Leaf photosynthetic and growth responses on four tropical tree species to different light conditions in degraded tropical secondary forest, Peninsular Malaysia.

Leaf ecophysiological responses and height growth were studied in four indigenous tree seedlings planted under different size gaps in degraded tropical secondary forest. Dyera costulata, Dipterocarpus baudii, Neobalanocarpus heimii, and Pouteria sp. were selected for study species. The leaf photosynthetic rate at light saturation (Amax), light compensation point (Ic), leaf nitrogen content, and SPAD value were measured at two months after planting. The ratio of variable to the maximum fluorescence (Fv/Fm), which represents the maximal photochemical efficiency of photosystem II was also determined at two months after planting. All measurement leaves were old leaves, which had acclimated before the planting light condition. Canopy openness above the seedlings was estimated from a hemispherical photograph, ranged from 6 to 53%. The relationships between canopy openness and Amax among species were categorized into two groups. The first group (N. heimii and Pouteria), which had relatively high wood density and late successional status, showed that the maximum Amax appeared under relatively low canopy openness such as approximately 10%. Amax of the second group (D. costulata and Dip. baudii), which had relatively low wood density and high light demand, maximized from 20 to 40% of canopy openness. Seedling height growth of the first group was lower than the second group. The first group also showed lower Fv/Fm at high canopy openness than the second group. These responses indicated that the first group may be categorized to less tolerant species for strong light conditions during the early transplanted stage. Ic of D. costulata, N. heimii and Pouteria decreased with decreasing canopy openness. These species have high acclimation ability to shade conditions from the early transplanted stage, since these responses contribute to raise the photosynthetic efficiency under shade conditions

Growth and photosynthetic response of four Malaysian indigenous tree species under different light conditions.

Growth and photosynthetic response of four indigenous tree seedlings, i.e. Dyera costulata, Dipterocarpus baudii, Neobalanocarpus heimii and Gonystylus affinis were studied under different light conditions in a degraded secondary forest. Maximum photosynthesis (Amax) was measured at 2 and 12 months after planting. The ratio of variable to maximum fluorescence (Fv/Fm) was determined. Leaves measured at 2 and 12 months after planting were old leaves present on the seedlings and new leaves that had expanded after planting respectively. Seedling growth was measured over four years. Changes in the growth rate and Amax with canopy openness were categorised into two groups. The growth and Amax of the first group (D. costulata and D. baudii) were maximum at 30-40% canopy openness. This group may be suitable for planting under large canopy gaps. The second group (G. affinis and N. heimii) showed maximum growth and Amax at relatively low canopy openness (less than 20%). Leaves in the second group suffered chronic photoinhibition under large gap. These species were suitable to be planted under low light conditions

Photosynthetic Production in Abies veitchii Advance Growths Growing under Differeent Light Environmental Conditions (III) Diurnal Fluctuation in Xylem Water Potential

プレッシャー・チェンバー法でS，I，O′区のシラベ稚樹の木部圧ポテンシャルの日変化を調べた。木部圧ポテンシャルの日変化には，樹冠の上下位置，方位による違いはなかった。木部圧ポテンシャルは，晴れ，曇りの日にはいずれの区でも－15bar前後まで低下したが，雨，霧の日には，夜間とほぼ同じ－2bar前後にしか低下しなかった。計測前の2時間の積算照度は，木部圧ポテンシャルの日変化に大きな影響をあたえていることがわかった。Diurnal fluctuations in xylem water potential of Abies veitchii LINDL. saplings were investigated in the plots S, I and O′ by the pressure chamber method on July 22 to 28 and August 17 to 21, 1980. Diurnal fluctuations in xylem water potential were not different at any positions or directions in a crown. In each plot, the xylem water potential decreased to -15 bar on fine or cloudy days, but to only -2 bar throughout the day on rainy or foggy days. The fluctuations in xylem water potential (XWP, bar) were closely related with the light intensity cumulated for 2 hours before the measurement of XWP (LC2, klx・hr・hr-1). The relations were represented by the following equations; Plot S: XWP=-1.25・LC2-2.0 Plot I: XWP=-0.22・LC2-1.5 Plot O′: XWP=-0.067・LC2-1.

