Extractives of <Emphasis Type="Italic">Quercus crispula</Emphasis> sapwood infected by the pathogenic fungi <Emphasis Type="Italic">Raffaelea quercivora</Emphasis> I: comparison of sapwood extractives from noninfected and infected samples

The extracts of Quercus crispula infected by the ambrosia fungus, Raffaelea quercivora, were investigated. Phenol and tannin analyses indicated that normal sapwood (NS) contained a considerable amount of hydrolysable tannins, while infected colored sapwood (IS) contained less hydrolysable tannins and more phenols than NS. In treating pentagalloyl glucose (PGG), which is a model compound of hydrolysable tannins, with a culture medium of R. quercivora, PGG was rapidly hydrolyzed to produce gallic acid. The resulting gallic acid decreased in concentration over the subsequent cultivation period eventually disappeared. Measuring tannase and laccase activities of the culture medium of R. quercivora, tannase activity increased gradually from the beginning, while laccase activity increased rapidly at 5 days of incubation and disappeared at 8 days. An oxidative product from gallic acid treated with laccase was isolated by preparative high performance liquid chromatography, and was identified as purprogallincarboxylic acid (PGCA) by nuclear magnetic resonance spectroscopy and electron-impact mass spectrometry. PGCA was present in a 70% aqueous acetone extract of IS, and showed slight growth inhibition against R. quercivora. Part of this study was presented at the 57th Annual Meeting of the Japan Wood Research Society, Hiroshima, Japan, 2007     

Relationships between mass mortality of two oak species (Quercus mongolica Turcz. var.grosseserrata Rehd. et Wils. andQ. serrata Thunb.) and infestation by and reproduction ofPlatypus quercivorus (Murayama) (coleoptera: Platypodidae)

This study investigated the number of adults ofPlatypus quercivorus (Murayama) captured on host oak (Quercus spp.) trees, the attack density (the number of entry holes per 100 cm²), and the number of emerging adults to clarify the relationships between the beetle’s colonization on trees in oak stands and tree mortality. The initial attack ofP. quercivorus, which was the most intense attack, was observed on most living trees simultaneously. Although some attacked trees died within the year of the attack or in the next year, a high density of attack did not usually cause the death of host trees. Surviving trees suffered low levels of consecutive attack after the initial attack. BecauseP. quercivorus successfully produced broods only in the dead trees, the population of the insect seems to be maintained only in stands where oak mortality occurs. However, the adults that landed on most of the surviving trees appeared unable to reproduce probably due to degradation of host quality. Thus, oak mortality probably ceases within 3 or 4 years after the start of infestation in a stand, with subsequent reductions in population density of the borer.     

A low <Emphasis Type="Italic">Platypus quercivorus</Emphasis> hole density does not necessarily indicate a small flying population

The ambrosia beetle Platypus quercivorus causes mass mortality of Fagaceae trees in Japan, and tree species differ in their susceptibility to P. quercivorus. We hypothesized that interspecific differences in susceptibility are caused by differences in beetle infestation patterns, that is, how many beetles fly to a tree and how many of those arriving bore holes. To examine how tree susceptibility is related to these parameters, two tree species with different degrees of susceptibility were studied (highly susceptible Quercus crispula and less susceptible Q. salicina). Specifically, we measured the number of male beetles per unit area that flew to the host trees (NFM) and the density of holes bored by male beetles (DH). From these two values, we calculated the proportion of male beetles flying to a host tree that bored holes (PBM). These parameters were compared for the two Quercus species. Although the two species did not differ in NFM in 2003, PBM was markedly lower for Q. salicina than for Q. crispula and DH was significantly lower for Q. salicina than for Q. crispula. Thus, the lower susceptibility of Q. salicina is partly explained by its low PBM.     

