木本植物叶片热值测试和分析

[目的]本研究致力于探讨木本植物叶片的热值分布规律及其与化学组成的内在联系,相应为科学评估其火灾危险性以及能源利用提供基础数据和工程计算方法。[方法]选取27种不同科属的木本植物叶样,开展工业分析、元素分析及热值测试。[结果]表明,植物叶样的干基高位热值HHVd在17.48~24.01 MJ·kg-1之间变化,平均值为21.16 MJ·kg-1。同科属的植物叶片热值一般较为接近,样品自身灰分含量对干基高位热值的影响可以忽略。分析证实,干基高位热值的变化与样品挥发分和固定碳含量分布密切相关。植物叶片中挥发分和固定碳含量比值随着其化学组成中氧碳摩尔比增加而增大,并且固定碳在可燃组分中的相对含量反映样品木质素含量水平。[结论]样品氧碳摩尔比和氢碳摩尔比的增加意味着其木质素含量降低,使得其干基高位热值减小。对于所涉木本植物叶片来说,其干基高位热值可以分别由经验式HHVd=0.189 3VMd+0.369 5FCd和HHVd=0.447 8Cd+1.4072Hd-0.283 7Od准确计算获得,还可以据此迅速确定样品收到基热值。     

The effect of land use type on net nitrogen mineralization on abandoned agricultural land: Silver birch stand versus grassland

The effect of land use type on the dynamics and annual rate of net nitrogen mineralization (NNM) in a naturally generated silver birch stand and in a grassland, both on abandoned agricultural land, was assessed in situ in the upper 0–20 cm soil layer using the method of buried polyethylene bags. Annual NNM rate in the birch stand (156 kg N ha⁻¹ year⁻¹) was higher than in the grassland (102 kg N ha⁻¹ year⁻¹); in both cases NNM covered a major part of the plants annual nitrogen demand. The rate of NNM in the upper 0–10 cm soil layer in the birch stand (99 kg N ha⁻¹ year⁻¹) exceeded the respective rate of NNM in the grassland (51 kg N ha⁻¹ year⁻¹) roughly two times. In the grassland the rates of NNM in the 0–10 and 10–20 cm layers were equal; in the birch stand NNM in the 0–10 cm layer was 1.7 times higher than in deeper 10–20 cm layer. The intensity of daily NNM in the upper 0–10 cm soil layer in the birch stand was the highest in June and in the grassland in May, 776 and 528 mg kg⁻¹ N day⁻¹, respectively. In our study no significant correlation was found between NNM and the environmental factors monthly mean soil temperature, soil moisture content and pH.     

Effect of species and spacing of fast-growing nurse trees on growth of an indigenous tree, Hopea odorata Roxb., in northeast Thailand

We tested the effects of species and spacing of nurse trees on the growth of Hopea odorata, a dipterocarp tree indigenous to Southeast Asia, in a two-storied forest management system in northeast Thailand. Eucalyptus camaldulensis, Acacia auriculiformis, and Senna siamea were planted as nurse trees in 1987 at spacings of 4 m × 8 m, 2 m × 8 m, 4 m × 4 m, and 2 m × 4 m in the Sakaerat Silvicultural Research Station of the Royal Forest Department, Thailand. Seedlings of H. odorata were planted in the nurse tree stands at a uniform spacing of 4 m × 4 m and in control plots (no nurse trees) in 1990. Stem numbers of some nurse trees were thinned by half in 1994. The stem diameter and height of all trees were measured annually until 1995 and again in 2007. The mean annual increment (MAI) in volume was estimated as 8.2–10.1 m³ ha⁻¹ year⁻¹ for E. camaldulensis and 0.9–1.2 m³ ha⁻¹ year⁻¹ for S. siamea, smaller than reported elsewhere. This suggests that the site properties were not suitable for them. The MAI of A. auriculiformis was 7.9–9.8 m³ ha⁻¹ year⁻¹, within the reported range. Survival rates of H. odorata in the S. siamea stands and the control plots decreased rapidly during the first 2 years but then stayed constant from 1992. In contrast, survival rates of H. odorata in the E. camaldulensis and A. auriculiformis stands were initially high (>70%), but then decreased after 1995. Stem diameter, tree height, and stand basal area of H. odorata were large in both the S. siamea stands and the control plots from then. The growth of H. odorata was largest in the 2 m × 8 m S. siamea stands. In contrast, it was restricted in the E. camaldulensis and A. auriculiformis stands owing to strong shading by their canopies. Thinning by 50% tended to facilitate the growth of H. odorata temporarily in the E. camaldulensis and A. auriculiformis stands. The stand basal areas of nurse trees and of H. odorata showed a trade-off. These results suggest that the growth of H. odorata was maximized in the S. siamea stands. We assume, however, that the growth of H. odorata could be improved even in the E. camaldulensis and A. auriculiformis stands by frequent or heavy thinning.     

