Long-term re-use of tree roosts by European forest bats

The few studies that have assessed the long-term patterns of re-use of tree cavities by bats all concern North American bats. We studied long-term re-use of tree cavities by two species of European bat, Daubenton's bats (Myotis daubentonii) and noctules (Nyctalus noctula). Cavities were inspected during consecutive years via direct capture of bats (more than 340 positive capture events, ca 2950 captured bats), observations of emerging bats, or by listening for bats during the early evening when bats emit typical vocalization (over 160 positive checks, over 450 observed bats). Between 1968 and 2007, we found 80 tree cavities used by bats (mostly excavated by woodpeckers) in the Czech Republic. Although more than half of the cavities were occupied for ≤4 summers, 28 cavities (35%) were re-used for 5–10 years. The longest period a cavity was used was 11 and 16 years for Daubenton's and noctule bats, respectively. Sixteen tree cavities (20%) were occupied solely by Daubenton's bats and 33 cavities (41%) were occupied only by noctules. The other 31 cavities (39%) were used by both species, either at separate times or simultaneously. Our data suggest that the larger volume of a cavity, the longer duration of re-use and the greater the probability of being occupied by both species. Continuous excavation of cavities by woodpeckers prevented the overgrowth of old cavities by calluses, which keep cavities accessible to bats. We suggest that woodpeckers may be the most important providers of suitable roosts for forest bats in Central Europe. Roosts were found in both economically valuable trees (Quercus robur and Tilia cordata) and less valuable tree species (Salix fragilis and Alnus glutinuosa). Economically valuable trees in our study area were long-lived and likely provide roosting habitat for longer periods but matured at a greater age. However, less economically valuable trees reached maturity and started to decay in a relatively short time, which may provide suitable cavities at a younger age. Maintaining both types of trees within forests may help provide suitable roosting oportunities for tree-dwelling bats in the Czech Republic.     

Use of modified water sources by bats in a managed pine landscape

In eastern North Carolina, USA, intensively managed pine (Pinus spp.) forests, a primary forest type in the Southeastern United States, often are established where water levels are maintained via ditching. In these landscapes, water occurs in numerous linear ditches and several small ponds (heliponds), used by helicopters for the suppression of forest fires. Changes to the physical structure of water sources may be important to bats that use these sources for drinking and foraging. Therefore, we examined bat activity in a managed pine landscape and an adjacent natural wetland in relation to water source type (heliponds, ditches, and natural wetland) and insect abundance. We sampled bat activity using remote acoustic detectors; we sampled insects using passive traps. Insect abundance did not differ among water source types. Bat activity was most concentrated at modified water sources within the managed pine landscape (heliponds and ditches). Feeding activity was highest at heliponds. Heliponds and ditches were important sources of open water and insect prey for bats in the managed pine forest landscape. We suggest management for bats in similar forest landscapes should include maintenance of open and accessible water sources such as heliponds.     

Collembola communities and soil conditions in forest plantations established in an intensively managed agricultural area

The challenges of a changing climate have directed greater attention to afforestation,but the effects of afforestation on soil fertility and soil biota have not been fully clarified.To explore changes in the soil conditions in two 20-year-old forest plantations established in formerly intensively fertilized plots of agricultural land,we focused on the current developmental state of the sites that received the most fertilizer and evaluated soil properties and Collembola(springtails) communities.Sessile oak(Quercus petraea) and black locust(Robinia pseudoacacia) that had been planted in the afforestation sites were assessed for differences between plantations of native and invasive species.Five adjacent reference associations,including forests and open habitats,were also analyzed and compared.Results showed that the soils in the two afforested sites were similar in their properties and Collembola communities to those of the control cultivated forests,but differed from each other in pH,calcium,phosphorus,and ammonium content.The available potassium and phosphorus contents in the soil of the sessile oak plantation were still high,while the soil organic matter content was adequate(SOM 2.0%) in both plantations.Species richness of Collembola ranged from 18 in the cultivated arable land to 43 in the relict forest.Only a few species typical for forests(e.g.,Neanura muscorum,Isotomiella minor,Entomobrya muscorum) were detected in the young plantations,while species characteristic of open habitats(e.g.,Protaphorura campata,Lepidocyrtus cyaneus) occurred as well.Although more individuals and species of Collembola were present in the soil of young plantations than in arable fields,their community diversities were significantly lower compared to the control forest stands.Collembola community diversity differed significantly also between the two plantation types(with native and non-native tree species).Mean abundance in the afforested sites was about 2.5 times higher than in the cultivated arable land,yet far lower than the mean abundance in the control forests.     

