Injured Trees Research Articles

Fungal inoculations and mechanical wounding of trees have limited efficacy for snag creation two decades after treatment

Standing dead trees (snags) support multiple functions within forest ecosystems by providing vertical structure, contributing to nutrient flows and carbon cycling, and serving as habitat elements for a diversity of organisms. In many forest landscapes, managers often use snag creation to enhance structural diversity, particularly in areas where snag loss is high and natural snag recruitment is low. Despite snag creation being used across a range of forest types on both private and public lands, a dearth of long-term studies has led to uncertainty about which techniques work best to create snags and support deadwood-dependent organisms over long (>15 y) timescales. In this study, I assessed the long-term consequences of varied snag creation treatments applied to live Douglas-fir (Pseudotsuga menziesii) trees in two study areas near Coos Bay, in southwestern Oregon, USA. Treatments included chainsaw topping, fungal inoculation, topping + inoculation, and mechanical wounding at the base. Trees were revisited 18–20 y after treatment and nearly all focal trees (97.6%, n = 809) remained standing when relocated. Markers of decay – including whether a tree was broken, cracked along the bole, had peeling bark, or harbored shelf fungi – were most pronounced on trees that had experienced one of two chainsaw topping treatments, differentiated by the number of retained branch whorls. In contrast, limited decay was observed on trees subjected to fungal inoculation and mechanical wounding treatments, likely due to the slow pace of decay processes in injured trees. The same pattern held for both bark cover and cavity cover, the latter an index of created snag use by woodpeckers, a keystone group within forest ecosystems. Finally, adding fungal inoculation to chainsaw topping of trees led to little additional decay relative to chainsaw topping alone. These findings indicate that managers should choose snag creation methods that align with the timeframe they require decaying trees to be available to deadwood-dependent organisms. They also show that combining different snag creation approaches that vary in timing of tree mortality and decay is likely to provide a longer window of use by wildlife and require lower implementation costs. Although snag creation is a widespread management tool, additional research is needed to ascertain the effectiveness of snag treatments across space and time, and to quantify the tradeoffs between the ecological benefits and financial costs that result from intentional snag creation.

Trunk injection to control Xylosandrus germanus (Coleoptera: Curculionidae) in topworked apple trees.

Xylosandrus germanus (Blandford) is an invasive species of ambrosia beetle known to attack apple trees in North America. Xylosandrus germanus are attracted to ethanol produced by stressed and injured trees and can be a serious problem when grafting a new cultivar onto established fruit trees (topworking). The objective of this study was to evaluate the efficacy of 2 insecticides (emamectin benzoate and azadirachtin) and injection timing (fall and spring) on their ability to control X. germanus colonization in apple trees with simulated topworking. Our study shows evidence that both emamectin benzoate and azadirachtin injections can reduce X. germanus infestations; however, our results were inconsistent. The timing of injections influenced X. germanus, with spring injected azadirachtin being more effective than fall injections. Residue analyses of emamectin benzoate and azadirachtin showed the presence of residues in woody tissue comparable to those found in leaves.

Assessment of Wound Recovery and Radial Growth 10 Years after Forest Operations in Hardwood Stands

Damage to the residual stand caused by forest operations can have detrimental impacts on the biological processes of stand growth. This study shows the details from monitoring damages related to manual motor ground-based timber operations in a mountain mixed hardwood forest. The harvesting system was cut-to-length, and logs were extracted by wheeled cable-skidders. Data were collected from the remaining trees immediately after logging and 10 years after the logging session. The parameters assessed included stem injury, radial growth increment and wound healing rate for five hardwood species of commercial interest. The number of injured trees represented 15% of the residual stand, 23% of the wounds were related to the felling operation and 76% to extraction. Wound height, wound size and damage to bark, due to felling, were larger than those in extraction, while wound width and damages to cambium and wood caused by extraction were larger than those triggered by felling. Ten years after harvesting, average longitudinal and radial growth increments were reduced by 38% and 24%, respectively. Wound healing rates ranged from 12.90 mm yr−1 for extraction wounds to 19.70 mm yr−1 for felling ones within 10 years. On average 73% of all wounds were still unrecovered and 17% of these were decayed, while only 10% were fully healed within a 10-year recovery period. The analysis showed that the best recovering performance among damaged trees was mostly achieved in shade-intolerant species with a diameter less than 40 cm, located in the dominant canopy layer with a wound size smaller than 100 cm2. In addition to the significant effect on log quality, the ecological longevity of residual trees has major implications for pre-planning harvesting operations that can preserve the quality and value of residual trees. Understanding the damage inflicted upon residual trees is essential to reduce economic losses, improve planning of harvest operations and, ultimately, ensure a sustainable harvest of mixed hardwood stands in mountain regions.

