Spatial patterns of past wood exploitation,natural wood supply and growth conditions: indications of natural tree species distribution by anthracological studies of charcoal-burning remains

In close-to-nature silviculture one strives to derive the advantages of the natural adaptations of tree species to different growth conditions. Evidence of the natural distribution of tree species is obtained through vegetation science (recent ground vegetation, primeval forest relicts), studies of old written sources, and pollen and macrofossil analyses. Here we have analysed macrofossil samples of charcoal kiln sites and the recent ecological conditions in the vicinity of these sites, as well as secondary written sources on forest and land-use history. From charcoal analysis of kiln sites we were looking for spatial patterns of past tree species exploitation, with special regard to regional and local differences in the forest growth conditions and the natural wood supply. Therefore, we selected remote forest areas characterised by a high density of kiln sites and significant differences in the ecological conditions. The sample sites ranged over a landscape profile of 40 km, covering many ecological site types. The anthracological results of 181 post-medieval kiln sites were evaluated, considering two spatial scales: the total 40-km profile and a fine-scale profile of 4 km. Considering the charcoal material analysed as a whole, all of the tree taxa to be expected based on the natural conditions were found. The frequencies of the exploited taxa also reflected a natural situation. Wood of the climax vegetation, Fagus, Abies and Picea, was mainly used and all other taxa were quantitatively unimportant. The results for the individual sites showed considerable differences in taxa composition, from which regular spatial patterns of the past tree species distribution were deduced. These regional and local patterns are explained by natural differences in the ecological conditions in the vicinity of the sample sites. At the same time, new indications of the natural tree species composition of our forests are inferred. A pronounced dependency of charcoal production on the local natural wood supply is discernible. No indications of tree species selection or forest degradation could be found.     

Climatology of Acacia mearnsii. 1. Characteristics of natural sites and exotic plantations

Climatic variation in the natural distribution of Acacia mearnsii in Australia was analysed. Data from sites where the species has been successfully grown in plantations and trials in Africa, Asia and South America were used to determine the species' climatic adaptability. Annual mean temperatures at these plantations and trial sites ranged from 13.9 to 23.9°C, whilst annual mean precipitation ranged from 693 to 2263 mm. The coldest month minimum temperature at these sites was –0.6°C. This information, along with other details of climatic requirements presented in the paper, will assist in selecting sites for future trials at new locations.     

Bioclimatic analysis to assist provenance selection for trials

Eighteen bioclimatic factors were estimated for 315 locations within the natural distribution of Acacia mearnsii. These climatic data were used to classify the locations into 12 groups, which formed the basis for selecting 22 provenances. It was concluded that the method can assist in identifying environmental variability within a species' natural distribution and ensure that the range of climatic conditions are appropriately sampled.     

Influence of different forest conversion strategies on ground vegetation and tree regeneration in pine (<Emphasis Type="Italic">Pinus sylvestris</Emphasis> L.) stands: a case study in NE Germany

The conversion of anthropogenic into more natural, self-regenerating forests is one of the major objectives of forestry throughout Europe. In this study, we present investigations on permanent plots with different silvicultural treatment in NE German pine stands. Management of old-growth pine stands on acidic and nutrient-poor sandy sites differs in fencing, thinning, and planting of certain tree species. The investigations were carried out on the community, population, and individual level of the pine forest ecosystems. Thus, vegetation changes, size and height of tree populations, and height increment of tree individuals were observed over a time span of 6 years. Special attention was paid to short-lived tree species such as, e.g., Frangula alnus and Sorbus aucuparia, as well as to Fagus sylvatica as one of the most typical forest tree species of Central Europe. Vegetation changes are interpreted as a consequence of natural regeneration of formerly degraded forest sites, involving an increase in nutrient availability. High browsing pressure can be considered as a key factor for the inhibition of tree seedlings and growth of saplings. Some Sorbus aucuparia individuals, however, succeeded in growing out of the browsing height also in unfenced stands. Few found specimens of Fagus sylvatica proved that this species is able to establish spontaneously on these relatively dry, acidic sites under continental climate influence. Such natural regeneration processes, also including spontaneous rejuvenation of trees, can be integrated into silviculture as passive forest conversion management. An active management like thinning of stands, planting of trees, and fencing can accelerate forest conversion with regard to height growth and species number of trees.     