Effects of mass inoculation on induced oleoresin response in intensively managed loblolly pine

Oleoresin flow is an important factor in the resistance of pines to attack by southern pine beetle, Dendroctonus frontalis Zimm., and its associated fungi. Abiotic factors, such as nutrient supply and water relations, have the potential to modify this plant-insect-fungus interaction; however, little is known of the effects of inoculation with beetle-associated fungi on oleoresin flow. We observed that constitutive and induced resin yield in loblolly pine, Pinus taeda L., were affected by either fungal inoculation (with the southern pine beetle-associated fungus Ophiostoma minus (Hedgcock) H. & P. Sydow) or silvicultural treatment. The effects of mass wounding (400 wounds m(-2)) and mass wounding and inoculation with O. minus were assessed by comparison with untreated (control) trees. The treatments were applied to trees in a 2 x 2 factorial combination of fertilizer and irrigation treatments. Fertilization did not significantly affect constitutive resin yield. Even as long as 105 days post-treatment, however, mass-inoculated trees produced higher induced resin yields than control or wounded-only trees, indicating a localized induced response to fungal inoculation. We noted no systemic induction of host defenses against fungal colonization. Although beetles attacking previously attacked trees face a greater resinous response from their host than beetles attacking trees that had not been previously attacked, the effect of an earlier attack may not last more than one flight season. Despite mass inoculations, O. minus did not kill the host trees, suggesting that this fungus is not a virulent plant pathogen.     

Selection of roosting habitat by forest bats in a diverse forested landscape

Many studies of roost selection by forest-dwelling bats have concentrated on microhabitat surrounding roosts without providing forest stand-level preferences of bats; thus, those studies have provided only part of the information needed by managers. We evaluated diurnal summer roost selection by the bat community at the forest-stand level in a diversely forested landscape in the Ouachita Mountains of central Arkansas. Over a 6-year period, we evaluated 428 roost locations for 162 individual bats of 6 species. Using Euclidean distance analysis and individual bat as the experimental unit, all 6 species were selective (P < 0.05) in their choice of roosting habitat. Five of six species preferred (P < 0.05) to roost in or near mature (≥50 years old), mixed pine-hardwood forest that had undergone recent partial harvest, midstory removal, and burning; 41.3% of roosts were located in that habitat but it comprised an average of only 22.8% of available habitat. Five of six species also preferred older (≥100 years old), relatively unmanaged, mixed pine-hardwood forest. Although 19.9% of roosts from all species were located in 50- to 99-year-old, second-growth forests of mixed pine-hardwood (average of 21.0% of available habitat), that habitat was preferred by no species of bat. In partially harvested stands, unharvested buffer strips (greenbelts) surrounding ephemeral streams were used at differing levels by each species; most (90%) eastern pipistrelle (Pipistrellus subflavus) roosts were in greenbelts whereas few (2.7%) Seminole bat (Lasiurus seminolus) roosts were in greenbelts. Older forests, thinned mature forests with reduced midstories, and greenbelts retained in harvested areas were all important roosting habitats for the bat community in the Ouachita Mountains. Our results demonstrate the importance of open forest conditions and a diversity of stand types to bat communities of the southeastern U.S.     

Spatial distribution of the fruiting bodies of Agaricales in a Japanese red pine (Pinus densiflora) forest

To examine the effect of the spatial distribution of litter and intergeneric interaction on the spatial distribution of agaric fruiting bodies, we surveyed spatial distribution of fruiting bodies of Agaricales in a mixed forest dominated by Pinus densiflora (Sieb et Zucc.) from July 1999 to July 2002. Three 10 × 10-m plots with different vegetation and positions on a slope were established: Top-Mixed, Top-Pinus, and Bottom-Pinus. Litter thickness in the Top-Mixed plot was the thinnest among the three plots. During the study, we counted 3563 fruiting bodies in 27 genera from 13 families. The dominant genera were Collybia, Marasmius, Mycena, Rhodophyllus, and Lactarius, and showed an intrageneric aggregated distribution at a quadrat size of 1 m². Collybia and Lactarius formed fruiting bodies in arcs. The spatial distribution of Collybia, Marasmius, and Lactarius fruiting bodies tended to overlap in two consecutive years. In the Top-Mixed plot, the number of Marasmius fruiting bodies increased with increasing litter thickness, while that of Lactarius decreased with litter thickness. Values of C′_δ indicating degree of overlap were calculated for particular pairs of dominant fungal genera and the values differed between plots and years: for example, fruiting bodies of Marasmius and Mycena in the Bottom-Pinus plot were distributed aggregately in 1999 and 2000, but randomly in 2001, while they were distributed segregatedly in the Top-Pinus plot every year. Our study suggests that the spatial distribution of fungal fruiting bodies is affected by the distribution of litter in and between plots and that fungal flora is affected by vegetation.     