Effects of a nursery CO2 enriched atmosphere on the germination and seedling morphology of two Mediterranean oaks with contrasting leaf habit

The use of an enriched CO₂ atmosphere in tree nurseries has been envisaged as a promising technique to increase productivity and to obtain seedlings with a higher root/shoot ratio, an essential trait to respond to water stress in Mediterranean-type ecosystems. In that framework, we have analyzed the effects of three levels of atmospheric CO₂ concentration (350, 500 and 700ppm) on the germination rate, growth and morphology of seedlings of two Mediterranean oaks used in reforestation programs: the evergreen Quercus ilex L. and the deciduous Quercus cerrioides Wilk. et Costa. CO₂ enrichment increased the germination rate of Q. cerrioides (from 70±7 to 81±3%) while it decreased that of Q. ilex (from 71±10 to 41±12%). Seedlings of both species increased approximately 60% their total biomass in response to CO₂ enrichment but at two different CO₂ concentrations: 500ppm for Q. cerrioides and 700ppm for Q. ilex. This increase in seedlings biomass was entirely due to an augmentation of root biomass. Considering germination and biomass partitioning, an enriched CO₂ atmosphere might not be appropriate for growing Mediterranean evergreen oaks, such as Q. ilex, since it reduces acorn germination and the only gains in root biomass occur at a high concentration (700ppm). On the other hand, a moderate CO₂ enrichment (500ppm) appears as a promising nursery technique to stimulate the germination, growth and root/shoot ratio of deciduous oaks, such as Q. cerrioides.     

Stand structure and composition of a 60-year-old larch (Larix kaempferi) plantation with retained hardwoods

Tree retention is understood as a key practice in creating complexity, leading to heterogeneity in resources and habitats in managed stands. In this article, we clarify the long-term effects of tree retention on stand structure and tree-species composition in a 60-year-old Larix kaempferi plantation in central Japan. In our study plot (1.5 ha) there were 18 stems/ha of retained trees (determined by tree-ring analysis), mostly Quercus crispula. We conducted spatial analyses and tested the hypothesis that tree abundance, size structure, and species composition and diversity change with distance from the retained trees. Near the retained trees, L. kaempferi showed a reduction of 40%–60% in basal area, due presumably to the shading effect. In contrast, the nearby area showed greater species diversity in the canopy layer. The retained trees created patches of different species composition in the understory. The spatial gradient of shade and colonization opportunity provided by retained trees greatly affect the distribution of the colonized species, according to their shade tolerance and seed-dispersal ability, which resulted in the stand structure with a heterogeneous shrub-layer vegetation. Retention proved particularly important for the enhancement and long-term maintenance of structural and compositional complexity in L. kaempferi plantations.     

Water use by Tabor and Kermes oaks growing in their respective habitats in the Lower Galilee region of Israel

We estimated water use by the two main oak species of the Lower Galilee region of Israel—Tabor (Quercus ithaburensis) and Kermes (Quercus calliprinos)—to develop management options for climate-change scenarios. The trees were studied in their typical phytosociological associations on different bedrock formations at two sites with the same climatic conditions. Using the heat-pulse method, sap flow velocity was measured in eight trunks (trees) of each species during a number of periods in 2001, 2002 and 2003. Hourly sap flux was integrated to daily transpiration per tree and up-scaled to transpiration at the forest canopy level. The annual courses of daytime transpiration rate were estimated using fitted functions, and annual totals were calculated. Sap flow velocity was higher in Tabor than in Kermes oak, and it was highest in the youngest xylem, declining with depth into the older xylem. Average daytime transpiration rate was 67.9 ± 4.9 l tree⁻¹ d⁻¹, or 0.95 ± 0.07 mm d⁻¹, for Tabor oak, and 22.0 ± 1.7 l tree⁻¹d⁻¹, or 0.73 ± 0.05 mm d⁻¹, for Kermes oak. Differences between the two oak species in their forest canopy transpiration rates occurred mainly between the end of April and the beginning of October. Annual daytime transpiration was estimated to be 244 mm year⁻¹ for Tabor oak and 213 mm year⁻¹ for Kermes oak. Adding nocturnal water fluxes, estimated to be 20% of the daytime transpiration, resulted in total annual transpiration of 293 and 256 mm year⁻¹ by Tabor and Kermes oaks, respectively. These amounts constituted 51% and 44%, respectively, of the 578 mm year⁻¹ average annual rainfall in the region. The two species differed in their root morphology. Tabor oak roots did not penetrate the bedrock but were concentrated along the soil–rock interface within soil pockets. In contrast, the root system of Kermes oak grew deeper via fissures and crevices in the bedrock system and achieved direct contact with the deeper bedrock layers. Despite differences between the two sites in soil–bedrock lithological properties, and differences in the woody structure, annual water use by the two forest types was fairly similar. Because stocking density of the Tabor oak forests is strongly related to bedrock characteristics, thinning as a management tool will not change partitioning of the rainfall between different soil pockets, and hence soil water availability to the trees. In contrast, thinning of Kermes oak forests is expected to raise water availability to the remaining trees.     