The Use of UAV-Acquired Multiband Images for Detecting Rockfall-Induced Injuries at Tree Crown Level

In this paper, we present an identification of rockfall-injured trees based on multiband images obtained by an unmanned aerial vehicle (UAV). A survey with a multispectral camera was performed on three rockfall sites with versatile tree species (Fagus sylvatica L., Larix decidua Mill., Pinus sylvestris L., Picea abies (L.) Karsten, and Abies alba Mill.) and with different characterizations of rockfalls and rockfall-induced injuries. At one site, rockfall injuries were induced in the same year as the survey. At the second site, they were induced one year after the initial injuries, and at the third site, they were induced six years after the first injuries. At one site, surveys were performed three years in a row. Multiband images were used to extract different vegetation indices (VIs) at the tree crown level and were further studied to see which VIs can identify the injured trees and how successfully. A total of 14 VIs were considered, including individual multispectral bands (green, red, red edge, and near-infrared) by using regression models to differentiate between the injured and uninjured groups for a single year and for three consecutive years. The same model was also used for VI differentiations among the recorded injury groups and size of the injuries. The identification of injured trees based on VIs was possible at the sites where rockfall injuries were induced at least one year before the UAV survey, and they could still be identifiable six years after the initial injuries. At the site where injuries were induced only four months before the UAV survey, the identification of injured trees was not possible. VIs that could explain the largest variability (R2 > 0.3) between injured and uninjured trees were: inverse ratio index (IRVI), green–red vegetation index (GRVI), normalized difference vegetation index (NDVI), normalized ratio index (NRVI), and ratio vegetation index (RVI). RVI was the most successful, explaining 40% of the variance at two sites. R2 values only increased by a few percentages (up to 10%) when the VIs of injured trees were observed over a period of three years and mostly did not change significantly, thus not indicating if the vitality of the trees increased or decreased. Differentiation among the injured groups did not show promising results, while, on the other hand, there was a strong correlation between the VI values (RVI) and the size of the injury according to the basal area of the trees (so-called injury index). Both in the case of broadleaves and conifers at two sites, the R2 achieved a value of 0.82. The presented results indicate that the UAV-acquired multiband images at the tree crown level can be used for surveying rockfall protection forests in order to monitor their vitality, which is crucial for maintaining the protective effect through time and space.

Contrasting Behavioral and Electrophysiological Responses of Eucryptorrhynchus scrobiculatus and E. brandti (Coleoptera: Curculionidae) to Volatiles Emitted from the Tree of Heaven, Ailanthus altissima.

Simple SummaryEucryptorrhynchus scrobiculatus (Motschulsky) and E. brandti (Harold) are significant pests of tree of heaven, Ailanthus altissima, often leading to tree death. Monitoring systems that involve host–plant based attractants need to be developed for both insect pest species. Here, we compared the behavioral and electrophysiological responses of E. scrobiculatus and E. brandti to volatiles emitted by various parts of the host plant. Host plant-derived volatiles showed to play a greater role in the foraging behavior of E. brandti than in E. scrobiculatus. Volatile components of phloem were found to be particularly attractive to E. brandti.Eucryptorrhynchus scrobiculatus and E. brandti (Coleoptera: Curculionidae) are host-specific pests of Ailanthus altissima (Mill.) Swingle (Sapindales: Simaroubaceae), causing extensive damage to the host. There are no effective attractants available for pest management. The main aim of this study was to explore the role of host plant-derived volatiles in the behavioral response of both weevil species. In a field experiment, both weevil species showed positive response to phloem, and there was no preference for phloem associated with healthy or injured trees. Significantly more E. brandti adults responded to the olfactory treatments compared to E. scrobiculatus. In a large-arena experiment, both males and females of E. scrobiculatus significantly preferred phloem from the tree trunk while adults of E. brandti responded in significantly greater numbers to tree limbs than to any other parts of host. Females and males of E. scrobiculatus responded positively to all parts of host tested in the Y-tube bioassay, while E. brandti adults were only attracted by the phloem from healthy and injured trees. There were dissimilar electroantennographic responses to compounds such as 1-hexanol and (1S)-(−)-β-pinene between the two weevil species. This study represents the first report documenting behavioral and electrophysiological responses of E. scrobiculatus and E. brandti to volatiles from various parts of A. altissima and findings may aid efforts to develop attractants.

