Saproxylic beetles in high stumps and residual downed wood on clear-cuts and in forest edges

Abstract

This study evaluates how the placement and the different possible outcomes of a spruce retention tree affected species richness and assemblages of spruce-associated saproxylic beetles. In a field experiment in the boreal zone of central Norway, high stumps were created and compared with residual wood pieces (i.e. top boles with branches), in clear-cuts versus in forest edges. Flight interception traps were mounted close to the substrate. The results were analysed using rarefaction techniques, ordination (DCA) and anova. It was found that the placement of retention trees of spruce does matter: beetle assemblages were significantly different in stumps in the four treatments. For all species pooled, the species richness was higher in stumps in clear-cuts than in stumps or boles in the forest edge. Four red-listed species were more abundant near stumps than boles, and two red-listed species were more abundant in clear-cuts than forest edge. To cater for the variety of habitat preferences among forest beetles in managed forest, managers should leave both standing spruce trees (many of which will end up as windthrown, downed boles) and some high stumps (to secure some upright dead wood), in both exposed clear-cut and semi-shaded forest edge.     

Distribution of red wood ants (Hymenoptera: Formicidae) in the clear-cut areas of a managed forest in Western Poland

Red wood ants (RWAs) play an important role as predators and competitors in invertebrate communities in forest ecosystems. The abundance of RWAs in managed forest clear-cut areas was investigated in 2007 in Western Poland. The ants were counted in 1 × 1 m squares along transects that led from the edge to the centre of clear-cut areas. Squares that contained RWAs were located significantly closer to the edge as compared with squares without ants. The RWA density decreased significantly from the edge to the centre of clear-cut area. The pattern of the decrease of RWAs towards the clear-cut area centre may have serious consequences for ant-sensitive invertebrates. It can be expected that species richness and species diversity of invertebrates will be affected by forest clear-cut areas, which generate ant-free conditions.     

Assimilateentzug und Zuwachsminderung an Forstpflanzen durch Baumläuse (Lachnidae) unter dem Einfluß von Waldameisen (Formicidae)

Zusammenfassung An 245 Kiefern (Pinus silvestris L., 40j?hrig) wurde durch Zuwachsmessungen der Einflu? einer erh?hten Saugt?tigkeit von Bauml?usen (Lachnidae) unter dem Einflu? von hügelbauenden Waldameisen (Formica rufa-Gruppe) untersucht. Als Ma? für die Verlausung der B?ume diente ihre Entfernung von zwei 1958 künstlich angesiedelten Ameisennestern (Formica polyctena F?rst.). W?hrend in der „ameisenfreien” Periode (1949–1958) die Zuwachswerte in allen drei Entfernungsstufen (1–20 m, 21–40 m, über 40 m) ann?hernd gleich verliefen, zeigte sich in den zehn Jahren mit Ameiseneinflu? (1959–1968) eine deutliche Staffelung. Gegenüber den weiter entfernten B?umen (über 40 m) zeigte sich im engeren Nestbereich (1–20 m) eine Minderung um 9% (p<0,05) beim H?henzuwachs und 16% beim Radialzuwachs. Da diese Zuwachseinbu?en nur kleinfl?chig vorkommen, fallen sie forstlich und waldbaulich nicht ins Gewicht.

---

Deprivation of assimilates and losses in increment of forest trees caused by lachnids (Lachnidae) associated with wood ants (Formicidae)

Summary Height and radial increments of 245 pines (Pinus silvestris L., 40 years old), deprived of assimilates by lachnids (Lachnidae) tended by red wood ants (Formica rufa-group) was measured. The degree of infestation by the lachnids was inferred from the distance of the trees from two ant nests (Formica polyctena F?rst.) founded artificially in 1958. During ten years without the presence of ants (1949–1958), increment growth was approximately the same at all distances from the ant nests. From 1959–1968, however, distinct differencies occurred. Compared to trees more than 40 m from the nests, pines within 20 m showed losses of 9% (p<0.05) in height increment and 16% in radial increment. However, since these losses occur only over small areas, they can be considered silviculturally and economically insignificant.

