Stem Breakage Research Articles

Canopy stay-green and yield in non-stressed sunflower

Delayed leaf senescence during the grain filling phase, or stay green (SG), may be functional or cosmetic; the first being considered a valuable trait in breeding of many crop species. To establish whether canopy senescence patterns exhibited by two sunflower ( Helianthus annuus L.) hybrids visually selected for slow post-anthesis canopy leaf area index (LAI) loss reflected functional, rather than cosmetic, SG, LAI dynamics and total biomass increase between anthesis and physiological maturity were followed in three separate experiments in which the putative SG hybrids were compared with standard (i.e., non stay green, NSG) hybrids exhibiting normal rates of canopy senescence under non- or minimal-water stress conditions. In two experiments, pairwise (i.e., one SG vs. one NSG) comparisons were made at two crop population densities. In the third experiment, grown at a single crop population density, four NSG hybrids were contrasted with the two SG hybrids. Canopy senescence dynamics were well described by fitted bilinear functions which discriminated between an initial, slow phase of leaf area loss and a second phase of rapid canopy senescence. No differences between hybrids in the rate of senescence during the first phase were found, but the putative SG hybrids exhibited a significantly slower rate of senescence during the second phase and a significantly higher LAI at physiological maturity (as % of LAI at anthesis). One NSG hybrid showed a greater rate of second-phase senescence than the remaining three hybrids in this category. Across experiments, the anthesis-physiological maturity increment in total oil-corrected biomass and radiation use efficiency (RUE) were significantly greater in the SG hybrids. Cluster analysis based on these four attributes, using data from Exp. 3, clearly discriminated between SG and NSG hybrids. Examination of specific leaf N (SLN) dynamics suggests that the lower RUE values observed in one of the NSG hybrids could be attributable to lower SLN values, but this was not the case for the remaining NSG hybrids. It is also possible that very rapid canopy LAI loss in another NSG hybrid may underlie its lower RUE. The failure of SG hybrids to translate greater post-anthesis biomass increment into grain yield across experiments was associated with their slightly shorter times to anthesis and their significantly lower biomass at anthesis. Grain number, the component of yield most strongly associated with yield, was associated with biomass at anthesis. A further contributing factor was that the duration of grain-filling tended to be shorter in SG hybrids. In the one experiment in which this variable was measured, resistance to stalk breakage was greater in the SG hybrids than the NSG one to which they were compared. We conclude that the SG observed in the hybrids with slower canopy senescence is functional and not cosmetic, and that for this to be translated into a yield advantage all hybrids need to reach anthesis at the same time and grain-filling duration also has to be the same across hybrids. Stay green is an interesting secondary trait to select for and should lead to higher and more stable yields in environments in which stem breakage (lodging) is a problem.

Impacts of moose (Alces alces) browsing on paper birch (Betula papyrifera) morphology and potential timber quality

Although moose browsing effects on the growth and morphology of birch are well studied, effects of moose browsing on potential timber quality of birch have received little attention. Here, an assessment was made of the impacts of moose (Alces alces L.) damage to Paper Birch (Betula papyrifera Marsh.) trees from a 20-year old clear cut area in a sub-boreal spruce forest within the Aleza Lake Research Forest, near Prince George, British Columbia, Canada. Specifically, differences in overall tree architecture and in the internal characteristics of trees that had been severely damaged and suppressed by moose winter browsing were compared to birch trees that had not been damaged by moose in this way and were considered free-to-grow. The average stem diameter, number of annular growth rings, and height of stem breaks made by moose on suppressed birches at the point of breakage was 17.9 ± 6.6 mm, 4.6 ± 1.2, and 141.8 ± 32.0 cm, respectively. Stem diameters and the heights above-the-ground of stem breaks made by moose during sequential breakage events were not significantly different (all p ≥ 0.05) from one another. Decay was significantly (all p ≤ 0.001) more extensive in trees where branches had been broken off by moose than in trees with no breaks or where breaks were from unknown agents. Suppressed birches were significantly (p = 0.048) more exposed (farther from their nearest tree neighbor) when compared to birches that were free-to-grow. The distance from birch trees to species-specific neighbors (of any species) did not differ (all p ≥ 0.05) between suppressed and free-to-grow birches. Suppressed birches damaged from intense browsing and stem breakage were significantly (≤ 0.001) farther away from other birches showing signs of slight to moderate browsing than free-to-grow birches were from similar conspecifics. Because moose appear to impact the potential wood quality of birch, forest managers should consider the impacts that browsing and stem breakage can have on birch timber where these trees co-occur with and are eaten by moose.

