and the factors of microclimate. Differential global positioning system (DGPS) was used to get the coordinate data of plots and road. Furthermore, linking the spatial and attribute data of plantation in geographic information system (GIS). According to the analysis of the soil, it showed the pH was in the range of extreme acid, and much podzol distributed in the site. The diameter degree of Taiwan Red Cypress was less than 40 cm, and most of were 10 to 25 cm in the Taiwan Red Cypress plantation. The rate of bifurcation of Taiwan Red Cypress were more than 50 %, and the more bifurcation, the average diameter, height and volume per tree would be lower. Besides, some broadleaf trees had invaded into the Taiwan Red Cypress plantation, i.e., Cinnamomum randaiense. So accomplishing the thinning treatment of 30, 50 and 60 % thinning degree by the parameter diameter basal area, and mixture planting Cinnamomum kanahirai, Machilus Zuihoensis and Michelia compressa. In order to evaluate and construct the multi-storied forest with productivity and diversity, enhanced the adaptability of environmental stress, balanced between the utility of forest resource and the ecological conservation, and reached the goals of ecosystem management with sustainability and integrity. So choosing the soil properties of L-asparaginase activity, microbial biomass-N, pH, organic matter, total N, ratio of C and N, CEC, and the factors of microclimate (temperature and relative light intensity) be environmental indicators. Biological indicators included the 39 plants, i.e. Taiwan Red Cypress, Schima superba, Taiwania cryptomerioides and Cinnamomum randaiense. Besides, carnivorous insects of Apotomopterus asuteri and Culicidae, omnivorous insect of Formicidae, phytophagous insects of Cicadellidae and Cecidomyiidae, detritivorous insects of Silphidae, Calliphoridae, Scatopsidae and Poduridae, and aboveground animals of primary carnivore and detritivorous-phytophage would be monitoring candidacy species. Furthermore, community indicators included species abundance indices and models. Ecosystem diversity (ED), total system throughput (TST), system ascendancy (A) and system overhead (L) could be ecosystem indicators. Besides, economic indicators were emergy and emergy value. For realizing the structure and function of forest ecosystem, and making the simulating ecological scenarios would be more close to the true state of ecosystem, it had to unite the multidiscipline sub-projects, and to achieve the sufficient integrated forest inventory and monitoring. So it was needed to correct the ecological models according to enhance the research of biomass, production and consumption of each taxonomic group, and surveying the litter and animal detritus. The purpose of this study was via the Taiwan Red Cypress plantation and the broadleaf secondary forest to construct the theoretic model of ecosystem management, and provided the basis to apply in landscape in the future.