• 作者： 王子定; 郭寶章
• 作者服務機構： 國立臺灣大學森林學系
• 中文摘要： 凡欲控制松鼠對林木之為害，須自基本上及實際上研究松鼠之種類、習性、食性、生態及防
  治方法。本研究即為此一綜合性研究之一部份。
  本研究之目的有三：(一)松鼠種類之鑑定；(二)松鼠對樹種之為害；(三)松鼠為害與樹齡之關係。
  據本研究之結果顯示：為害林木之松鼠種類中，當推赤腹松鼠為著。帶紋松鼠、荷士東松鼠
  雖具為害，然不若赤腹松鼠為甚。故本研究主以赤腹松鼠為對象。赤腹松鼠之分佈遍及全省各地
  ，自平地以至山區，惟以海拔800～1,500公尺為其適生區域。松鼠之日間活動有兩個高峰，一
  在黎明（6～8時），一在黃昏（16～18時），惟以黎明出現機會較多。松鼠之出沒以單獨行動為
  最多。松鼠極喜食果實類，尤嗜食含糖份或汁液較多之果實；松鼠之為害林木呈季節性之變化，
  冬季由於潤葉樹果實成熟，林木少遭為害，夏、秋兩季因盛產百香果，為害亦較少，春季因天然
  食物短缺，且林木含樹液較多，松鼠為吮食樹液，遂予齧食，致形成較大之為害。赤腹松鼠每年
  門齒之生長速度為0.248公分，藉樹皮類之硬物予以磨擦，以阻止生長，而利取食。故松鼠磨損
  門齒亦為樹皮遭撕剝之另一重要原因。
  赤腹松鼠對樹種之為害頗具選擇性，針葉樹之為害大於?葉樹；引進樹種如柳杉、杉木、琉
  球松、濕地松等，遠較臺灣固有之臺灣杉、紅檜、臺灣二葉松及臺灣五葉松等為害嚴重。然亦有
  例外，如本地種之臺灣肖楠、香杉，殊遭嚴重為害。
  松鼠為害林木之部位不同，遂影響林木之發育及木材之性質，?葉樹種以果實、花芽受害為
  多；針葉樹種則以樹皮受害為大。
  赤腹松鼠為害與樹齡間具相關性。柳杉各齡級之為害率呈極顯著之差異；以幼齡木為害較輕
  ，壯齡木為害嚴重，老齡木又趨輕微，然較幼齡木為著。幼齡木之受害部位以樹幹下段為主，隨
  樹齡之增加，受害部位則漸移向上部或樹冠層。
• 英文摘要： It is essential in the control of squirreldamage to forest plantations in Taiwan that acareful study be made of the squirrels thatexist in the forests. This involves a study ofthe species, habitat, food habits and ecology ofthe squirrels. The damage caused by squirrelsin this study refers to the bark-peeling bysquirrels which usually retards the growth oftrees and reduces the wood quality of the tim-ber. Squirrel damage to forest plantations hasbeen a critical problem in Taiwan in its reforest-ation program due to lack of knowledge ofthe squirrels and their habits and of controlmeasures. The objectives of the study are: 1. To identify the species of squirrel thatdamage the forest plantations. 2. To find out the species of trees whichare damaged by squirrels. 3. To find out the relationship betweensquirrel damage and the age of forest planta-tions. The area of study covers many forest dis-tricts under the control of the Taiwan ForestryBureau. Most of the results obtained were fromthe Chitou District of the Experimental Forestof the National Taiwan University located inthe middle part of Taiwan. It was found from this study that the mainsquirrel damage to Taiwan forest plantationswas caused by the red-bellied tree squirrel(Callosciurus erythraeus). Two other species ofsquirrels: Formosan stripped squirrel (Tamiopsmaritimus) and Perny's long-nosed squirrel (Dre-momys pernyi) have caused less damage to forestplantations as compared to the red-bellied treesquirrel. Therefore, the results reported in thisstudy are mostly about those damages caused byred-bellied squirrel. Red-bellied tree squirrels are distributed allover this island from the lowlands to the highmountains. However, an elevation of 800 to1,500 meter provides the best condition for theirhabitat. Squirrels start their intensive activityin the forest twice a day: in the early morningand early evening. It is belived that more squirrelscome out in the morning than in the evening.Squirrels like to eat tree fruits, especially thekinds with high sugar and juice content. There are seasonal differences in the squirreldamage to forest plantations. Less damage oc-curs during the winter due to the plentifulproduction of hardwood fruits from the naturalforests. The summer and autumn seasons alsohave less damage because of a good supply ofpassion fruit. Spring presents the most seriousdamage because of the short supply of naturalfood. There are two other reasons that mayexplain the occurrence of serious damage: treesap running in the spring may attract squirrelto lick the juice and the gnawing behavior ofsquirrels permits necessary wear of incisors. Squirrel damage to forest plantations variesgreatly with the species of trees. As a rule,conifers are more heavily damaged than thehardwoods. Introduced tree species, such asCryptomeria (Cryptomeria japonica), China fir(Cunninghamia lanceolata), Luchu pine (Pinesluchuensis) and slash pine (Pinus elliottii) areeasily damaged by squirrels. Native tree speciessuch as Taiwania (Taiwania cryptomerioides),Taiwan red pine (Pinus taiwanensis), Taiwan redcypress (Chamaecyparis formosensis) and Taiwanwhite pine (Pinus morrisonicola) are less suscep-tible to their damage. However, some locallydistributed trees such as Taiwan incense cedar(Calocedrus formosana) and Luanta fir (Cunning-hamia konishii) are liable to be heavily damagedby squirrels. In the hardwoods, the fruits and flower budsare the main food of the squirrels, while inconiferous forests the bark is peeled by squirrels. There is a significant correlation betweenthe age of Cryptomeria trees and the squirreldamage to trees as observed in this study.Young and old plantations appear less damagedthan the moderate-aged stands. In the saplingstage, the lower part of the trunk is more heavilydamaged. However, the damage will proceedupward to the crown of tree as tree grows older.
• 中文關鍵字： --
• 英文關鍵字： --