Community structure and biodiversity in plantations and natural forests of seabuckthorn in southern Ningxia, China

Two types of sampling plots of seabuckthorn (Hippophae rhamnoides) communities were investigated in Pengyang County of Ningxia region by a typical sampling method to study the characteristics of community structure and biodiversity. Composition and dominant species of each community were analyzed by the importance value of species as an index. The number of individuals and the importance value, as well as Sorensen’s similarity coefficient, Shannon-Wiener diversity index, Pielou’s evenness index and Simpson’s dominance index, were used as indices to compare characteristics of community structure, similarity and biodiversity between plantations and natural forests of seabuckthorn. The results indicate that the importance values of species of natural seabuckthorn communities were dispersed and the difference between dominant species was not statistically significant. Diversity indices of natural seabuckthorn communities reflected by species richness and evenness were higher than that of plantations. Com-munity structure of natural seabuckthorn forests is more complex. We propose that natural forest can be used as sample to guide se-lection of plant species in silviculture in order to improve biodiversity of plantation.     

云杉属树种谱系地理学研究

云杉属谱系地理学主要是研究云杉属种群遗传结构的历史动态规律,以及气候振荡和地质变迁对种群分布范围、种群间基因渐渗及遗传分化的影响。文中综述了国内外云杉属谱系地理学的研究进展,结论如下:我国西南山区和青藏高原（QTP）地区云杉属树种谱系地理学研究,验证了上新世QTP上升和第四纪冰期气候振荡对该物种进化起到推动作用,该物种在这2个时期快速分化;在云杉属争议种的研究中,通过对云杉属复合种群的群体结构展开研究,揭示了种群间的基因渐渗常存在于有较低基因流的基因组,方向通常是由本土树种向入侵树种渗透;某些种群之间的基因渐渗可有助于在一些基因位点上增加这些种群和其他种群之间的分化,导致生殖隔离的产生;云杉属天然杂种多被发现在种群的对称分布区边缘、或者其重叠分布区,杂种经过异地扩张又形成了新种,验证了云杉属网状进化的历史,并证明了生境特征决定杂交优势种的分布边界。     

Spatiotemporal density patterns of the pest predator Rhynchium haemorrhoidale (F.) along a land-use gradient in cacao agroforestry systems

Tropical insect species show year-round breeding activity due to favourable climatic conditions. However, most species also display seasonal reproductive peaks, but little is known about underlying causes of temporal density changes. We investigated population dynamics of the pest predator Rhynchium haemorrhoidale (F.) (Hymenoptera: Eumenidae) and its natural enemies in relation to season, climate and varying shade tree composition in cacao agroforestry systems in Central Sulawesi (Indonesia). Nesting of R. haemorrhoidale showed clear seasonality with highest densities in the wet season and lowest in the dry season, which was not related to changes in temperature. Wasp densities increased with land-use intensity, presumably because less-shaded areas offer more favourable climatic conditions and higher densities of the major prey, the cacao pest Agathodes caliginosalis (Lepidoptera: Pyralidae). Pupal body size was higher in June than in November indicating increasing intraspecific competition due to high wasp densities and food shortage at the beginning of the wet season. Body size between habitat types was similar, thus season appeared to be more important than habitat in terms of food supply. High wasp densities in the wet season were associated with high diversity of the altogether seven parasitoid species. In conclusion, we found a pronounced seasonality of the wasp R. haemorrhoidale and a preference for little shaded agroforestry, which may be due to enhanced temperature and density of its prey. Our data indicate a high potential for biological control of a major cacao pest by management of nesting sites of R. haemorrhoidale.     

A comparative assessment on regeneration status of indigenous woody plants in Eucalyptus grandis plantation and adjacent natural forest

Diversity, density and species composition of naturally regenerated woody plants under Eucalyptus grandis plantation and the adjacent natural forest were investigated and compared. Twenty plots, with an area of 20 m × 20 m for each, were established in both of E. grandis plantation and adjacent natural forest, independently. In each plot, species name, abundance, diameter and height were recorded. Numbers of seedling were collected in five sub-plots (4 m²) within each major plot. A total of 46 species in the plantation, and 52 species in the natural forest, which belongs to 36 families were recorded. The diversity of species (H′) is 2.19 in the plantation and 2.74 in the natural forest. The density of understory woody plant was 3842 stems/ha in the plantation and 4122 stems/ha in the natural forest. The densities of seedlings in the natural forest and the plantation were 8101 stems/ha and 4151 stems/ha, respectively. High similarity of woody species composition was found between the natural forest and the plantation. The E. grandis plantation was found favoring the regeneration and growth of Millitia ferruginia and Coffea arabica in a much better way than other underneath woody species.     