Photosynthetic Production in Abies veitchii Advance Growths Growing under Different LightEnvironmental Conditions (II) Photosynthesis and Respiration

S（林内），I（林縁），O（皆伐跡天然更新地）区に生育するシラベ前生稚樹の光合成・呼吸速度を調べた。測定は切り枝について人工条件下で，1979年の全生長期間にわたって行なった。光合成・呼吸速度と照度・気温の関係には，生育場所，枝葉齢，季節による違いがみられた。当年生枝葉の光合成能力はS区5.8，I区5.5，O区3.2mgCO2・gd. w.-1・hr-1（8月30日）と暗い区ほど大きかった。CO2 exchanges in shoots detached from Abies veitchii LINDL. advance growths were compared among the shaded plot (Plot S) under the deep canopy of the subalpine natural forest, the intermediate plot (Plot I) near the forest border, and the open plot (Plot O) on a cut-over area where clear-cutting had been made with expectation of natural regeneration in 1970. The measurements were made under the controlled light and temperature conditions throughout a growing season of 1979

Photosynthetic Production in Abies veitchii Advance Growths Growing under Different Light Environmental Conditions (IV) Computed CO2-balance based on Simulation Model and Adaptation in Photosynthetic Production to Different Light Condition

コンピュータを用いたCO2収支モデルを開発し，様々な光環境下（S区：うっ閉した天然林内，I区：天然林内の林縁部，O区：伐採跡地）に生育するシラベ稚樹のCO2収支を比較した。さらに，これまでの報告で得た知見を総合的に検討し，光合成生産の面からシラベ前生稚樹の光環境への順応について考察した。CO2収支モデルは，生育地の平均相対照度と各部分の重さを与えることによって，任意の個体の任意の生育環境下でのCO2収支が計算できるものである。本モデルは，いくつかの妥当性の検証によってほぼ信頼できるものであった。Differences in photosynthetic production and respiratory consumption of Abies veitchii advance growths growing under the deep forest canopy (plot S), near the forest edge (plot I), and in the open land (plot O) were estimated by the computer simulation method. Their adaptation to different light conditions was studied from the view point of CO2-balance. By applying the relative light intensity in each habitat and the dry weight of each section to newly developed CO2 balance model for simulation, the CO2 blance was able to calculate in any individual under various light environmental conditions arbitrarily chosen

Photosynthetic Production in Abies veitchii Advance Growths Growing under Different Light Environmental Conditions (I) Seasonal Growth, Crown Developement, and Net Production

天然更新作業による上層木の伐採は，前生稚樹の光環境を大きく変化させる。前生稚樹が後継樹として順調な生育を続けていくには，こうした環境の変化に順応しなくてはならない。ここでは上層木の皆伐による光環境の変化にすでに順応し生育しているシラベ前生稚樹および皆伐されなかった林内の稚樹を対象に，光合成生産に関する生態生理的特性について，一連の研究を行なった。In the sub-alpine natural coniferous forests in the central Honshu, the stands abundant advance growths of Abies veitchii LINDL. on the forest floor are found frequently. When the clear-cutting of upper story with expecting the natural regeneration is made, these advance growths having been under deep shade will be exposed directly to the severe radiation. The success of regeneration may depend on physiological adaptability of them to the open conditions. In this series of studies, I try to make clear the difference in some eco-physiological characters relating to photosynthetic production among advance growths of A. veitchii having been adapted to various light conditions

Analyses of the Wind Damage Caused by Typhoon 15 in 1981 at Tokyo University Forest in Hokkaido

