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Within the framework of a series of forest recovery researches of a subtropical evergreen broadleaved forest, this study was carried out to measure mortality rates of tree stumps changed by species diameter at breast height (DBH) based on the surveys of 62 woody species and 1,893 tree stems taller than 1.2m in four 20m X 10m plots were recorded in 1993. At\nan August 1998 tree census five years after clearcut, all sprouting stems higher than 1.0m were identified, and the statuses of all the residual stumps were checked. The investigation showed that 382 stumps were dead without any living sprouts whereas 1,511 stumps were survived with living sprouts. The further studies showed that the mortality rates of stumps did not vary with DBH of the stand, but vary with the species DBH remarkably. The mortality rates by stump DBH within species for these whose total stump numbers ≧10 stems in the study plots were divided into four patterns: (a) With the increasing DBH, the mortality rates increased, (b) Inversely, with the increasing DBH in a certain extent, the mortality rates decreased, (c) With an increasing DBH, the mortality rates decreased at first and then increased to some extent, (d) The mortality rates were independent of DBH. The above results suggested that different species might have different mortality patterns, and that different tree species might have different rational DBH ranges for sprout natural regeneration. This knowledge could be much useful for forest recovery forecasting when the severe forest disturbances occurred in subtropical regions., 本研究は、亜熱帯常緑広葉樹林の森林回復に関する研究の一環として、1993年に沖縄島北部の琉球大学農学部与那フィールドの林地に設置された試験地を対象に、皆伐施業5年後の1998年に根株の生育と毎木調査を実施した。今回は主として、根株の生育、とくに枯死状態について報告する。皆伐施業試験地では、設定された天然林当時の樹高1.2m以上の立木62樹種、1,893個体のうち、382個体の根株が枯死し、1,511個体の根株に萌芽が認められた。根株の枯死率は、全個体で胸高直径間には明確な差がなく、樹種別の胸高直径間に差がみられた。根株個体数が10個体以上の33樹種別および胸高直径別の根株枯死率は4型に類別された：(a)胸高直径の増加にともなって枯死率も増加した（カクレミノ､タイミンタチバナなど7種）；(b)胸高直径の増加にともない一定の直径範囲で枯死率が減少した（イヌガシ､イタジイなど9種）；(c)胸高直径の増加にともない枯死率は初め減少し、その後増加した（サクラツツジ、ヤブツバキなど4種）；(d)枯死率は胸高直径と関係がなかった（イジュ、ツゲモチなど13種）。萌芽力に対して、根株枯死率の類型別に異なることが示唆された。, 紀要論文

本研究は、亜熱帯沖縄における天然林の資源植物学的研究の一環として、亜熱帯・沖縄県の主要島嶼の沖縄島、宮古島、石垣島、西表島を対象に既応の著書・文献を用いて分布植物のデータベース化をはかるために森林植物を中心とした全ての在来植物の分布種及び外来種を明らかにするために行ったものである。琉球列島全体の分布植物は、琉球植物目録(FRSAI、1994)で238科、1688属、5,473種で最も多く、Flora of Okinawa and Southern Ryukyu Island (FOSRI、1976)で239科、1,061属、2,560種、琉球列島維管束植物集覧(FRSAI、1997)、200科、949属、2,275種、琉球植物誌(FR、1975)182科、863属、2,142種の順であった。全体的に総分布種は文献間に差異があり、その主な要因は外来種の分布の取り扱いによるものと思料される。在来植物の種の構成は沖縄島FR 1,451、FRSAI 1,445、CLVFR 1,404、宮古島FR 640、FRSAI 656、CLVFR 633、石垣島FR 1,099、FRSAI 1,132、CLVFR 1,119、西表島FR 1,151、FRSAI 1,139、CLVFR 1,142で各島嶼とも分布種に大きな差異はなかった。また、島嶼別の在来種は沖縄島>西表島>石垣島>宮古島の順であった。宮古島が最も少ないのは、同島の大部分が隆起サンゴ礁の石灰岩でおおわれ、平坦な島であるため、分布植物において山地性植物の森林植物が他島に比べて少ないものと思料される。島嶼別固有植物はいずれの文献も沖縄島に多くの固有植物が分布しVJOO 16種、FR 15種、CLVFR 33種であった。ついで西表島で多くVJOO 13種、FR 10種、CLVFR 9種、宮古島、石垣島では1～3種であった。