Estimation for the timing of the internal developmental processes of acorns from fruit size in <Emphasis Type="Italic">Quercus serrata</Emphasis> Thunb. ex Murray

To evaluate the relative importance of the factors affecting the premature abortion of acorns in Quercus serrata Thunb. ex Murray during the course of their development, inner developmental processes of acorns were observed by microscope, and applicability of the diameter of fruits (acorns with cupules) as an indicator of the inner developmental processes was discussed. Based on the observations using microscope, the developmental processes of acorns were classified into five stages; one prezygotic and four postzygotic stages (stages I to V). The diameter of sound fruits increased exponentially until 14 weeks after pollination, and the variance of diameter in each tree was fairly small (CV = 6%) during the process. Diameter of fruits can be used as a good indicator of developmental stages of acorns at individual level, and effective for the evaluation of the ecological factors affecting the premature abortion of acorns.     

Urease activity in soil as a factor affecting the succession of ammonia fungi

We studied the activity of urease in soils of Castanopsis cuspidata, Quercus serrata, and Chamaecyparis obtusa forests in western Japan to determine why succession of ammonia fungi takes place synchronously on soils treated simultaneously with the same level of urea among different vegetation types regardless of the time of year that the treatments are conducted. The activity was determined by the amount of urea remaining after urea addition and incubation on three soil layers, O, A, and B, on nine occasions. As a result, we found that the activity was significantly the highest in the O layer, that it did not differ according to vegetation type, and that it did not change through sampling occasions. The results indicate that the O layer is strongly implicated in generating favorable conditions for ammonia fungus proliferation by its overwhelming ability to decompose urea to ammonia. In soils treated simultaneously with urea, it appears that the ammonium-N concentration increases in similar patterns among different types of vegetation and at different times of the year.     

Root growth enhancement by rhizospheric aluminum treatment in Quercus serrata Thunb. seedlings

This article discusses the effect of aluminum on root growth of Querucus serrata Thunb. In a 9-week hydroponics experiment, the effects of various concentrations (0 to 5.0 mM) of Al on root growth were examined. Results revealed that root biomass increases with the increase in Al concentration up to 2.5 mM, and then it tended to decrease. In the next experiment, the effects of H⁺ and Al³⁺ on roots were compared in a 4-week hydroponics experiment using three treatment solutions: control (pH 6.0), −Al (without Al, pH 3.5), and +Al (with 2.5 mM Al, pH 3.5). No clear difference in the biomass and root length between the control and −Al treated roots was observed, and root and shoot biomass were increased by Al treatment. These results confirmed that the H⁺ concentration level, at a pH of 3.5, is not toxic for Q. serrata and the Al-induced increase in root biomass is not caused by the amelioration of H⁺ toxicity by Al. In the third experiment, roots were exposed to an Al solution (pH 3.6) intermittently. This treatment clarified that Al stimulated rooting and root elongation. In the fourth experiment, the effect of 1 mM Al on root growth during a 15-month period in a sand culture were examined. This experiment confirmed that Al stimulated good growth and development of root systems at appropriate concentrations. Therefore, it is considered that Al-induced root growth enhancement occurs as a long-term and short-term phenomenon.     

Monitoring genetic stability inQuercus serrata Thunb. somatic embryogenesis using RAPD markers

Genetic stability of propagules regeneratedvia somatic embryogenesis is of paramount importance for its application to clonal forestry. Random amplified polymorphic DNA (RAPD) markers were used to determine the genetic stability in somatic embryogenesis ofQuercus serrata Thunb. (Japanese white oak). Forty samples from an embryogenic line, consisting of regenerated plantlets, somatic embryos, and embryogenic calli, were examined using 54 decanucleotide primers. A total of 6520 clear reproducible bands obtained from these studies exhibited no aberration in RAPD banding pattern among the tested samples. Our results show that somaclonal variation is absent in our plant propagation system. The genetic stability is discussed in terms of the origin of somatic embryos.     

