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種類：　原著論文／社会経済－計画－経営
Title： 　 Determining the shape of the productivity function for mechanized felling and felling-processing
巻頁：　J For Res 17 (5): 397–402
題名：　機械化伐倒および伐倒造材の生産性の関数形決定
著者：　Rien Visser, Raffaele Spinelli
所属：　Forest Engineering, Canterbury University, New Zealand
抄録：　Productivity studies in forest operations are often carried out on new equipment, or on equipment being used in new conditions. Understanding how stand and terrain parameters impact the productivity of harvesting machines is important for determining their optimum use. Such information is normally presented as a productivity or efficiency function; that is, a regression equation that best represents the data. Most studies establish that piece size is the dominant predictor that impacts overall productivity. A common concept known as the “piece-size law” is that productivity increases at a decreasing rate with increasing piece size. What is not well understood is the upper limit to this piece-size law. That is, as the trees get “too” large, we can expect the machine to start to struggle, resulting in a decrease in productivity. Four different data sets—two based in New Zealand and two in Italy—are presented that clearly show an “optimum” piece size for maximum productivity. On average, productivity tended to decrease gradually, not drop off suddenly beyond the optimum. Using more complex statistical functions, it was possible to correctly correlate piece size to productivity.

 

種類：　原著論文／環境
Title： 　Factors affecting the infiltration capacity in bamboo groves
巻頁：　J For Res 17 (5): 403–412
題名：　竹林の浸透能の規定要因
著者：　平岡真合乃，恩田裕一
所属：　筑波大学大学院生命環境科学研究科
抄録：　竹林における浸透能に対するリターと表層土壌特性の影響を把握するために，モウソウチク（Phyllostachys pubescens）の7林分，マダケ（P. bambusoides）の1林分で，振動ノズル式散水装置を用いたプロットスケールの現地散水実験を行った。本研究では最大最終浸透能（FIR_max）を算出して浸透能と定義し，FIR_maxと地表面状態について相関分析を行った。得られたFIR_maxは9～308 mm h⁻¹で，リター被覆とほとんど相関を示さず，表層土壌のかさ密度（0.3～0.9 g cm⁻³）と土壌有機物量（10.4～45.9%）と弱い相関を示した。このことから，竹林における浸透能の規定要因は，地表面被覆ではなく，表層土壌のかさ密度と土壌有機物量であると考えられた。かさ密度はタケの地下茎で構成される土壌有機物量と強い相関を示したことから，地下茎量が多いほど表層土壌にマクロポアが発達し，浸透能が高くなると考えられた。タケの立木密度は，有意ではないものの，土壌有機物量と弱い正の相関を示し，FIR_maxと正の相関を示した。したがって，竹林の浸透能はタケの稈密度や地下茎の増加にともなって高くなる可能性が考えられた。

 

種類：　原著論文／環境
Title： 　Effects of ecological water conveyance on the ring increments of Populus euphratica in the
lower reaches of Tarim River
巻頁：　J For Res 17 (5): 413–420
題名：　タリム川下流におけるPopulus euphraticaの年輪成長に生態学的水輸送が及ぼす影響
著者：　Pujia Yu, Hailiang Xu, Mao Ye, Shiwei Liu, Junjun Gong, Hongyan An, Jinyi Fu
所属：　Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, China
抄録：　Because of long-term drying of the lower reaches of the Tarim River, oasis ecosystems are facing serious threats and have started to degenerate. An ecological water conveyance project has been started in the lower reaches of the Tarim River to save the degenerated ecosystem. The effects of ecological water conveyance on the ring width increments of Populus euphratica were studied by use of the trend analysis method, the moving t test technique, and a regression equation based on ring increment data from the past 40 years in the lower reaches of the Tarim River. Results showed that the ring increments of Populus euphratica in four monitoring transects along the river can be divided into two parts, 1970–2001 and 2002–2008. This division implies that ecological water conveyance had a positive effect on the increase of ring increments. The ring increments of Populus euphratica in Yinsu, Kardayii, Alagan, and Yiganbjma increased by 79.37, 174.5, 75.61, and 71.81% after ecological water conveyance. The years 2002, 2001, 2001, and 2002 were the transition years in the Yinsu, Alagan, Kardayi, and Yiganbjma transects, respectively. The ring width increments in Yinsu, Kardayi, Alagan, and Yiganbjma as a result of ecological water conveyance were 1.41, 0.987, 0.265, and 0.671 mm, respectively. The main cause of the changes in ring width increments was the rise of groundwater level. The results from this study should contribute to improved management of the ecosystems in the lower reaches of the Tarim River, and can also provide a scientific basis for implementing similar projects in other arid and semiarid areas.