東京大学北海道演習林において，1981年夏の台風第15号により大規模な風害が発生した。そこで筆者らは，数量化による多変量解析の手法を用いて，被害率と地形および林況要因との関係を検討した。地形要因には，標高，露出度，斜面方位，斜面上の相対位置，斜面形状，傾斜角，土壌深をとり上げ，地形図および土壌図から読みとった。林況要因には，森林率，林冠疎密度，高木層のみの林冠疎密度，針葉樹混交率をとり上げ，空中写真から読みとった。多変量解析に先立って，被害率と各要因とを個別に比較した結果，露出度と斜面方位が被害発生に大きく関与することがわかった。数量化II類による判別分析では，無被害と小，中，激害の正判別率がいずれも70パーセント以上となり，かなりよく判別された。数量化I類による重回帰分析では，重相関係数は0.60であった。これらの多変量解析の結果から以下のことがわかった。i）周囲の3/4以上が露出していてかつ，斜面方位が暴風の主風方向を中心に左右約70°の範囲にある林分が，とくに大きな被害を受けた。ii）傾斜がゆるやかな林分および針葉樹混交率が高い林分も，概して被害を受けやすい傾向にあった。また，重回帰分析の予測値を用いて，調査地内の風害発生予測図を描くと，一部の地域を除いて実測値の分布図とよく一致した。The forests in Tokyo University Forest in Hokkaido were severely damaged by typhoon 15 in 1981. We tried analyses of the relation between wind damage and some topographical and certain stand condition factors by consulting topographical map, soil map and air photographs. Seven items for topographical factors―altitude, exposure, facing of the slope, relative position on the slope, land type on the slope (relief), inclination, soil depth―and 4 items for stand condition factors―forest area percentage, canopy density of trees higher than 4m, canopy density of trees higher than 14m and mixture percentage of conifer trees―were selected for quantification analyses. On the quantification analysis Hayashi-2, correct discrimination percentage between no damaged areas and damaged areas was more than 70 per cent. On the quantification analysis of Hayashi-1, multiple correlation coefficient was 0.60. Among the 11 items, exposure and facing of the slope were significantly related to the occurrence of wind damage. The following stands were severely damaged: those which face to the main direction of the stormy wind in the range of approximately 70 degree from the center. Generally, it is recognized that stands which are on gentle slopes or have high mixture percentage of conifer trees were easily damaged. As the result of drawing a predictive map of wind damage with the predictive scores of Hayashi-1, the map is generally fitted to the distribution of wind damage percentage of actual scores with some exceptions

Growth of Abies veitchii and A. mariesii Advance Growths after the Clear-Cutting of Overstory Trees in Relationship to Microtopographic Factors

亜高山帯針葉樹天然林の伐採跡地で，シラベ，アオモリトドマツを主とした前生稚樹による天然更新の進行状況を調べ，微地形その他との関係を検討した。調査地は秩父山系西寄りの大弛峠付近にあり，9～14年前に上木が皆伐され前生稚樹による天然更新にまかされているが，更新状況は場所による差が大きい。現在生育している針葉樹稚樹のほとんどは，上木伐採当時の樹高が40～50cm以下の前生稚樹である。更新状況の指標として，ここでは樹冠被覆度を用いたが，樹冠投影面積合計，稚樹密度，稚樹葉量と高い正の相関があり、有効な指標とみとめられた。空中写真と地形図からえた樹冠被覆度と微地形その他の要素について，現地で検定したのち，両者の関係を数量化I類を用いて解析した。樹冠被覆度に対して標高，斜面方位，斜面形状の各要素の影響がつよかった。更新成績は北斜面，凸地形，高い場所でよいばあいが多く，南斜面，凹地形，低い場所ではわるいことが多い。こうした違いがおこる理由として，伐採作業時における地表面の人為的攪乱と，土壌の乾燥の程度の微地形による差を考えた。A series of investigations have been carried on through the mesh-sampling on topographical maps on 1/5000 and field surveys in an area of subalpine coniferous forest, mainly composed of Abies veitchii, A. mariesii and Tsuga diversifolia, in the central Honshu, in order to know whether or not this area can been regenerated by advance growths of these conifers after the clear-cutting of overstory trees and how microtopography or land features affect it. The natural forests in this area (ca. 75ha) were clearly cut in 1965 to 1970 with the expectation of regeneration by abundant advance growths of Abies. The progress of natural regeneration 9 to 14 years after the clear-cutting varies with land features. The saplings of Abies growing on the cut-over area seem to be exclusively survivors from the advance growths which were from 20 to 40 cm in height at the time of clear-cutting. The crown coverage, expressed as a ratio of the area overcast by crowns of conifer saplings in a quadrat area and easily estimated from aerial photographs, is closely correlated with sapling density, total overcast area of crown projection and total leaf weight, and seems useful as a parameter of the progress of natural regeneration. The analyses of correlation between the crown coverage and the micro-topographic factors estimated from topographic maps make obvious that the crown coverage is larger on N and NW facing convex slopes at higher elevations than on W to S facing concave slopes at lower elevations. This result suggests that the conditions of soil surface disturbed by logging and skidding and the soil moisture conditions are the most important among many factors affecting the growth of advance growths and the progress of natural regeneration