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.     

Comparison of organic matter dynamics in soil between Japanese cedar (Cryptomeria japonica) forest and adjacent Japanese red pine (Pinus densiflora) forest established on flatland

In order to clarify the effects of tree species on organic matter dynamics in soil, we investigated the amount of forest floor material, leaf litter decomposition rate, soil chemical characteristics, soil respiration rate and cellulose decomposition rate in a Japanese cedar forest (cedar plot) and an adjacent Japanese red pine forest (pine plot) established on a flatland. The amount of forest floor material in the cedar plot was 34.5 Mg ha⁻¹ which was greater than that in the pine plot. Because the leaf litter decomposition rate was higher in the pine plot than in the cedar plot, it is likely that the difference in the amount of forest floor material between the plots is caused by the difference in the leaf litter decomposition rate. The C concentrations of soil in the cedar plot were 1.2–2.1 times higher than those in the pine plot. Soil pH(H₂O)s in the cedar plot were significantly higher than those in the pine plot. The soil respiration rates and the rates of mineralized C in the cedar plot byin vitro incubation were higher than those in the pine plot. From this result, it is assumed that soil organic matter in the cedar plot was decomposed relatively faster compared with the pine plot. Furthermore, microbial activities, which were reflected as cellulose decomposition rates in the cedar plot, were higher than those in the pine plot. A part of this paper was presented at the 109th Annual Meeting of the Japanese Forestry Society (1998).     

Response of ground beetles (Coleoptera: Carabidae) to forest gaps formed by a typhoon in a red pine forest at Gwangneung Forest,Republic of Korea

In Korea, damaging typhoons related to climate change have increased steadily since the 1990s. Red pine (Pinus densiflora) forests in Gwangneung Forest were greatly disturbed by typhoon Kompasu in 2010. A survey was carried out to clarify differences in ground beetle (Coleoptera: Carabidae) communities between forest gaps and undamaged forests. Ground beetles were sampled using pitfall traps from early May to late October 2011. Vegetation changes, litter layer, organic matter layer, and soil conditions were also measured. A total of 1035 ground beetles of 32 species were collected. Contrary to our expectation, species richness, abundance, and community structure of the ground beetles in forest gaps were similar to those in undamaged forests. Species richness and abundance of habitat type were also similar. However, species diversity and estimated species richness in forest gaps were significantly higher than in undamaged forests. These findings suggest that forest gaps formed by a typhoon did not lead to great change in ground beetle communities.     

Comparison of potential non-timber forest products in intensively managed young stands and mature/old-growth forests in south-central British Columbia

Development of understory vegetation has been influenced by the many densely stocked second-growth forest stands in North America, which have an extended stem exclusion successional stage. Understory composition and structure is important for ecosystem functioning, while also having social and economic value through the harvest of certain herb and shrub species. The potential for co-management of young and mature, managed and unmanaged stands for timber and non-timber forest products (NTFPs) was assessed in two separate replicated experiments. Experiment A examined pole-sized lodgepole pine (Pinus contorta) stands that had been pre-commercially thinned (PCT) to target densities of 250, 500, 1000, and 2000 stems/ha. Half of each of these four thinning units was repeatedly fertilized, resulting in eight experimental units. Experiment B examined six different stand types: young plantations, pole-sized lodgepole pine stands either PCT, PCT plus repeated fertilization, or unthinned, mature, and old growth. Fifty-four herb and shrub species were identified as potential NTFPs, with the responses of individual species, as well as mean total herb, shrub, berry-producing and overall total NTFPs being assessed. In Experiment A, mean total abundance (crown volume index) of NTFPs, as well as mean total herb NTFPs were significantly greater in fertilized than in unfertilized stands. Thinning treatments did not significantly affect NTFP volume, however, fertilization treatments produced five significant responses by individual species (Achillea millefolium, Epilobium angustifolium, Taraxacum officinale, Arctostaphylos uva-ursi, Rubus idaeus). In Experiment B, four of the six species responses that were significant had greater abundance in young, managed stands (young plantation, thinned, or thinned-fertilized) than in the unmanaged stands. Mean total NTFP volume and mean total herb NTFP volume also followed this pattern. A. uva-ursi, E. angustifolium, Lonicera involucrata, Sorbus sitchensis and Thalictrum occidentale all had significantly higher abundance in young, managed stands than in all other treatments. Results suggest that co-management for timber and NTFPs is possible in this ecosystem, with further research needed to evaluate livelihood values of these crops.     