     

Cohabitation of tree holes by ants and breeding birds in a temperate deciduous forest

A previously unknown association of ants with birds breeding in tree holes is described. Ants Lasius brunneus Latreille (Hymenoptera: Formicidae) were found in c. 15% of nests of Parus major L. and Poecile palustris L. (Paridae) breeding in tree holes in the primeval deciduous forest located in the Bia?owie?a National Park (Poland). The ants preferably used holes located higher above the ground. As such holes are warmer than the unused holes or other nest sites, it is suggested that the ants cohabit holes utilized by the tits to gain thermal benefits.     

Growth rate of mosses and their environmental determinants in subalpine coniferous forests and clear-cuts at the eastern edge of the Qinghai-Tibetan Plateau, China

Mosses cover most of the forest floor of subalpine forests at the eastern edge of the Qinghai-Tibetan Plateau, the origin of many important rivers in China. They play a crucial role in preventing soil erosion and conserving large amounts of water thereby regulating the water budget of local ecosystems. This area has a harsh climate due to low temperatures and low air pressure at high elevations. But the temperature varies considerably during the growing season, which does not favor the regeneration of spruce seedlings on clear-cuts after logging. Leaves of mosses have a single layer of cells and are thus sensitive to environmental changes. This attribute may be useful for monitoring environmental conditions and guide artificial regeneration. The growth of mosses has never been studied in this area and the variables indicating their growth in the subalpine forest ecosystems still needs investigation. Growth rates of mosses have been rarely studied worldwide because the methods are time consuming and often inaccurate. A more simple and accurate method for measuring moss growth would help and encourage relevant research. We have found a method that will promote the efficiency in field measurements. Because of the special growth properties of mosses, the apical cell of branches initiates growth and the preceding leaves will stay where they were as the tips grow. Once mosses are marked with red oil at the tip of branches surrounded by young leaves, that portion of the branch above the marked leaves represents growth after labeling. Two plots, one in an old-growth spruce forest and another in a nearby clear-cut, were selected to label mosses in a subalpine area of western Sichuan Province during the growing season in 2001. The labeling was done on May 7 and measurements were made on August 7. Microclimate measurements on both sites were simultaneously carried out. Of the six mosses, five species were present in both the forest and on the clear-cut. One species, Entodon conncinus, was found only on the clear-cut. The growth rates of mosses varied among species and habitats. Hylocomium splendens grew the fastest while Dicranum assamicum had the slowest growth rate. Habitat conditions have a distinct effect on the growth of Hylocomium splendens, Dicranum assamicum and Thuidium lepidoziaceum and their growth rates were higher in forests than on clear-cuts. The growth rates of these mosses increased as their habitat approached the forest. Actinothuidium hookeri and Rhytidiadelphus triquetrus have moderate growth rates and is almost entirely independent of the type of habitat. The mosses can therefore be classified into habitat-sensitive and habitat-insensitive types. Analysis of microclimate characteristics shows that from May to July, the solar radiation level is lower and the environment is drier in the forest than those on the clear-cut. But a vapor pressure deficit (VPD) regime shows that the VPD in the morning is almost always lower in the forest than that on the clear-cut. With lower radiation and VPD, forests are more favorable to moss growth. For habitat-insensitive species, favorable micro-topographic factors might have offset the effect of habitat type. VPD is strongly correlated with the growth of mosses. Eco-physiological characteristics, such as poikilohydry, play an important role in the survival and growth of mosses under harsh climatic conditions. Temperature and humidity are two factors critical for seedling establishment in artificial regeneration processes in the subalpine areas of western Sichuan. Since the growth of mosses is a function of the two factors, moss growth rates can be used to indicate the more favorable habitats. Therefore, the status of moss growth can be used to indicate habitats potentially favorable to the growth of tree seedlings. __________ Translated from Journal of Plant Ecology, 2007, 31(3): 464–469 [译自: 植物生态学报]     

Untersuchungen zur forstlichen Bedeutung der holzzerstörenden Robameisen unter Verwendung der Tracer-Methode

Summary Carpenter ants (GenusCamponotus) are well known as wood destroying insects in north- and southeuropean forests. As was demonstrated in a north-bavarian forest (340 mtrs. about sealevel) carpenter ants can cause important damage in Central Europe too. Whereas single stems with carpenter ants are spread over whole the forest area we found a high percentage of infestated stems in sunny and warm margin zones. The ants prefer in this region Norway Spruce, but settle also in Pines and occasionally in oaks, beeches and birchs. The forest damage was caused byC. herculeanus L. which is living more arboricol thanC. ligniperda Latr.Basing on the high tendency to regurgitations in the feeding behaviour of ants, the tracermethod (J¹³¹ in honey-water-solution) was used to determine exactly the nest area ofCamponotus-colonies. These experiments demonstrated the nesting-area of a single colony covering several stems and beeing much more wider than can be supposed by external visible damage.     