 

種類：　原著論文／生物－生態
Title： 　Demographic and height growth response of native broad-leaved deciduous tree saplings to overhead canopy release in a coastal Pinus thunbergii forest in Hokkaido, northern Japan
巻頁：　J For Res 17 (5): 421–431
題名：　北海道のクロマツ海岸林内に生育する在来広葉樹稚樹の個体数動態および樹高成長における受光伐への応答
著者：　真坂一彦，佐藤創，今博計，福地稔
所属：　北海道立総合研究機構林業試験場
抄録：　北海道における海岸林の損失を避けるためにはマツ材線虫病対策を講じておく必要もある。その方法の一つに，前生樹を利用してクロマツ林を在来の広葉樹に置き換えるという案が提示できる。しかし，受光伐に対する前生樹の応答についての知見は多くない。本研究では，クロマツ海岸林内に生育する広葉樹前生樹の個体数動態および樹高成長について，林内光量の変化に対する応答を明らかにするため，受光伐を行い，その後6年間にわたって稚樹群を追跡調査した。光量の増加に伴って，エゾヤマザクラとハリギリの稚樹の樹高成長は抑制された。とくに暗い場所に生育していたハリギリほど光環境の変化によって顕著な衰退を示した。そのため暗所では，極端な光環境をもたらすような受光伐は避けるべきだろう。対照的にミズナラおよびカシワでは，光量の増加とともに樹高相対成長率が高くなり，また暗所に生育しているものほど死亡する傾向が認められた。ナナカマドの枯死は研究期間中に認められず，鬱閉した林冠下でさえ良好な樹高成長を示した。ナナカマドは暗い環境に適応しているようである。カシワとハリギリは北海道における天然生海岸林の主要構成種であり，そのためクロマツ海岸林の密度管理に沿ったかたちで林内の前生樹を育成するよう，徐々に受光伐を行うのが適当と考えられる。

 

種類：　原著論文／生物－生態
Title： 　 Tree species diversity of a 20-ha plot in a tropical seasonal rainforest in Xishuangbanna, southwest China
巻頁：　J For Res 17 (5): 432–439
題名：　中国南西部シーサンパンナの熱帯季節林に設置した20 haプロットの木本種の多様性
著者：　Guoyu Lan, Hua Zhu, Min Cao
所属：　Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, China
抄録：　We censused all free-standing trees ≥1 cm diameter at breast height (dbh) in a 20-ha plot established in a tropical seasonal rainforest in Xishuangbanna National Nature Reserve, southwest China. A total of 95,834 free-standing trees ≥1 cm dbh were recorded, and 95,498 individuals (accounting for 99.65% of the total), including 468 morphospecies in 213 genera and 70 families, were identified. Thirteen of 468 species (2.78%) had more than 1,000 individual ≥1 cm dbh, which represented 56.36% individuals of the total. On the other hand, 230 of 468 species (49.14%) had a mean density of ≤1 tree per ha, and 69 of 468 species (14.74%) were singletons in the 20-ha plot. The mean species richness, density and basal area per ha were 216.50 species, 4,791.70 stems and 42.34 m², respectively. Pittosporopsis kerrii (20,918 stems, ≥1 cm dbh) of Icacinaceae and Parashorea chinensis (7,919 stems, ≥1 cm dbh) of Dipterocarpaceae were the two most abundant species dominating the emergent layer and treelet layer, respectively. Compared with other 50-ha plots established in other equatorial regions, tree species richness per ha and tree abundance per ha of the plot were at the moderate level.

 

種類：　原著論文／生物－生態
Title： 　 Allelopathic effects of Araucaria angustifolia needle extracts in the growth of Lactuca sativa seeds
巻頁：　J For Res 17 (5): 440–445
題名：　レタス種子の発芽に及ぼすパラナマツ針葉抽出物のアレロパシー効果
著者：　Jessie Willian Braine, Gustavo Ribas Curcio, Cyntia Maria Wachowicz, Fabricio Augusto Hansel
所属：　Embrapa Florestas, Estrada da Ribeira, Brazil
抄録：　Araucaria forest, named due to the high abundance of Araucaria angustifolia, occurs mainly in the southern Brazilian highlands, and the abundance of A. angustifolia in the forest is a current forest issue. The present study aimed at evaluating a potential allelopathic effect of A. angustifolia needle extracts that could mediate plant successional dynamics in the Araucaria forests. Senescent araucaria needles from A. angustifolia were evaluated for their allelopathic potential on Lactuca sativa through an in vitro study. The effect was evaluated by determining the germination of seeds, length of seedling and germination rate. The allelopathic potential of the A. angustifolia was confirmed for the highest doses tested (187.5 and 250 mg of the extracts). The potential allelochemical compounds identified were ent-kaurene and phyllocladene. In conclusion, A. angustifolia showed a potential allelophatic effect that may play an important role in successional dynamics of Araucaria forests.

 

種類：　短報／生物－生態
Title： 　 Isolation and characterization of eight microsatellite loci in the Otton frog, Babina subaspera
巻頁：　J For Res 17 (5): 446–448
題名：　オットンガエル（Babina subaspera）におけるマイクロサテライトマーカーの開発
著者：　岩井紀子，正田‐加賀谷悦子，濱口京子
所属：　森林総合研究所
抄録：　オットンガエルは珍しい生態や形態を持つ森林性の希少なカエルである。本種の保全に必要な情報を提供するため，８つのマイクロサテライトマーカーを開発し，鹿児島県奄美大島のサンプルについてその有効性を検証した。各遺伝子座で観察された多型は9～19（平均13.9）であり，ヘテロ接合度の観察値（H_O）は0.71－0.92，期待値（H_E）は0.83～0.92であった。これらのマーカーは保全遺伝学的解析に有用と考えられる。