Optimum pruning intensity for reducing crop suppression in a <Emphasis Type="Italic">Gmelina</Emphasis>–maize smallholder agroforestry system in Claveria,Philippines

On-farm trials were conducted to assess the effects of four branch pruning levels on maize grain yield, tree growth and stem shape. The experimental plots consisted of Gmelina (Gmelina arborea R.Br.) trees planted at 1 × 10 m with maize intercropped in the 10 m-wide alleys between lines of trees. Pruning levels consisted of retaining a live crown ratio of 60–70% (T ₁), 40–50% (T ₂); 30–40% (T ₃) and of 20–30% (T ₄). At the end of the experiment, the total maize grain yield was highest under the high pruning intensity (T ₄) (18.06 t ha⁻¹) and lowest under T ₁ (14.48 t ha⁻¹). Maize grain yield under the pruning regime T ₂ and T ₃ were 16.08 and 17.21 t ha⁻¹, respectively. Mean annual increment (MAI) in tree diameter was greater (5.0 cm year⁻¹) under T ₁ than those at T ₄ (4.1 cm year⁻¹). Pruning regimes T ₂ and T ₃ resulted in a MAI of 4.7 and 4.5 cm year⁻¹, respectively. Financial analysis showed that maize-tree systems under T ₄ were more profitable than under T ₁ as long as the reduction of the average dbh at harvest were not greater than 1 cm. Pruning trees intensively also generated greater returns from labour than moderate pruning, as the greater maize grain yields under T ₄ compensated for the cost of pruning and the lower timber yield. In the context of resource-poor farmers, intensive branch pruning was a practice that prolonged the period of profitable intercropping and was compatible with commercial timber production.     

Estimation of annual suspended sediment yield from a Japanese cypress (Chamaecyparis obtusa) plantation considering antecedent rainfalls

Japanese cypress (Chamaecyparis obtusa) is one of the most common plantation species in Japan. In most Japanese cypress plantations, closure of the forest canopy hinders understory growth because of insufficient management practices. Thus leaf litter barely covers the soil surface. Such plantations are vulnerable to surface erosion triggered by rainfalls, and could yield large amounts of suspended sediment (SS). However, few studies have investigated the annual SS yield. This study aimed to develop a modified model of SS yields, and to accurately estimate and characterize the annual SS yield from a Japanese cypress plantation. For this, hydrological surveys were conducted for 5 years, and stream water was sampled weekly as well as sequentially at 15–60 min intervals in each of 14 rain events in a small forested watershed of Japanese cypress. The root mean square error (RMSE) and the annual SS yield estimates were obtained using three different equations: the rating curve derived from instantaneous SS concentration versus stream discharge relationship (SSC − Q equation); the rating curve derived from cumulative SS yield versus cumulative specific discharge relationship (∑SS − ∑Q equation); and the multiple regression of cumulative SS yield expressed as functions of cumulative specific discharge and antecedent rainfalls (∑SS − ∑Q × AR equation). The ∑SS − ∑Q × AR equation is a modified model considering the effects of antecedent rain history on the SS yield. The parameters in each equation were determined by a nonlinear least square method. Of the three equations, the RMSE was the highest using the SSC − Q equation. Although the ∑SS − ∑Q equation and the ∑SS − ∑Q × AR equation gave similar RMSE values, the SS yields extrapolated by the ∑SS − ∑Q equation would be overestimated. Thus, the 5-year average of annual SS yield estimated by the ∑SS − ∑Q equation was three times larger than that estimated by the ∑SS − ∑Q × AR equation. These results indicate that the ∑SS − ∑Q × AR equation more accurately estimates the annual SS yield, compared with the other two equations. The results also suggest that antecedent rain history, as well as stream discharge, should be considered for appropriately estimating the annual SS yield. The annual SS yield estimated by the ∑SS − ∑Q × AR equation was the largest among 25 undisturbed forested watersheds, except for two watersheds dominated by sandstone. Our results suggest that the annual SS yield is greater from a Japanese cypress plantation under current management practices than from other undisturbed forests.     