Climate and wildfire effects on radial growth of Pinus sylvestris in the Khan Khentii Mountains, north-central Mongolia

The warming climate of recent decades has led to further aridity of the Mongolian landscape and has had major effects on forest growth and wildfire occurrence. Here, we investigated drought and wildfire effects on the growth of Pinus sylvestris along an ecologically diverse transect in semiarid north-central Mongolia using two separate subsets. Tree-ring width series of the first subset, represented by trees without fire scars, were clustered into three regional chronologies reflecting environmental differences of delineated geo-vegetation zones. Tree-ring growth reflected June drought signal at all three zones. The increasing radial growth trend was found in the dark taiga zone, likely supported by permafrost summer thawing, primarily caused by temperature increases. The second subset, represented by injured trees, showed that most wildfires occurred during the dormant season and in the forest-steppe zone; April–May drought conditions substantially contributed to triggering wildfires. Nevertheless, an increased frequency of wildfires in the study area was not observed, despite temperature increases since 1940. Our study highlights the significance of the effect of the ongoing temperature increase on north-central Mongolian pine forests, and, correspondingly, the need to conserve an endangered ecosystem of the dark taiga and to undertake afforestation activities in devastated pine forests.

Logging damage and injured tree mortality in tropical forest management

AbstractUsing insights from the forest ecology literature, we analyze the effect of injured trees on stand composition and carbon stored in above‐ground biomass and the implications for forest management decisions. Results from a Faustmann model with data for a tropical forest on Kalimantan show that up to 50% of the basal area of the stand before harvest can consist of injured trees. Considering injured trees leads to an increase in the amount of carbon in above‐ground biomass of up to 165%. These effects are larger under reduced impact logging than under conventional logging. The effects on land expectation value and cutting cycle are relatively small. The results suggest that considering injured trees in models for tropical forest management is important for the correct assessment of the potential of financial programs to store carbon and conserve forest ecosystem services in managed tropical forests, such as reducing emissions from deforestation and forest degradation and payment for ecosystem services.Recommendations for Resource ManagersConsidering the role of injured trees is important for managing tropical forestsThese trees can cover up to 50% of basal area and contain more than 50% of the carbon stored in above‐ground biomassReduced impact logging leads to a larger basal area of injured trees and more carbon stored in injured trees than conventional loggingInjured trees play an important role when assessing the potential for carbon storage in the context of payment for forest ecosystem services.

Adaptability and Growth of a Fast-Growing <i>Neolamarckia cadamba</i> (Roxb.) Bosser Clone in the South Subtropical Region of China

