Microflora of sound-looking wood in Picea abies stems

Ascocoryne spp. (A. cylichnium and A. cf. sarcoides) were found in 48 % of 262 60-year-old Picea abies stems. They were isolated with increasing frequency towards the pith from the lower 2-3 m, more often from thicker than from thinner stems. Neobulgaria premnophila was present in 10 % of the stems, more evenly distributed, and with no difference in occurrence between thicker and thinner stems. Nectria fuckeliana was situated at random in 8 % of the trees.     

Wound occlusion and decay in Picea abies stems

In forest stands, Picea abies is commonly subjected to logging and bark stripping injuries. Most mechanical wounds do not exceed 300 cm², but their pathological consequences are unclear. The aim of the study was to estimate the rate of wound occlusion and the probability of decay in P. abies stems in relation to initial wound size and wounding season. The study included forty-five stems with 1-, 2-, 3-, 4- and 5-cm-wide by 15-cm-long wounds (15–75 cm²), and eighty-three stems with 15-cm-wide by 20-cm-long wounds (300 cm²), made either in January or in August. After 19–21 years, each wound was assessed for occlusion rate and the presence of decay. All 1- to 2-cm-wide wounds were occluded, compared to 58–70% of the 3- to 4-cm-wide wounds, 25% of the 5-cm-wide wounds, and 0% of the 15-cm-wide wounds. On average, it took 3.6, 5.5, 10.4, 12.7 and 14.7 years to occlude wounds ranging in size from 1- to 5-cm-wide, respectively. After 21 years, the observed size of wounds comprising an initial area of 300 cm² ranged between 14 and 481 cm². Wounding season and stem DBH had no impact on wound healing. Wound decay incidence correlated positively with the initial width of injury (r = 0.925; P < 0.05). All 1- to 2-cm-wide wounds lacked any decay, while the proportions of decay among 3-, 4-, 5- and 15-cm-wide wounds were 58.3, 50.0, 83.3 and 100%, respectively. Length of decay comprised 35–225 cm. Consequently, wounds on P. abies stems greater than 5 cm width are unlikely to be occluded and more prone to decay development.     

The elasticity and vertical distribution of stress within stems of Picea sitchensis

Eight 22-year-old Picea sitchensis (Bong.) Carr. trees growing in a Scottish forest were bent using a winch and cable. The shapes of the bent stems were modeled using the structural theory of a cantilever beam, with non-uniform stem taper and large deflections taken into account. The Young's modulus of elasticity for the stems was estimated to be 2.0-6.4 GPa, which is lower than that reported for sawn green timber of this species, but similar to that for intact green stem sections. The longitudinal distribution of stress along the stems had a maximum at a height that was dependent on taper. Maximum stress occurred higher up in the more tapered stems.     

云杉属树种嫁接育苗试验

以红皮云杉不同苗龄型为砧木、采用不同嫁接高度培育白杆嫁接苗,结果表明：S2-2苗龄型的嫁接成活率最高,为80．8％;嫁接高度以距砧木地际10cm处效果最好,成活率为75．5％。嫁接植株经过3a生长,平均株高为34．4cm。     

生态系统文化服务研究综述

随着人们对生态系统服务认识的逐步加深,生态系统文化服务作为生态系统服务的重要组成部分,已被学者们广泛认可。但是,由于生态系统文化服务自身的"无形性",很难和其他服务放在同等重要的研究地位。在越来越多的实证研究中,生态系统文化服务不仅没有受到相应的重视,还经常被研究者们回避和忽略,因此急需对生态系统文化服务进行更深入细致的梳理和研究。文章通过回顾国内外关于生态系统文化服务的文献,总结生态系统文化服务的概念发展、特征属性,通过整理研究内容和研究方法、归纳研究现状、总结生态系统文化服务的研究局限,认为完善生态系统文化服务的理论基础和研究框架、关注文化服务间的协同效应、改进货币化核算方法并推动空间映射制图及研究由静态向动态转变是生态系统文化服务未来的研究方向。     

Phylogenetic relationship of Picea mongolica with other Picea species in the same area based on chloroplast gene variations

Picea mongolica is a conifer with a limited distribution in China and its taxonomic status is controversial.In order to explore genetic differences between P.mongolica and other nearby Picea species and to investigate its taxonomic status,phylogenetic relationships were analyzed between P.mongolica and Picea koraiensis,Picea meyeri and Picea wilsonii by three chloroplast gene sequences matK,chIB and atpA.The length of joint chloroplast sequence is 2379 bp.The fifteen haplotypes were identified by haplotype network analysis,among which two were major haplotypes and nine were unique.In addition,the genetic diversity of the sample collection species was inferred.Based on the haplotype network and Neighbor Joining phylogenetic tree analysis,P.mongolica was located on the basal clade of the phylogenetic tree which had more primitive taxa,and the genetic diversity of P.mongolica was highest.The significant differences between P.mongolica and these other Picea species were identified by this research.     