Characterizing structural conditions in mature managed red pine: Spatial dependency of metrics and adequacy of plot size

Restoration of the range of forest types and stages that once composed the landscape mosaic of the Upper Great Lakes region of North America will involve manipulating managed red pine stands to recreate now rare structural conditions. Because many of the attributes used to characterize structural condition depend upon spatial arrangement, sampling schemes to assess condition must match sampling extent to attribute variability. To evaluate the metrics and scales appropriate for characterizing structural complexity in managed red pine, we applied metrics that incorporated one-, two-, and three-dimensional structural attributes to eight 1.0 ha mature stem-mapped stands. Most metrics were also calculated within simulated moving windows of 0.05–1.0 ha in sampling extent (“plot size”) within each stand. Two standards were used to evaluate the adequacy of plot sizes for these metrics: (1) estimates were precise, varying less than 10% among moving windows for a given scale, and (2) estimates were accurate to within 10% of the 1.0 ha value at both the 5th and 95th percentiles of the moving window distributions. Necessary sample sizes to achieve precise and accurate estimates were also calculated for each scale.     

Modelling soil carbon sequestration of intensively monitored forest plots in Europe by three different approaches

Information on soil carbon sequestration and its interaction with nitrogen availability is rather limited, since soil processes account for the most significant unknowns in the C and N cycles. In this paper we compare three completely different approaches to calculate carbon sequestration in forest soils. The first approach is the limit-value concept, in which the soil carbon accumulation is estimated by multiplying the annual litter fall with the recalcitrant fraction of the decomposing plant litter, which depends on the nitrogen and calcium content in the litter. The second approach is the N-balance method, where carbon sequestration is calculated from the nitrogen retention in the soil multiplied with the present soil C/N ratio in organic layer and mineral topsoil. The third approach is the dynamic SMART2 model in combination with an empirical approach to assess litter fall inputs. The comparison is done by first validating the methods at three chronosequences with measured C pools, two in Denmark and one in Sweden, and then application on 192 intensive monitoring plots located in the Northern and Western part of Europe. Considering all three chronosequences, the N-balance method was generally most in accordance with the C pool measurements, although the SMART2 model was also quite consistent with the measurements at two chronosequences. The limit-value approach generally overestimated the soil carbon sequestration. At the intensive monitoring plots, the limit-value concept calculated the highest carbon sequestration, ranging from 160 to 978 kg ha⁻¹ year⁻¹, followed by the N-balance method which ranged from 0 to 535 kg ha⁻¹ year⁻¹. With SMART2 we calculated the lowest carbon sequestration from −30 to 254 kg ha⁻¹ year⁻¹. All the three approaches found lower carbon sequestration at a latitude from 60 to 70° compared to latitudes from 40 to 50 and from 50 to 60. Considering the validation of the three approaches, the range in results from both the N-balance method and SMART2 model seems most appropriate.     

A comparison of the medieval and the current fire regimes in managed pine forests of Catalonia (NE Spain)

We compared the fire regimes in Mediterranean pine forests during two periods, 1370–1466 and 1966–1996 A.D. Medieval fire regime was estimated from the ‘claveria’ books of the Tortosa city, which record the city expenditures, including those for fighting fires that were burning in the city forest. We used the amount spent as an estimate of fire magnitude. Current fire regime was estimated for the same area from the local environment agency data bank, which includes date, location and burned area. The mean number of recorded fires per year, which mostly occurred in summer, is not significantly different between the two periods. Time-since-fire distributions of both periods fitted the negative exponential model, and they were not significantly different. The probability of fire occurring within 1-year interval was 0.44 for the 1379–1466 period and 0.46 for the 1966–1996 period. In both cases, small fires were more abundant, although there are some differences in the medieval series, 13% of all documented fires accounted for 47% of the suppression effort, whereas in the 20th century series, one single fire accounted for 88% of the area burned. Analysis of extreme fire also indicates that in the medieval series the largest fire per year needed one or less days of suppression effort in 58% of the years, whereas in the current period, fires were smaller than 1 ha in 78% of the years. We found that fire suppression in the Middle Ages was associated with forest exploitation. Although we cannot compare the two data sets accurately, there is not evidence of differences in fire frequency between the medieval and the current periods. Differences in fire magnitude distributions of both series of records may be explained by the different purposes and technical resources involved in the fire suppression practices.     