, Within the frame work of a series of plant resource studies on the natural forests in the subtropical Okinawa, the present study was undertaken to clarify the distribution of forest plant for both indigenous and exotic species on the Ryukyu Islands, especially for the 4 main Islands, i.e. Okinawa, Miyako, Ishigaki and Iriomote Islands in the Ryukyus based on the database of the five reference books. The considerable difference was found for the total number of species among the references. The plants distributed in the entire Ryukyu Islands were 238 families, 1,688 genera and 5,473 species based on Flora of the Ryukyus, Southern of Amami Island (FRSAI), which had the highest number of species, while Flora of Okinawa and Southern Ryukyu Island (FOSRI, 1976) recorded 239 families, 1,061 genera and 2,560 species. According to Check List Vascular Flora of the Ryukyu Islands (CLVFR), 200 families, 949 genera and 2,275 species were present. Flora of the Ryukyus (FR) recorded the least species with a total of 182 families, 863 genera and 2,142 species. The methods of the handling of plant distribution to the exotic species may be responsible for the obvious differences in the main factor on the total number of species among these references. For the composition of the indigenous species, in Okinawa Island, 1,451 (FR), 1,445 (FRSAI) and 1,404 (CLVFR) species were recorded; 1,099 (FR), 1,132 (FRSAI) and 1,119 (CLVFR) species in Ishigaki Island; 1,151 (FR), 1,139 (FRSAI) and 1,142 (CLVFR) species in Iriomote Island. No obvious differences were found among the 3 references. Moreover, for the abovementioned indigenous species, the order of species number were Okinawa > Iriomote > Ishigaki > Miyako. As for the least value of indigenous species in Miyako Island, it is thought that the greater part of the Island is covered with the limestone of the upheaval coral reef, and the mountainous forest plant is less than other Islands because of its smooth landform on the Island. Each reference recorded a lot of endemic plants in the Okinawa Island, with 16 species recorded in VJOO, 15 species in FR, and 33 species in CLVFR, while Iriomote Island had the second highest value for endemic plants with 13 species recorded in VJOO, 10 species in FR and 9 species in CLVFR. In Miyako or Ishigaki Islands, few endemic plants were present with a range of 1-3 only., 紀要論文

この研究は, 亜熱帯沖縄における森林植物の希少植物等の探索・収集・保存・増殖に関する研究の一環として, 石垣島於茂登岳山麓において自生が確認されたサキシマスオウノキ(Heitiera littoralis)林を対象に生育木の現状および生育地の植生を明らかにしたものである。調査の結果は次のとおりである。1. サキシマスオウノキは通常マングローブの後背湿地や海岸付近に分布する。しかし, 石垣島於茂登岳山麓の宮良川上流底原の沢沿い(標高50∿80m)にもサキシマスオウノキが分布することが明らかになった。2. 於茂登岳山麓のサキシマスオウノキは, 沢沿いでほとんどが礫の堆積地に分布していた。3. 現在, サキシマスオウノキは流域全体で174本の生育が確認され, そのうち5本は折損木であった。また, 10個の切り株が確認された。4. この流域で樹齢が最も古いものと推定されるサキシマスオウノキが3本確認された。しかし, 一本は健全に生育しているが, 他の2本は地上高1.70mで伐倒され, そのうち1本は枯死し, 残りの1本は萌芽していた。5. 本群落はサキシマスオウノキを優占種とし, 湿地∿湿潤地性の種と多くの山地性の種を構成種とする特異な植生であることが明らかになった。特異な立地に成立する要因についていくつかの考察を行ったが, これについては今後の課題である。6. 於茂登岳山麓のサキシマスオウノキは西表島の古見の群落に比べて, 標高の高い特異な立地に群落を形成することから, これらがどのように定着し, 林分を形成したのか非常に興味深く, これらの更新動態についてさらに研究を進めていきたい。7. 石垣島於茂登岳山麓のサキシマスオウノキは, 特異な例として内陸部に分布することから石垣市の天然記念物に指定すべきであろう。さらに将来は, 沖縄県あるいは西表島のサキシマスオウノキと同様に国指定の天然記念物に指定すべきであろう。