The present study investigated the adaptability and growth of a fast-growing clone (BN1) of N. cadamba planted as short-rotation plantation species in the south subtropical region of China, using 17 sampled sites representing different environments, planting models and ages, and local weather station temperature records. BN1’s growth characteristics were further compared with the most productive eucalypts planted nearby. The survival of BN1 seedlings raised and transplanted with tissue-culture micro-cuttings was >94.0% in the 1st year, and the percentage of the effective trees with diameter at breast height ( Dbh ) ≥ 8 cm was >71.0% over 30-month old. Most of the sampled sites and trees were susceptible to low-temperature or frost injury in the 1st winter, with average damage index ( Id ) ranging from 0.1 to 2.6. Some sites/trees were infected by caterpillar or borer pests, but the damage was neglectable. The injured trees quickly sprouted out leading shoots and recovered their growing vigor from low temperature or insect damage. Temperature factors were closely related to Id (P °C) with risk of significant frost damage on BN1 trees; one site (No. 9) was not suitable with frequent and heavy cold damage ( Id =2.6 ). BN1 grew extremely fast, with average diameter at breast height ( Dbh ) ranging from 14.5 - 20.3 cm and average tree height ( Ht ) from 12.3 - 16.0 m at 54-month old, and Dbh from 17.8 - 22.7 cm and from 14.4 - 15.9 m at 66-month old, over different sites/soils and planting models. Peak for both Dbh and Ht appeared in the 2nd year, but after 6-year old for average individual tree volume ( Vt ). BN1 was faster in Dbh at most sites but slower in Ht at all sites than eucalypts compared. Some sampled sites of BN1 performed similarly as or obviously better than most productive eucalypts in stock volume (Vs). With properly planting density, tending and rotation, BN1 could be expected to outperform fast-growing eucalypts in terms of Dbh , Vt and Vs, and to produce all diameter grades of timbers if the rotation age is extended beyond 8 to 9 years. Discussion was also given to potential silvicultural models, risks and limitations of planting BN1 and other superior N. cadamba varieties.

Motorlu testere ile odun hammaddesi üretim çalışmalarının verim ve kalan ağaç zararı açısından incelenmesi: Bahçe Orman İşletme Şefliği örneği

Investigation of timber harvesting operations using chainsaw considering productivity and residual stand damage: The case of Bahce Forest Enterprise Chief Abstract: Timber harvesting activities are often performed in difficult conditions caused by the mountainous terrain conditions in Turkey. One of the most difficult and dangerous stages of the timber harvesting activities are felling, delimbing, and bucking stages. In some of the European countries with intensive forestry activities, felling, delimbing and bucking stages of timber harvesting are performed with harvesting machines (i.e. harvester, feller-buncher) while these processes are mostly performed with chainsaw in Turkey. The chainsaw operations which are not properly planned and implemented may results in considerable amount of time and productivity losses and environmental damages. At the same time, the risk of work accidents increases during the felling activities. Thus, it is very important to investigate productivity and residual stand damage of chainsaw operations. In this study, harvesting activities using chainsaw were evaluated in terms of productivity and environmental aspects. The field studies were conducted in Brutian Pine stands within Bahce Forest Enterprise Chief of Osmaniye Forest Enterprise Directorate, located in Adana Forest Regional Directorate. Average productivity and timber volume were calculated as 4.06 m3/hr and 0.30 m3, respectively, and productivity increased as the amount of timber production increased. The results indicated that total number of injured trees as a result of felling operation was 43 in which 13 injuries were on live wood while 30 injuries were on tree barks. It was found that sapwood and bark injuries occurred at the top of the trees during felling activities due to tree hang ups. Keywords: Felling, delimbing, bucking, chainsaw, productivity, residual stand damage Motorlu testere ile odun hammaddesi uretim calismalarinin verim ve kalan agac zarari acisindan incelenmesi: Bahce Orman Isletme Sefligi ornegi Ozet: Ulkemizde odun hammaddesi uretim calismalari cogunlukla daglik arazi kosullarindan kaynaklanan zor sartlarda gerceklesmektedir. Odun hammaddesi uretim calismalarinin en guc ve tehlikeli asamalarindan birini kesme, dal alma ve boylama asamalari olusturmaktadir. Ormanciligin yogun olarak gerceklestigi bazi Avrupa ulkelerinde uretim calismalarindan kesme, dal alma ve boylama asamalari uretim makineleri (hasatci, kesici-istifleyici) ile gerceklestirilirken ulkemizde genellikle motorlu testere ile gerceklestirilmektedir. Uygun yontemlerle planlanmayan ve uygulanmayan motorlu testere calismalarinda onemli zaman ve verim kayiplari ile cevresel acidan zararlar meydana gelebilmektedir. Ayni zamanda, kesme ve devirme calismalari sirasinda is kazasi riski de artmaktadir. Bu nedenle, motorlu testere ile uretim calismalarinin verim ve cevresel etkileri bakimindan arastirilmasi buyuk onem tasimaktadir. Bu calismada motorlu testereyle uretim calismalari verim ve kalan agac zarari acisindan degerlendirilmistir. Arazi calismalari Adana Orman Bolge Mudurlugu, Osmaniye Orman Isletme Mudurlugu, Bahce Orman Isletme Sefligi sinirlarinda Kizilcam (Pinus brutia Ten.) mesceresinde uygulanmistir. Saatlik ortalama verim ve ortalama hacim sirasiyla 4,06 m3/saat ve 0,30 m3 olarak tespit edilmis olup, uretilen odun hammaddesi arttikca verimde artmistir. Kesme ve devirme calismalari sonucu 13 adet diri odun yarasi ve 30 adet kabuk yarasi olmak uzere toplam 43 adet agacin yaralandigi tespit edilmistir. Agaclarin devrilmesi sirasinda kalan agaclara takilmasi ve carpmasi sonucu agaclarin ust kisimlarinda diri odun ve kabuk yaralari meydana geldigi tespit edilmistir. Anahtar Kelimeler: Kesme, dal alma, boylama, motorlu testere, verim, kalan agac zarari Received (Gelis): 06.07.2015 - Revised (Duzeltme): 31.07.2015 - Accepted (Kabul): 08.08.2015 Cite (Atif): Gulci, N., Akay, A.E., Erdas, O., 2016. Investigation of timber harvesting operations using chainsaw considering productivity and residual stand damage: The case of Bahce Forest Enterprise Chief. Journal of the Faculty of Forestry Istanbul University 66(2): 357-368. DOI: 10.17099/jffiu.11250