Retention of aspen (Populus tremulae) at final cuttings - The effect of dead wood characteristics on saproxylic beetles

To preserve biodiversity in managed forest landscapes dead and living trees are retained at final cuttings. In the present study we evaluated the effect of these practices for saproxylic (wood-dependent) beetles inhabiting dead aspen trees (Populus tremulae). For saproxylic beetles, tree retention at final cuttings can be expected to be especially valuable for species adapted to sun-exposed dead wood, a substrate that only rarely occurs in well managed forest stands. Therefore, the current evaluation was conducted as a comparison of species richness, species density (number of species per sample), assemblage composition and occurrence of individual species between clear-cuts, where aspen trees were retained, and closed forest stands with aspen trees. The study was conducted in central Sweden and the beetles were sampled by sieving of bark from CWD (coarse woody debris) of aspen. There was no significant difference in rarefied species richness between forest and clear-cut sites. Species composition differed significantly between the two stand types. Generalized linear mixed-effects models predicted the species density to be 34% lower in CWD objects in forest sites than on clear-cuts. This pattern could partly be explained by differences in CWD diameter, decay class and bark types between the two stand types (clear-cut/forest). Stand type was a significant predictor of occurrence in individual CWD objects for 30% of analysed individual beetle species. For all species except one, the variable stand type predicted higher occurrence on clear-cuts than in forest stands. To conclude, our results demonstrate that retention of aspen on clear-cuts contributes to population recruitment of a different assemblage of species than CWD within stands.     

Effects of management on coarse woody debris volume and composition in boreal forests in northern Sweden

Forest management practices have led to a reduction in the volume and a change in the composition of coarse woody debris (CWD) in many forest types. This study compared CWD volume and composition in reserves and two types of managed forest in the central boreal zone of Sweden. Ten areas were surveyed, each containing clear-cut, mature managed and old-growth stands, to determine the volume of standing and lying CWD in terms of species composition, decay class and size class. Volumes of CWD on clear-cuts and in mature managed forests were high compared with previous studies. Old-growth forests (72.6 m³ ha^?1) contained a greater volume of CWD than mature managed forests (23.3 m³ ha^?1) and clear-cuts (13.6 m³ ha^?1). Differences were greatest for the larger size classes and intermediate decay stages. Despite stand ages being up to 144 years, CWD volume and composition in managed forests was more similar to clear-cuts than to old-growth forests.     

The effect of red wood ant (<Emphasis Type="Italic">Formica rufa</Emphasis> group) mounds on root biomass,density, and nutrient concentrations in boreal managed forests

Red wood ants (Formica rufa group, RWAs) are common insects in boreal forests in Fennoscandia, and they build large, long-lived mounds as their nests. RWA mounds are enriched with carbon and nutrients, but little information is available about how they affect root distribution and the nutrient uptake of trees. In this study, we investigated the biomass, biomass density, nutrient concentrations, and amounts of fine (<2 mm) and coarse (>2 mm) roots in RWA mounds, and compared them with those of surrounding forest soil in mixed coniferous stands of different age classes in Finland. Neither fine nor coarse root biomasses differed significantly between the aboveground parts of the mounds and the organic layer of the soil. Root biomass density was lower in mounds than in the organic layer. However, fine root biomass and biomass density were higher in the belowground parts of mounds than in the surrounding mineral soil. Macroelement (N, Ca, K, P, S, Mg) and Zn and Cu concentrations in roots in the mounds were significantly higher than those in the organic layer. Root biomass and biomass density did not differ between stands of different age classes. The results of this study indicate that RWA mounds increase heterogeneity in root distribution in forest ecosystems, and also increase the availability of nutrients for plants that extend their roots inside RWA mounds.     