Detection of mycoplasmalike organisms in declining oaks by polymerase chain reaction

By polymerase chain reaction, mycoplasmalike organisms (MLOs) were detected in several declining trees of Quercus robur sampled at two locations of Germany. The MLOs associated with declining oaks were, within the 16S rDNA studied, genetically uniform and closely related to the MLOs associated with European stone fruit yellows and apple proliferation.     

Volatile composition analysis by solid-phase microextraction applied to oak wood used in cooperage (Quercus pyrenaica and Quercus petraea): effect of botanical species and toasting process

The purpose of this study was to investigate the sorption of selected volatile substances from oak wood-chip samples (Quercus pyrenaica Willd. and Quercus petraea L.) subjected to different toasting levels, namely, without toasting, with medium toasting, and with strong toasting, through the use of solid-phase microextraction (SPME). The main volatile compounds identified as a function of the toasting level and botanical species were furfural, hexanal, α-pinene, d-limonene, decanal, vitispirane, ethyl hexanoate, cis-3-methyl-γ-octalactone (“oak lactone” or “whisky lactone”), α-terpineol, p-xylene, and nonanal. Considering the data obtained from the toasted woods (medium and strong intensity) in comparison with those of nontoasted woods, it can be pointed out that the average peak area and the number of compounds identified in the gas chromatogram decreased during the toasting process. In general, regarding the compounds analyzed, quantitative differences were found between the two oak wood species under study. High values of volatile compounds were found in Quercus pyrenaica oak wood chips. In addition, for the number of compounds identified in oak wood extracts and directly extracted from solid oak wood chips by SPME, it is concluded that the best extraction process for volatile compounds from oak wood is the use of oak wood-chip liquid extracts.     

Multihydroxylation of ursolic acid by Pestalotiopsis microspora isolated from the medicinal plant Huperzia serrata

The structural modification of ursolic acid by an endophytic fungus Pestalotiopsis microspora, isolated from medicinal plant Huperzia serrata was reported for the first time. The structure diversity was very important for the SAR study of ursolic acid and its derivatives. Incubation of ursolic acid 1 with P. microspora afforded four metabolites: 3-oxo-15α, 30-dihydroxy-urs-12-en-28-oic acid (2), 3β, 15α-dihydroxy-urs-12-en-28-oic acid (3), 3β, 15α, 30- trihydroxy-urs-12-en-28-oic acid (4) and 3,4-seco-ursan-4,30-dihydroxy-12-en-3,28-dioic acid (5). All products were new compounds and their structures elucidation was mainly based on the spectroscopic data.     

Indirect effects of precipitation variation on the decomposition process of Mongolian oak (Quercus mongolica) leaf litter

The effect of precipitation variation on the chemistry of Mongolian oak (Quercus mongolica) leaf litters was examined by analyzing litters of Mongolia oak saplings under four precipitation gradients. The decomposing process of these leaf litters in the Mongolian oak dominated forest was assessed using litter bag method. Compared with the litters of the Mongolian oak saplings from the natural precipitation site (A), litters produced by Mongolian oak from the driest precipitation gradient (A₄₅₀) had significantly higher concentrations of nitrogen (N), phosphorus (P) and potassium (K) while lower acid-insoluble fraction (AIF) concentration. The decomposition study showed that A₄₅₀ exhibited significantly higher decomposition rate, mineralization rates of N, P and K as well as much shorter N and P net immobilization periods. On the contrary, litters produced by seedlings from wettest gradient (A₈₅₀) showed a totally opposite pattern. Litters from saplings that received comparable precipitation (A₆₅₀) to those at the natural site (A) had significantly higher N concentration and faster decomposition rate as well as release rates of N, P and K. The mass loss patterns for the four litter types fitted the exponential model and the decay constant (k) can be well predicted by initial AIF/N. During the decomposition period, N concentration was best related to the percentage of mass remaining of the litters with relatively higher AIF concentrations and lower N concentrations, but the percentage of mass remaining of litters with lower AIF concentrations and higher N concentrations correlates strongly with AIF con centration. Our study proved that changes in precipitation significantly altered the litter quality, and therefore indirectly changed the decay process of leaf litters. __________ Translated from Chinese Journal of Applied Ecology, 2007, 18(2): 261–266 [译自: 应用生态学报]     