Damage to forest plantations by tufted capuchins (Sapajus nigritus): Too many monkeys or not enough fruits?

Damage to agricultural and forest plantations caused by wild animals, including primates, is increasing globally due to shrinking habitats and the expansion of plantations. Over recent decades there has been an increase in reports of Sapajus nigritus causing damage (bark-stripping) to commercial Pine plantations in Southern Brazil. We conducted a two-year census and a phenological study of plant species consumed by S. nigritus to investigate if bark-stripping behavior is associated with overpopulation and/or food scarcity. We obtained a density of 2.23±1.09individuals/km2 in our study area, which is lower than previously reported in the literature for this species. The population experienced periods of food shortage from July to November, coinciding with a peak in damage to Pinus by S. nigritus. Thus, our results suggest that S. nigritus tree damage is primarily related to seasonal fluctuations in fruit and seed availability. Nevertheless, short term remediation strategies based on forestry management may be effective. These include planting less-preferred pine species, and reducing economic losses by optimizing both the timing of removal of injured trees, and the use of damaged trees depending on the type and intensity of the injury. In the longer term, native forests could be enriched with plant species that produce fruits during the period of fruit scarcity.

Occurrence and development of Eucryptorrhynchus brandti and E. chinensis (Coleoptera: Curculionidae) on Ailanthus altissima trees subjected to different levels of mechanical damage

Eucryptorrhynchus brandti (Harold) and E. chinensis (Oliver) are herbivores of Ailanthus altissima (Mill.) Swingle (tree of heaven) in China. Eucryptorrhynchus brandti has been recommended as a potential biological control agent of A. altissima in North America. In China, the majority of adults of both species were found on tree trunks 0–5 m above the ground, from May to September. In October and November, most adults were found at the base of A. altissima trees. Trees were subjected to different levels of mechanical injury: very low mechanical injury, one to two 0.015 m2 bark sections were removed; low, two to four bark sections were removed; moderate, 8 to 22 bark sections removed; high, tree was girdled; and extreme, tree was felled and the remaining stump was sampled. Very low and low mechanical injury trees had very few adult emergence holes with few larvae developing beyond the first or second instar after 29 months. The health of these trees remained good. An increase in adult emergence holes occurred in moderately injured trees that appeared as healthy as very low to low mechanically injured trees. This may indicate that only a small increase in tree stress can increase the adult emergence rate and thus hasten a decline in tree health. Moderate, high and extreme mechanically injured trees had significantly more emergence holes/m than very low and low injured trees and late larval stages were present. The development of Eucryptorrhynchus species was more successful the greater the degree of mechanical injury. Based on this study both Eucryptorrhynchus species appear to be secondary pests of A. altissima in China.