氮、磷、钾配比施肥对辣木生长及叶片养分吸收的影响

[目的]为明确辣木生长对养分的需求及叶片养分吸收状况。[方法]研究采取田间小区实验,设置N_(80)、N_(80)P_(20)、N_(80)K_(40)、P_(20)K_(40)、N_(80)P_(20)K_(40)、N_(60)P_(20)K_(60)和不施肥对照7个处理,测定分析不同氮、磷、钾配比施肥对辣木生长及叶片养分吸收的影响。[结果]不同氮、磷、钾配比施肥处理下,辣木生长速度先快后缓慢,处理90 d后株高、冠幅和鲜叶生物量的最高值及地径的次高值均出现在N_(80)中,N_(60)P_(20)K_(60)的株高、地径及N_(80)K_(40)的鲜叶生物量仅次于N_(80)处理;不同氮、磷、钾配比施肥均促进了辣木叶片中全氮、全磷含量的累积,但降低了全钾含量;除N_(80)外,其它处理叶片叶绿素含量均低于CK,高氮处理的叶绿素含量均高于P_(20)K_(40)和N_(60)P_(20)K_(60),N_(80)P_(20)高于N_(80)K_(40)。[结论]各元素对辣木生长影响大小为NKP,对叶片中叶绿素含量影响大小为NPK,叶片中营养元素含量大小为NKP。综合试验结果中辣木主要生长指标的生长及叶片养分吸收情况,配比施肥最优处理为N_(80),且该施肥处理主要适用于辣木幼龄及速生生长阶段。     

华北落叶松液流速率的优势度差异及其对林分蒸腾估计的影响

将实测的杨树液流速率和林木边材厚度(或胸径)经尺度扩展得到林分蒸腾,已成为常用的野外测定方法,但此法没有考虑其他树形因子的影响,当林分密度大、光竞争激烈时,会导致蒸腾估计误差偏大。为认识主要树形因子对液流速率的影响,并为改进样树液流向林分蒸腾的尺度扩展方法提供依据,在六盘山北侧半干旱区华北落叶松人工林内,利用热扩散探针对5株不同优势度样树的液流速率进行了连续观测,研究了生长季中期(叶面积指数达到峰值并保持稳定)不同土壤水分条件下不同优势度树木的液流速率差异。结果表明:优势度越大的树木,其液流在日内的启动越早,结束越晚,到达峰值越早,峰值也越大;日均液流速率明显比优势度小的树木高;液流速率对太阳辐射和饱和水汽压差瞬时变化的响应敏感性比优势度小的树木高,而对土壤水分条件的响应敏感性则弱于后者,但整体上对环境条件的响应趋势一致,不同优势度树木间液流速率的相对差异比较稳定。相关分析表明:液流速率与优势度(或相对树高)、树高呈极显著正相关,与冠长、胸径显著正相关,而与冠幅、边材面积正相关但不显著。利用拟合的优势度与液流速率之间的线性关系(R²=0.95)计算了样地内所有树木的液流速率及其平均值,即林分平均液流速率,该值比常用方法计算结果低16%。建议今后在利用样树液流速率测定结果进行尺度扩展计算林分液流速率和蒸腾时,增加考虑优势度等主要树形因子的影响。     