Combined occurrence of wind, snow loading and soil frost with implications for risks to forestry in Finland under the current and changing climatic conditions

This work focuses on the combined occurrence of wind, snow loading and soil frost with implications for risks to forestry in Finland under the current and changing climatic conditions. For this purpose, we employ meteorological datasets, available for the period of 1971–2009 and global climate model (GCM) simulations for the current climate 1971–2000, and periods 2046–65 and 2081–2100 applying the A1B-climate change scenario. Based on our results, the wind and snow induced risks to Finnish forests are projected to increase in the future although the change in the occurrence of strong winds is small. This is because soil frost depths that support tree anchorage from late autumn to early spring in Finland are projected to nearly disappear in the southern and central parts of the country. Heavy snow loads > 30 kg m are becoming more common in southern and eastern Finland despite that the average cumulative 5-day snow loads decrease in these areas by 18 to 50%, respectively. As a result of the changes in the combined occurrence of wind, snow loading and soil frost, the risk of climatic conditions making conifers liable to uprooting are projected to increase in southern, central and eastern Finland. In the north, the risk of stem breakage is becoming more pronounced under snow loading > 20 kg m. Despite some uncertainties related to this work, we assume that the findings can serve as valuable support for the risk assessment of wind and snow induced damages to Finnish forests and for forestry, in general.–2–2

The tree mortality regime in temperate old-growth coniferous forests: the role of physical damage

Aspects of the tree mortality regime were characterized for old-growth conifer forests in Mount Rainier National Park, Washington, USA, using individual tree (stems ≥5 cm diameter at breast height (dbh)) records from a network of permanent forest research plots. Average annual forest-wide mortality rates of trees ≥15 cm dbh never exceeded 1% on a stem-density or basal-area basis; mortality was slightly higher for stems <15 cm dbh. Physical agents of mortality (uprooting, stem breakage, and crushing by falling debris) accounted for approximately 40% and 45% of mortality events in trees <15 and ≥15 cm dbh, respectively. These physical processes were chronic sources of mortality: they were not associated with a single or few disturbance events. Preexisting decay fungi were associated with trees that died proximately due to stem breakage (41%) and uprooting (22%), consistent with a predisposing role of decay fungi in trees that die due to mechanical damage. Given the importance of physical processes in the tree mortality regime, we suggest that a richer mechanistic understanding of the causes and consequences of tree mortality in natural forests will be achieved with models that consider the physical, as well as the physiological, attributes of trees and forests.

Mechanical resistance of wheat to stem breakage in the late growth period considering mineral nitrogen and organic fertilisation

In a long-term field trial IOSDV at Jable near Ljubljana (SLO) the impact of mechanical resistance of wheat stem to breakage and its dependency of N fertilisation rate and organic fertilisation were examined. The investigation was undertaken at the beginning of the waxy growth stage (EC 81/82). Results confirmed that organic fertilisation has a moderate impact on the N-content (mg N g−1 DM) in wheat stem and on the bending moment (M) at stem breakage. The mechanical resistance of wheat stem to break was the strongest (M ≈ 0.1 Nm) at low mineral N fertilisation (65 kg ha−1), while at the variants without mineral N fertilisation, bending moment was the lowest (M ≈ 0.02–0.03 Nm). N-content in the stem increased exponentially to the highest N fertilisation step (195 kg ha−1), however there is not enough evidence to show that concentration of N in stem significantly effected bending moment at stem breakage.