Abundance and distribution of<Emphasis Type="Italic"> Xylosandrus germanus</Emphasis> (Blandford 1894) (Coleoptera,Scolytidae) in Belgium: new observations and an attempt to outline its range

In Belgium, the current distribution and abundance of Xylosandrus germanus (Coleoptera, Scolytidae), a relatively new species to the Belgian fauna, is poorly known. Therefore, data on the range and population levels of this ambrosia beetle, on a regional and local scale respectively, are presented. Based on those results, the beetles range is discussed. Among the analysed biotic and abiotic factors that could influence the species settlement and population levels, climatic ones, and temperature in particular, seem to exert a crucial influence.     

Regeneration niches of Norway spruce (<Emphasis Type="Italic">Picea abies</Emphasis> [L.] Karst.) saplings in small canopy gaps in mixed mountain forests of the Bavarian Limestone Alps

Natural regeneration measurements are the main silvicultural objective in overaged protective forests of the Bavarian Limestone Alps. While manifold problems with these stands, especially the impact of browsing, are widely recognised, the regeneration niches of Norway spruce (Picea abies [L.] Karst.) are insufficiently known. The purpose of this study was to determine favourable combinations of site factors for the development of spruce in small, unfenced canopy gaps, located on Aposerido-Fagetum caricetosum albae forest sites. We recorded the occurrence of spruce saplings (as dependent variable) and of six site factors (as independent variables) on 480 0.5 m²-subplots. In addition, we estimated the coverage of six acid adapted plant species to determine correlations with the humus depth. A binary logistic regression analysis was used to predict the probability of the occurrence of a spruce sapling in dependency of the different site factors. Supported by other studies, we assumed that the supply of solar radiation was adequate for the sufficient regeneration of spruce within the canopy gaps. Other site factors significantly determined the regeneration niches of spruce saplings. More spruce saplings were found near hindrances and on rough surfaces than would be expected from a random occurrence of saplings. These microsite types may have characteristics, especially protection against snow gliding that promotes spruce establishment. A calculated “hindrance index”, which accounted for the number, and the distance of surrounding hindrances might be a good specific value to describe the influence of hindrances on steep slopes. The sapling establishment decreased on thin humus layers. Our assumption for the sites was that thick organic layers might represent a good seedbed for spruce. Decayed dead wood was scarce, but was exceedingly favoured by spruce saplings. Results obtained suggest that the natural regeneration establishment of spruce on steep slopes can be successfully influenced by site factors which inhibit the influence of snow gliding. According to a “positive microsite” concept, we recommend for artificial regeneration measurements with spruce, microsites close to hindrances (e.g. stumps, downed trees) and Vaccinium myrtillus as a predictor for thick, acid humus layers.     

Determining the climatic suitability of Eucalyptus dunnii for plantations in Australia,China and Central and South America

Climatic conditions within the naturaldistribution of Eucalyptus dunnii were determinedusing interpolated relationships developed forAustralia. Climatic interpolation relationships forAfrica, Central and South America and China as well asAustralia were then used to examine locations where E.dunnii has been successfully grown in trials and todetermine the species' climatic adaptability outsideits natural range. The original climatic profile wasrevised and maps were produced to show climaticallysuitable regions in Australia, China and Central andSouth America.     

Serological marking of <Emphasis Type="Italic">Pnigalio agraules</Emphasis> (Hymenoptera: Eulophidae) for field dispersal studies

The parasitoid wasp Pnigalio agraules (Wlk.) is a key natural enemy of the horsechestnut leafminer Cameraria ohridella Deschka and Dimić (Lepidoptera: Gracillariidae). As a basis for mark-release-recapture studies, aimed at investigating the dispersal of this parasitoid in the field, adults of P. agraules were marked using a vertebrate-specific immunoglobulin (IgG). The marker was later detected by double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA). The IgG was either applied externally by spraying or internally by feeding an IgG-enriched diet. Different concentrations of the marker were used and the influence of abiotic (climatic conditions, time elapsed between marking and marker examination) and biotic factors (sex and age of the parasitoids) on the detection of the immunomarker was tested. External marking by spraying led to more homogeneous labelling than feeding the marker. Parasitoids labelled with 0.25 mg rabbit IgG per ten individuals contained enough immunomarker to be easily distinguished from unmarked ones. Neither the climatic conditions nor the sex or age of the insects had an influence on the detection of the marker. The IgG remained well detectable during the entire lifespan of the parasitoids, which was not negatively affected by the marking procedure. Serological marking can be used to investigate the dispersal behaviour of beneficial insects within mark-release-recapture studies.     