Songbird response to experimental retention harvesting in red pine (Pinus resinosa) forests

Traditional harvesting practices frequently result in simplification of the structure and composition within managed forest stands in comparison to their natural counterparts. In particular, loss of heterogeneity within stands may pose a problem for maintaining biodiversity in perpetuity. In this study, we survey breeding bird diversity and abundance in response to different spatial harvesting patterns in mature red pine forests located on the Chippewa National Forest of northern Minnesota, USA. Treatments are designed to increase structural complexity over time and include three overstory manipulations (dispersed retention, aggregate retention with small gaps, and aggregate retention with large gaps), one understory manipulation (brush removal), and controls (no harvesting, and/or no brush removal). In 2003, the first breeding season following the harvest, we found little difference in bird community composition between control and treatment stands. In 2005, the third breeding season following harvest, avian abundance, richness, and diversity were all greater within treatments. Species associated with edge, shrub, and early successional habitats generally show positive response to treatments (e.g. Chestnut-sided Warbler [Dendroica pensylvanica], Mourning Warbler [Oporornis philadelphia], Chipping Sparrow [Spizella passerine]), as do some species associated with mature forest (e.g., Pine Warbler [Dendroica pinus], Rose-breasted Grosbeak [Pheucticus ludovicianus]). Ovenbirds (Seiurus aurocapilla) and Black-throated Green Warblers (Dendroica virens) were more abundant in control stands. There are, as of yet, no discernable differences in avian community composition among the three overstory treatments or between the single understory treatment and the understory control, but differences are expected as the treatments diversify due to understory development. While overstory retention harvests provide habitat for a diverse and abundant bird community, the temporal divergence in avian community composition that we observed between treatment and control stands reveals the importance of uncut, mature red pine forest as a component of a biodiverse landscape.     

湖南省马尾松毛虫灾害与松林林分状况的关系

马尾松毛虫灾害与松林林分状况关系密切,松阔混交林、国外松占40%以上松林和植被覆盖度达90%以上的松林一般不发生松毛虫灾害。松林蓄积量越大,松毛虫发生面积越小。     

Soil nitrogen mineralization at various levels of canopy cover in red pine (Pinus resinosa) plantations

The objective of this study was to determine the rate of nitrogen (N) mineralization in response to various levels of canopy cover in red pine (Pinus resinosa Ait.) stands. Experimental plots consisted of various levels of canopy cover,i.e., clearcut, 25% (50% during first sampling year), 75%, and uncut in red pine plantations in northern Lower Michigan, USA. Net N mineralization and nitrification in the top 15 cm of mineral soil were examined during the first two growing seasons (1991–1992) following the canopy cover manipulations, using anin situ buried bag technique. Mean net N mineralization over the course of both growing seasons (May–October) ranged from 26.9 kg ha⁻¹ per growing season in the clearcut treatment to 13.4 kg ha⁻¹ per growing season in the uncut stand. Net N mineralization and nitrification increased significantly in the clearcut treatment compared to the uncut treatment during the second growing season only. However, net N mineralization and nitrification did not differ significantly between the partial canopy cover treatments and the uncut stand. Increased N mineralization and nitrification in the clearcut during the second growing season may be associated with increased soil temperature and changes of organic matter quality with time since canopy removal. This study was supported in part by the USDA Forest Service and Michigan Technological University.     

Relationships between seasonal appearance and longevity of fruitbodies of Agaricales and meteorological factors in a Japanese red pine forest

We investigated the seasonal appearance and longevity of fruitbodies of Agaricales in a mixed forest dominated by Pinus densiflora (Sieb et. Zucc.) for about 3 years. A total of 3563 fruitbodies in 27 genera from 13 families appeared; Collybia, Marasmius, Mycena, Rhodophyllus, and Lactarius were dominant. The seasonal trend of appearance of fruitbodies differed among genera. There were no significant relationships between any factors of temperature and the number of fruitbodies in any of the dominant genera or Amanita. The number of fruitbodies of Mycena and Lactarius increased with the indices of precipitation. The longevity of fruitbodies ranged from 2.6 days in Mycena to 71.9 days in Lactarius. The longevity in Collybia and Mycena, which appeared in early summer, increased as the highest daily temperature became higher. On the other hand, that of Marasmius, Amanita, Rhodophyllus, and Lactarius, which appeared in autumn, increased as the lowest daily temperature became lower. The longevity of fruitbodies in every genus surveyed except Amanita decreased as the frequency of precipitation increased. It is possible that the rate of deterioration is higher in June–July than in September–December, and the longevity of fruitbodies might vary with the temperature. On the other hand, precipitation would facilitate the appearance of fruitbodies and shorten their longevity in Mycena and Lactarius.