Reconstruction of Near-Surface Tornado Wind Fields from Forest Damage

Abstract Tornado intensity is usually inferred from the damage produced. To foster postevent tornado intensity assessments, the authors present a model to reconstruct near-surface wind fields from forest damage patterns. By comparing the structure of observed and simulated damage patterns, essential parameters to describe a tornado near-surface wind field are derived, such as the ratio Gmax between circular and translational velocity, and the deflection angle α between peak wind and pressure gradient. The model consists of a wind field module following the Letzmann analytical tornado model and a tree module based on the mechanistic HWIND tree model to assess tree breakage. Using this method, the velocity components of the near-surface wind field, the track of the tornado center, and the spatial distribution of the Fujita scale along and across the damage path can be assessed. Necessary requirements to apply the model are knowledge of the tornado translation speed (e.g., from radar observations) and a detailed analysis of the forest damage patterns. One of the key findings of this analysis is that the maximum intensity of the tornado is determinable with an uncertainty of only (Gmax + 1) times the variability of the usually well-known tornado translation speed. Further, if Letzmann’s model is applied and the translation speed of the tornado is known, the detailed tree model is unnecessary and could be replaced by an average critical velocity for stem breakage υcrit independent of the tree species. Under this framework, the F3 and F2 ratings of the tornadoes in Milosovice, Czech Republic, on 30 May 2001 and Castellcir, Spain, on 18 October 2006, respectively, could be verified. For the Milosovice event, the uncertainty in peak intensity was only ±6.0 m s−1. Additional information about the structure of the near-surface wind field in the tornado and several secondary vortices was also gained. Further, this model allows for distinguishing downburst damage patterns from those of tornadoes.

Impact of ice-snow damage on nutrient distribution of a Cunninghamia lanceolata woodland

During January to February in 2008, severe ice-snows occurred on 2.09 × 106 km2 of south China and caused tremendous damage to the forests. Stem damage and crown debris input from the ice-snow in a Cunninghamia lanceolata stand in northern Guangdong Province, China, were investigated to determine the extent of ice-snow damage to trees and the nutrient distribution characteristics on woodland. Icicles were produced on branches and leaves of the C. lanceolata trees by sleets, resulting in all live trees were damaged by stem breakage. A strong positive correlation was found between the broken position of trees and diameter at breast height (DBH). Nutrient concentrations varied according to components of crown debris. Total nutrient concentration graded in the following order: leaves > stembark > branches > stemwood. Crown debris input from ice-snows was 19.11 t·ha−2, and branches, stemwood, leaves and stembark accounted for 37%, 28%, 27% and 8%, respectively. Nutrient distributions between components of crown debris differed drastically in 2008. The contribution of leaves to total nutrient accumulation of crown debris was 70%, whereas branches, stemwood and stembark contributed 13%, 7% and 10%, respectively. Accumulations of N, P and K by the woodland were 105 067.9 t·ha−2 in 2008, and the nutrients of crown debris, litter and the stand soil accounted for 0.18%, 0.03% and 99.79%, respectively. The order of nutrient accumulation in leaves, branches, stembark, stemwood of crown debris and litter was N>K>P, but the nutrients stored in the soil were in the order of K > N > P. The N and P concentrations of litter in 2009 were greater than those in 2008, whereas its K concentration was smaller than that of the latter. N and P concentrations of stemwood and stembark in 2009 were slightly greater than those in 2009, whereas their K concentration was smaller than the latter. The N and P accumulations of stemwood and stembark of crown debris in 2009 were close to those in 2008, whereas their K accumulation was slightly smaller than the latter. The N, P and K accumulations of litter in 2009 was greater than those in 2008.