Alpha and beta diversity of Lianas in Yasunı́, Ecuador

Stems of 4348 lianas from 12 subsampled 1 ha plots in Yasunı́, Ecuador represented more than 311 species of climbing woody plants. The plots (each 0.2 ha in area), which individually included up to 106 species among 314 stems, were established in the Huaorani Ethnic Reserve and Yasunı́ National Park and represent terra firme and floodplain habitats. Yasunı́ is one of the richest areas sampled for liana diversity in the neotropics. A relatively small group of species (∼38) comprise the dominants in this forest, as defined by species contributing consistently to 50% of all stems to samples from either habitat. Distance-related diversity (i.e., beta) is low across both spatially adjacent and distant plots. Floodplain habitats show a slightly higher decay of similarity with distance than either terra firme habitats or cross-habitat comparisons. Cross-habitat comparisons are significantly less similar than same-habitat comparisons at all distances. Habitat-related beta diversity probably contributes to total richness in Yasunı́ although abundant liana species in Yasunı́ rarely show absolute restriction to one habitat or the other. A comparison of these data to other sampled sites in the neotropics highlights the problems inherent in comparisons among areas sampled by different methods.     

Comparison of growth response ofAbies andPicea species to climate in Mt. Norikura, Central Japan

Tree-ring chronologies were developed fromAbies mariesii Masters andPicea jezoensis ssp.hondoensis (Mayr) P. Schmidt collected at different altitudes of Mt. Norikura, central Japan. The tree-ring parameters of ring width and maximum density were measured by soft X-ray densitometry. The measurement series were detrended by fitting a 33-year cubic smoothing spline and autoregressive model. The correlation between species and between sites showed different responses of the species to climate in terms of ring width and maximum density. The correlation coefficient between sites within a species was higher than that between species for a site in the ring width, and the coefficient between species for a site was higher in maximum density. The correlation coefficient between tree-ring chronology and monthly climate data set showed different responses of radial growth to climate. The different response was probably explained by the difference in the length of the growing season. High summer temperature increased the maximum density of the two species and the radial growth inAbies mariesii. Summer precipitation correlated negatively to maximum density, but it did not affect the ring width of either species. The climatic signals could be extracted from ring-width and maximum-density chronologies of both species.     

我国麋鹿放归野化概况及放归地适宜性评估

麋鹿在我国经过37年的繁衍、复壮及野外放归,目前麋鹿种群已全面覆盖历史分布区,分布地点从重引入时的2个增至现在的89个迁地保护场所,种群数量已逾1.2万只,其中建立6处野生种群,数量达5 258只。从重引入到成功放归野化,中国麋鹿保护已成为全球野生动物保护史上的范例。麋鹿放归野化成功的关键在于科学、合理地选择放归地,通过介绍我国麋鹿放归野化的概况,并针对放归地的适宜性开展评估,主要包括天然植被资源可利用性、天然水资源的水质和水量、疾病风险、种间竞争、人鹿冲突、捕食天敌、突发自然灾害等,为我国麋鹿放归野化标准化管理提供依据,为其他物种放归野化提供参考。     

Variation in needle longevity of Pinus tabulaeformis forests at different geographic scales

Needle longevity of conifer species is known to increase with latitude, but little is known about intraspecific variation and associated factors within a location. Chinese pine (Pinus tabulaeformis Carr.) forests were investigated to identify patterns of needle longevity at seven sites with distinctive climatic conditions along a latitudinal gradient (33-38 degrees N) in Shaanxi province, northwest China. A demographic approach was used to quantify needle longevity as an index of entire foliage population adjusted to needle-age-specific mortality rates. There were significant differences in needle longevity of Chinese pine stands across sites and across sample plots within a site. Individual tree needle longevity ranged from 0.62 to 3.75 years for 276 samples across sites. Needle longevity increased with latitude (R2 = 0.40, P < 0.0001), but decreased with mean January temperature (R2 = 0.63, P < 0.0001). Foliage retention of Chinese pine stands at the regional level was generally associated with climatic variability, indicating that variation in needle longevity was primarily an environmental acclimation to low temperature in winter. Stand characteristics were closely associated with needle longevity at three sites located within the same climatic zone. Needle longevity was positively correlated with tree age (R2 = 0.48, P < 0.0001) and stand density (R2 = 0.26, P = 0.0015) at Huanglong and Huangling, respectively, whereas it was negatively associated with total tree height at Zhidan (R2 = 0.50, P < 0.0001). It is concluded that, at the stand and individual tree level, intraspecific variation in needle longevity is most likely a result of adaptation to patchy microsite environments.     