Precipitation chemistry at a high elevation forest in central Taiwan

High elevation ecosystems are particularly sensitive to environmental change. Mountain agriculture is extending to areas at high elevations in Taiwan but the effects on nutrient cycling of the surrounding ecosystems are largely unknown. We examined precipitation chemistry at Piluchi Experimental Forest in central Taiwan to evaluate the contributions of local air pollution and long-range transport of air pollutants on nutrient cycling at this seemingly remote forest. Sea-salt aerosols and anthropogenic pollutants resulting from long-range transport of air pollutants and mountain agriculture activities are the key factors affecting precipitation chemistry at Piluchi Experimental Forest. Precipitation chemistry was dominated by ions of oceanic origin in the summer and by anthropogenic pollutants SO₄ ²⁻, NO₃ ⁻ and NH₄ ⁺ in the winter and spring, the northeast monsoon season. The much higher concentrations of S and N in the northeast monsoon season than the summer suggest a substantial contribution from long-range transport as the prevailing air masses moved from inland China and passed over the industrialized east coast of China before arriving in Taiwan. The very high concentration of NH₄ ⁺ (22 μeq L⁻¹) in the spring, when the local application of N-containing fertilizers was high, signifies the influences of mountain agriculture. Despite very low concentrations relative to other sites in Taiwan, annual input of NH₄ ⁺ (3.6 kg ha⁻¹ year⁻¹), NO₃ ⁻ (7.2 kg ha⁻¹ year⁻¹) and SO₄ ²⁻ (10 kg ha⁻¹ year⁻¹) via precipitation was substantial suggesting that high elevation ecosystems of Taiwan are not free from the threat of atmospheric deposition of pollutants.     

不同栽培措施对尾巨桉生长的影响及经济效益分析

试验采用列区试验设计,设造林密度和追肥2个因素,每个因素6个水平,4次重复.密度因子作主区,追肥因子作副区,各个因素和各处理按随机区组排列.每个试验小区面积0.04 hm2(20 m×20 m),共计144个小区,连续5 a观测.经过方差分析得出,造林试密度对林分平均高、平均胸径和蓄积量都有极显著的影响.在6种参试密度中,造林密度越大,林分平均高、胸径越小,蓄积量越大;6种配方追肥对林分平均高影响不显著,对胸径和蓄积量生长影响显著;密度与追肥的交互作用不显著.在所有36个列区试验组合中,按经济效益排列前5名的密度和追肥最佳组合分别为:2 222株.hm-2和每公顷施N、P、K分别为200、150、100 kg,1 667株.hm-2和每公顷施N、P、K分别为300、200、200 kg;1 667株.hm-2和每公顷施N、P、K分别为200、150、100 kg;2 222株.hm-2和每公顷施N、P、K分别为100、50、50 kg;1 250株.hm-2和每公顷施N、P、K分别为200、150、100 kg.它们的蓄积量分别为183.94、188.43、169.95、164.33、163.03 m3.hm-2;利润值分别为14 977.44、14 965.09、13 832.83、13 785.80和13 345.18元.hm-2.     

Methane and nitrous oxide emissions from mature forest stands in the boreal forest, Saskatchewan, Canada

Despite the spatial significance of Canada's boreal forest, there is very little known about CH₄ and N₂O emissions from non-peatlands within it. The primary objective of this project was to study the atmosphere–soil exchange of CH₄ and N₂O at three sites in the boreal forest of central Saskatchewan. In the summers of 2006 and 2007, CH₄ and N₂O emissions were measured along transects in three different mature forest stands (aspen, black spruce and jack pine) using a sealed chamber method. At the aspen site, the gross rates of mineralization and nitrification, and the relative contribution of nitrification and denitrification to N₂O emissions, were also measured using the ¹⁵N isotope dilution technique. Results indicated that the jack pine and black spruce sites were slight sinks of CH₄ (−0.123 g CH₄–C m⁻² yr⁻¹and −0.017 g CH₄–C m⁻² yr⁻¹ respectively in 2006 and −0.095 g CH₄–C m⁻² yr⁻¹and 0.045 g CH₄–C m⁻² yr⁻¹ respectively in 2007), whereas the aspen site was a net source (4.40 g CH₄–C m⁻² yr⁻¹ in 2006 and 19.60 g CH₄–C m⁻² yr⁻¹ in 2007). The high CH₄ emissions at the aspen site occurred at depressions that were water-filled due to above-average precipitation levels in 2005–2007. All three sites had very low cumulative N₂O emissions, ranging from −0.002 to 0.014 g N₂O–N m⁻² yr⁻¹ in both years. The ¹⁵N results indicated that N cycling at the aspen site was very conservative, allowing little N to escape the system as N₂O; the emissions that did occur were due primarily to a nitrification-related process.     