Vertical stratification and effects of crown damage on maximum tree height in mixed conifer–broadleaf forests of Yakushima Island, southern Japan

We investigated vertical stratification and effects of crown damage on maximum tree height in two mixed conifer–broadleaf forests in Yakushima Island, southern Japan. In both research plots, the conifer trees dominated the upper canopy while the broadleaved trees dominated the middle to lower canopy. Most broadleaved trees were shorter than the median crown-base height (H CB) of the conifer trees. Estimates of the maximum height (H max) of the conifer trees were greater than those of the broadleaved trees. Crown damage had significant negative effects on maximum height of the conifer trees. Crown damage was observed for 72.8–88.7% of the conifer trees, and severe types of damage such as stem breakage and top die-back were the most predominant. The H max of the damaged conifer trees was 16–17% shorter than that of the intact trees and as much as 16–28% shorter than the potential maximum height estimated from the diameter–height relationship of the tallest intact trees. We inferred that crown disturbance is an important factor determining the maximum height of the canopy of the two mixed forests. Our results suggested that vertical stratification between conifer and broadleaved trees may be an important mechanism contributing to their coexistence and additive basal area of mixed forests on Yakushima Island.

Genetic variation for susceptibility to storm-induced stem breakage in Solidago altissima: The role of stem height and morphology

While storms can have obvious ecological impacts on plants, plants’ potential to respond evolutionarily to selection for increased resistance to storm damage has received little study. We took advantage of a thunderstorm with strong wind and hail to examine genetic variation for resistance to stem breakage in the herbaceous perennial Solidago altissima. The storm broke the apex of nearly 10% of 1883 marked ramets in a common-garden plot containing 26 genets of S. altissima. Plant genets varied 20-fold in resistance to breakage. Stem height was strongly correlated with resistance to breakage, with taller stems being significantly more susceptible. A stem’s growth form (erect versus nodding) had no detectable effect on its resistance to breakage. Therefore, we rejected the hypothesis that a function of the nodding, or “candy-cane,” morphology is protection of the apex from storm damage. The significant genetic variation in S. altissima for stem breakage suggests that this plant has the capacity to respond to selection imposed by storms – particularly through changes in mean stem height. Tradeoffs between breakage resistance and competition for light and pollinators may act to maintain a large amount of genetic variation in stem height.

Retrograde Genocephalic Removal of Fractured or Immovable Femoral Stems in Revision Hip Surgery

Revision arthroplasty for femoral stem breakage can be challenging. We report a new method for the removal of the distal stem segment performed in 6 cases between 2004 and 2008. After extracting the proximal part of the femoral component, the femoral canal was opened at the knee joint and a modified intramedullary nail was used to dislodge the distal stem under fluoroscopic control. In five cases the surgery was uneventful. In one case femoral perforation occurred due to the contour of the cement mantle at the tip of the stem. In the postoperative period all patients progessed well. Removal of a broken stem using our method has limited indications, and it is not recommended in septic cases or when the cement mantle at the tip of the stem has an oblique contour. It also requires opening of the knee joint, but the technique is simple, saves surgical time and in selected cases it does not weaken the femur.

Snag degradation pathways of four North American boreal tree species

Many studies have highlighted the importance of deadwood, whether standing (snags) or fallen, in boreal ecosystems dynamics. However, a dearth of literature exists regarding the persistence and degradation pathways of these structures in northeastern American boreal species.Degradation pathways were examined in four tree species of the eastern boreal mixedwood and conifer forests of Canada: Trembling aspen (Populus tremuloides Michx.), balsam fir (Abies balsamea (L.) Mill.), jack pine (Pinus banksiana Lamb.) and black spruce (Picea mariana (Mill.) BSP). Sampling was conducted in unharvested forests of northwestern Québec. Discs where collected on 363 snags and logs and dendrochronological analyses conducted to determine year of death by crossdating.Survival curves were constructed for each species and degradation pathways were documented based on the shape of the relationship, lag time if applicable (time period from death to fall onset) and half-life (time required for half the stems to fall).Most species survival curves exhibited a reverse sigmoid function. Trembling aspen, jack pine and to a lesser extent balsam fir presented significant lag times before initiation of a period with high fall rates. Black spruce experienced more snag losses during the first years following death. Jack pine was clearly the most persistent species due to snags high resistance to fall and stem breakage. Within the range of tree diameters in our study area, diameter per se did not significantly influence fall probability. Differential degradation pathways of the four species translate individualistic responses that are related to species autecology. This has important implications for all ecological functions related to deadwood and should be considered when planning retention strategies of legacy trees in an ecosystem management perspective.