Niche analysis and tree species introduction

A method to determine the climatic requirements of tree species is outlined and related to the concept of multidimensional niche. The Bioclimate Prediction System devised by Nix, Busby and Hutchinson is used to analyse the bioclimatic component of the ‘realized niche’ of the species. The bioclimatic component of the ‘fundamental niche’ is then estimated using data from field trials outside the natural range. The method is demonstrated using the following eucalypt species: Eucalyptus citrodora, E. cladocalyx, E. fastigata, E. globulus spp. globulus, E. gomphocephala, E. grandis, E. maculata, E. paniculata, E. regnans, E. resinifera, E. robusta, E. sideroxylon and E. tereticornis. The bioclimates of their natural distributions in Australia are compared with conditions at trial sites in Africa. The method offers an explicit procedure for describing bioclimatic requirements and should assist the selection of appropriate species for trials.     

Climatic favourability zones for Eucalyptus rust in Brazil

Brazilian forest‐based industries are supported by more than 5.5 million hectares of Eucalyptus growing under different climatic conditions with different degrees of favourability for rust Puccinia psidii, including both traditional and expanding areas, where such disease is of major concern for the industry, foresters and scientists. The main objective of this study was to define favourable climatic zones for Eucalyptus rust in Brazil with the following aims: (i) to develop a spatial method for estimating the mean night‐time temperature (T_ng); (ii) to assess and validate a Eucalyptus rust model; and (iii) to map Eucalyptus rust favourability zones in Brazil based on the proposed model. A straightforward method, based only on latitude, day of the year, maximum and minimum air temperatures, was developed to estimate T_ng, which is a key variable for a proper application of Ruiz rust model. Based on 37 field experiments with natural rust occurrence, it was observed that climatic conditions are determining factors for disease severity. Significant correlations between disease severity observed in the field and climatic conditions were found: a negative correlation with temperature (r = .50, p < .01) and a positive correlation with relative humidity (r = .89, p < .0001). A significant correlation (r = .81, p < .0001) between the normalized infection index, produced from Ruiz model, and the average rust score was also observed. Once the model was validated under field conditions, it was applied using historical average data of air temperature and leaf wetness duration to obtain monthly Eucalyptus rust favourability maps for the whole country. These final maps show that favourable climatic zones for Eucalyptus rust are extremely dynamic, with high temporal and spatial variability in Brazil and that climatic conditions should be considered for expansion of Eucalyptus to new areas, in breeding programmes, and for defining the most suitable seasons for forest establishment in each climate of the country. These results provide forestry managers with practical tools to reduce uncertainty about the expected severity of Eucalyptus rust in Brazil.     

Effects of forest structure and microhabitat on the distribution and flowering of a rare understory plant, Actaea elata

Knowing which environmental characteristics constrain forest understory species’ distribution and reproduction can inform conservation decisions about habitat management and locations for reintroduction efforts. Differential plant performance is common in varying environmental conditions, such as levels of canopy closure. Actaea elata (tall bugbane) is a rare, perennial, forest understory herb found from Oregon to British Columbia. Populations throughout this species’ range commonly occur in managed forests. We assessed the importance of environmental variation on the distribution and flowering of A. elata at both microhabitat and site-level scales. At four sites encompassing a variety of forest types, we measured several biotic and abiotic variables at vegetative and reproductive plants, as well as at random points. We measured these same variables at three sites where A. elata has been extirpated. Within occupied sites, reproductive plants were more likely to be located in canopy gaps than were vegetative plants. Both vegetative and reproductive plants were more likely to be found in areas of high herb cover compared to random points. These results indicate that gaps in the canopy may be critical for this species’ ability to reproduce, but survival may be possible in a broader range of forest understory conditions (similar to other co-occurring herb species). Random points at extirpated and occupied sites both tended to be located in areas of lower canopy openness and moisture availability than points in occupied sites where A. elata was present. Extirpated sites were either densely forested or clearcut, while occupied sites contained stands of intermediate density. Circaea alpina, Geranium robertianum, and Lactuca muralis were indicator species for A. elata and normally indicate moist soils, with Circaea alpina being a strong indicator of the presence of flowering A. elata. Taken together, our results suggest that maintenance of canopy gaps is important to promote flowering, and understory species that indicate moist sites, particularly Circaea alpina, can be used as aids to locate new populations of A. elata.