Pathogenicity of Phytophthora multivora to Eucalyptus gomphocephala and Eucalyptus marginata

Phytophthora multivora is associated with the rhizosphere of declining Eucalyptus gomphocephala, Eucalyptus marginata and Agonis flexuosa. Two pathogenicity experiments were conducted. The first experiment examined the pathogenicity of five P. multivora isolates and one Phytophthora cinnamomi isolate on the root systems of E. gomphocephala and one P. multivora isolate on the root system of E. marginata. In the second experiment, the pathogenicity of P. multivora to E. gomphocephala and E. marginata saplings was measured using under‐bark stem inoculation. In Experiment 1, the P. cinnamomi isolate was more aggressive than all P. multivora isolates causing significant loss of fine roots and plant death. Two P. multivora isolates and the P. cinnamomi isolate caused significant losses of E. gomphocephala fine roots 0–2 mm in diameter and significantly reduced the surface area of roots 0–1 mm in diameter. One P. multivora and the P. cinnamomi isolate significantly reduced the surface area of roots 1–2 mm in diameter. Two of the P. multivora isolates significantly reduced the number of E. gomphocephala root tips. In E. marginata, the length and surface area of roots 0–1 mm in diameter and number of root tips were significantly reduced by P. multivora infestation. Rhizosphere infestation with the P. multivora isolates and P. cinnamomi isolate on E. gomphocephala, and one P. multivora isolate on E. marginata, did not significantly influence the foliar nutrient concentrations. In Experiment 2, under‐bark inoculation with P. multivora caused significant lesion extension in E. gomphocephala and E. marginata saplings, compared to the control. We propose that P. multivora is inciting E. gomphocephala and E. marginata decline by causing fine root loss and subsequently interfering with nutrient cycling throughout the plant. The impact of fine root loss on the physiology of plants in sites infested with P. multivora requires further research.     

Characteristics of the temperature coefficient, Q 10, for the respiration of non-photosynthetic organs and soils of forest ecosystems

The temperature coefficient, Q ₁₀ (fractional change in rate with a 10°C increase in temperature) describes the temperature sensitivity of soils, roots, and stems, as well as their possible performance in global warming processes. It is also a necessary parameter for the estimation of total CO₂ efflux from each element. A number of studies have focused on Q ₁₀ values to date; however, their conclusions are not universal and do not always agree. A review of these reported Q ₁₀ values therefore becomes necessary and important for a global understanding of the temperature sensitivity of different forest types and elements. The aims of our present paper are, first, to find the frequency distribution pattern of soils, roots, and stems (branches) and compare their temperature sensitivity; then, to find the Q ₁₀ differences between conifer and deciduous tree species and the effect of methodology on Q ₁₀ values; finally we want to give a perspective on future Q ₁₀-related studies. We found that most Q ₁₀ values of each element were concentrated in a relatively narrow range despite a total data distribution over quite a wide range. For soil respiration, the median Q ₁₀ value was 2.74 and the center of the frequency distribution was between 2.0 and 2.5 with a percentage of 23%. Most of the data (>80%) were within the range from 1.0 to 4.0. The median Q ₁₀ value for root respiration was 2.40 and the center of the frequency distribution was from 2.5 to 3.0 with a percentage of 33%. Most of the results (>80%) ranged from 1.0 to 3.0. For stem respiration, the median Q ₁₀ value was 1.91 and the frequency distribution was concentrated between 1.5 and 2.0. Over 90% of the data ranged from 1.0 to 3.0. Obvious differences in Q ₁₀ value were found between different elements, stem < root < soil including root < soil excluding root. The differences between woody organisms of stems, roots, and soils excluding roots were statistically significant (p<0.05), indicating that heterotrophic respiration from microorganism activity may be more sensitive to global warming. The duration of the period with leaves slightly affects the temperature sensitivity of woody organisms since the Q ₁₀ values for root and stem of coniferous evergreen trees did not differ significantly from deciduous trees (p>0.10). CO₂ analytical methods (soda lime absorption method, IRGA (Infra-read gas analysis), and chromatograph analysis) and root separation methods (excised root and trenched box) slightly affected the Q ₁₀ values of soil and root respiration (p>0.10), but an in vitro measurement of stem respiration yielded a significantly higher Q ₁₀ value than an in vivo method (p<0.05). In general, although the Q ₁₀ values of non-photosynthetic organisms stayed within a relatively conservative range, considerable variation between and within elements were still detectable. Accordingly, attention should be paid to the quantitative estimation of total CO₂ efflux by Q ₁₀-related models. In future studies, the biochemical factors and the environmental and biological factors controlling respiration should be emphasized for precise estimation of total CO₂ efflux. The difficulty is how to clarify the underlying mechanism for fluctuations of Q ₁₀ values for one specific habitat and element (e.g. temperature acclimation or adaptation of Q ₁₀ values) and then allow the Q ₁₀ values to be more conservative for representation of temperature sensitivity in global warming processes. __________ Translated from Acta Phytoecologica Sinica, 2005, 29(4) [译自:植物生态学报, 2005, 29 (4)]     