Spatial distribution of dead wood and the occurrence of five saproxylic fungi in old-growth timberline spruce forests in northern Finland

Adequate understanding of the factors that determine the establishment and survival of dead-wood-dependent species in natural forests is a prerequisite to the successful maintenance of these species in managed forests. This study investigated the factors affecting the occurrence of five wood-inhabiting polypores in old-growth timberline spruce forests in northern Finland, including the substrate availability and the spatial arrangement of large-diameter logs. The volume of coarse woody debris (CWD) varied significantly between the sites (range 15–30 m3 ha−1), large-diameter logs comprising on average 35% of the total CWD volume. However, the within-site variation in CWD volume was 10–15 times larger than the between-site variation. The spatial distribution of large-diameter logs was aggregated or initially aggregated on four sites and random on one site, creating local patches of high CWD volume. An individual target species occurred on average on 8% of all large-diameter logs, and on 11% of optimal logs (as determined by the decay stage). The characteristics of the logs and stand variables explained partly the occurrence of the target species; furthermore, the mortality pattern of trees (stem breakage versus uprooting) and the presence of primary decomposers also significantly affected the occurrence of the target species. The results indicate that besides substrate availability and quality, local habitat factors and species interactions also play a role in the occurrence of wood-inhabiting fungi in boreal timberline forests.

Clinical experience of novel interconnected porous hydroxyapatite ceramics for the revision of tumor prosthesis: a case report

BackgroundAs for being cautious with tumor prostheses, revision of uncemented tumor prostheses in particular, it is necessary to remove cortical bone from the stem circumference with a chisel when the stem is extracted. This assures that bone in-growth will occur within the stem in itself. As a result, re-substitution of mass autogenous bone graft round a new stem is subsequently necessary. When rivision of uncemented tumor prosthesis of distal femur was performed, we evade fibula transplant by transplanting interconnected porous hydroxyapatite ceramic (IP-CA: Neobone) with a self bone, and reports its experience with the case that acquired enough strength.Case reportIn this report, we present the case of a 27-year-old female with stem breakage of tumor prosthesis and do revision surgery for prosthetic failure. In the case of revision surgery, autologous bone and Neobone were mixed, and this was transplanted to stem circumference. The Radiological Evaluation System of the ISOLS showed excellent results for all items. She can walk without using a cane or orthosis, and the score of the MSTS is 80%.ConclusionWhen revision of uncemented tumor prostheses of the distal femur was performed, we avoided fibula graft by using Neobone with the patient's own bone tissue. Our experience with this case may indicate that adequate strength is achieved.

Crown structure and wood properties: Influence on tree sway and response to high winds

Wind can alter plant growth and cause extensive, irreversible damage in forested areas. To better understand how to mitigate the effects of wind action, we investigated the sensitivity of tree aerodynamic behavior to the material and geometrical factors characterizing the aerial system. The mechanical response of a 35-yr-old maritime pine (Pinus pinaster, Pinaceae) submitted to static and dynamic wind loads is simulated with a finite element model. The branching structure is represented in three dimensions. Factor effects are evaluated using a fractional experimental design. Results show that material properties play only a limited role in tree dynamics. In contrast, small morphological variations can produce extreme behaviors such as either very little or nearly critical dissipation of stem oscillations. Slender trees are shown to be relatively more vulnerable to stem breakage than uprooting. Dynamic loading leads to deflections and forces up to 20% higher near the base of the tree than those calculated for a static loading of similar magnitude. Effects of branch geometry on dynamic amplification are substantial yet not linear. The flexibility of the aerial system is found to be critical to reducing the resistance to the airflow and thus to minimizing the risk of failure.