, The state of growth of Heritera littoralis, natural colonies, which were discovered at the foot of Mt. Omoto on Ishigaki Island, and the vegetation at sites of its growth were studied as part of research concerning the exploration, collection, preservation, and proliferation of rare plants in subtropical forest of Okinawa. The following results were obtained. Heritiera littoralis is usually distributed in mangrove swamps and coastal areas. However, it was found to be distributed also along the streams in Sokobaru (altitude 50-80) upstream of the Miyara River at the foot of Mt. Omoto, Ishigaki Island. Heritiera littoralis at the foot of Mt. Omoto was distributed along the stream mostly in gravel deposits. To date, 174 growths of Heritera littoralis have been confirmed in the entire river basin, and 5 of them were damaged. Also, 10 stumps have been confirmed. Three growth of Heritera littoralis estimated to be the oldest in the river basin have been identified. One was growing intact, but the other two were cut at a high of 1.70m from the ground. One them were dead, and the other was budding. Heritiera littoralis was dominat in the tree layer of two stands, which was chracteristic vegetation consist of many species in the forest of back mangrove and inland. It showed some considerations on the cause where the stand had grown at the foot of Mt. Omoto, it should be studied in future. The colonies of Heritiera littoralis at the foot of Mt. Omoto grew at a higher attitude than the colonies in Komi, Iriomote Island. Therefore, the processes of their distribution and formation of forest stands are extremely interesting, and further studies on the dynamics of their changes are needed. Since Heritera littoralis at the foot of Mt. Omoto on Ishigaki Island shows unique inland distribution, it should be designated as a natural treasure of Ishigaki City. It should further be designated as a natural treasure of the nation similarly to Heritiera littoralis of Okinawa Prefecture or Iriomote Island., 紀要論文

この研究は, 亜熱帯沖縄における森林植物の希少植物等の探索・保存・増殖に関する研究の一環として, 石垣島平久保のヤエヤマシタン(Pterocarpus indicus)林を対象に生育木の現状および生育地の植生調査を行ったものである。調査の結果は, 次のとおりである。1. 平久保のヤエヤマシタンは, 1972年5月15日に国の天然記念物に指定された。2. 現在, ヤエヤマシタンは石垣島で自生木, 栽培木を合わせて78本の生育が確認された。3. 平久保では, 現在の天然記念物の2個体の他に, 1991年7月に胸高直径20cm, 樹高11.5mの1本, 今回新たに胸高直径13cm, 樹高8mの幼齢樹が確認された。4. これまで, 1莢当たりの種子数は1個とされているが, 1∿4個の種子が含まれていることことが明らかとなった。5. 376莢のうち1莢当たりの種子数の出現頻度は, 1粒莢が43%, 2粒莢が39%, 3粒莢が17%, 4粒莢が1%で, 1粒莢が最も多かった。6. 種子の発芽は, 1粒莢の種子では播種後2日目から7日目に発芽がみられ播種後4日目と6日目に3粒ずつの最大発芽がみられた。7. 天然記念物2個体のうち1個体は幹および根が, 他の個体は根がそれぞれ削り取られており, 傷跡は深く, いずれの切り口も腐朽しており, 早急に損傷部の回復をはかる必要がある。8. 林分は自然林に人為干渉を受けて変質しているが,低地帯森林植生のリュウキュウガキーナガミボチョウジ群団に属するヤエヤマシタン群落と考えられる。, As a part of studies on the research for preservation, reproduction of rare forest plants in subtropical Okinawa, we examined the present status of growth trees and vegetation in the habitat in a Yaeyamashitan (Pterocarpus indicus) forest in Hirakubo on Ishigaki Island. The following results were obtaind. 1. Yaeyamashitan in Hirakubo was designated as a national treasure in May 15,1972. 2. Growth of 78 spontaneous trees and cultivars was confirmed on Ishigaki Island. 3. In Hirakubo, in addition to 2 trees as a national treasure, 1 tree (diameter at breast height, 20cm; tree height, 11.5m) and 1 young growth (diameter at breast height, 13cm; tree height, 8m) were confirmed in July, 1991 and December 1994,respectively. 4. Though the number of seeds per legume had been considered to be 1,1∿4 seeds per legume were observed. 5. One seed/legume was observed in 43% of 365 legumes, 2 seeds/legume in 39%, 3 in 17%, and 4 in 1% the incidence of 1 seed/legume was the highest. 6. Germination of seeds occurred 2∿7 days after seedling in 1 seed legumes, and maximum germination of 3 seeds each was observed 4 days and 6 days after seedling. 