Effects of side-chain hydroxyl groups on pyrolytic <Emphasis Type="Italic">β</Emphasis>-ether cleavage of phenolic lignin model dimer

Effects of side chain hydroxyl groups on pyrolytic β-ether cleavage of phenolic model dimers were studied with various deoxygenated dimers under pyrolysis conditions of N₂/400°C/1 min. Although phenolic dimer with hydroxyl groups at the C _α ⁻ and C _γ ⁻positions was much more reactive than the corresponding nonphenolic type, deoxygenation at the C _γ -position substantially reduced the reactivity up to the level of the nonphenolic type. These results are discussed with the cleavage mechanism via quinone methide intermediate formation, which is activated through intramolecular hydrogen bonds between C _α ⁻ and C _γ ⁻ hydroxyl groups.     

宁夏六盘山香水河小流域华北落叶松人工林乔木层生物量的坡面变化和尺度效应

生物量受坡面环境条件变化影响而有坡面变化与尺度效应。本文在六盘山半湿润区的香水河小流域选择了33 a生华北落叶松人工林的一个斜坡长480 m,水平长398 m的典型坡面,在整个坡面上建立了宽30 m的调查样带,均匀分为空间连续的16个样地,在2014年生长季中期调查不同坡位的样地生物量,分析其坡面变化规律。结果表明:生物量存在明显的坡位差异。坡面生物量t·hm^-2平均值为118.59,其变化范围为96.19 139.18,变幅为42.99,变异系数为0.12;随着离坡顶距离的增加,生物量总体上呈现先升高后降低的变化趋势,在坡面的中上部(水平坡长为87.71 m)达到最大。生物量存在坡面空间尺度效应,即随着相对坡长(X₁)的增加,生物量的顺坡滑动平均值(Y₁)先增大后减小,其回归关系式为:Y₁=23.004X₁³-60.834X₁²+31.786X₁+123.43(R²=0.84),坡面尺度效应表现为每100 m水平坡长生物量变化的数值为6.12 t·hm^-2;各样地生物量与整个坡面平均值的比值(Y₂,小数)随相对坡长有很好的非线性关系,基本上呈先增加后下降、后趋于稳定的变化趋势,其关系式为Y₂=1.722 6X₁³-2.844 5X₁²+1.033 8X₁+1.000 1(R²=0.57),可基于此将特定坡位样地的生物量换算成整个坡面的估算值。造成生物量坡面变化的主要原因是太阳辐射和光照时间随海拔的变化等多种因素造成的。     

New piezoelectric moduli of wood: <Emphasis Type="Italic">d</Emphasis><Subscript>31</Subscript> and <Emphasis Type="Italic">d</Emphasis><Subscript>32</Subscript>

This article reports the piezoelectric moduli of wood d ₃₁, d ₃₂, and d ₃₆. The piezoelectric moduli of wood d ₃₁ and d ₃₂ have not been previously reported, although there has been much research on the d ₁₄ and d ₂₅ moduli of wood. The moduli d ₃₁, d ₃₂, and d ₃₆ were measured carefully because their absolute values were considerably smaller than those of d ₁₄ and d ₂₅. For Softwoods, d ₃₆ values were mostly negative, whereas the values for hardwoods had either positive or negative values. The other moduli, d ₃₁ and d ₃₂, were a mixture of positive and negative values in softwoods and hardwoods. The existence of d ₃₁ and d ₃₂ suggests the presence of an electrical polarity of the cellulose crystal in the fiber direction of the wood. The polarities of d ₃₁ and d ₃₂ became clear from wood in the outer part of the trunk, where the crystallinity of cellulose is large and the alignment of the crystals becomes parallel to the fiber direction.     