Automatic Storm Damage Detection in Forests Using High‑Altitude Photogrammetric Imagery

Climate change has increased the occurrence of heavy storms that cause damage to forests. After a storm, it is necessary to obtain knowledge about the injured trees quickly in order to detect and aid in collecting the fallen trees and estimate the total damage. The objective in this study was to develop an automatic method for storm damage detection based on comparisons of digital surface models (DSMs), where the after-storm DSM was derived by automatic image matching using high-altitude photogrammetric imagery. This DSM was compared to a before-storm DSM, which was computed using national airborne laser scanning (ALS) data. The developed method was tested using imagery collected in extreme illumination conditions after winter storms on 8 January 2012 in Finland. The image matching yielded a high-quality surface model of the forest areas, which were mainly coniferous and mixed forests. The entire set of major damage forest test areas was correctly classified using the method. Our results showed that airborne, high-altitude photogrammetry is a promising tool for automating the detection of forest storm damage. With modern photogrammetric cameras, large areas can be collected efficiently, and the imagery also provides visual, stereoscopic support for various forest storm damage management tasks. Developing methods that work in different seasons are becoming more important, due to the increase in the number of natural disasters.

Assessment and analysis of rockfall-caused tree injuries in a Turkish fir stand: A case study from Kastamonu-Turkey

Rockfalls can cause serious damage to people, property, facilities and transportation corridors. Furthermore, rockfalls are major hazards in mountain areas with negative impacts on individual trees and forested ecosystems. We conducted a study of rockfall events on 117 mapped (91% of total trees in the stand with > 1.3 m in height and > 5 cm diameter at breast height) Turkish fir trees (Abies bornmuelleriana Mattf.) in a stand within the Kayaarkasi-Topcular Village, Inebolu district, Kastamonu province of Turkey. The study site of 0.35 Ha is located on the transition zone of frequently passing rockfall fragments (∼ 40 cm in diameter) generally causing healable injuries. Parameters of trees and injuries were recorded and analysed as to injury number, height and size. Bivariate correlation analysis were used to investigate the relationships between: a) diameter at breast height and number of injuries per tree, b) diameter at breast height and total injury size, c) the number of injuries and total injury size and d) the number of injuries per tree and distance from the source of the rockfall area. Results indicate that the average height of injury, average number of injuries and average injury area to be 81.3 cm (STDEV: 49.8), 7.46 (STDEV: 4.4) and 628.6 cm2 (STDEV: 678.2), respectively. In total 84% of all injuries were recorded within 160° sector at the upslope side of trees and callus tissue that had closed wounds was observed in 79.1% of all injuries. Furthermore 14.5% of injured trees had callus tissue in the process of closing wounds while 6.4% of injuries had not formed any callus tissue. The most common injury types were bark and wood injuries. Bivariate correlation analysis indicated strong relationships between diameter at breast height and the number of injuries (rs = 0.524), injury number and total injury area (rs = 0.653) and distance from rockfall area and injury numbers relations (rs = −0.518). A weaker relationship was found between diameter at breast height and total injury area (rs = 0.363). These results indicate that bigger trees are more prone to rockfall injuries. As expected, trees further from the rockfall area seem to be less prone to rockfall injuries. From our results, it can be inferred that the protection of people and property can be increased through the maintanance of forest in areas immediately below areas prone to rockfall. This stand is still managed in selective forest management system. In order to protect the settlement at the deposition zone it has to manage for protective goals with uneven-aged and multilayered stand structure.