Ant abundance increases with clearing size

Ants are an important part of biodiversity and are useful bioindicators. Our aim was to determine whether ant species richness and composition differ among large clear-cuts (ca. 3000 m²), small forest gaps (ca. 400 m²), and areas of mature forest. The research was conducted in a large plantation of Picea abies in the Jizerske Mountains in the Czech Republic at an elevation of ca. 900 m a.s.l. Ants were sampled using pitfall traps in three areas, each of which had a large clear-cut, mature forest, and gaps; a randomized complete block design was used. Species richness and composition of ant assemblages differed significantly among plots in the three treatments. The results showed that ant abundance and diversity were similarly low in small gaps and in closed-canopy mature stands; in comparison, large clear-cuts supported significantly higher species richness, more complex species composition, and a higher abundance of ants. Six species were found in large clear-cuts, but only one and two species were collected in small gaps and mature forests, respectively. Our findings suggest that small-scale forest management is not suitable for maintaining ant diversity.     

A comparison of biodiversity values in boreal forest regeneration areas before and after forest certification

Abstract

In this study, 236 regeneration areas (mostly clear-cuts) in southern Norway were selected by random stratified selection: 118 of the study units were cut before and 118 after the introduction of forest certification in 1998. The degree of compliance with biodiversity measures established in the prevailing certification standard (ISO 14001 and the Norwegian standard “Living Forests”) was compared in a field study, and the differences were analysed. In some aspects, a clear difference could be seen, most clearly in an increasing number of green retention trees and an increasing mean width of buffer-strips left along rivers, bogs and lakes in the postcertification units compared with the precertification units. Even though there was a significant increase in the mean number of retention trees, as much as 21% of the postcertification regeneration areas still did not have sufficient retention trees to comply with the certification standard and 41% had either too few retention trees or too few spruce trees according to the standard. Concerning the management of small swamp forests, and the damage done to terrain and prelogging coarse dead wood by off-road transport, little improvement was seen. The discussion examines whether it is probable that the changes seen are a result of forest certification in Norway.     

Surface temperature change of spruce forest as a result of bark beetle attack: remote sensing and GIS approach

In the 1990s, a bark beetle (Ips typographus [L.]) infection caused the decay of spruce forest (Picea abies [L.] Karst.) in the central part of the Šumava Mountains, the Czech Republic, bordering the Bavarian Forest National Park, Germany, where the bark beetle infection started in the late 1980s. Some areas were left without human intervention and, consequently, the trees around these areas were removed to stop further bark beetle outbreak. The objective of our study was the assessment of surface temperature (ST) change in spruce forest decayed under bark beetle and following clear-cutting. The change detection of ST is based on the comparison of modelled values and thermal satellite data. For this purpose, Landsat scenes from July 11th, 1987 and July 28th, 2002 were used. The models describe the dependence of ST of living spruce forest on topography. The topography effect is based on the Altitude and Hillshade index, which expresses the influence of Aspect and Slope on the relief illumination. Then the modelled ST values were extrapolated for decayed spruce forest and clear-cut areas. In order to increase model accuracy, the forest edge zones (90 m wide) were removed because of their different energy balance; then explained variability value (R ²) increased from 0.37 to 0.55. The results of comparing modelled values with satellite ST in the decayed spruce forest and clear-cut areas show an average increase of ST by 5.2 and 3.5°C, respectively. The thermal satellite data from 1987 were used for model validation. This showed that the accuracy of ST modelling using topography was sufficient, because the difference between the modelled ST with and without decayed spruce forest and clear-cut areas was at most only 0.4°C.     

Short-term effects of retention felling at mire sites on boreal spiders and carabid beetles