林木直径大小多样性量化测度指数的比较研究

[目的]为了客观恰当地量化表达林分水平上的林木直径大小多样性。[方法]采用6块定位样地数据,对比分析基于直径分布的Simpson(D_N)、Shannon(H_N)及单木断面积Gini系数(GC),基于直径大小分化度的Simpson(DT)、Shannon(HT)及其均值(T-)这6种林木直径大小多样性量化测度指数,筛选出符合逻辑排序且具有较好辨别能力的直径大小多样性量化测度指数。[结果]6块样地的林木直径大小多样性逻辑排序为吉林胡桃楸针阔混交林经营样地吉林胡桃楸针阔混交林对照样地甘肃锐齿栎阔叶混交林经营样地甘肃锐齿栎阔叶混交林对照样地北京油松落叶松人工混交林样地北京侧柏人工纯林;林木直径大小多样性为天然林高于人工林,更为成熟的吉林老龄林样地高于甘肃中龄林样地,经过至少5年结构化经营的样地高于对照样地,人工混交林样地高于人工纯林样地。基于直径分布的DN、HN和GC测度的6块样地林木直径大小多样性排序结果与逻辑排序不一致;基于直径大小分化度的D_T、H_T和珔T测度的各林分林木直径大小多样性排序与逻辑排序一致。[结论]基于直径分布的D_N、H_N和GC量化测度指数不能恰当地表达林木直径大小多样性。基于直径大小分化度的D_T、H_T和珔T量化测度指数能恰当表达林木直径大小多样性;相对D_T和H_T,珔T是一个连续型变量的测度指数,而且能从林分整体水平上量化林木间的大小分化程度,易于解释其生物学意义。因此,认为珔T是恰当表达及区分各林分林木直径大小多样性的最优量化测度指数。     

Effects of flooding stress on the photosynthetic apparatus of leaves of two <Emphasis Type="Italic">Physocarpus</Emphasis> cultivars

We applied under pot-culture conditions and the double-casing pot method to study the characteristics of photosynthetic gas exchange and chlorophyll fluorescence in the leaves of Physocarpus amurensis Maxim (PA) and Physocarpus opulifolius under flooding stress. Our results indicate a significantly higher flooding tolerance of P. opulifolius compared to P. amurensis. Especially in P. amurensis, the limitation of non-stomatal factors played a major role in the advanced stages of flooding stress, observed as a rapid increase of the intercellular CO₂ concentration (C _i) and a decrease of the stomatal limitation value (L _s). The maximal PSII photochemical efficiencies (F _v/F _m) and actual photochemical efficiency (Ф _PSII) in the leaves of P. opulifolius were significantly higher, and the extent of decrease during the flooding process was smaller than in P. amurensis. In addition, the non-chemical quenching (NPQ) in the leaves of P. opulifolius significantly increased from the 10th day under flooding stress, while the variation of NPQ in the leaves of P. amurensis was much smaller. This indicates that the leaves of P. opulifolius had not only higher PSII photochemical activity, but also improved tolerance to flooding stress, which may be caused by its ability to dissipate excess excitation energy by starting NPQ. At the 16th day under flooding stress, the P _IABS significantly decreased with greater extent of decrease than F _v/F _m in the leaves of both Physocarpus, but the decreasing extent of P _IABS in P. opulifolius was significantly smaller than in P. amurensis. In the 16th day under flooding stress, the fluorescence at J and I point (V _J and V _I) in P. amurensis were significantly higher, and the extent of increase in V _J was greater than V _I. However, the variations of V _J and V _I in the leaves of P. opulifolius were smaller, suggesting that the damage sites of flooding stress to PSII in the leaves of P. amurensis were mainly located in the electron transport process from Q_A at the PSII receptor side to Q_B. Flooding stress reduced the proportion (φE _o ) of luminous energy absorbed by the PSII reaction center for the electron transport following Q _A ^? , while the maximum quantum yield (φD _o) of non-photochemical quenching increased. However, the TR_o/RC and ET_o/RC in the leaves of P. amurensis decreased accompanied by a dramatic increase of energy (DI_o/RC) from the dissipation in the reaction center. This further indicated that the function of the PSII reaction center in the leaves of P. amurensis was significantly lower than in P. opulifolius.     