What was behind the bark? – An assessment of decay among urban <em>Tilia</em>, <em>Betula</em> and <em>Acer</em> trees felled as hazardous in the Helsinki City area

Old trees growing in urban environments are often felled due to symptoms of mechanical defects that could be hazardous to people and property. The decisions concerning these removals are justified by risk assessments carried out by tree care professionals. The major motivation for this study was to determine the most common profiles of potential hazard characteristics for the three most common urban tree genera in Helsinki City: Tilia, Betula and Acer, and in this way improve management practices and protection of old amenity trees. For this research, material from approximately 250 urban trees was collected in cooperation with the City of Helsinki Public Works Department during 2001 2004. From the total number of trees sampled, approximately 70% were defined as hazardous. The tree species had characteristic features as potential hazard profiles. For Tilia trees, hollowed heartwood with low fungal activity and advanced decay caused by Ganoderma lipsiense were the two most common profiles. In Betula spp., the primary reason for tree removal was usually lowered amenity value in terms of decline of the crown. Internal cracks, most often due to weak fork formation, were common causes of potential failure in Acer spp. Decay caused by Rigidoporus populinus often increased the risk of stem breakage in these Acer trees. Of the decay fungi observed, G. lipsiense was most often the reason for the increased risk of stem collapse. Other fungi that also caused extensive decay were R. populinus, Inonotus obliquus, Kretzschmaria deusta and Phellinus igniarius. The most common decay fungi in terms of incidence were Pholiota spp., but decay caused by these species did not have a high potential for causing stem breakage, because it rarely extended to the cambium. The various evaluations used in the study suggested contradictions in felling decisions based on trees displaying different stages of decay. For protection of old urban trees, it is crucial to develop monitoring methods so that tree care professionals could better analyse the rate of decay progression towards the sapwood and separate those trees with decreasing amounts of sound wood from those with decay that is restricted to the heartwood area.

Treatment of stem fractures in tumor prostheses by connecting different systems with a special adapter / Behandlung von Schaftfrakturen bei Tumorprothesen durch Kopplung verschiedener Prothesensysteme mit einem speziellen Adapter

In long-term survivors, oncologic surgeons are regularly faced with the problem of revising stem breakage of first generation Kotz modular femoral and tibial reconstruction system (KMFTR) prostheses. To avoid a whole prosthesis-exchange, we invented an adapter which allows connecting original KMFTR devices to new modular universal tumor and revision system (MUTARS) components. The adapter was used in 10 patients after a mean time span of 16.6 years after primary implantation of KMFTR prostheses. Reasons for revision included femoral stem breakage in five cases, breakage of tibial component in three cases and periprosthetic fracture in two cases (one femoral, one tibial). The femoral stem (three cases), the tibial stem (two cases) or the tibial plateau and body (two cases) were exchanged to MUTARS and connected to the remaining KMFTR parts. Three cases were converted to a total femur. Postoperative complications included one cone-dislocation and one aseptic loosening. In all patients, the pre-incidence function could be restored. The mean Musculoskeletal Tumor Society score was 81.7% of normal function. The presented adapter enables restoration of the long-term extremity function with relatively minor revision.

Finite element analysis of the effect of proximal interlocking on primary fixation of the Intra-Medullary Cruciate stem

Background.The primary fixation of cementless hip prostheses is related to the shape of the stem. When there is a complication of loading in the rotational direction, the mechanical fixation of a hip stem is considered to provide good primary fixation. The purpose of this study was to evaluate whether the Intra-Medullary Cruciate stem with a characteristic fixation method, which was developed by a group at Kitasato University, contributes to primary fixation by finite element analysis. Methods.Analysis was performed at a friction coefficient of 0.1 with automatic contact, under the restriction of the distal femoral end. The following three loading conditions were applied: (1) step loading of the joint resultant force in the region around the hip stem; (2) loading in the rotational direction, simulating torsion; and (3) loading of the femoral head equivalent to that during walking. Displacement of an Intra-Medullary Cruciate stem and a reference stem along the x-, y-, and z-axes and rotational direction was calculated by simulation, and the stress distributed on the stem and femur was determined. Results.Relative displacement along the z-axis of distal parts, which is a clinical problem with hip prosthesis stems, was lower for the Intra-Medullary Cruciate stem than for the reference stem. Displacement of the stem along the z-axis direction was low, indicating a low risk of sinking. The interlocking mechanism, which is a characteristic of the Intra-Medullary Cruciate stem, functioned to suppress its displacement, indicating that the locking method of this stem contributed to its stability. Because no stress concentration was detected in certain regions, it was thought that there are no risks of breakage of the Intra-Medullary Cruciate stem and femur. Conclusions.It was suggested that effective fixation of the Intra-Medullary Cruciate stem can be achieved because its displacement is lower than that of the reference stem and displacement of the stress level is appropriate for primary fixation.