Seedling survival and growth of three species of mountain cloud forest in Mexico,under different canopy treatments

The survival and growth of Quercus germana Schltdl. & Cham., Q. xalapensis Humb. & Bonpl. and Magnolia dealbata Zucc. was evaluated in three treatments: (1) under the canopy of Pinus maximinoi H.E. Moore; (2) under the canopy of Liquidambar macrophylla Oersted, and (3) in open areas. The following hypothesis was presented: P. maximinoi and L. macrophylla canopy facilitate the establishment of Quercus germana, Q. xalapensis, and Magnolia dealbata. After one year, the survival of seedlings and the growth rate in height and basal diameter were significantly different between treatments and species (p < 0.05). The results suggest a facilitation establishment of Magnolia dealbata under the canopy of Pinus and Liquidambar, whereas the tolerance was observed for Quercus germana and Q. xalapensis. The results will allow to identify restoration strategies of the mountain cloud forest in Mexico.Resumen. Se evaluó la supervivencia y crecimiento de Quercus germana, Q. xalapensis y Magnolia dealbata, en tres tratamientos; (1) bajo el dosel de Pinus maximinoi, (2) bajo el dosel de Liquidambar macrophylla y (3) en áreas abiertas. La hipótesis planteada fue; la cobertura de P. maximinoi y L. macrophylla facilitan el establecimiento de Quercus germana, Q. xalapensis y Magnolia dealbata. Después de un año, la sobrevivencia de plántulas, y las tasas de crecimiento en altura y diámetro de la base, fueron significativamente diferentes entre tratamientos y especies (p < 0.05). Los resultados sugieren que el establecimiento de Magnolia dealbata es facilitado bajo el dosel de Pinus y Liquidambar, mientras que para Quercus germana y Q. xalapensis se observó tolerancia. Los resultados permitirán identificar estrategias de rehabilitación del bosque mesófilo de montaña en México.     

Potential fecundity of the bamboo gall maker,Aiolomorphus rhopaloides (Hymenoptera: Eurytomidae), and its inquiline,Diomorus aiolomorphi (Hymenoptera: Torymidae), in relation to gall size and body size

I examined the adult potential fecundity of the bamboo gall maker,Aiolomorphus rhopaloides Walker (Hymenoptera: Eurytomidae), and its inquiline,Diomorus aiolomorphi Kamijo (Hymenoptera: Torymidae) by dissection just after emergence, and at death after rearing. Emerging females ofA. rhopaloides hadca. 80 mature eggs in their ovaries. The number of eggs at emergence and after death at rearing was not significantly different. However, emerging females ofD. aiolomorphi had no eggs in their ovaries but hadca 20 eggs at death after rearing. These results suggest thatA. rhopaloides is pro-ovigenic andD. aiolomorphi is synovigenic. Female body sizes of both species were positively correlated with the size of galls from which each emerged. Number of eggs in each species was also correlated with female body size, suggesting that gall size might be a good predictor of potential fecundity. This study was supported in part by a Grant-in-Aid for scientific Research (No. 11460068) from the Ministry of Education, Science, Sports, and Culture, Japan.     

模拟气候变暖和林内穿透雨减少对干旱年暖温带锐齿栎林土壤呼吸的影响

[目的]研究土壤呼吸对气候变暖和干旱的响应,阐明全球气候变化与土壤碳排放之间的反馈关系。[方法]采用红外辐射增温和林内穿透雨减少技术模拟气候变暖和干旱,通过LI-8100土壤CO2通量测定系统对生长季土壤呼吸速率进行观测,分析了干旱年不同处理(对照、增温+减雨、增温、减雨)对土壤呼吸速率的影响。[结果]显示:生长季,以上4种处理的土壤呼吸速率分别为1.78、1.84、2.02和2.01μmol·m~(-2)·s~(-1),5 cm土壤温度和土壤湿度分别可以解释土壤呼吸速率变异的68.2%87.5%和51.0%66.6%。干旱期,以上4种处理的土壤呼吸速率均低于生长季,增温处理降低了土壤呼吸速率与土壤温度的相关性,但增加了土壤呼吸速率与土壤湿度的相关性。[结论]干旱年内,土壤温度和湿度是影响该区土壤呼吸速率的主要环境因子,干旱期增温处理引起土壤湿度对土壤呼吸的限制作用削弱了气候变暖与土壤碳排放之间的正反馈作用。     