云杉属的种和种源选择试验

于湖北省宜昌市夷陵区国有樟村坪林场营造云杉属5个种18个种源的种和种源试验林,进行云杉属的种和种源选择试验。结果表明：5种云杉18个种源的造林成活率为76%～92%,平均85.0%;保存率为27%～73%,平均46.1%。欧洲云杉的平均成活率和平均保存率最高,分别达89.0%和60.0%,其中4号、6号2个种源的平均成活率和平均保存率分别达87.5%和67.0%。6年生欧洲云杉的平均树高比其它4个种的平均树高生长量提高36.85%,其中最优良种源是4号和6号种源,该2个种源的平均树高生长量比5号和7号2个种源提高26.63%;4～6年生林不同种源的保存率与历年生长量的差异均达到了显著或极显著水平;4年生林树高和地径之间、5年生林树高和冠幅之间、6年生林树高和地径之间的相关系数均在0.5以上,指标间具有极显著的正相关关系。     

Preliminary evaluation of Epicoccum purpurascens as a biocontrol agent against wound pathogens on stems of Picea abies

Epicoccum purpurascens was applied to stem wounds of Norway spruce for a preliminary assessment of its potential as a biological protection against decay fungi. E. purpurascens had a significant influence on the composition of the mycoflora of the wounds, analysed 8 months after inoculation.     

Vessel length distribution in the stems of three New Zealand species of Nothofagus

Summary A modification of the Zimmermann and Jeje (1981) latex paint infusion technique was utilized to determine vessel length distributions in N. fusca (Hook.f.) Oerst., N. menziesii (Hook.f.) Oerst. and N. solandri var. cliffortioides (Hock.f.) Poole. In all thirty trees examined, the majority of vessels were less than 2 cm long; with 97% of the vessels shorter than 6 cm in N. menziesii and N. solandri, with the same percentage being shorter than 8 cm in N. fusca. The longest individual vessels recorded were 24 cm for N. menziesii, 22 cm for N. solandri and 33 cm for N. fusca. The longest vessels in all three species occurred in the earlywood and also exhibited the largest diameters.     

优良绿化树种青扦云杉引种栽培技术

青扦云杉 (PiceawilsoniiMast.) ,别名青扦 ,为松科云杉属常绿高大乔木 ,树冠枝叶繁密、层次清晰 ,是一种极为优良的绿化树种。青扦云杉为我国特有树种 ,属稍阴性 ,耐全光 ,适应性强 ;在土壤湿润、深厚、排水良好的微酸性地带生长良好。主要产于内蒙古、河北、山西、青海等省区 ,为我国云杉属中分布较为广泛的树种之一。黑龙江省引种栽培青扦云杉至少有 2 0年的历史 ,只要选择适宜的生长环境 ,青扦云杉就可在黑龙江省南部地区正常生长 ,表现出较强的适应性 ,在园林绿化上具有较高的推广价值。1　种子采集与调制9月下旬当球果由绿色变成黄褐…     

Impact of molecular biology on forest pathology: A literature review

Rapid developments in the field of molecular biology have produced a number of very powerful analytical tools by unifying techniques of genetics, biochemistry and cell biology. As reviewed in the present paper, these tools will become important and indispensable in forest pathology studies of the genetic machinery and regulatory mechanisms that control fungal products implicated in the complex tree-pathogen interactions. Understanding these interactions will enhance the development of efficient control methods of forest pathogens.     