Post-fire attractiveness of maritime pines (Pinus pinaster Ait.) to xylophagous insects

The spectrum and dynamics of xylophagous insects infesting Pinus pinaster after a fire event were studied from November 2007 to December 2008 at Sierra de Outes (Galicia, NW Spain). Insects were collected within and outside the fire area. Relationships among species status, species abundance, tree parameters and tree injury were assessed. Mortality of injured trees was also recorded. Insect colonization built up consistently during the first year after the fire, although the pests did not colonize unburned trees in nearby areas. Thirteen insect species from six xylophagous families were collected. Tomicus spp., Buprestis novenmaculata, Anobium punctatum and Pissodes castaneus were the first species detected. Tomicus spp. (29%) and Ips sexdentatus (23%) were the dominant taxa. Bole char height and soil burn severity were positively correlated with insect presence. Trees with short stem diameter and thinner bark were also preferred. B. novenmaculata presence was positively correlated with crown scorch. Loss of cambium hydration was negatively related to the occurrence of pests, likely because sapwood desiccation and loss of nutrient impede brood development. About 33.3% of the fire-scorched pines died. The results recommend the removal of injured and dying pines after fire, to avoid the rise of pest population threatening recovering trees in the burned areas.

Adaptations of Casuarina Windbreak Stands to Land Subsidence on the Southwestern Coast of Taiwan

In this study, we investigated the adaptive behavior of Casuarina windbreak stands along the southwestern coast of Taiwan to land subsidence. Based on surveys and measurements of 17 indicators, such as soil factors, the external appearance of individual trees, damage sustained by individual trees etc., we applied a maximum variance reciprocal matrix method of a factorial analysis to obtain sets of reciprocal matrices, together with weighting factor adjustments, and then we derived the state of health of the stands. The analytical results indicated that the vitality of the tree crowns, soil salinity, soil pH, tree diseases, tree flowering, and root damage were the 6 major factors affecting differences in the adaptive performance of Casuarina windbreak stands. Finally, the maximum variance reciprocal matrices of the factorial analysis identified 3 factors of tree status, crown vitality, and changes in the soil environment as influential indicators. Furthermore, the analysis indicated that there was a seasonal fluctuation in the tree health status with a decrease observed in summer and autumn compared to winter and spring. This study confirmed that coastal Casuarina windbreak stands of southwestern Taiwan have already been affected by land subsidence, and the adaptive characteristics of injured trees and a seasonal fluctuation of their health status were observed.

Changes in Wood Anatomy in Tree Rings of Pinus pinaster Ait. Following Wounding by Flash Floods

This paper analyzes the anatomical response of Pinus pinaster Ait. following wounding by flash floods. A total of 14 wood samples were taken from 14 different scarred trees located on the river banks of the Arroyo Cabrera torrent (Spanish Central System). In addition, 20 increment cores were collected from undisturbed and healthy P. pinaster trees to build a local reference chronology. For the injured trees, analysis focused on growth changes in early earlywood (EE) tracheids, namely on differences in (i) lumen size; (ii) cell-wall percentage and cell-wall thickness; (iii) radial length and tangential width of tracheids; as well as (iv) in the abundance of resin ducts in earlywood (EW) and latewood (LW) following wounding. Results indicate that tissues bordering flash-flood wounds are characterized by reduced growth rates and a decrease of EE tracheid lumen area by 51%. In addition, cell-wall percentage increases by 34% in the increment rings formed after the event and significant changes are observed in the radial length and tangential width of EE tracheids. Observations on resin ducts do not yield any significant results. Based on these anatomical parameters, detecting and dating past flash-flood events in growth rings is now possible for Mediterranean species, specifically P. pinaster.

400 Years of Debris-Flow Activity and Triggering Weather Conditions: Ritigraben, Valais, Switzerland

Three major rainfall events have caused considerable damage in the Valais region (Swiss Alps) since 1987. Substantial debris flows originating from periglacial environments were recorded during the August 1987 and September 1993 rainfall events, whereas no debris flows occurred in October 2000. This paper aims at putting these large-area events and the apparent increase in debris-flow frequency into a wider context by reconstructing the past debris-flow activity in the Ritigraben torrent (Mattertal, Valais) with dendrogeomorphological methods. Tree-ring analysis allowed the reconstruction of 53 events, going back to the year 1605. Previously, only 10 debris flows had been known for the torrent, and these were limited to the period between 1922 and 2002. Results further show that the apparently above-average concentration of events since 1987 was mainly caused by insufficient and short archival data. In fact, debris flows occurred even more frequently in the nineteenth century than they do today. The spatial distribution of injured trees in particular years further indicates that significant events, like the one in 1993, always occurred in the torrent. Finally, reconstructed event years were compared with archival data on flooding in neighboring catchments. The comparisons prove that large-area events like those in 1987, 1993, or 2000 have at least been as common in the past as they are today.