Growth rates of Heterobasidion annosum s.s. and H. parviporum in functional sapwood of Pinus sylvestris and Picea abies

Growth rates of H. annosum s.s. and H. parviporum were investigated in the functional sapwood of young Pinus sylvestris and Picea abies plants as an indicator of the relative susceptibilities of the hosts to these pathogens. The stems of 520 five‐year‐old P. abies and 321 four‐year‐old P. sylvestris plants were inoculated and the extent of infection determined 16 weeks later. H. annosum s.s. grew further than H. parviporum in P. sylvestris sapwood, while in P. abies, no differences between the two Heterobasidion spp. were found. Both H. annosum s.s. and H. parviporum spread faster in the sapwood of P. abies than in P. sylvestris. There was high within‐host species variation in growth rates for both P. sylvestris and P. abies suggesting it may be possible to identify tree genotypes with lower susceptibility.     

Contributions of salmon-derived nitrogen to riparian vegetation in the northwest Pacific region

We examined the relationship between the annual escapement of salmon and the δ ¹⁵N of willow (Salix spp.) leaves to evaluate the contribution of marine-derived nutrients (MDN) to riparian vegetation around the Pacific Northwest and Northeast regions. Foliar δ ¹⁵N values ranged from −3.42‰ to 4.65‰. The value increased with increasing density of carcasses up to 500 fish/km and 1500 fish/km. δ ¹⁵N values were variable at carcass densities below 500 fish/km. Possible factors affecting the fluctuation of δ ¹⁵N at reference sites are: (1) denitrification; (2) the presence of N₂-fixing trees, such as alder; and (3) agricultural runoff. δ ¹⁵N values at the sites with carcass densities over 500 fish/km were consistently high, while a value of δ ¹⁵N below zero was observed at only one site (Rusha River; δ ¹⁵N = −1.87‰). At this site, most adult pink salmon returned to limited locations near the estuary because steeper channel gradients acted as a migration barrier, resulting in the negative δ ¹⁵N value. Nevertheless, we concluded that our results showed evidence of the feedback of MDN to terrestrial vegetation, although the use of the δ ¹⁵N value as a terrestrial end member at spawning sites is limited. If the relationship between the enrichment index, which is expressed as the values using a mixing model, and salmon abundance was estimated, the availability of MDN in riparian ecosystems could possibly be evaluated and will lead to the establishment of escapement goals. An erratum to this article is available at .     

Lästlinge und Schädlinge an Textilien

Zusammenfassung Während der entomologischen Arbeiten im Laboratorium für Textilzoologie wurden 51 unterschiedliche Tierarten an den 1961–1963 zur Untersuchung eingesandten Textilien gefunden. Von wirtschaftlich wichtiger Bedeutung sind jedoch nur die Wollschädlinge. Den 55 Textilschäden durch Tineiden-Larven stehen 110 beschädigte Textilien gegenüber, die von Dermestiden-Larven entwertet wurden. Wolltextilien werden heute in der Bundesrepublik Deutschland stärker von Käfer-als durch Mottenlarven bedroht.

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Summary In the course of applied entomological research at the Laboratory of Textile Zoology 51 different types of animals were determined during the years 1961–1963 on damaged textiles sent in. Of economic important are only the insects who eat wool. Today the actual main wool pests in the German Federal Republic are not the moths of the familyTineidae but the beetles of the familyDermestidae: the carpet beetles.

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Résumé Pendant le travail entomologique entre 1961 et 1963 dans le Laboratoire de Zoologie Textile 51 différentes sortes d'annimaux ont été trouvés dans des tissus endommagés. Seuls les insectes kératinophages: les Mites (microlépidoptères), les Anthrènes et les Attagènes (coléoptères) sont d'une importance économique. Mais pendant les années derniéres les larves des coléoptères anthrènes et attagènes ont causé plus de dommage dans l'Allemagne Fédéral que les mites.

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Herrn Dr. Adolf Herfs zum 70. Geburtstag gewidmet. ® — eingetr. Warenzeichen.