Green-tree retention is an integral part of forest management in the boreal zone. Retention of small spruce mires, proposed as ‘key habitats’ for many forest organisms, is recommended while logging, but the efficiency of such practices for the maintenance of forest species is poorly understood. Hence, we studied boreal spiders and carabid beetles at 11 retained mire patches (up to 0.55 ha) in Eastern Finland during 1998–2001. The adjacent surrounding drier forests of the focal mires were clear-cut during the winter of 1998/1999. We evaluated the importance of micro-habitat type (retention, edge or clear-cut plot), time since logging, and retention-patch size in determining the assemblages of spiders and carabids. Following logging, species associated with forests and mires generally decreased both in the retained mire patches and in their adjacent clear-cuts. In a GLMM, the number of standing trees in a retention patch – a surrogate for retention-patch size – had no significant effect on most of the tested species, but plot type (retention patch, its edge or clear-cut) was significant for many species. Semi-open-habitat species and open-habitat specialists increased following logging, especially in the clear-cut plots but even within the retention patches. In contrast, mature-forest and moist-habitat specialists became significantly less abundant in clear-cuts than in retention patches following logging. Spider assemblages showed pre-harvest differences among the mires, their edges and adjacent drier forests, but the fauna of logged plots rapidly diverged from that of mire and edge plots. However, after a 1–2 summers time lag, the spider fauna of mires and edges changed toward clear-cuts. For spiders, the post-harvest sample heterogeneity was significantly lower in clear-cuts than in retention patches, including their edges. Carabid responses were generally ambiguous. Multivariate regression trees showed that the number of trees in a forest patch better determined the spider assemblage structure than study area, study year or micro-site type (retention patch, its edge or clear-cut), indicating a strong impact of logging. For carabids, however, the study area better determined the assemblage structure; the other factors were of minor importance. Our results suggest that, as the spider and carabid faunas of the retention patches had drastically changed following logging, (i) retention patches should be considerably larger than the studied size range to efficiently maintain a ‘mire core’ spider and carabid assemblage; (ii) the effect of logging may take years to appear; (iii) spiders were more sensitive to habitat change than carabids; and (iv) harvesting not only changes the relative abundances of forest- and open-habitat associated species but it may also locally decrease the faunal variation.     

松阿扁叶蜂天敌—富氏凹头蚁的初步研究

松阿扁叶蜂(Acantholyda posticalis Matsumura)危害樟子松、油松和红松针叶,危害严重时造成整株整片松树死亡。世界各国都十分重视对松阿扁叶蜂的防治,化学防治资料较多,生物防治仅在少数文献中提到。1987年,笔者等在黑龙江讷河县宽余林场,首次发现富氏凹头蚁(Formica fukaii Wheeler)捕食松阿扁叶蜂。通过三年的观察,该蚁捕食量大,性情凶猛,是很有利用价值的松阿扁叶蜂天敌。通过对其形态、习性的研究,并人工助迁、定植后,表明控制松扁叶蜂的能力明显。现将结果报道如下。     

塞罕坝林业功能分区及经营措施探讨

以2012年塞罕坝二类森林资源调查数据为基底,结合塞罕坝地形地貌特征等自然条件和森林经营传统等方面因素,划分为自然保护区、森林公园景观林区、生态防护林区和商品用材林区4个林业功能区,并分析了各区的森林资源现状与特点,有针对性地提出了保护区人工林天然化、景观林多层次多树种改造、防护林控制皆伐性采伐、用材林市场化经营的管理思路。     

The forest vegetation and its differentiation under disturbance in a temperate mountain, China

Composition and structure of the main forest types, as well as the species changes under disturbance, were described as the representation of the forest vegetation in the north slope of Changbai mountain, northeast China. There were 3 forest zones from 600 m to 2,000 m asl, (1) broad-leaved-conifer mixed forest zone, 600–1,100 m asl, dominated byPinus koraiensis, Tilia amurensis, Acer mono, Ulmus japonica, (2) coniferous forest zone, 1,100–1,700 m asl, dominated byPicea jezoensis var.komarovii, P. koraiensis, Abies nephrolepis, and (3)Betula ermanii forest zone, 1,700–2,000 m asl, dominated byBetula ermanii, except for the east slope which was occupied byLarix olgensis. The evergreen component increased with elevation up to the upper limit of the coniferous forest zone (1,700 m), but disappeared in theB. ermanii zone. Species richness was significantly related to elevation. Towards higher elevation, the lapse rate of species-number was 1.6 species per 100 m, and it was only one species near the timberline. Species richness was reduced sharply under intensive disturbance, such as clear cutting, windfalletc. The species diversity was very low in the early stage of succession, and high in the later.     