Recovery of canopy trees and root collar sprout growth in response to changes in the condition of the parent tree after a fire in a cool-temperate forest

The relationship between the recovery of canopy trees after fire and root collar sprout dynamics was investigated during 1998–2000 in a secondary cool-temperate broad-leaved forest consisting of Quercus mongolica var. grosseserrata and Betula platyphylla var. japonica trees, in northern Hokkaido, Japan, which burned in April 1998. All of the Betula trees that were severely damaged, two-thirds of those slightly damaged, and half of those intact in 1998, died within three growing seasons after the fire. By contrast, half of the Quercus trees that were slightly damaged and half of those severely damaged recovered their foliage, and no slightly damaged or intact trees died during the three growing seasons after the fire. Many Betula trees developed several fruiting bodies of wood-destroying fungi on their stems, irrespective of damage severity. Fungi also infected some of the surviving Quercus, although the crowns tended to recover. Although many sprouting Betula were observed in 1998, the number of sprouts declined rapidly over the study period. Multiple regression analyses showed that the survival and growth of Betula sprouts were positively influenced by the number of sprouts in 1998, damage severity in 1998, and the degree of recover or decline during the study period, and were negatively influenced by parent tree size. On the other hand, a few sprouts of Quercus remained alive. Quercus remained dominant and the dominance of Betula was rapidly reduced after the fire. However, many Betula sprouts remained alive. Stand structure will change drastically for the time being.     

Response of two oak species to extensive defoliation: Tree growth and vigor, phytochemistry, and herbivore suitability

This study was developed to experimentally determine whether the differential mortality of white oak versus black oak observed following defoliation events in the oak-dominated forests of the central hardwoods region of the eastern USA may be due to differences in carbon allocation between the two species. Black oak and white oak growing in a common garden were artificially defoliated (90%) using scissors in two consecutive years. Concurrent with the second defoliation event, herbivore performance and phytochemical characteristics were measured, followed immediately by measures of tree growth. In the dormant season following the second defoliation event, roots were sampled to assess tree vigor. Species-specific differences in foliar chemistry and herbivory were evident, regardless of defoliation. Defoliation-induced changes in above-ground biomass were evident in white oak, but not black oak. Defoliation-induced changes in foliar chemistry were more evident in black oak; these were reflected in greater differences in herbivore suitability. Herbivore consumption was correlated with depressed foliar C:N ratios and elevated foliar nitrogen. White oak root starch concentrations were markedly lower in defoliated trees, suggesting that white oak vigor is especially sensitive to resource limitations in the form of photosynthate loss. The implications of these results with respect to defoliation events and white oak mortality, as well as potential phylogenetic differences in response to severe defoliation between the red and white oak groups, are discussed.     

Production and phenology of the fruit shrub Eugenia stipitata in agroforestry systems in Costa Rica

Arazá (Eugenia stipitata), a fruit shrub originating from Western Amazonia, was evaluated growing in association with timber shade trees (Acacia mangium or Cordia alliodora) or with plantain (Musa sp.) as a potential commercial species for the tropical moist lowlands of Talamanca, Costa Rica. Height and crown width of the four-year-old shrubs varied between 2.7–2.8 m and 2.9–3.1 m, respectively. Flowering was positively correlated with initial fruit formation 1 month later and initial fruit formation with fully developed fruits a subsequent month after that. Three to four-year-old plants produced 20.0, 20.0, and 24.5 t ha⁻¹ yr⁻¹ (fresh fruits) in associations with A. mangium, C. alliodora and plantain, respectively, with higher production in rainy months. Fruit production in later years under C. alliodora (six to eight-year-old shrubs) was 26.5 t ha⁻¹ yr⁻¹. Where markets exist for E. stipitata fruit, the association can be recommended for tropical humid lowlands of Central America.