Vulnerability to strong winds for major tree species in a northern Japanese mixed forest: analyses of historical data

AbstractThis study examined historical census data to evaluate the vulnerability of major tall‐tree species in northern Japan to strong winds. Intensive data, which measured more than 20,000 damaged trees (defined as trees that were killed or lost their major crown) in >500 ha of a natural mixed forest, were collected immediately after a severe typhoon in 1954. More than half of the damaged trees had been uprooted, and the negative size‐dependency was found for the proportion of uprooting throughout species. Simple correlation analyses with respect to the averaged species‐specific characteristics suggested that tree species with a high crown‐depth/height tended to uproot (against to stem breakage) in a size‐class with diameter at breast height 30–50 cm. Although the census data had yielded no information about non‐damaged trees, the estimation of pre‐disturbed stand (based on 63 1‐ha plot data together with aerial photographs and GIS) revealed that the observed damage reached ca. 25% in terms of basal area. The proportion of damaged trees seemed to be doubled among species (15–42% in basal area). A higher proportion of uprooting, which indicates a large supply of tip‐up mounds, and mixture of less vulnerable species, might contribute to recovery process after a wind disturbance in this type of mixed forests.

3-Pentanol: A New Attractant Present in Volatile Emissions from the Ambrosia Beetle, Megaplatypus mutatus

Megaplatypus mutatus (=Platypus mutatus) (Coleoptera: Platypodidae) is an ambrosia beetle that is native to South America. It attacks only standing live trees and causes severe stem breakage and death in commercial poplar (Populus) plantations. Previous work showed that male M. mutatus emits a sex pheromone composed mainly of (+)-sulcatol and sulcatone. We collected male volatile emissions during the hours of maximum emergence by using a specific polar microextraction phase; analyzed the extract by GC-MS; and tested the biological activity of selected compounds in the extract with a walking behavioral assay. Female M. mutatus emerged primarily between 7 and 11 h. In the chemical analyses of volatiles, a third compound, 3-pentanol, was identified in a small percentage of samples. Walking behavioral bioassays with video image analysis showed that at the doses tested, 3-pentanol elicited an attractive response from females.

Cyclone Effects on the Structure and Production of a Tropical Upland Rainforest: Implications for Life-History Tradeoffs

Wind is known to alter the structure and functioning of forest ecosystems. Because the intensity and frequency of severe wind events are likely to increase, it is important to understand the species- and substrate-specific effects of these disturbances. We assessed the structure and production among 63 species of trees in an Australian tropical rainforest before and after Cyclone Larry (March 2006). We assessed forest occurring on two different substrates: nutrient-poor schist and relatively nutrient-rich basalt. Leaf area reduction and stem breakage were markedly variable among species, but were more evident on basalt soils than schist soils, and were positively correlated with leaf N and P. In the 18-month period following the cyclone, litterfall, stem biomass increment, and ANPP were 44, 20, and 27% of pre-cyclone measurements and did not differ between soils. More severe modification of leaves, branches, and stems on basalt soils, relative to schist soils, suggests that trees/species growing on nutrient-limited soils are less susceptible to high winds. Disturbance regime and resource availability are likely to interact, creating potential plant strategies that increase fitness either by enhanced investments in carbon or enhanced investments in nitrogen and phosphorus.