7. Of the trees as a national treasure, 1 showed cuts in the trunk and root, and the other showed cuts in the root. This damage was deep, and each cut surface was decayed. Restoration of the damage parts is urgently necessary. 8. The forest stand is considered a Pterocarpus indicus community of Diospyros maritima-Psychouia manilensis alliance in the lowland vegetation. Though the vegetation has been changed by the human disturbance., 紀要論文

本研究は, 亜熱帯地域における有用樹種の育林技術を確立するためにおこなったものである。この研究では, ヤエヤマシタンの発芽試験及びさし木試験をこころみた。実験の結果を要すると, 次のとおりである。1.1莢中における種子数の比率は, 1個で35%, 2個で40%, 4個で5%であった。2.種子の大きさは, 長径, 短径及び重量(100粒当り)は, それぞれ12.6mm, 5.0mm, 1.1gであった。3.発芽に対する最適温度は25∿30℃で, その発芽率は100%であった。4.発根率は, 薬剤処理は無処理よりもよく, なかでもルートン及びメネデール50倍は他のものよりもよかった。5.用土別には, 鹿沼土がよく, ついでバーミキュライト, 海砂の順であった。, The present study was done in order to establish planting techniques for useful trees in the subtropics. In this study, the authors tried germination and cutting tests of the Pterocarpus indicus Willd. The results of the study are summarized as follows : 1. The percentages of the number of seeds per pad were 35% for one, 40% for two, 20% for three and 5% for four, respectively. 2. Major axis, minor axis and weight (per 100 grains) of seeds were 12.6mm, 5.0mm and 1.1g, respectively. 3. The opitimum temperature for germination was from 25℃ to 30℃, and its percentage was 100%. 4. The rooting of cuttings for treatments with chemicals gave better effect than the control. The rooting percentage of cutting for treatment with rooton powder and diluted solution 50 times of Menedael gave better effect than the other one. 5. By the rooting percentage of used soils, Kanumado gave the best effect, Vermiculite the second and Sea sand the third., 紀要論文

本研究は, 巨大ギンネムの実生及びさし木による繁殖を向上させるためにおこなったものである。本実験では種子の発芽試験をおこない, さらにさし穂のさしつけ用土別, 薬剤処理別, 径級別の発根の比較をこころみた。実験の結果を要約すると次のとおりである。1.巨大ギンネムの種子は, 長径, 短径, 重量ともに在来種よりも大きく, それぞれ1.3,1.5,1.8倍であった。2.発芽に対する最適温度及び温水処理はそれぞれ35℃, 70℃で, その発芽率は80%であった。3.用土別の発根率は, バーミキュライトは海砂及び鹿沼土よりもよかった。4.薬剤処理の発根は無処理よりもよく, とくにメネデール50倍がよかった。5.径級別の発根は1.0∿1.5cm級が他の径級よりもよく, その発根率は約70%であった。, The present study was done for the purpose of promoting vegetative propagation by seedling and cutting of the Giant Ipil-ipil (K28). In this report, the authors tried a germination test of seed and made a comparison of rootings among used soils (Vermiculite, Sea sand and Kanumado), treatments of chemicals, and diameter class, of the cutting. The results of the study are summarized as follows : 1. Maior axis, minor axis and weight (per 100 grains) of the K28 seeds were lager 1.2 times, 1.5 times and 1.8 times than local seeds, respectively. 2. The optimum temperature and hot water temperature for germination were 35℃ and 70℃, respectively, and the percentage of germination was 80%. 3. On the rootings by used soils, Vermiculite gave better effect than Sea sand and Kanumado. 4. The rooting of the cuttings for treatments with chemical gave better effect than the control. the rooting percentage of the cuttings for treatment with diluted solution 50 times of Menedael gave better effect than the other one. 5. On the rootings by the diameter class, rootings of 1.0-1.5cm class gave better among the others, and its rooting percentage was about 70%., 紀要論文