Influence of temperature and bark injuries on the development of Phytophthora cactorum and P. Citrophthora on peach trees

The effect of temperature and bark injuries on the occurrence of crown rot of peach trees caused by P. cactorum and P. citrophthora were examined in field and laboratory. Lesions developed at 35 °C (the complete range of temperatures tested) but maximum development occurred at 20–25 °C. Greatest growth of these fungi on cornmeal agar (CMA) also occurred between 15 and 30 °C. Both pathogens could infect injured trees up to 20 days after wounding, but could not infect uninjured plants or plants wounded 40 and 30 days before inoculation, respectively. This study showed that temperature is a critical factor for the development of Phytophthora crown rot of peach trees. In addition, crown rot developed from recent wounds inoculated with agar plugs of Phytophthora.

Radial growth of hardwoods following the 1998 ice storm in New Hampshire and Maine

Ice storms and resulting injury to tree crowns occur frequently in North America. Reaction of land managers to injury caused by the regional ice storm of January 1998 had the potential to accelerate the harvesting of northern hardwoods due to concern about the future loss of wood production by injured trees. To assess the effect of this storm on radial stem growth, increment cores were collected from northern hardwood trees categorized by crown injury classes. For a total of 347 surviving canopy dominant and subdominant trees, a radial growth index was calculated (mean annual increment for 1998–2000 divided by the mean annual increment for 1995–1997). Sugar maple (Acer saccharum Marsh.), yellow birch (Betula alleghaniensis Britt.), white ash (Fraxinus americana L.), and red maple (Acer rubrum L.) categorized in injury class A (crown loss of less than one-half) had mean growth index values of approximately 1.0, indicating no loss of mean radial growth after 3 years. For injury class B (crown loss of one-half to three-quarters) and class C (crown loss greater than three-quarters), growth index values significantly decreased for sugar maple, yellow birch, and red maple. For white ash, growth index values of classes B and C were not significantly different from those of class A trees. Growth index values of A. saccharum and A. rubrum in injury class C were the lowest of those measured. These results indicated that the severity of growth loss due to crown injury depends on tree species and crown replacement as well as the extent of crown loss.

Logging damage and the subsequent dynamics of a dipterocarp forest in East Kalimantan (1990–1996)

The effects of logging damage on forest dynamics processes were assessed in a lowland dipterocarp forest of East Kalimantan, Indonesia. From 1990 to 1991, twelve 4 ha plots ( 200 m×200 m) each divided into four 1 ha subplots were set up and all trees with dbh ≥10 cm measured and identified at least at the generic level. Logging was carried out from November 1991 to March 1992 in nine plots while three plots served as control. The 48 subplots were grouped according to the proportion of remaining basal area after harvesting, as follows: group 1 with more than 80% of the original basal area remaining, group 2 with 70–79%, group 3 with less than 70%, and group 4 as control plots. Remeasurements were carried out just after logging in 1992 and then every 2 years until 1996. Felling intensity varied from 1 to 17 stems ha −1 (50–250 m 3 ha −1). In primary forest, mean annual mortality remained constant to 1.5% per year throughout the study period while mean annual mortality rate was significantly higher in logged-over forest (2.6% per year). This higher rate resulted from a higher mortality of injured trees (4.9% per year). Four years after logging, mortality rates in logged-over and primary forest were similar. Recruitment remained constant at 8 trees ha −1 per year in primary forest and varied from 14 to 32 trees ha −1 per year in logged-over stand in proportion with the amount of damage. In stands with the lowest remaining basal area, the establishment and growth of dipterocarps was strongly limited by the strong regeneration of pioneer species. This study suggests that total basal area removed by logging in primary forest (harvested trees and trees killed during felling and skidding) should not exceed 15% of the original one; reduced-impact logging (RIL) techniques applied with a maximum harvesting intensity of 8 trees ha −1, can keep logging damage under this threshold.