福山試驗林楠櫧林著生植物生物量與營養鹽之研究

Abstract

位於宜蘭的福山實驗林，屬於暖溫帶雨林，主要組成樹種以樟科及殼鬥科為主，屬於楠櫧林帶（Machilus－Castanopsis Zone ) ，此地的年雨量超過 2500 公釐，而一年中的降雨天數更是超出兩百天以上，氣候十分溫暖潮溼，也因此著生植物在試驗林中佔了相當的比例。 本研究在福山試驗林內選擇一面積約為1200平方公尺的樣區，隨機選取各 DBH 等級的樹木樣本各4－6株 ，總共選擇22株樹木，除苔蘚以次樣本估計外，其他著生植物則全部剝除稱重，以估計著生植物的生物量。樣區內，扣除 DBH < 5cm 的小樹及灌木，共計樹木樣本142株，利用外插法估計樣區內著生植物總生物量。 估計樣區內著生植物總乾重約為401 . 6kg ，據此本研究推算出福山試驗林內著生植物的生物量約為3346.7kg / ha ，著生植物的養分總含量為（kg•ha-1 ) : N = 42.41 ; P = l.9 ; Mg = 5.52 ; Na = 1.3 ; Ca = 14 .46 ; K = 28.78 。 福山試驗林內著生植物的生物量佔福山試驗林全林分生物量1.2％? 1.7 % ，但卻相當於地上部葉片生物量的42.8％?69.6 % ，由於著生植物的所儲存的養分和喬木的葉片類似，屬於分解較快的養分，因此本結果顯示出著生植物在福山森林生態系內的養分循環過程，可能佔有重要的地位。

A Plot of 1200m2 was set up to reprent average epiphyte abundance in the Fushan hardwood forest. In the plot all epiphytes of 22 sample trees representing every classes of DBH (without DBH<5cm) were removed and weighed to determine the composition, biomass, and nutrient content. Results from above were extrapolated to estimate total biomass and nutrient content of epiphytes for the Fushan hardwood forest. According to the estimation, epiphyte biomass in this forest is 3346.7 (kg/ha) , The nutrient capital (kg. ha-1) is N=42.41;P=1.9 ; Mg=5.52 ; Na=1.3 ; Ca=14.46 ; K=28.78 . Although epiphyte biomass constitutes only 1.2?1.7 percent of total aboveground dry weight, It is equivalent to 42.8－69.6 percent of dry weight of total foliage in the ecosystem. Since the nutrient content in the epiphyte and foliage is more readily available to other organisms in this ecosystem than that is held in woody components, epiphytes may play a greater role in ecosystem nutrient dynamics than those relative small biomass indicated.