The Ant Species Richness and Diversity of a Primary Lowland Rain Forest, the Pasoh Forest Reserve, West-Malaysia

Malsch A, Rosciszewski K, Maschwitz U. The Ant Species Richness and Diversity of a Primary Lowland Rain Forest, the Pasoh Forest Reserve, West-Malaysia. In: Okuda T, Manokaran N, Matsumoto Y, Niiyama K, Thomas SC, Ashton PS, eds. Pasoh: Ecology of a Lowland Rain Forest in South East Asia. Tokyo: Springer Japan; 2003: 347-373

Courses of Height Growth of Cryptomeria japonica Trees Planted on a Slope : Comparison among the near ridge, the mid-slope and the near bottom in the Tokyo University Forest in Chiba

東京大学千葉演習林において，スギ造林木の樹高生長経過と土壌の理化学性およびスギ針葉の養分濃度との関係を，斜面上部，中部，下部間で比較検討した。老齢林の樹高は，斜面上部から下部にむかうにしたがって高くなる傾向がみられたが，若齢林や幼齢造林地では，上部と下部との樹高差が著しい調査地と大差ない調査地とがみられた。樹幹解析によってえた老齢林2調査地の樹高生長経過は，中，下部では，両調査地ともそれぞれ対応する地位の樹高生長曲線と似ていた。一方，上部では，20～30年生頃までは樹高生長曲線とにた生長経過であるが，その後生長が頭打ちとなる調査地と初期生長はよくないが中～後期にかけてもあまり頭打ちにならない調査地とにわかれた。中～後期にかけて生長が頭打ちであった調査地の土層は薄く，あまり頭打ちのみられなかった調査地の土層は比較的厚かった。それぞれの調査地の初期生長経過のちがいは，それぞれの老齢林を皆伐した後に植栽されたスギ苗木の生長でもみられた。土壌の化学性は，中，下部では，調査地による差が小さかった。上部では，pH値等に違いがみられ，初期生長の良い調査地の土壌は，pH値が6以上と中性にちかく，生長の劣る調査地は，相対的に酸性度の強い土壌であった。土壌の化学性は，位置的に近く，母材の同じ調査地で似ていたことから，母材の違いが影響していると考えられる。幼齢造林地での葉分析の結果，斜面上部，中部，下部で，それぞれ樹高生長のよい調査区ほど，針葉の窒素濃度が高い傾向がみられた。窒素濃度が同程度の場合，中，下部に比べて，上部で生長が劣る傾向がみられた。調査地間での土壌の理化学性の差が小さい斜面中，下部では，樹高生長経過の調査地間での差が小さく，一方，上部では，調査地間で土壌の化学性や土層の厚さ等の差が大きく，それに対応して生育初期や中～後期の樹高生長経過の調査地間の差が大きかった。Differences in course of height growth of Cryptomeria japonica trees planted on a slope were compared among near ridge, mid-slope and near bottom. The study was made in 14 study areas in the Tokyo University Forest in Chiba and causes of the difference were discussed in relation to properties of soil and nutrients contents of needle. In study areas of older stands, the height of Cryptomeria tree increased from ridge to bottom along the slope, while of younger stands and younger plantations before canopy closing, this difference was various, apparent in some cases and not apparent in other cases. On mid-slope and near bottom in the two study areas of older stands, the courses of height growth observed by stem analysis paralleled with the curves in each corresponding site class of the yield table. Near ridge, the height growth followed the yield table until 20-30-yr-old and depressed thereafter in the one area where soil layer was thinner, and the growth was not excellent in early stage but the depression with age was not obvious in the other area where soil layer was thicker. The similar difference in height growth in early stage was seen in seedlings planted on the study areas after clear-cutting of older stands. Differences in chemical properties of soil among the study areas were found near ridge, but was not apparent on mid-slope and near bottom. The height growth was affected by pH of soil, the values higher than 6 resulted in excellent growth and lower values in poor one. The chemical properties of soil depended on bed rock. In each part along the slope, the height growth increased with nitrogen content of needle. In comparison of the same level of nitrogen content, the height growths on mid-slope and near bottom were higher than near ridge. The differences in height growth between on mid-slope and near bottom were smaller reflecting smaller differences in physical and chemical properties of soil among the study areas. But near ridge the course of height growth was various throughout the earlier, middle and later stages resulting from different soil properties among the study areas