Water content and bark thickness of Norway spruce (Picea abies) stems: phloem water capacitance and xylem sap flow

To determine the relationship between phloem transport and changes in phloem water content, we measured temporal and spatial variations in water content and sucrose, glucose and fructose concentrations in phloem samples and phloem exudates of 70- and 30-year-old Norway spruce trees (Picea abies (L.) Karst.). Large temporal and spatial variations in phloem water content (1.4-2.6 mg mg(dw)(-1)) and phloem total sugar concentration (31-70 mg g(dw)(-1)) paralleled each other (r(2) = 0.83, P < 0.0001 for the temporal profile and r(2) = 0.96, P < 0.008 for the spatial profile), indicating that phloem water content depends on the total amount of sugar to be transferred. Changes in phloem water content were unrelated to changes in bark thickness. Maximum changes in phloem water content calculated from dendrometer readings were only 8-11% of the maximum measured changes in phloem water content, indicating that reversible changes in bark thickness did not reflect changes in internal water relations. We also studied the relationship between xylem sap velocity and changes in bark thickness in 70-year-old trees during summer 1999 and winter 1999-2000. Sap flow occurred sporadically throughout the winter, but there was no relationship between bark shrinkage or swelling and sap velocity. In winter, mean daily xylem sap velocity was significantly correlated with mean daily vapor pressure deficit and air temperature (P < 0.0001, in both cases). Changes in bark thickness corresponded with both short- and long-term changes in relative humidity, in both winter and summer. Under controlled conditions at > 0 degrees C, changes in relative humidity alone caused changes in thickness of boiled bark samples. Because living bark of Norway spruce trees contains large areas with crushed and dead sieve cell zones-up to 24% of the bark is air-filled space-we suggest that this space can compensate for volume changes in living phloem cells independently of total tissue water content. We conclude that changes in bark thickness are not indicative of changes in either phloem water capacitance or xylem sap flow.     

Policy design for forest carbon sequestration: A review of the literature

Forest carbon enhancement provides a low-cost opportunity in climate policy, but needs efficient policy design to be implemented. This paper reviews studies in economics on efficient design of policies for forest carbon sequestration and compares their findings against design systems in practice. Specific design problems are associated with the heterogeneity of landowners, uncertainty, additionality, and permanence in carbon projects. Different types of discounting of the value of the forest carbon sink compared with emissions abatement are suggested in the literature for management of most design problems, together with optimal contract design and emissions baselines for managing additionality and permanence in carbon sequestration. Design systems in practice, where forest carbon corresponds to 0.5% of all carbon volume subject to a pricing mechanism, mainly rely on additionality tests by approved standards on a project-by-project basis, and on buffer credits for management of permanence. Further development of forest carbon sinks as offsets in voluntary and compliance markets can be facilitated by applying tools for contract design and offset baseline management recommended in the literature.     

Temperature variation and distribution of living cells within tree stems: implications for stem respiration modeling and scale-up

Few studies have examined variation in respiration rates within trees, and even fewer studies have focused on variation caused by within-stem temperature differences. In this study, stem temperatures at 40 positions in the stem of one 30-year-old Norway spruce (Picea abies (L.) Karst.) were measured during 40 days between July 1994 and June 1995. The temperature data were used to simulate variations in respiration rate within the stem. The simulations assumed that the temperature-respiration relationship was constant (Q10 = 2) for all days and all stem positions. Total respiration for the whole stem was calculated by interpolating the temperature between the thermocouples and integrating the respiration rates in three dimensions. Total respiration rate of the stem was then compared to respiration rate scaled up from horizontal planes at the thermocouple heights (40, 140, 240 and 340 cm) on a surface area and on a sapwood volume basis. Simulations were made for three distributions of living cells in the stems: one with a constant 5% fraction of living cells, disregarding depth into the stem; one with a living cell fraction decreasing linearly with depth into the stem; and one with an exponentially decreasing fraction of living cells. Mean temperature variation within the stem was 3.7 degrees C, and was more than 10 degrees C for 8% of the time. The maximum measured temperature difference was 21.5 degrees C. The corresponding mean variation in respiration was 35% and was more than 50% for 24% of the time. Scaling up respiration rates from different heights between 40 and 240 cm to the whole stem produced an error of 2 to 58% for the whole year. For a single sunny day, the error was between 2 and 72%. Thus, within-stem variations in temperature may significantly affect the accuracy of scaling respiration data obtained from small samples to whole trees. A careful choice of chamber position and basis for scaling is necessary to minimize errors from variation in temperature.     