Cost-benefit analysis of wood and food components of agri-silviculture in Nigerian forest zone

Costs and revenue of agri-silviculture in Nigerian forest zone were estimated. Two crop combinations were considered: Gmelina arborea Roxb., a hardwood species was interplanted with (a) yam (Dioscorea rotundata) and maize (Zea mais) and (b) cassava (Manihot utilissima) and maize. Agri-silviculture increases the farmer's income in this zone. The ratios of total cost to revenue are 1:2.3 for yam and maize and 1:2.4 for cassava and maize. The farmer's net income is U.S. $4065.86 from yam and maize and U.S. $2790.24 from cassava and maize. When the trees are clear-cut after five years, the ratio of cost to revenue is 1:2.4. The farmer's net income from wood is U.S. $2872.95. If 5 per cent of the farm families in the area practices agri-silviculture, each family cultivating one hectare, there will be enough fuelwood after five years' growth.     

Recovery of boreal forest structures near abandoned villages in Western White Sea Karelia,Russia

Regeneration of natural forest structures and dead wood has a key role in the long-term maintenance of biodiversity in most parts of the boreal zone. In order to obtain benchmarks for practical dead wood management rapidly, we utilised unintended historical experiments in land use by studying the recovery of forests surrounding abandoned villages along 2.5-km transects in NW Russia. The signs of past human forest use declined as a function of distance from villages. We found that the closest forests were 130 yr old or younger and contained very few elements typical of natural forests. Forests at a distance of between 1 and 1.5 km were older than 150 yr but showed marks of selective cuttings and had a less complete continuum of dead wood than forests that were 2–2.5 km from the villages. The most remote stands, which were generally older than 200 yr, predominantly had no signs of past forest use and had the most diverse dead wood composition. Our study shows that full recovery of the dead wood continuum in middle boreal forests is a slow process and also that less intensive past forest use can have a significant effect on the dead wood continuum.     

Application of an expert knowledge system in the study of forest spatial patterns

For the sake of exploring how the pattern of Chinese pine （Pinus massoniana Lamb） community changed after the invasion of the pine wood nematode （Bursaphelenchus xylophilus （Steiner ＆ Buhrer） Niclde） in Zhoushan, Zhejiang Province, we established a test area in the local Chinese pine community. Landsat5 TM images from 1991 and 2006 were integrated with auxiliary data from field investigation and spectral data as additional sources of information. A method of expert knowledge classifier was applied to establish the expert knowledge dataset of the main vegetation cover types from which we obtained a forest type distribution map. The spatial patterns and stability of the forest, before and after the invasion of the pine wood nematode, were analyzed in terms of community patterns. The results indicated that the predominant coniferous forest type changed to a mixed forest. As a result, the forest structure became complex and the interaction between coniferous forest patches became weakened over the period from 1991 to 2006. Therefore, the resistance of the forest eco-system to plant diseases and insect pests and the stability of forest eco-system enhanced.     

Role of topography, canopy structure, and floristics in nest-site selection and nesting success of canopy songbirds

Although oaks (Quercus spp.) have historically dominated many forests in eastern North America, forest composition is changing due to anthropogenic impacts on disturbance regimes. Silvicultural practices, such as partial harvesting, are one component of management to promote oak regeneration. From 2007 to 2009 our research examined nest-site selection and nesting success for a guild of five canopy songbirds in upland mixed-oak forests in southeastern Ohio, USA. We monitored >700 nests across three state forests in both open canopy shelterwood stands harvested to approximately 50% stocking, and closed-canopy mature second-growth. Habitat attributes, including topography, canopy structure, and floristics, were measured at nest sites and random plots ?100 m from nests representing microhabitat available within the territory. Canopy songbirds selected specific topographic microclimates: Eastern Wood-pewees (Contopus virens) nested on xeric ridgetops, Blue-gray Gnatcachers (Polioptila caerulea) favored valleys, and Cerulean Warblers (Dendroica cerulea) preferred productive northeast-facing slopes. Nest sites differed among species in terms of concealment, nest support, topographic position on the slope, and basal area of trees >38 cm dbh. Four of the five focal species selected Quercus alba as the nest substrate more than twice as much as available, and three species avoided Quercus rubra. Daily survival rates of nests were negatively associated with basal area of red oak species (both Quercus velutina and Q. rubra) for several species individually and across the canopy-nesting guild. Additional factors related to success included time of season for Eastern Wood-pewees, nest age for Cerulean Warblers, and concealment and size of the support branch for Scarlet Tanagers (Piranga olivacea). In the long-term management for oak regeneration could benefit canopy songbirds, but our results indicate that white oaks, especially Q. alba, may be preferable to red oak species.