Anatomical characteristics, properties and use of traditionally used and lesser-known wood species from Mozambique: a literature review

Mozambique is a country with vast forestry resources that include native wood species with high commercial value. Thus, the trade of timber as raw material, as well as wooden finished products are commercial options of considerable valuable for the country. This work presents information about anatomical characteristics, physical and mechanical properties and use of some native wood species from Mozambique, namely, Afzelia quanzensis, Androstachys johnsonii, Erytrophleoum suaveolens, Khaya nyasica, Pterocarpus angolensis, Milletia stuhlmannii and the emerging lesser-known species Pericopsis angolensis, Sterculia appendiculata and Sterculia quinqueloba. The study concludes that these Mozambican wood species are similar in several aspects. They are generally described as very hard, dense, having high mechanical strength and durable. The study also concludes that although the lesser-known wood species, S. quinqueloba, has similar properties to the traditionally used one, A. quanzensis, it is less used because of its poorly known properties and potential uses. Thus, further research to determine the properties and suitable end uses of other lesser know species is likely to be beneficial to the country.     

The costs and benefits of REDD+: A review of the literature

The costs and benefits of the Reducing Emissions from Deforestation and Forest Degradation (REDD⁺) projects are often reported in isolation. There is a lack of comprehensive understanding of the types of REDD⁺ costs and benefits reported in the literature. In this paper, we conducted a review of 60 unique REDD⁺ costs and benefits studies. We found that no single study covers all categories of costs and benefits in a comparable form. A total of 56 comparable estimates were available for opportunity costs, 21 for transaction and implementation costs, 23 for total costs, and only four for direct monetary benefits. We found that, on average, the total REDD⁺ cost ($24.87/tCO₂e) was 2.23 times higher than the opportunity cost and the opportunity cost was 3.28 times higher than the transaction and implementation costs. Costs estimates among studies vary widely based on estimation approach used and the scale of the studies. We noted that future REDD⁺ costs and benefits studies should provide estimates of all relevant costs and benefits, and the distribution of these costs and benefits among project stakeholders. These findings have implications in REDD⁺ project design and implementation.     

Mycelial fan formation of three sympatric Armillaria species on excised stem segments of Picea abies

Mycelial fan formation was studied in five Armillaria cepistipes, ten A. borealis and ten diploid and six haploid A. ostoyae strains on excised stem segments of Picea abies. Stem segments were either non‐autoclaved or autoclaved, representing dying and dead wood, respectively. To confirm the identity of mycelial fans on non‐autoclaved stem segments, re‐isolations were made and isolates characterized with microsatellite markers. Mycelial fan formation on autoclaved stem segments was fast and reliable for most of the tested Armillaria strains. On non‐autoclaved stem segments, mycelial fan formation was slower, more erratic and less predictable. Mycelial fan formation was fastest in A. cepistipes closely followed by A. borealis and was slowest in A. ostoyae. For two A. cepistipes and four A. ostoyae strains (all diploid), growth rates of mycelial fans were estimated in a time course experiment. They ranged between 5.1 and 8.7 mm/day for autoclaved and between 1.4 and 4.7 mm/day for non‐autoclaved stem segments. The haploid A. ostoyae strains also formed mycelial fans on autoclaved stem segments, but typically slower and less reliably than the diploid strains. Whether haploid strains are able to produce mycelial fans on non‐autoclaved stem segments remains unknown because of accidental diploidization of the original haploid strains which was likely caused by basidiospores introduced into the study system on the non‐autoclaved stems. Overall, the method developed in this study may be useful for further investigations into the genetic, physiological and biochemical nature of mycelial fan formation in the genus Armillaria.     

欧洲云杉、黑云杉、白云杉苗期对比试验

选择欧洲云杉3个种源、黑云杉3个种源、白云杉3个种源、青海云杉1个种源进行了不同种、种源的苗期生长性状变异试验。结果表明：云杉不同种、种源间苗期性状差异显著。4个种的1年生苗以苗高进行排序：欧洲云杉〉黑云杉〉白云杉〉青海云杉。欧洲云杉、黑云杉、白云杉各个种的不同种源间有很大的变异及选择潜力。因此在进行云杉引种时,应选择不同的种、种源,才能取得更好的效果。     

A novel isoflavone from the stems of Ageratum conyzoides

A novel isoflavone glycoside, 5,7,2′,4′-tetrahydroxy-6,3′-di-(3,3-dimethylallyl)-isoflavone 5-O-α-l-rhamnopyranosyl-(1→4)-α-l-rhamnopyranoside (1), was isolated from the stems of Ageratum conyzoides.